The concept of synapomorphy explains why we are more closely-related to animals, than we think. But what is a synapomorphy?
Guys! Maybe sometime it may have crossed your mind and you may have wondered what would happen if one animal cross breeds with a another animal – – What would be the result? – Wha…
A graphically enhanced answer to a question found on ResearchGate: the difference between cladistics and phylogenetics, and a quote from Joe Felsenstein's 2001 article: "The Troubled Growth of Statistical Phylogenetics", Syst. Biol. 50: 465–467
Hybrids, once treated as biological misfits, play a vital role in the evolution of many animal species. Now conservationists are trying to reconcile that truth with policies.
A typical lancelet Branchiostoma. Drawing by Giovanni Maki. If you recall last time I have briefly talked about the kinds of animals that make up Phylum Chordata, what unites us all in this extraordinary lineage, and some of the conflicting phylogenetic work on the interrelationships among the chordate subphyla. All of this can be read here. Today in Part II of the series will be a post on the lancelets of Subphylum Cephalochordata. Brief Introduction The lancelets (also referred to as "amphioxus" or "amphioxi") are small, translucent and elongated fishlike chordates that are entirely marine and live in shallow sandy environments. They are often used in classrooms as "living fossils" to describe the ancestral chordates. I do find "fishlike" to be too broad of a term to describe these marine invertebrates. I would say they look (though vaguely) resemble lamprey larva or fry in overall shape. And despite what professors in college talk about, are lancelets really good model organisms? Systematics and Evolutionary History Cephalochordata has the smallest number species of the three subphyla with at least 34 species. They are classified in the Order Amphioxiformes which is also the only extant clade in Class Leptocardii. Within Amphioxiformes we have two families and a total of three extant genera: Branchiostomidae which only contains the genus Branchiostoma Asymmetronidae which includes the genera Epigonichthys and Asymmetron Pikaia fossil. Photo by Jstuby. The fossil record of lancelets is very scarce due to their small, translucent bodies. Needless to say there are at least three fossil genera, which unsurprisingly look like modern lancelets. Indeed lancelets as a whole have virtually unchanged for 530 million years. Although I should point out there is a whole cast of fossil chordates and/or stem-chordates that resemble lancelets such as the relatively famous Pikaia gracilens. These primitive chordates and lancelets probably were similar in anatomy, although it should be noted that these animals can not be placed firmly in any of the three modern subphyla (Lacalli, 2012). Despite this, this makes lancelets prized as lab animals or modeled organisms in college classrooms and labs when discussing about the earliest chordates. I can certainly understand the attraction, although I think we need to be mindful that lancelets could be slightly more derived than an animal like Pikaia. What is more, the probable behavior and some aspects of their biology in lancelets and early chordates was probably a bit different (Morris & Caron, 2012). Needless to say, lancelets still serve a purpose in understanding the evolution of chordate anatomy. Anatomy A closeup look at the head of a lancelet. Note the cilia. As mention earlier the overall appearance of these chordates is somewhat not unlike that of lamprey larva. However lancelets lack a cranium case around the head region, thus they lack a distinctive head shape. The brain is very simple and lacks most of the sensory organs, although they have a photoreceptive frontal organ which is ancestral to the vertebrate eye. The pharynx and the gill slits act as filter-feeding apparatus, which the movement of water containing food particles goes through via cilia action. The cilia are dozens of tentacle-like structures near the opening or the ridges of the mouth known as the "wheel of organ". Another series of tentacle-like organs are the oral cirri which also partakes in the action. A - Lamprey larva; B - Lancelet adult. Being a invertebrate it has no true backbone. To protect the notochord lancelets have stiffen cells that surround the region. The notochord extends from the tip of the snout to the end of the tail. In addition to giving the animal support and structure, it also helps lancelets to burrow themselves in the sand in coastal waters. To move around lancelets swim in side-to-side action with the help of the myomeres. The tail is fishlike in appearance and can swim surprisingly well. They do not have an recognizable fins except for a dorsal fin. But what is peculiar about the overall anatomy of lancelets is that most of the organ systems are alternated on either sides of the animal as opposed to being set in a series of successions on either side seen in vertebrates. Not surprisingly, their organ systems in particular their circulatory system and digestive system is simple in comparison to our own For example the lancelets do not have a recognizable true heart nor neural control for pumping blood; the circulatory system is more large and open and no red blood cells. There is no muscular stomach, liver and pancreas (though midgut cecum might be homologous to the last two organs; Pough et. al, 2005). Lancelets have multiple gonads that produce large quantities of sperm and eggs (noticed the circular organs in the image above in this post.), which leads us to our final segment for the lancelets. Life History Typical feeding fashion. Photo by Colin Gray. All species of lancelets have more or less the same life story. All species reproduce sexually and spawn sperm and eggs which simultaneously fertilized in the water. Once the young hatch they buried themselves in the sand where they mature. Most of their adult too is buried in the sand, with their heads sticking out as they are filtering out the food from the environment. However lancelets are forever capable of free-swimming animals and they hardly changed their physical appearance. It would probably surprise some people to know that lancelets are considered to be a food source in Asian countries, often used as animal feed for domesticated animals. What's Next? The next group will be the tunicates. As they are the most diverse and numerous of the groups that will be cover in this series, there might be a two-part articles concerning them. In the first post of the two articles will be in similar fashion to this article, but in the second post will briefly go over the life histories of the three classes of the tunicates. References Hildebrand, M. & Goslow, G. (2001). Analysis of Vertebrate Structure. John Wiley & Sons, 24-25. Lacalli, T. (2012). The Middle Cambrian fossil Pikaia and the evolution of chordate swimming. EvoDevo, 3(1), 1-6. Li, G., Yang, X., Shu, Z., Chen, X., & Wang, Y. (2012). Consecutive spawnings of Chinese amphioxus, Branchiostoma belcheri, in captivity. PloS one, 7(12), e50838. Morris, S. C., & Caron, J. B. (2012). Pikaia gracilens Walcott, a stem‐group chordate from the Middle Cambrian of British Columbia. Biological Reviews, 87(2), 480-512. Pough, F. H., Janis, C. M., & Heiser, J. B. (2005). Vertebrate Life. Pearson/Prentice Hall, 23; 27.
Guys! Maybe sometime it may have crossed your mind and you may have wondered what would happen if one animal cross breeds with a another animal – – What would be the result? – Wha…
This article looks briefly at how our current supremely woolly concept of the genus Homo has come about, as background for urging a more rational approach to defining it.
This article looks briefly at how our current supremely woolly concept of the genus Homo has come about, as background for urging a more rational approach to defining it.
Guys! Maybe sometime it may have crossed your mind and you may have wondered what would happen if one animal cross breeds with a another animal – – What would be the result? – Wha…
In taxonomy, a group is paraphyletic if it consists of the group's last common ancestor and most of its descendants, excluding a few monophyletic subgroups. The group is said to be paraphyletic with respect to the excluded subgroups. In contrast, a monophyletic group includes a common ancestor and all of its descendants. The terms are commonly used in phylogenetics and in the tree model of historical linguistics. Paraphyletic groups are identified by a combination of synapomorphies and symplesiomorphies. If many subgroups are missing from the named group, it is said to be polyparaphyletic.
A graphically enhanced answer to a question found on ResearchGate: the difference between cladistics and phylogenetics, and a quote from Joe Felsenstein's 2001 article: "The Troubled Growth of Statistical Phylogenetics", Syst. Biol. 50: 465–467
Have you ever seen a fossil plant series in a museum display or textbook on evolution? I haven’t.
A graphically enhanced answer to a question found on ResearchGate: the difference between cladistics and phylogenetics, and a quote from Joe Felsenstein's 2001 article: "The Troubled Growth of Statistical Phylogenetics", Syst. Biol. 50: 465–467
The concept of synapomorphy explains why we are more closely-related to animals, than we think. But what is a synapomorphy?
Guys! Maybe sometime it may have crossed your mind and you may have wondered what would happen if one animal cross breeds with a another animal – – What would be the result? – Wha…
A typical lancelet Branchiostoma. Drawing by Giovanni Maki. If you recall last time I have briefly talked about the kinds of animals that make up Phylum Chordata, what unites us all in this extraordinary lineage, and some of the conflicting phylogenetic work on the interrelationships among the chordate subphyla. All of this can be read here. Today in Part II of the series will be a post on the lancelets of Subphylum Cephalochordata. Brief Introduction The lancelets (also referred to as "amphioxus" or "amphioxi") are small, translucent and elongated fishlike chordates that are entirely marine and live in shallow sandy environments. They are often used in classrooms as "living fossils" to describe the ancestral chordates. I do find "fishlike" to be too broad of a term to describe these marine invertebrates. I would say they look (though vaguely) resemble lamprey larva or fry in overall shape. And despite what professors in college talk about, are lancelets really good model organisms? Systematics and Evolutionary History Cephalochordata has the smallest number species of the three subphyla with at least 34 species. They are classified in the Order Amphioxiformes which is also the only extant clade in Class Leptocardii. Within Amphioxiformes we have two families and a total of three extant genera: Branchiostomidae which only contains the genus Branchiostoma Asymmetronidae which includes the genera Epigonichthys and Asymmetron Pikaia fossil. Photo by Jstuby. The fossil record of lancelets is very scarce due to their small, translucent bodies. Needless to say there are at least three fossil genera, which unsurprisingly look like modern lancelets. Indeed lancelets as a whole have virtually unchanged for 530 million years. Although I should point out there is a whole cast of fossil chordates and/or stem-chordates that resemble lancelets such as the relatively famous Pikaia gracilens. These primitive chordates and lancelets probably were similar in anatomy, although it should be noted that these animals can not be placed firmly in any of the three modern subphyla (Lacalli, 2012). Despite this, this makes lancelets prized as lab animals or modeled organisms in college classrooms and labs when discussing about the earliest chordates. I can certainly understand the attraction, although I think we need to be mindful that lancelets could be slightly more derived than an animal like Pikaia. What is more, the probable behavior and some aspects of their biology in lancelets and early chordates was probably a bit different (Morris & Caron, 2012). Needless to say, lancelets still serve a purpose in understanding the evolution of chordate anatomy. Anatomy A closeup look at the head of a lancelet. Note the cilia. As mention earlier the overall appearance of these chordates is somewhat not unlike that of lamprey larva. However lancelets lack a cranium case around the head region, thus they lack a distinctive head shape. The brain is very simple and lacks most of the sensory organs, although they have a photoreceptive frontal organ which is ancestral to the vertebrate eye. The pharynx and the gill slits act as filter-feeding apparatus, which the movement of water containing food particles goes through via cilia action. The cilia are dozens of tentacle-like structures near the opening or the ridges of the mouth known as the "wheel of organ". Another series of tentacle-like organs are the oral cirri which also partakes in the action. A - Lamprey larva; B - Lancelet adult. Being a invertebrate it has no true backbone. To protect the notochord lancelets have stiffen cells that surround the region. The notochord extends from the tip of the snout to the end of the tail. In addition to giving the animal support and structure, it also helps lancelets to burrow themselves in the sand in coastal waters. To move around lancelets swim in side-to-side action with the help of the myomeres. The tail is fishlike in appearance and can swim surprisingly well. They do not have an recognizable fins except for a dorsal fin. But what is peculiar about the overall anatomy of lancelets is that most of the organ systems are alternated on either sides of the animal as opposed to being set in a series of successions on either side seen in vertebrates. Not surprisingly, their organ systems in particular their circulatory system and digestive system is simple in comparison to our own For example the lancelets do not have a recognizable true heart nor neural control for pumping blood; the circulatory system is more large and open and no red blood cells. There is no muscular stomach, liver and pancreas (though midgut cecum might be homologous to the last two organs; Pough et. al, 2005). Lancelets have multiple gonads that produce large quantities of sperm and eggs (noticed the circular organs in the image above in this post.), which leads us to our final segment for the lancelets. Life History Typical feeding fashion. Photo by Colin Gray. All species of lancelets have more or less the same life story. All species reproduce sexually and spawn sperm and eggs which simultaneously fertilized in the water. Once the young hatch they buried themselves in the sand where they mature. Most of their adult too is buried in the sand, with their heads sticking out as they are filtering out the food from the environment. However lancelets are forever capable of free-swimming animals and they hardly changed their physical appearance. It would probably surprise some people to know that lancelets are considered to be a food source in Asian countries, often used as animal feed for domesticated animals. What's Next? The next group will be the tunicates. As they are the most diverse and numerous of the groups that will be cover in this series, there might be a two-part articles concerning them. In the first post of the two articles will be in similar fashion to this article, but in the second post will briefly go over the life histories of the three classes of the tunicates. References Hildebrand, M. & Goslow, G. (2001). Analysis of Vertebrate Structure. John Wiley & Sons, 24-25. Lacalli, T. (2012). The Middle Cambrian fossil Pikaia and the evolution of chordate swimming. EvoDevo, 3(1), 1-6. Li, G., Yang, X., Shu, Z., Chen, X., & Wang, Y. (2012). Consecutive spawnings of Chinese amphioxus, Branchiostoma belcheri, in captivity. PloS one, 7(12), e50838. Morris, S. C., & Caron, J. B. (2012). Pikaia gracilens Walcott, a stem‐group chordate from the Middle Cambrian of British Columbia. Biological Reviews, 87(2), 480-512. Pough, F. H., Janis, C. M., & Heiser, J. B. (2005). Vertebrate Life. Pearson/Prentice Hall, 23; 27.
A graphically enhanced answer to a question found on ResearchGate: the difference between cladistics and phylogenetics, and a quote from Joe Felsenstein's 2001 article: "The Troubled Growth of Statistical Phylogenetics", Syst. Biol. 50: 465–467
In taxonomy, a group is paraphyletic if it consists of the group's last common ancestor and most of its descendants, excluding a few monophyletic subgroups. The group is said to be paraphyletic with respect to the excluded subgroups. In contrast, a monophyletic group includes a common ancestor and all of its descendants. The terms are commonly used in phylogenetics and in the tree model of historical linguistics. Paraphyletic groups are identified by a combination of synapomorphies and symplesiomorphies. If many subgroups are missing from the named group, it is said to be polyparaphyletic.
A graphically enhanced answer to a question found on ResearchGate: the difference between cladistics and phylogenetics, and a quote from Joe Felsenstein's 2001 article: "The Troubled Growth of Statistical Phylogenetics", Syst. Biol. 50: 465–467
A graphically enhanced answer to a question found on ResearchGate: the difference between cladistics and phylogenetics, and a quote from Joe Felsenstein's 2001 article: "The Troubled Growth of Statistical Phylogenetics", Syst. Biol. 50: 465–467
Analogous color schemes in interiors. They are some of my favorite, but they can be tricky. What are analogous colors? They are two or three
In business, as in life, the least complex idea is often the right one.
Guys! Maybe sometime it may have crossed your mind and you may have wondered what would happen if one animal cross breeds with a another animal – – What would be the result? – Wha…
The Fayum Depression of Egypt has yielded fossils of hystricognathous rodents from multiple Eocene and Oligocene horizons that range in age from ∼37 to ∼30 Ma and document several phases in the early evolution of crown Hystricognathi and one of its major subclades, Phiomorpha. Here we describe two new genera and species of basal phiomorphs, Birkamys korai and Mubhammys vadumensis, based on rostra and maxillary and mandibular remains from the terminal Eocene (∼34 Ma) Fayum Locality 41 (L-41). Birkamys is the smallest known Paleogene hystricognath, has very simple molars, and, like derived Oligocene-to-Recent phiomorphs (but unlike contemporaneous and older taxa) apparently retained dP4∕4 late into life, with no evidence for P4∕4 eruption or formation. Mubhammys is very similar in dental morphology to Birkamys, and also shows no evidence for P4∕4 formation or eruption, but is considerably larger. Though parsimony analysis with all characters equally weighted places Birkamys and Mubhammys as sister taxa of extant Thryonomys to the exclusion of much younger relatives of that genus, all other methods (standard Bayesian inference, Bayesian “tip-dating,” and parsimony analysis with scaled transitions between “fixed” and polymorphic states) place these species in more basal positions within Hystricognathi, as sister taxa of Oligocene-to-Recent phiomorphs. We also employ tip-dating as a means for estimating the ages of early hystricognath-bearing localities, many of which are not well-constrained by geological, geochronological, or biostratigraphic evidence. By simultaneously taking into account phylogeny, evolutionary rates, and uniform priors that appropriately encompass the range of possible ages for fossil localities, dating of tips in this Bayesian framework allows paleontologists to move beyond vague and assumption-laden “stage of evolution” arguments in biochronology to provide relatively rigorous age assessments of poorly-constrained faunas. This approach should become increasingly robust as estimates are combined from multiple independent analyses of distantly related clades, and is broadly applicable across the tree of life; as such it is deserving of paleontologists’ close attention. Notably, in the example provided here, hystricognathous rodents from Libya and Namibia that are controversially considered to be of middle Eocene age are instead estimated to be of late Eocene and late Oligocene age, respectively. Finally, we reconstruct the evolution of first lower molar size among Paleogene African hystricognaths using a Bayesian approach; the results of this analysis reconstruct a rapid latest Eocene dwarfing event along the lineage leading to Birkamys.
A graphically enhanced answer to a question found on ResearchGate: the difference between cladistics and phylogenetics, and a quote from Joe Felsenstein's 2001 article: "The Troubled Growth of Statistical Phylogenetics", Syst. Biol. 50: 465–467
A graphically enhanced answer to a question found on ResearchGate: the difference between cladistics and phylogenetics, and a quote from Joe Felsenstein's 2001 article: "The Troubled Growth of Statistical Phylogenetics", Syst. Biol. 50: 465–467
A graphically enhanced answer to a question found on ResearchGate: the difference between cladistics and phylogenetics, and a quote from Joe Felsenstein's 2001 article: "The Troubled Growth of Statistical Phylogenetics", Syst. Biol. 50: 465–467
It's that time of year again! I haven't been particularly active on here, but it's been a big year for me. Sarah (CCNHM collections manager) and I are now running 100% of the museum officially (before it was... unofficial), we bought a house, and we received our first permission to collect at a "land site" here in the Summerville/Ladson area of SC - which resulted in several weeks worth of day trips and thousands of specimens collected for CCNHM. I also taught my first course written from scratch - Applied Paleontology, which was (fortunately) a hit. Oddly enough, the foundation of the course coalesced from posts I had written up on this very blog! It's also been a big year for marine mammal paleontology. The toothed baleen whale Llanocetus has finally been described after a 30 year wait (Fordyce and Marx, 2018, below), a major milestone in baleen whaleontology. Two other major long-neglected fossils have been finally written up as well: Allodesmus demerei (written up by yours truly and Morgan Churchill), collected even earlier than Llanocetus (1984) and languishing unstudied at the Burke Museum, and Titanotaria, otherwise known as the walrus "Waldo", collected in 1993 from the Capistrano Formation in Orange County (fun fact: this specimen would have been the core specimen for a prospective Ph.D. thesis had I gone to San Diego State University, but that did not work out and I ended up studying eomysticetids at U. Otago in NZ instead, which worked out just fine). Some great fine-scale taphonomic/diagenetic work has been done on fossil cetaceans (Decree et al., Gioncada et al.) and an enormous pile of ziphiid skulls from really, really far south (Kerguelen islands) is reported by Lambert et al. A bunch of new mysticetes are named (Gol'din, Peredo and Pyenson, Peredo et al., Solis-Anorve et al., Tanaka et al.) meaning I have a LOT of coding to do to update my matrix! A large number of papers this year are published by students, and a flurry of papers from Leonard Dewaele (U. Ghent) and Carlos Peredo (George Mason U.) have come from the final stages of their respective doctoral programs (congratulations gentlemen). It's also been a fantastic year for pinnipeds: 1 out of 5 papers were on pinnipeds! (10 total, out of 50 papers) We're undergoing a bit of a pinniped renaissance at present; the last time so many well-formulated papers on fossil pinnipeds were being published was the early 1990s. Any way, without further adieu, here are the abstracts of all newly published articles from 2018. Disclaimer: as always, I leave out papers published initially in late 2017 but with formal publication dates in 2018, because they were already covered last year. No, I do not have the time to update the publication dates on all of these, and you should feel ashamed for asking. Go look it up yourself! I guarantee that there are inconsistencies in the citation format, so if you find one, congratulations! I don't care. The entire point of this is to provide younger researchers with a comprehensive source of new publications. With that last point in mind, if I have forgotten anything, please leave a comment or send me a email, twitter, or facebook message informing me - unless of course it deals with modern species only (in which case it's not paleontological, although morphological and probably very evolutionary informative) or if it was first published in 2017 (see above). Notably NOT included here are a bunch of extended conference abstracts on largely Italian fossils by a veritable battalion of Italian student paleontologists published in the new journal "Fossilia". I'm interpreting these as conference proceedings for now as full-length papers are not yet in evidence. However, if you're interested in what these students have worked on, take a look here: https://www.fossiliajournal.com/volumes/volume-1 Albright, L.B., A.E. Sanders, and J.H. Geisler. 2018. An unexpectedly derived odontocete from the Ashley Formation (upper Rupelian) of South Carolina, U.S.A. Journal of Vertebrate Paleontology. Online Early. https://www.tandfonline.com/doi/abs/10.1080/02724634.2018.1482555?journalCode=ujvp20 Fossil whale material from the Oligocene-aged marine beds underlying the region around Charleston, South Carolina, has provided an unparalleled view of post-archaeocete cetacean evolution. Both the Chattian-aged Chandler Bridge Formation and the underlying Rupelian-aged Ashley Formation have yielded dozens of specimens, many yet-to-be described, that document an explosive evolutionary radiation at this time, particularly in odontocetes, but in early mysticetes as well. Specimens include early odontocetes, such as Ashleycetus planicapitis, Xenorophus sloanii, and Agorophius pygmaeus; the earliest baleen-bearing mysticetes, such as Eomysticetus whitmorei and E. carolinensis; and even multiple species of archaeocete-like toothed mysticetes, such as the recently described Coronodon havensteini. Herein, we describe yet another species of odontocete from the Ashley Formation, but one that is surprisingly derived relative to contemporary species noted above that maintain a pronounced intertemporal constriction, with broad exposure of the parietals across the skull roof. In contrast to those taxa, Ediscetus osbornei, gen. et sp. nov., shows an unexpectedly advanced degree of ‘telescoping’ whereby there is no exposure of the parietals across the vertex of the skull and only minimally exposed ‘parietal triangles’ at the lateral margins of the nearly lost intertemporal constriction. Phylogenetic analyses of a supermatrix of morphological and molecular data place E. osbornei slightly outside the odontocete crown group, with the presence of double-rooted teeth and a deep maxillary cleft, among other features, supporting this position. The holotype also has a well-developed articular ridge on the petrosal, typically considered a platanistoid synapomorphy, indicating that this character shows more homoplasy than generally realized. Berta, A., M. Churchill, and R.W. Boessenecker. 2018. The origin and evolutionary biology of pinnipeds: seals, sea lions, and walruses. Annual Review of Earth and Planetary Sciences 46:203-228. https://www.annualreviews.org/doi/10.1146/annurev-earth-082517-010009 The oldest definitive pinniped fossils date from approximately 30.6–23 million years ago (Ma) in the North Pacific. Pinniped monophyly is consistently supported; the group shares a common ancestry with arctoid carnivorans, either ursids or musteloids. Crown pinnipeds comprise the Otariidae (fur seals and sea lions), Odobenidae (walruses), and Phocidae (seals), with paraphyletic “enaliarctines” falling outside the crown group. The position of extinct Desmatophocidae is debated; they are considered to be closely related to both otariids and odobenids or, alternatively, to phocids. Both otariids and odobenids are known from the North Pacific, diverging approximately 19 Ma, with phocids originating in the North Atlantic or Paratethys region 19–14 Ma. Our understanding of pinniped paleobiology has been enriched by studies that incorporate anatomical and behavioral data into a phylogenetic framework. There is now evidence for sexual dimorphism in the earliest pinnipeds, heralding polygynous breeding systems, followed by increased body sizes, diving capabilities, and diverse feeding strategies in later-diverging phocid and otarioid lineages. Bianucci, G., A. Collareta, G. Bosio, et. al. 2018. Taphonomy and palaeoecology of the lower Miocene marine vertebrate assemblage of Ullujaya (Chilcatay Formation, East Pisco Basin, Southern Peru). Palaeogeography, Palaeoclimatology, Palaeoecology https://www.sciencedirect.com/science/article/pii/S0031018218304838 The taphonomy and palaeoecology of the early Miocene (Burdigalian) vertebrate assemblage of Ullujaya (East Pisco Basin, Peru) is here described. Vertebrate remains are concentrated in marine facies (Ct1a association) of the exposed Chilcatay Formation (dated 19–18 Ma) deposited within a 30–40 m deep, semi-enclosed, offshore environment. Coupled with ichnological observations, the size distribution of pyrite framboid relics reveals fluctuation of euxinic and oxic-dysoxic conditions at the seafloor. The assemblage is dominated by toothed cetaceans (kentriodontids, squalodelphinids, physeteroids, and the eurhinodelphinid-like Chilcacetus), together with a large dermochelyid turtle, some bony fish, and diverse elasmobranchs, mostly juveniles of Carcharhinus brachyurus and Cosmopolitodus hastalis. The vertebrate assemblage comprises a coastal community, dominated by mesopredators, representative of a warm-temperate, sheltered embayment connected with riverine and open-ocean environments. Vertebrate skeletons are typically disarticulated and incomplete, and some bone elements display shark bite marks. Microborings are observed at the bone surface. Bones exhibit a good degree of apatite mineralisation and bone cavities are locally filled by Ca-Mg carbonates. Our taphonomic observations suggest prolonged flotation of carcasses during which they were subject to biogenic and physical processes of partial destruction (including scavenging by sharks), before final deposition on a soft compact substrate. Preservation was favoured by the oxygen-deficient bottom conditions that inhibited the action of benthic macro-scavengers. Bianucci, G., G. Bosio, E. Malinverno, et al. 2018. A new large squalodelphinid (Cetacea, Odontoceti) from Peru sheds light on the early Miocene platanistoid disparity and ecology. Royal Society Open Science 5:172302. https://royalsocietypublishing.org/doi/full/10.1098/rsos.172302 The South Asian river dolphin (Platanista gangetica) is the only extant survivor of the large clade Platanistoidea, having a well-diversified fossil record from the Late Oligocene to the Middle Miocene. Based on a partial skeleton collected from the Chilcatay Formation (Chilcatay Fm; southern coast of Peru), we report here a new squalodelphinid genus and species, Macrosqualodelphis ukupachai. A volcanic ash layer, sampled near the fossil, yielded the 40Ar/39Ar age of 18.78 ± 0.08 Ma (Burdigalian, Early Miocene). The phylogenetic analysis places Macrosqualodelphis as the earliest branching squalodelphinid. Combined with several cranial and dental features, the large body size (estimated body length of 3.5 m) of this odontocete suggests that it consumed larger prey than the other members of its family. Together with Huaridelphis raimondii and Notocetus vanbenedeni, both also found in the Chilcatay Fm, this new squalodelphinid further demonstrates the peculiar local diversity of the family along the southeastern Pacific coast, possibly related to their partition into different dietary niches. At a wider geographical scale, the morphological and ecological diversity of squalodelphinids confirms the major role played by platanistoids during the Early Miocene radiation of crown odontocetes. Boessenecker, R.W. 2018. Problematic archaic whale Phococetus (Cetacea: Odontoceti) from the Lee Creek Mine, North Carolina, USA, with comments on geochronology of the Pungo River Formation. Pal Z. Online early. https://link.springer.com/article/10.1007/s12542-018-0419-3 Heterodont cetaceans are abundant in Eocene, Oligocene, and early to middle Miocene deposits worldwide. Taxonomic practice in the 19th and early 20th centuries led to the establishment of a multitude of names based on isolated teeth. Some of these taxa, such as Phococetus vasconum from the lower Miocene (Burdigalian) of France, have been alternatively interpreted as archaeocetes, odontocetes, and mysticetes. Isolated teeth resembling Phococetus vasconum from the Pungo River Formation in the Lee Creek Mine (Beaufort County, North Carolina, USA) also share features with the enigmatic early Miocene odontocete Inticetus vertizi, suggesting that Phococetus may represent a large heterodont odontocete. Boessenecker, R.W. and M. Churchill. 2018. The last of the desmatophocid seals: a new species of Allodesmus from the upper Miocene of Washington, USA, and a revision of the taxonomy of Desmatophocidae. Zoological Journal of the Linnean Society 184:1:211-235. https://academic.oup.com/zoolinnean/article-abstract/184/1/211/4783131 The family Desmatophocidae represents an early radiation of extinct pinnipeds that peaked in diversity during the middle Miocene. Although represented by abundant well-preserved fossils, the taxonomy and evolutionary relationships of this family remain poorly known. Late Miocene desmatophocids have been recorded, although none have been formally described, preventing a thorough appraisal of their decline and extinction. We report the discovery of a new species, Allodesmus demerei sp. nov., represented by a partial skeleton with cranium, mandibles, and axial skeleton, from the upper Miocene Montesano Formation of Washington, prompting reinterpretation of desmatophocid taxonomy, phylogeny, and extinction. Phylogenetic analysis (95 characters, 26 taxa) found strong support for monophyletic Desmatophocidae and Allodesmus. Desmatophocidae was found as sister to Phocidae with poor support. Allodesmus demerei was placed within the Allodesmus as the sister taxon to Allodesmus kernensis. The geochronologically young age (10.5–9.1 Mya) of Al. demerei establishes this species as the last of the desmatophocid seals. The middle Miocene peak in desmatophocid diversity coincides with the middle Miocene climatic optimum, suggesting that declining sea surface temperature played a role in their decline and extinction. Walruses diversified and increased in body size during the mid- to late Miocene as desmatophocids declined, suggesting some form of ecological displacement. Boessenecker, R.W. and J.H. Geisler. 2018. New records of the archaic dolphin Agorophius (Mammalia: Cetacea) from the upper Oligocene Chandler Bridge Formation of South Carolina, USA. PeerJ 6:e5290. https://peerj.com/articles/5290/ The stem odontocete Agorophius pygmaeus (Ashley Formation, lower Oligocene, South Carolina; 29.0–26.57 Ma) has been a critical point of comparison for studies of early neocete evolution owing to its early discovery as well as its transitional anatomy relative to archaeocete whales and modern odontocetes. Some time during the late nineteenth century the holotype skull went missing and has never been relocated; supplementary reference specimens have since been recently referred to the species from the Ashley Formation and the overlying Chandler Bridge Formation (upper Oligocene; 24.7–23.5). New crania referable to Agorophius sp. are identifiable to the genus based on several features of the intertemporal region. Furthermore, all published specimens from the Chandler Bridge Formation consistently share larger absolute size and a proportionally shorter exposure of the parietal in the skull roof than specimens from the Ashley Formation (including the holotype). Furthermore, these specimens include well-preserved ethmoid labyrinths and cribriform plates, indicating that Agorophius primitively retained a strong olfactory sense. These new crania suggest that at least two species of Agorophius are present in the Oligocene of South Carolina, revealing a somewhat more complicated taxonomic perspective. Boessenecker, S.J., R.W. Boessenecker, and J.H. Geisler. 2018. Youngest record of the extinct walrus Ontocetus emmonsi from the Early Pleistocene of South Carolina and a review of North Atlantic walrus biochronology. Acta Palaeontologica Polonica 63:279-286. https://www.app.pan.pl/article/item/app004542018.html The extinct North Atlantic walrus Ontocetus emmonsi is widely reported from Pliocene marine deposits in the eastern USA (New Jersey, Florida), Belgium, Netherlands, Great Britain, and Morocco. Ontocetus was slightly larger than the modern walrus Odobenus rosmarus, may have had wider climatic tolerances (subtropical), and likely originated in the western North Pacific before dispersing through the Arctic. Owing to geochronologic uncertainties in the North Atlantic Plio-Pleistocene walrus record, it is unclear whether Ontocetus and Odobenus overlapped in time and thus may have competed, or whether the two were temporally separate invasions of the North Atlantic. A new specimen of Ontocetus emmonsi (CCNHM-1144) from the Austin Sand Pit (Ridgeville, South Carolina, USA) is a complete, well-preserved left tusk that is proximally inflated and oval in cross-section, relatively short (maximum length: 369 mm) and markedly curved (radius of arc of curvature 197 mm). Globular dentine is present, confirming assignment to Odobenini; proportions and curvature identify the specimen as Ontocetus emmonsi rather than Odobenus. Hitherto unstudied deposits in the Austin Sand Pit lack calcareous macro and microinvertebrates, but vertebrate biochronology provides some temporal resolution. The co-occurrence of a giant beaver (Castoroides sp.) and a snaggletooth shark (Hemipristis serra) indicate an age of 1.1–1.8 Ma (Early Pleistocene) and correlation with the Lower Pleistocene Waccamaw Formation. The vertebrate assemblage is named the Ridgeville Local Fauna. The composition of the marine mammal assemblage from the Austin Sand Pit is intermediate between that of the lower Pliocene Yorktown Formation (North Carolina, USA) and the modern North Atlantic fauna. This record reported here is the youngest of Ontocetus emmonsi from the Atlantic Coastal Plain. A review of North Atlantic Plio-Pleistocene walrus records reveals no overlap between extinct Ontocetus and extant Odobenus—suggesting independent dispersal to the North Atlantic and a lack of competition. Churchill, M., J.H. Geisler, B.L. Beatty, and A. Goswami. 2018. Evolution of cranial telescoping in echolocating whales (Cetacea: Odontoceti). Evolution 72:1092-1108. https://onlinelibrary.wiley.com/doi/abs/10.1111/evo.13480 Odontocete (echolocating whale) skulls exhibit extreme posterior displacement and overlapping of facial bones, here referred to as retrograde cranial telescoping. To examine retrograde cranial telescoping across 40 million years of whale evolution, we collected 3D scans of whale skulls spanning odontocete evolution. We used a sliding semilandmark morphometric approach with Procrustes superimposition and PCA to capture and describe the morphological variation present in the facial region, followed by Ancestral Character State Reconstruction (ACSR) and evolutionary model fitting on significant components to determine how retrograde cranial telescoping evolved. The first PC score explains the majority of variation associated with telescoping and reflects the posterior migration of the external nares and premaxilla alongside expansion of the maxilla and frontal. The earliest diverging fossil odontocetes were found to exhibit a lesser degree of cranial telescoping than later diverging but contemporary whale taxa. Major shifts in PC scores and centroid size are identified at the base of Odontoceti, and early burst and punctuated equilibrium models best fit the evolution of retrograde telescoping. This indicates that the Oligocene was a period of unusually high diversity and evolution in whale skull morphology, with little subsequent evolution in telescoping. Decree, S., D. Herwartz, J. Mercadier, et al. 2018. The post-mortem history of a bone revealed by its trace element signature: the case of a fossil whale rostrum. Chemical Gelology 477:137-150. https://www.sciencedirect.com/science/article/abs/pii/S0009254117307027?via%3Dihub Studies dedicated to palaeoenvironments and taphonomy have made wide use of rare earth elements (REE) contents of fossil bones as proxies. However, the complex diagenetic history of individual specimens combined with intra-bone REE fractionation and the uncertain timing of REE uptake generally prevents the robust interpretation of REE patterns. In this case study we show that combining REE analysis with, on the one hand, histology and microstructural observations and, on the other hand, additional analyses of other trace elements, allows deciphering at least three distinct trace element uptake stages, as well as one leaching event. More than 35 trace elements (including the REE) are analysed using laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) within compact rostrum bones of the Miocene-Pliocene beaked whale Globicetus hiberus from deep-sea deposits and a comparable extant specimen (Blainville's beaked whale Mesoplodon densirostris). Comparison of the extinct and the extant bones allows a better quantification of the diagenetic trace element content. This study highlights the crucial role played by diagenetic minerals such as the Fe-Mn oxyhydroxides in the uptake and release of trace elements (Co, Ni, Ti, V, Zr, Hf and Nb) and REE by bones, in response to changes of the diagenetic fluid redox conditions over time. Such changes of the geochemical environment help constraining the post-mortem history of the bone and its interaction with diagenetic fluids. We conclude that the unique interpretation of geochemical proxies within individual fossil bones requires a thorough investigation of each individual specimen. Dewaele, L., O. Lambert, and S. Louwye. 2018. A late surviving Pliocene seal from high latitudes of the North Atlantic realm: the latest monachine seal on the southern margin of the North Sea. PeerJ 6:e7534. https://peerj.com/articles/5734/ The family of true seals, the Phocidae, is subdivided into two subfamilies: the southern Monachinae, and the northern Phocinae, following the subfamilies’ current distribution: extant Monachinae are largely restricted to the (sub-)Antarctic and the eastern Pacific, with historical distributions of the monk seals of the genus Monachus in the Caribbean, the Mediterranean and around Hawaii; and Phocinae to the northern temperate and Arctic zones. However, the fossil record shows that Monachinae were common in the North Atlantic realm during the late Miocene and early Pliocene. Until now, only one late Pliocene record is known from the Mediterranean, Pliophoca etrusca from Tuscany, Italy, but none from farther north in the North Atlantic. Dewaele, L., O. Lambert, M. Laurin, et al. 2018. Generalized osteosclerotic condition in the skeleton of Nanophoca vitulinoides, a dwarf seal from the Miocene of Belgium. Journal of Mammalian Evolution. Online Early. https://link.springer.com/article/10.1007%2Fs10914-018-9438-9 In the fossil record, it has been shown that various clades of secondarily aquatic tetrapods experienced an initial densification of their bones in the early stages of their evolution, and developed spongier and lighter bones only later in their evolution, with the acquisition of more efficient swimming modes. Although the inner bone structure of most secondarily aquatic tetrapods has already been studied, no research hitherto focused on true seals, or Phocidae. However, preliminary observations previously made on a Miocene species, Nanophoca vitulinoides, suggested that this taxon showed pronounced specialization of bone structure as compared to other seals. This feature justifies a specific comparative study, which is the purpose of this article. Microanatomical analysis of bones of N. vitulinoides shows compactness values nearing 100%, which is much higher than in other semi-aquatic mammals, pinnipeds included. Osteohistological analyses show virtually complete remodeling of the medullary territory by Haversian substitution. Extreme bone compactness locally resulted from an imbalance, towards reconstruction, of this process. Cortical regions were less intensely remodeled. In a number of specimens, the cortex shows clear growth marks as seasonal lines of arrested growth. The results suggest that, despite the extreme compactness of long bones of N. vitulinoides and the small size of this taxon, the growth rate of the cortex, and that of the bones in general, did not differ strongly from that of other, larger phocids. Extreme skeletal compaction and densification must have increased body density in Nanophoca. Consequently, speed, acceleration, and maneuverability must have been low, and this taxon was most likely a near-shore bottom-dwelling seal. Consequently, dietary preferences were most likely oriented towards benthic food sources. Dewaele, L., O. Lambert, and S. Louwye. 2018. A critical revision of the fossil record, stratigraphy and diversity of the Neogene seal genus Monotherium (Carnivora, Phocidae). Royal Society Open Science 5:e171669. https://royalsocietypublishing.org/doi/full/10.1098/rsos.171669 Historically, Monotherium had been one of the few genera of extinct Phocidae (true seals) that served as a wastebin taxon. Consequently, it did neither aid in understanding phylogenetic relationships of extinct Phocidae, nor in understanding seal diversity in deep time. This urged the reassessment of the genus. Before our review, Monotherium included five different species: Monotherium aberratum, Monotherium affine, and Monotherium delognii from Belgium; Monotherium gaudini from Italy; and Monotherium? wymani from the east coast USA. In this work we redescribe the fossil record of the genus, retaining the type species M. delognii. Monotherium aberratum and M. affine are reassigned to the new phocine genus Frisiphoca. Monotherium gaudini is renamed and considered a stem-monachine (Noriphoca gaudini). The holotype of the monachine M.? wymani requires further study pending the discovery of new fossil material that could be attributed to the same taxon. Reinvestigating the stratigraphic context reveals that N. gaudini most likely represents one of the two oldest named phocid seals, or even the oldest, dated to the late Oligocene–earliest Miocene. Our results allow questioning the widespread idea that Phocidae originated in the western Atlantic and better appreciate their palaeobiogeography during the late Oligocene–Miocene interval in the North Atlantic realm. Dewaele, L., C.M. Peredo, P. Meyvisch, and S. Louwye. 2018. Diversity of late Neogene Monachinae (Carnivora, Phocidae) from the North Atlantic, with a description of two new species. Royal Society Open Science 5:172437. https://royalsocietypublishing.org/doi/full/10.1098/rsos.172437 While the diversity of ‘southern seals’, or Monachinae, in the North Atlantic realm is currently limited to the Mediterranean monk seal, Monachus monachus, their diversity was much higher during the late Miocene and Pliocene. Although the fossil record of Monachinae from the North Atlantic is mainly composed of isolated specimens, many taxa have been erected on the basis of fragmentary and incomparable specimens. The humerus is commonly considered the most diagnostic postcranial bone. The research presented in this study limits the selection of type specimens for different fossil Monachinae to humeri and questions fossil taxa that have other types of bones as type specimens, such as for Terranectes parvus. In addition, it is essential that the humeri selected as type specimens are (almost) complete. This questions the validity of partial humeri selected as type specimens, such as for Terranectes magnus. This study revises Callophoca obscura, Homiphoca capensis and Pliophoca etrusca, all purportedly known from the Lee Creek Mine, Aurora, North Carolina, in addition to their respective type localities in Belgium, South Africa and Italy, respectively. C. obscura is retained as a monachine seal taxon that lived both on the east coast of North America and in the North Sea Basin. However, H. capensis from North America cannot be identified beyond the genus level, and specimens previously assigned to Pl. etrusca from North America clearly belong to different taxa. Indeed, we also present new material and describe two new genera of late Miocene and Pliocene Monachinae from the east coast of North America: Auroraphoca atlantica nov. gen. et nov. sp., and Virginiaphoca magurai nov. gen. et nov. sp. This suggests less faunal interchange of late Neogene Monachinae between the east and west coasts of the North Atlantic than previously expected. Domning, D.P. 2018. Fossil sirenians (Mammalia) of the Miocene Chesapeake Group, Eastern United States. [in Godfrey, S.J., ed., The Geology and Vertebrate Paleontology of Calvert Cliffs, Maryland, USA] Smithsonian Contributions to Paleobiology 100:241-266. https://opensi.si.edu/index.php/smithsonian/catalog/book/107 The extensive Miocene vertebrate fauna collected from the Chesapeake Group in New Jersey, Delaware, Maryland, Virginia, and North Carolina includes relatively rare sirenians of the family Dugongidae. They are most abundant in the early to middle Miocene Calvert and equivalent formations and in the Calvert Cliffs and nearby exposures in southern Maryland, as well as in the Lee Creek phosphate mine in North Carolina. These Calvert-correlative deposits have yielded evidence of at least three sirenian taxa: the halitheriine dugongid Metaxytherium crataegense (=M. calvertense), the dugongine dugongid Nanosiren sp., and another dugongine, aff. Corystosiren sp. A possible fourth unidentified form may also be a dugongine. The stratigraphically higher St. Marys Formation contains remains that (in view of their late Miocene age) may be referable to Metaxytherium floridanum, but those so far collected are too fragmentary to be distinguished morphologically from M. crataegense. Fordyce, R.E., and F.G. Marx. 2018. Gigantism precedes filter feeding in baleen whale evolution. Current Biology 28:1670-1676. https://www.cell.com/current-biology/abstract/S0960-9822(18)30455-X Baleen whales (Mysticeti) are the largest animals on Earth, thanks to their ability to filter feed huge volumes of small prey from seawater. Mysticetes appeared during the Late Eocene, but evidence of their early evolution remains both sparse and controversial [1, 2], with several models competing to explain the origin of baleen-based bulk feeding [3–6]. Here, we describe a virtually complete skull of Llanocetus denticrenatus, the second-oldest (ca. 34 Ma) mysticete known. The new material represents the same individual as the type and only specimen, a fragmentary mandible. Phylogenetic analysis groups Llanocetus with the oldest mysticete, Mystacodon selenensis [2], into the basal family Llanocetidae. Llanocetus is gigantic (body length _8 m) compared to other early mysticetes [7–9]. The broad rostrum has sharp, widely spaced teeth with marked dental abrasion and attrition, suggesting biting and occlusal shearing. As in extant mysticetes, the palate bears many sulci, commonly interpreted as osteological correlates of baleen [3]. Unexpectedly, these sulci converge on the upper alveoli, suggesting a peridental blood supply to well-developed gums, rather than to inter-alveolar racks of baleen. We interpret Llanocetus as a raptorial or suction feeder, revealing that whales evolved gigantism well before the emergence of filter feeding. Rather than driving the origin of mysticetes, baleen and filtering most likely only arose after an initial phase of suction-assisted raptorial feeding [2, 4, 5]. This scenario differs strikingly from that proposed for odontocetes, whose defining adaptation—echolocation—was present even in their earliest representatives [10]. Galatius, A., Olsen, M.T., M.E. Steeman, et a. 2018. Raising your voice: evolution of narrow-band high-frequency signals in toothed whales (Odontoceti). Biological Journal of the Linnean Society. Online early. https://academic.oup.com/biolinnean/advance-article-abstract/doi/10.1093/biolinnean/bly194/5244783 Cetaceans use sound for communication, navigation and finding prey. Most extant odontocetes produce broadband (BB) biosonar clicks covering frequency ranges from tens of kilohertz to 150–170 kHz. In contrast, the biosonar clicks of some odontocetes are unique, being narrow in bandwidth with high centroid frequency (NBHF), peak frequencies being at 125–140 kHz and bandwidths of 11–20 kHz. Thirteen species within four families (Phocoenidae, Pontoporiidae, Kogiidae, Delphinidae) are known to produce these signals, implying convergent evolution under strong selective drivers. Several hypotheses have been proposed, including acoustic crypsis to escape predation by killer whales, but none has provided comprehensive explanation of the timing of NBHF evolution and the pressures driving sound production to such extremes. Using molecular phylogenetics and the cochlea anatomy of extinct and extant taxa, we demonstrate that early NBHF adaptations occurred at least 10 Mya, and possibly up to 18 Mya, indicating that killer whales cannot have been the sole driving force of NBHF signals, but that now extinct odontocetes may have provided similar pressures. Using palaeoclimate modelling, we further demonstrate that the upper advantageous spectral window for NBHF signals at around 130 kHz has persisted throughout most of the global sea area since the mid-Miocene, covering all known instances of NBHF evolution. Gilbert, K.N., L.C. Ivany, and M.D. Uhen. 2018/ Living fast and dying young: life history and ecology of a Neogene sperm whale. Journal of Vertebrate Paleontology 38:e1439038. https://www.tandfonline.com/doi/abs/10.1080/02724634.2018.1439038?journalCode=ujvp20 Physeteroidea (sperm whales) attained great diversity during the Miocene and early Pliocene, and the phosphatic sands of the U.S. Atlantic Coastal Plain have produced thousands of specimens. Although postcranial and cranial materials are rare, teeth are remarkably common and have the potential to provide valuable insight into the lives of these animals. We examine a suite of Physeteroidea indet. teeth from the Lee Creek Mine to better constrain the life history and ecology of this extinct group. Wear facets indicate that these animals, unlike modern sperm whales, had both maxillary and mandibular teeth, suggesting a raptorial feeding ecology more akin to killer whales. A relationship between tooth diameter and body size established for modern odontocetes suggests that these animals as adults were also about the size of modern killer whales. Because physeteroid teeth grow continuously over ontogeny and are not replaced, counts of accretionary growth layer groups can be used to ascertain the age of an animal at death. Tallies of growth increments from 10 teeth, including some of the largest available, reveal that life spans only rarely exceeded 20 years, significantly shorter than the 65+ years typical of modern sperm whales or orcas. Despite their large size, these odontocetes experienced a ‘fast’ life history, more like beluga whales today. We suggest that the rapid growth and short life span exhibited by the Lee Creek physeteroids are, like the modern beluga, evolutionary responses to high predation pressure imposed by large co-occurring predatory taxa, particularly including Carcharocles megalodon or other large macroraptorial physeteorids. Gioncada, A., K. Gariboldi, A. Collareta et al. 2018. Looking for the key to preservation of fossil marine vertebrates in the Pisco Formation of Peru: new insights from a small dolphin skeleton. Andean Geology 45:379-398. http://www.andeangeology.cl/index.php/revista1/article/view/3122 The upper Neogene Pisco Formation of Peru is known worldwide as one of the most significant Cenozoic marine vertebrate Konservatt-Lagerstätten, even featuring cetacean specimens that retain remains of soft tissues or stomach contents. Previous works showed that biomediated precipitation of dolomite concretions around large-sized decaying carcasses was one of the most relevant processes responsible for exceptional fossil preservation. In turn, little is known about the modes of fossilization of well-preserved small-sized vertebrates, which are rather common in the Pisco Formation, but mostly do not exhibit dolomite concretions. We report on a cetacean specimen, identified as belonging to the extinct short-snouted, small dolphin species Brachydelphis mazeasi (Pontoporiidae), preserved within a late Miocene sandy deposit at the site of Pampa Corre Viento. This specimen consists of a moderately disarticulated partial skeleton exhibiting well-mineralized bones; it is not enclosed within a dolomite concretion, being however delimited by an evident dark boundary in the host sediment. Scanning electron microscopy and microanalytical investigations identify Mn-oxides and apatite as early diagenetic minerals around the skeleton. We argue that a rapid burial of the specimen was pivotal for the preservation of the bones, and allowed the early establishment of anoxic processes for degradation of organic matter. Coupled with availability of P in porewater, the reducing conditions and the lowered pH allowed precipitation of Ca-phosphate while increasing Mn solubility close to the pontoporiid carcass. Mn-oxides precipitated at the redox boundary, the latter defining the outer edge of the volume of sediment affected by altered chemical conditions due to the decaying processes. The permeability of the sediment and the small size of the carcass were possible factors unfavorable to extensive sulfate reduction, thus preventing the formation of a dolomite concretion and allowing bone phosphatization. This record emphasizes the role of conditions favorable to bone mineralization in absence of an isolating carbonate concretion, in cases of high quality preservation of small-sized vertebrates observed in the Pisco Formation. The observation of patterns in the distribution of diagenetic minerals in the sediment enclosing vertebrate remains without, or with limited carbonate concretions provides insights into early taphonomic processes. Godfrey, S.J., M. Ellwood, S. Groff, and M.S. Verdin. 2018. Carcharocles-bitten odontocete caudal vertebrae from the coastal Eastern United States. Acta Palaeontologica Polonica 63:463-468. https://www.app.pan.pl/article/item/app004952018.html A description and analysis is given of three Neogene odontocete caudal vertebrae that were bitten by the extinct megatooth sharks Carcharocles megalodon or Carcharocles chubutensis. The peduncular caudal vertebrae show bilateral gouge marks consistent with having been actively bitten and wedged between adjacent teeth of C. megalodon or C. chubutensis. None of the vertebrae show signs of healing. The occurrence of bite marks on distal caudals suggests active predation (vs. scavenging) in order to immobilize even relatively small prey prior to consumption. Gol’din, P. 2018. New Paratethyan dwarf baleen whales mark the origin of cetotheres. PeerJ 6:e5800. https://peerj.com/articles/5800/ Family Cetotheriidae sensu stricto and several closely related taxa comprise the Cetotherioidea and represent a lineage of Neogene baleen whales that includes the smallest edentulous baleen whales in Earth history. Most of known cetotheriids came from the Late Miocene to Quaternary, and the earliest records from the latest Middle Miocene. The Paratethys region shows a great diversity of Middle to Late Miocene cetotheriids. That includes nominative taxon of the family, Cetotherium rathkii, and this suggests that the earliest cetotheriids may have lived in that region. Here, Ciuciulea davidi, a new genus and species from the Middle Miocene of southeastern Europe, is described as the chronologically earliest and earliest diverging member of Cetotheriidae. Also, a new specimen of Otradnocetus, a basal Cetotherioidea sensu Gol’din & Steeman, 2015 is identified from the Late Miocene deposits of Caucasus and compared with Otradnocetus virodovi from the Middle Miocene of the same region. Ciuciulea davidi is a dwarf whale displaying primitive traits: posterior ends of facial bones forming a single transverse line, a narrow occipital shield, and a relatively long interparietal region. Meanwhile, it shares some cetotheriid apomorphies: posteriorly telescoped wedge-shaped facial bones and an ovoid tympanic bulla with shallow lateral and medial furrows, a short anterior lobe and a short sigmoid process. Phylogenetic analysis suggests that Parietobalaena and Otradnocetus are branches diverging before the clade Cetotheriidae + Neobalaenidae. This is confirmed by the stepwise evolution of the anatomy of the squamosal, mandible, and ear bones across these groups. The re-described juvenile specimen of Otradnocetus differs from O. virodovi in the more primitive anatomy of the mandible and the autapomorphic anatomy of the humerus. Records of the earliest cetotheriids and related taxa in the Paratethys support the idea that this could be the region where Cetotheriidae evolved before their worldwide dispersal and radiation. Gol’din, P., and P. Radovic. 2018. A middle Miocene baleen whale from Bele Vode in Belgrade, Serbia. Rivista Italiana di Paleontologia e Stratigrafia 124:127-138. https://riviste.unimi.it/index.php/RIPS/article/view/9751 There was a fauna of baleen whales (Cetacea: Mysticeti) in the Central Paratethys, a Miocene water body which covered the area of present-day Central Europe. Most of the fossil baleen whales from the Central Paratethys have been found in strata assigned to the regional Badenian age and comprise endemic forms, known only from this region. Here a new description is provided for a fragmentary skeleton of a whale found in Belgrade, Serbia, and its age context and biological aspects are discussed. This specimen, consisting of a fragmentary horizontal ramus of the mandible and eight caudal vertebrae, is tentatively identified as ?Parietobalaena sp., a globally known Miocene taxon, with related forms having been recorded earlier from the Eastern Paratethys. An early Sarmatian age (i.e., about 12.7-12.4 Ma) is proposed for the specimen. Based on epiphyseal fusion of caudal vertebrae, the specimen’s age is identified as a subadult, with a body length of around 2.5 m and an estimated adult body length around 3-3.5 m, which is extremely small for baleen whales. This find represents one of the latest records of baleen whales in the Central Paratethys and one of the latest published records of Parietobalaena-like taxa in the world. Hernandez-Cisneros, E. 2018. A new group of late Oligocene mysticetes from Mexico. Palaeontologia Electronica 21:7A:1-30. https://palaeo-electronica.org/content/2018/2147-oligocene-mysticetes-from-mexico The Oligocene cetacean fossil record from Mexico represents an important element to understand the cetacean evolutionary history in the Pacific Basin. However, our knowledge of these fossils is poor, as the specimens have not yet been properly described. Nonetheless, recent observations on Oligocene fossils from the state of Baja California Sur offer new ideas with regard to the cetacean taxonomic composition and suggest a high diversity of mysticete fossils with several forms of toothless mysticetes. Consequently, a new group of extinct mysticetes from the late Oligocene (Chattian) of Mexico is described based on two different specimens (partial skulls), which share a phenetically similar periotic bone. These fossils were collected from the marine units of the San Juan Member (30 to 23 Ma) of the El Cien Formation in Baja California Sur. Furthermore, this new group of archaic mysticetes is distinct to eomysticetid-like animals, Mauicetus, Horopeta, and Whakakai mainly in the periotic morphology specifically in: a longer and anteroposteriorly flattened compound posterior process of the periotic, and a periotic (pars cochlearis, anterior process and body of the periotic) with an ovoid shape in lateral and medial views. Phylogenetic analysis suggests a closer relation to Sitsqwayk and eomysticetes than to Horopeta + Whakakai and crown Mysticeti. Oligocene cetaceans from Mexico are still poorly known in terms of their paleoecology and phyletic relationship. This work represents the first description of Oligocene mysticetes from Baja California Sur and shows the potential to further understanding of the biogeographic history of mysticetes in the Eastern Pacific. Hocking, D.P., F.G. Marx, R. Sattler, et al. 2018. Clawed forelimbs allow northern seals to eat like their ancient ancestors. Royal Society Open Science 5:172393. https://royalsocietypublishing.org/doi/pdf/10.1098/rsos.172393 Streamlined flippers are often considered the defining feature of seals and sea lions, whose very name ‘pinniped’ comes from the Latin pinna and pedis, meaning ‘fin-footed’. Yet not all pinniped limbs are alike. Whereas otariids (fur seals and sea lions) possess stiff streamlined forelimb flippers, phocine seals (northern true seals) have retained a webbed yet mobile paw bearing sharp claws. Here, we show that captive and wild phocines routinely use these claws to secure prey during processing, enabling seals to tear large fish by stretching them between their teeth and forelimbs. ‘Hold and tear’ processing relies on the primitive forelimb anatomy displayed by phocines, which is also found in the early fossil pinniped Enaliarctos. Phocine forelimb anatomy and behaviour therefore provide a glimpse into how the earliest seals likely fed, and indicate what behaviours may have assisted pinnipeds along their journey from terrestrial to aquatic feeding. Ichishima, H., H. Furusawam M. Tachibana, and M. Kimura. 2018. First monodontid cetacean (Odontoceti, Delphinoidea) from the early Pliocene of the northwestern Pacific Ocean. Papers in Palaeontology. Online early. https://onlinelibrary.wiley.com/doi/full/10.1002/spp2.1244 Monodontids are among the most enigmatic cetaceans due to their scarcity in the fossil record. Previously, except for fragmentary materials, only three skulls were known from the pre‐Pleistocene; these came from the east coast of the Pacific and both east and west coasts of the Atlantic. Haborodelphis japonicus, a new early Pliocene monodontid cetacean from the north‐west Pacific, significantly expands the palaeobiogeographical extent of the ancestral monodontids. The new taxon differs from all other monodontids in the following character states: the robust postorbital process for the skull size; the short rostrum relative to the whole skull length; the anterior dorsal infraorbital foramina posterior to the level of the antorbital notch; the premaxillary foramen on the level of the antorbital notch; the dorsally gently convex premaxillary sac fossa; the palatines wedged into the maxillae anteriorly on the midline; and the presence of the clearly excavated posteromedial sulcus. Monodontids were almost certainly adapted to warmer waters than their living counterparts Delphinapterus leucas and Monodon monoceros, both of which are confined to the high latitudes of the northern hemisphere. However, closer inspection (based mainly on fossil invertebrates) of the palaeoenvironments from which the monodontid fossils were produced, reveals that they may have preferred cooler conditions than previously thought. Due to the short climatic fluctuation cycles during the Pliocene in the northern hemisphere, and the increase of heterogeneity and regionality of the coastal environments, the dating of layers within a formation is critical for understanding palaeoenvironment in terms of the sea surface temperatures. Kimura, T., and K. Ishihara. 2018. A fossil phocoenid periotic from Nagasakibana, Chiba, Japan. Bulletin of the Gunma Museum of Natural History 22:73-77. http://www.gmnh.pref.gunma.jp/research_no22 We describe a fossil odontocete periotic from the Nagasakihana, Cyoshi, Chiba Prefecture Japan. The specimen was found as a pebble on the beach and no matrix was preserved. At the area from which the specimen was found, there are conglomerates representing the lowest part of the Naarai Formation (corresponding to planktonic foraminiferal zone PL1:latest Miocene - early Pliocene) and many fossils have been recovered from the Naarai Formation. But, at the same area, Kato (2017) reported several fossils from the unnamed Holocene deposit which is exposed a few meters below the coastal line. Therefore, the age of the present specimen remains unclear (possibly latest Miocene - early Pliocene or Holocene). The periotic displays a combination of the following morphological characters and diagnosed as genus Neophocaena: anterior bullar facet is not present; parabullary ridge is present but not so laterally developed as typically seen in the Delphinidae; outline of anterior process is quadrangular in lateral view; anterior process is directed slight medially; aperture for vestibular aqueduct opens dorsally as slit; dorsal tuberosity is not so developed; foramen sigulare is separated by spiral cribriform tract by high crest; periotic body is relatively narrow in comparison with the width of pars cochlearis. Since the present specimen has a much wider transverse crest in comparison with that of N. phocaenoides, here we report the present specimen as Neophocaena sp. Lambert, O., C. Auclair, C. Cauxeiro, et al. 2018. A close relative of the Amazon river dolphin in marine deposits: a new Iniidae from the late Miocene of Angola. PeerJ 6:e5556. https://peerj.com/articles/5556/ A few odontocetes (echolocating toothed cetaceans) have been able to independently colonize freshwater ecosystems. Although some extant species of delphinids (true dolphins) and phocoenids (porpoises) at least occasionally migrate upstream of large river systems, they have close relatives in fully marine regions. This contrasts with the three odontocete families only containing extant species with a strictly freshwater habitat (Iniidae in South America, the recently extinct Lipotidae in China, and Platanistidae in southeast Asia). Among those, the fossil record of Iniidae includes taxa from freshwater deposits of South America, partly overlapping geographically with the extant Amazon river dolphin Inia geoffrensis, whereas a few marine species from the Americas were only tentatively referred to the family, leaving the transition from a marine to freshwater environment poorly understood. Based on a partial odontocete skeleton including the cranium, discovered in late Miocene (Tortonian-Messinian) marine deposits near the estuary of the Cuanza River, Angola, we describe a new large iniid genus and species. The new taxon is compared to other extinct and extant iniids, and its phylogenetic relationships with the latter are investigated through cladistic analysis. The new genus and species Kwanzacetus khoisani shares a series of morphological features with Inia geoffrensis, including the combination of a frontal boss with nasals being lower on the anterior wall of the vertex, the laterally directed postorbital process of the frontal, the anteroposterior thickening of the nuchal crest, and robust teeth with wrinkled enamel. As confirmed (although with a low support) with the phylogenetic analysis, this makes the new taxon the closest relative of I. geoffrensis found in marine deposits. The geographic provenance of K. khoisani, on the eastern coast of South Atlantic, suggests that the transition from the marine environment to a freshwater, Amazonian habitat may have occurred on the Atlantic side of South America. This new record further increases the inioid diversity during the late Miocene, a time interval confirmed here as the heyday for this superfamily. Finally, this first description of a Neogene cetacean from inland deposits of western sub-Saharan Africa reveals the potential of this large coastal area for deciphering key steps of the evolutionary history of modern cetaceans in the South Atlantic. Lambert O., C. de Muizon, G. Duhamel, and J. Van der Plicht. 2018. Neogene and Quaternary fossil remains of beaked whales (Cetacea, Odontoceti, Ziphiidae) from deep-sea deposits off Crozet and Kerguelen islands, Southern Ocean. Geodiversitas 40:135-160. http://sciencepress.mnhn.fr/en/periodiques/geodiversitas/40/6 Although a high number of extant beaked whale species (Cetacea, Odontoceti, Ziphiidae) live in the Southern Ocean and neighbouring areas, only little is known about the past occupation of the region by these highly specialized, deep diving and echolocating cetaceans. Recently, longline fishing activities along the seafloor at depths of 500-2000 m off the sub-antarctic Crozet and Kerguelen islands, Indian sector of Southern Ocean, resulted in the accessory “capture” of tens of ziphiid fossil cranial remains. Our description and comparison of the best-preserved and most diagnostic crania from this sample lead to the identification of more than eight species in at least seven genera: the hyperoodontines Africanacetus ceratopsis, Khoikhoicetus kergueleni n. sp., Hyperoodontinae indet. aff. Africanacetus, and Mesoplodon sp. aff. Mesoplodon layardii, the ziphiines Izikoziphius rossi and Ziphius sp., and the ziphiids indet. Nenga sp. aff. Nenga meganasalis and Xhosacetus hendeysi. Unsurprisingly, with at least four species in common (A. ceratopsis, Izikoziphius rossi, X. hendeysi, and Ziphius sp.), the assemblage displays high similarities with assemblages described from deep-sea deposits off South Africa, providing thus new data on the palaeogeographic distribution of several extinct species and indicating a roughly similar geochronological age for at least a part of the assemblages. The limited amount of data available points to a pre-Pliocene age for a large part of the Crozet-Kerguelen assemblage, suggesting a relatively early, Miocene colonization of the Southern Ocean by crown ziphiids. Contrastingly, 14C radiometric dating of two specimens of Mesoplodon sp. aff. Mesoplodon layardii yielded latest Pleistocene-earliest Holocene ages. These results reveal the presence either of an extinct species of Mesoplodon in the Southern Ocean only a few thousands years ago, or of an up-to-now unidentified extant species closely related to the strap-toothed whale M. layardii. Magallanes, I., J.F. Parham, G-P. Santos, and J. Velez-Juarbe. 2018. A new tuskless walrus from the Miocene of Orange County, California, with comments on the diversity and taxonomy of odobenids. PeerJ 6:e5708. https://peerj.com/articles/5708/ We describe Titanotaria orangensis (gen. et. sp. nov.), a new species of walrus (odobenid) from the upper Miocene Oso Member of the Capistrano Formation of Orange County, California. This species is important because: (1) It is one of the best-known and latest-surviving tuskless walruses; (2) It raises the number of reported odobenid taxa from the Oso Member to four species making it one of the richest walrus assemblages known (along with the basal Purisima of Northern California); (3) It is just the second record of a tuskless walrus from the same unit as a tusked taxon. Our phylogenetic analysis places T. orangensis as sister to a clade that includes Imagotaria downsi, Pontolis magnus, Dusignathus spp., Gomphotaria pugnax, and Odobeninae. We propose new branch-based phylogenetic definitions for Odobenidae, Odobeninae, and a new node-based name (Neodobenia) for the clade that includes Dusignathus spp., G. pugnax, and Odobeninae. A richness analysis at the 0.1 Ma level that incorporates stratigraphic uncertainty and ghost lineages demonstrates maximum peaks of richness (up to eight or nine coeval lineages) near the base of Odobenidae, Neodobenia, and Odobenini. A more conservative minimum curve demonstrates that standing richness may have been much lower than the maximum lineage richness estimates that are biased by stratigraphic uncertainty. Overall the odobenid fossil record is uneven, with large time slices of the record missing on either side of the Pacific Ocean at some times and biases from the preserved depositional environments at other times. We recognize a provisional timescale for the transition of East Pacific odobenid assemblages that include “basal odobenids” (stem neodobenians) from the Empire and older formations (>7 Ma), to a mixture of basal odobenids and neodobenians from the Capistrano and basal Purisima (7–5 Ma), and then just neodobenians from all younger units (<5 add="" amount="" and="" change="" describe.="" existing="" extensions="" for="" large="" likely="" ma="" material="" new="" of="" p="" patterns="" range="" some="" taxa="" the="" undescribed="" we="" which="" will=""> Marx , F.G., T. Park, E.M.G. Fitzgerald, and A.R. Evans. 2018. A Miocene pygmy right whale fossil from Australia. PeerJ 6:e5025. https://peerj.com/articles/5025/ Neobalaenines are an enigmatic group of baleen whales represented today by a single living species: the pygmy right whale, Caperea marginata, found only in the Southern Hemisphere. Molecular divergence estimates date the origin of pygmy right whales to 22–26 Ma, yet so far there are only three confirmed fossil occurrences. Here, we describe an isolated periotic from the latest Miocene of Victoria (Australia). The new fossil shows all the hallmarks of Caperea, making it the second-oldest described neobalaenine, and the oldest record of the genus. Overall, the new specimen resembles C. marginata in its external morphology and details of the cochlea, but is more archaic in it having a hypertrophied suprameatal area and a greater number of cochlear turns. The presence of Caperea in Australian waters during the Late Miocene matches the distribution of the living species, and supports a southern origin for pygmy right whales. Matsui, K., Y. Kimura, M. Nagata et al. 2018. A long-forgotten ‘dinosaur’ bone from a museum cabinet, uncovered to be a Japan’s iconic extinct mammal, Paleoparadoxia (Desmostylia, Mammalia). Royal Society Open Science 5:e172441. https://royalsocietypublishing.org/doi/full/10.1098/rsos.172441 Here, we report a new ‘discovery’ of a desmostylian fossil in the geological collection at a national university in Japan. This fossil was unearthed over 60 years ago and donated to the university. Owing to the original hand-written note kept with the fossil in combination with interview investigation, we were able to reach two equally possible fossil sites in the town of Tsuchiyu Onsen, Fukushima. Through the interviews, we learned that the fossil was discovered during construction of a debris flow barrier and that it was recognized as a ‘dinosaur’ bone among the locals and displayed in the Village Hall before/until the town experienced a fire disaster in 1954. As scientific findings, the fossil was identified to be a right femur of Paleoparadoxia (Desmostylia), which shows well-preserved muscle scars on the surface. The age was estimated to be 15.9 Ma or younger in zircon-dating. This study shows an excellent case that historical and scientific significances could be extracted from long-forgotten uncatalogued specimens as long as the original information is retained with the specimens. McCurry, M.R. and N.D. Pyenson. 2018. Hyperlongirostry and kinematic disparity in extinct toothed whales. Paleobiology. Online early. https://www.cambridge.org/core/journals/paleobiology/article/hyperlongirostry-and-kinematic-disparity-in-extinct-toothed-whales/5B68F5FAD697EB11FDE6298106509722 Toothed cetacean (Odontoceti) lineages in the Miocene and Pliocene evolved rostra that are proportionally more elongate than any other aquatic mammal or reptile, living or extinct. Their similarities in cranial proportions to billfish may suggest a convergent feeding style, where the rostrum is swept through the water to hit and stun prey. Here we calculated second moment of area from rostral cross sections of these fossil odontocete taxa, as well as from extant ecological analogues, to infer variation in feeding behavior. Our results show that the extremely long rostra of extinct toothed whales vary considerably in functionally relevant measures of shape and likely exhibited a diversity of feeding behaviors, ranging from those similar to modern odontocetes to those convergent with billfish. Eustatic sea-level and temperature maxima of the Miocene likely led to changes in prey characteristics or abundance that enabled the repeated evolution of this extreme morphotype, which later went extinct during late Pliocene climatic deterioration. Nelson, M.D. and M.D. Uhen. 2018. First occurrence of a squalodelphinid (Cetacea, Odontoceti) from the early Miocene of Washington state. Journal of Vertebrate Paleontology 38:e1428197. https://www.tandfonline.com/doi/abs/10.1080/02724634.2017.1428197?journalCode=ujvp20 Here, we present a new indeterminate squalodelphinid from the early Miocene of Washington State. The Oligocene and Miocene formations of Washington State possess a rich, yet underreported record of fossil cetaceans. Specimen UWBM 87105 is the posterior third of the skull, with portions of the premaxillae, maxillae, nasals, frontals, lacrimals, and palatine. No associated periotic or ectotympanic bone has been preserved. In addition, undiagnostic rib fragments and vertebrae are present. This specimen represents a small odontocete that is characterized by a dramatically thickened supraorbital process. This feature is a synapomorphy of the taxon Squalodelphinidae C Platanistidae (Muizon, 1987). In the Platanistidae, such as in Platanista, this supraorbital process is so exaggerated as to be a supraorbital crest, whereas in the Squalodelphinidae the thickening is not so extreme. Due to the relatively minor thickening of the supraorbital process in UWBM 87105, we place it within the Squalodelphinidae. The Squalodelphinidae are also known for having mildly asymmetrical skulls (Muizon, 1987), although this is not considered a synapomorphy because such asymmetry is common within Odontoceti. Specimen UWBM 87105 is valuable in that it extends the known geographic range of the Squalodelphinidae and offers insight into the diversity of the Platanistoidea during the early Miocene. Peredo, C.M., N.D. Pyenson, C.D. Marshall, and M.D. Uhen. 2018. Tooth loss precedes the origin of baleen in whales. Current Biology 28:1-9. https://www.sciencedirect.com/science/article/pii/S0960982218314143 Whales use baleen, a novel integumentary structure, to filter feed; filter feeding itself evolved at least five times in tetrapod history but demonstrably only once in mammals [1]. Living baleen whales (mysticetes) are born without teeth, but paleontological and embryological evidence demonstrate that they evolved from toothed ancestors that lacked baleen entirely [2]. The mechanisms driving the origin of filter feeding in tetrapods remain obscure. Here we report Maiabalaena nesbittae gen. et sp. nov., a new fossil whale from early Oligocene rocks of Washington State, USA, lacking evidence of both teeth and baleen. The holotype possesses a nearly complete skull with ear bones, both mandibles, and associated postcrania. Phylogenetic analysis shows Maiabalaena as crownward of all toothed mysticetes, demonstrating that tooth loss preceded the evolution of baleen. The functional transition from teeth to baleen in mysticetes has remained enigmatic because baleen decays rapidly and leaves osteological correlates with unclear homology; the oldest direct evidence for fossil baleen is ∼25 million years younger [3] than the oldest stem mysticetes (∼36 Ma). Previous hypotheses for the origin of baleen [4, 5] are inconsistent with the morphology and phylogenetic position of Maiabalaena. The absence of both teeth and baleen in Maiabalaena is consistent with recent evidence that the evolutionary loss of teeth and origin of baleen are decoupled evolutionary transformations, each with a separate morphological and genetic basis [2, 6]. Understanding these macroevolutionary patterns in baleen whales is akin to other macroevolutionary transformations in tetrapods such as scales to feathers in birds. Peredo, C.M., J.S. Peredo, and N.D. Pyenson. 2018. Convergence on dental simplification in the evolution of whales. Paleobiology 44:434-443. https://www.cambridge.org/core/journals/paleobiology/article/convergence-on-dental-simplification-in-the-evolution-of-whales/29E0C07483DCB9108D18F96BE57A474B The fossil record of mammal dentition provides crucial insight into key ecological and functional transitions throughout mammalian evolutionary history. For cetaceans, both extant clades differ markedly from their stem ancestors; neither retains the differentiated dentition or the tribosphenic molars characteristic of Mammalia. We used quantitative measures of dental complexity across fossil and living cetaceans to identify a trend toward dental simplicity through the Neogene. Both extant cetacean clades depart from the ancestral mammalian condition and concurrently converge upon a reduced and simplified dentition; modern mysticetes all have become entirely edentulous (at birth), and living odontocetes possess teeth as single-rooted, conical pegs. These two parallel trends accompany major shifts in feeding strategy (i.e., filter feeding in mysticetes and echolocation in odontocetes), suggesting that these evolutionary innovations for prey acquisition are enabling factors for the loss of prey processing and subsequent convergence on dental simplification. Peredo, C.M. and N.D. Pyenson. 2018. Salishicetus meadi, a new aetiocetid from the late Oligocene of Washington state and implications for feeding transitions in early mysticete evolution. https://royalsocietypublishing.org/doi/10.1098/rsos.172336 Living baleen whales, or Mysticeti, lack teeth and instead feed using keratinous baleen plates to sieve prey-laden water. This feeding strategy is profoundly different from that of their toothed ancestors, which processed prey using the differentiated dentition characteristic of mammals. The fossil record of mysticetes reveals stem members that include extinct taxa with dentition, illuminating the morphological states that preceded the loss of teeth and the subsequent origin of baleen. The relationships among stem mysticetes, including putative clades such as Mammalodontidae and Aetiocetidae, remain debatable. Aetiocetids are among the more species-rich clade of stem mysticetes, and known only from fossil localities along the North Pacific coastline. Here, we report a new aetiocetid, Salishicetus meadi gen. et sp. nov, from the late Oligocene of Washington State, USA. Salishicetus preserves a near-complete lower dentition with extensive occlusal wear, indicating that it processed prey using shearing cheek teeth in the same way as its stem cetacean ancestors. Using a matrix with all known species of aetiocetids, we recover a monophyletic Aetiocetidae, crownward of a basal clade of Mammalodontidae. The description of Salishicetus resolves phylogenetic relationships among aetiocetids, which provides a basis for reconstructing ancestral feeding morphology along the stem leading to crown Mysticeti. Peredo, C.M., M.D. Uhen, and M.D. Nelson. 2018. A new kentriodontid (Cetacea: Odontoceti) from the early Miocene Astoria Formation and a revision of the stem delphinidin family Kentriodontidae. Journal of Vertebrate Paleontology 38:e1411357. https://www.tandfonline.com/doi/full/10.1080/02724634.2017.1411357 The Family Kentriodontidae is a diverse and abundant group of odontocetes from the late Oligocene and Miocene around the globe. Despite nearly a century of research on the group, the relationships across the family have remained poorly understood. Several recent studies have suggested that the family is polyphyletic and in need of major taxonomic revision. A new fossil stem delphinidan from the early Miocene of Washington State is described as Wimahl chinookensis, gen. et sp. nov., and is assigned to a revised Kentriodontidae. Wimahl chinookensis represents one of the oldest kentriodontids and is the northernmost kentriodontid described from the Pacific Ocean, extending their range in the eastern Pacific from central California up to Washington State. Its phylogenetic position relative to other stem delphinidans suggests that it is sister to Kampholophos serrulus from the middle Miocene Monterey Formation of California. Additional phylogenetic results guide the revision of stem delphinidans and new diagnosis and delimitation of the Family Kentriodontidae Rahmat, S., F. Muniz, A. Toscano, et al. 2018. First European record of Homiphoca (Phocidae: Monachinae: Lobodontini) and its bearing on the paleobiogeography of the genus. Historical Biology. Online Early. https://www.tandfonline.com/doi/full/10.1080/08912963.2018.1507030 Marine mammal fossils (except pinnipeds) have commonly been found in Pliocene marine siliciclastic layers of the Neogene Guadalquivir Basin in Southwest Spain. A few Neogene phocid innominate bones are known from the Western Paratethys and Western Atlantic. Here we describe a new innominate bone from the early Pliocene (5.3–3.6 Ma) of the Western Paratethys (Spain), which is typical of the subfamily Monachinae, and has a flattened ilium similar to representatives of the tribe Lobodontini, particularly Leptonychotes weddellii. Comparison with other fossil monachine innominates from North America, South America and South Africa reveals that this specimen represents the genus Homiphoca, but species classification remains premature. This is the first European record of the genus Homiphoca and has paleobiogeographic implications, questioning the geological age of the Varswater Formation ‘E’ Quarry, Langebaanweg, Cape Province of South Africa. This discovery from the eastern North Atlantic further implies a more regular transatlantic gene flow in Miocene and Pliocene times than today. We argue that during the Messinian-Zanclean crisis, monachines became isolated and retreated southward to lower latitudes, possibly due to climatic deterioration (during glacial stages) and competition from the cold-adapted phocines from the north. Ramasammy, B., O. Lambert, A. Collareta, et al. 2018. Description of the skeleton of the fossil beaked whale Messapicetus gregarius: searching potential proxies for deep-diving abilities. Fossil Record 21:11-32. https://www.foss-rec.net/21/11/2018/ Ziphiidae (beaked whales) are a successful family of medium- to large-sized toothed whales. Their extant members perform regular deep dives beyond the photic zone to forage for cephalopods and fish. Conversely, extinct long-snouted stem ziphiids are interpreted as epipelagic predators. However, some aspects of this hypothesis remain unclear due to the lack of clear morphological proxies for recognizing regular deep divers. We compared the forelimb, neck, and pterygoid sinus system of the fossil ziphiid Messapicetus gregarius with those of other odontocetes to evaluate the potential of these body regions as proxies to assess deep-diving specialization. The reconstructed musculature of the neck and forelimb of M. gregarius was also compared with that of other odontocetes. We also quantified variation in the proportions of the forelimb and the hamular fossa of the pterygoid sinus (HF) using 16 linear measurements. The degree of association between diving behaviour in extant odontocetes and these measurements was evaluated with and without phylogenetic correction. Reconstruction of the neck musculature suggests that M. gregarius possessed a neck more flexible than most extant ziphiids due to the lower degree of fusion of the cervical vertebrae and the large insertions for the M. longus colli and Mm. intertransversarii ventrales cervicis. While neck rigidity might be related to deep diving, differences in neck flexibility among extant ziphiids indicate a more complex functional interpretation. The relationship between forelimb morphology and diving behaviour was not significant, both with and without phylogenetic correction, suggesting that it cannot be used to assess deep-diving abilities with the parameters considered here. Measurements of the HF revealed successful to evaluate deep-diving abilities in odontocetes, with an enlargement of this structure in deep divers. Considering other evidence that suggests an epipelagic behaviour, we propose different scenarios to explain the observation of an enlarged HF in M. gregarius: (1) this species may have fed at different depths; (2) it performed deep dives to avoid potential predators; or (3) the enlarged HF and deep-diving habitat correspond to an ancestral condition, with M. gregarius returning to a more epipelagic habitat. Ritsche, I.S., J.M. Fahlke, F. Wieder, et al. 2018. Relationships of cochlear coiling shape and hearing frequencies in cetaceans, and the occurrence of infrasonic hearing in Miocene Mysticeti. Fossil Record 21:33-45. https://www.foss-rec.net/21/33/2018/ Baleen whales (Mysticeti) are known to use low frequencies (LF; 200Hz and below) and infrasound (<20hz able="" are="" communication.="" dontoceti="" for="" hearing="" limits="" lowest="" of="" produce="" the="" to="" toothed="" ultrasound="" whales="" which="">20kHz), reach low frequencies. Researchers have tried to understand the evolution of LF and infrasonic hearing in mysticetes by linking the shape of the inner ear cochlea or individual cochlear measurements to known hearing frequencies and making inferences to extinct species. Using landmark-based shape analysis of complete cochlear coiling, we show that cochlear coiling shape correlates with LF and high-frequency (HF; >10kHz) hearing limits in cetaceans. Very LF ( ≤ 50Hz) and infrasonic hearing are associated with, for example, a protruding second turn, a descending apex, and a high number of turns. Correlations between cochlear and cranial variables and cochlear and cranial shape indicate that low LF hearing limits are furthermore connected to longer cochleae and relatively larger cranial widths. Very LF hearing in Mysticeti appeared in the middle Miocene, and mysticete infrasonic hearing had evolved by the late Miocene. Complete cochlear coiling is suitable for estimating hearing limits in cetaceans, closely approximated by cochlear length times number of cochlear turns. Solis-Anorve, A., G. Gonzalez-Barba, and R. Hernandez-Rivera. Description of a new toothed mysticete from the late Oligocene of San Juan de la Costa, B.C.S., Mexico. Journal of South American Earth Sciences 89:337-346. https://www.sciencedirect.com/science/article/pii/S0895981118303882 This paper describes a toothed mysticete that belongs to a basal family found in Oligocene sedimentary rocks deposited in the North Pacific Ocean. The material that is described here belongs in the Chattian stage of the Oligocene, and it was collected near Arroyo El Saladito from the San Juan Member in the El Cien Formation, Baja California Sur, México. The sedimentary environment of this area has been interpreted to be a continental platform with nutrient-rich waters combined with anoxic conditions. Therefore, the specimens that have been found in the phosphorite layers lived in an environment of shallow coastal waters. The material described is a dentary fragment, a skull and fragments of the teeth. The new taxon is located within the Superfamily Aetiocetoidea due to the presence of functional teeth, which have a slightly globose shape with eight slightly triangular apices. Niparajacetus palmadentis presents a morphology that contrasts with other toothed whales. For example, it shows an elongated and wide skull in the posterior region with a triangular shape, and its estimated total length is 3.2–3.5 m. Tanaka, Y. M. and Watanabe. 2018. Geologically old and ontogenetically young Herpetocetus sp. from the late Miocene of Japan. Journal of Vertebrate Paleontology. Online Early. https://www.tandfonline.com/doi/full/10.1080/02724634.2018.1478842 An ontogenetically young fossil baleen whale from the lower part of the Horokaoshirarika Formation of Hokkaido, Japan, includes a partial skull, periotics, bullae, mandible, vertebrae, and a scapula. It is identified as Herpetocetus sp. because it exhibits a postglenoid process of the squamosal more transversely compressed than in Nannocetus, a deep and anteroposteriorly long fossa on the dorsal surface of the squamosal between the zygomatic process and the lateral wall of the brain case, and a prominent squamosal flange of the periotic. The Hokkaido specimen differs from currently described Herpetocetus species in having a large hiatus fallopii, and an angle at the anteromedial edge of the pars cochlearis, just medial to the hiatus fallopii. Because the lower part of the Horokaoshirarika Formation is late Miocene in age (approximately 7.7 to 6.8 Ma), the Hokkaido Herpetocetus specimen is the only record of Miocene Herpetocetinae from the western Pacific. Previously, Miocene Herpetocetinae were reported from the eastern North Pacific and western Atlantic. Accordingly, this new record of Herpetocetus from the upper Miocene of the western North Pacific suggests an earlier origin for both the genus and the subfamily. Tanaka, Y., H. Furusawa, and L.G. Barnes. 2018. Fossil herpetocetine baleen whales (Cetacea, Mysticeti, Cetotheriidae) from the lower Pliocene Horokaoshirarika Formation at Numata, Hokkaido, Northern Japan. Paleontological Research 22:295-306. www.bioone.org/doi/full/10.2517/2017PR025 Two mandibles of fossil mysticetes from the early Pliocene, upper part of the Horokaoshirarika Formation at Numata Town, Hokkaido, Japan, belong to the archaic, extinct cetotheriid baleen whale, Herpetocetinae gen. et sp. indet. by having an elongated angular process projecting posteriorly beyond the mandibular condyle. The new materials of the Herpetocetinae represent their northernmost occurrence in the North Pacific. Tanaka, Y., T. Ando, and H. Sawamura. 2018. A new species of middle Miocene baleen whale from the Nupinai Group, Hikatagawa Formation of Hokkaido, Japan. PeerJ 6:e4934 https://peerj.com/articles/4934/ A fossil whale from the Hikatagawa Formation (Middle Miocene, 15.2–11.5 Ma) of Hokkaido, Japan is described as a new genus and species Taikicetus inouei and its phylogenetic position is examined. Consistent with the result of Marx, Lambert & de Muizon (2017), the Cetotheriidae form a clade with the Balaenopteroidea, and “a clade comprising Isanacetus, Parietobalaena and related taxa” is located basal to the Balaenopteroidea + Cetotheriidae clade. Taikicetus inouei is placed in the clade with most of members of “Cetotheres” sensu lato comprising Isanacetus, Parietobalaena and related taxa. Taikicetus inouei can be distinguished from the other members of “Cetotheres” sensu lato in having an anteriorly swollen short zygomatic process, high triangular coronoid process, and angular process, which does not reach as far posterior as the mandibular condyle. Taikicetus inouei is only record of “Cetotheres” sensu lato from Hokkaido, Japan and the northern-most records of “Cetotheres” sensu lato in Japan. Tonomori, W., H. Sawamura, T. Sato, and N. Kohno. 2018. A new Miocene pinniped Allodesmus (Mammalia: Carnivora) from Hokkaido, northern Japan. Royal Society Open Science 5:172440. https://royalsocietypublishing.org/doi/full/10.1098/rsos.172440 A nearly complete pinniped skeleton from the middle Miocene Okoppezawa Formation (ca 16.3–13.9 Ma), Hokkaido, northern Japan, is described as the holotype of Allodesmus uraiporensis sp. nov. The new species is distinguishable from other species of the genus by having the palatine fissure (incisive foramen) that is located anterior to the canine, an anteriorly located supraorbital process of the frontal, and by having the calcaneum with a developed peroneal tubercle. Our phylogenetic analysis suggests that the subfamily Allodesminae are represented by two genera, Atopotarus and Allodesmus, and the latter genus is represented by at least six species; Al. kernensis, Al. sinanoensis, Al. naorai, Al. packardi, Al. demerei and Al. uraiporensis sp. nov. Allodesmus uraiporensis sp. nov. is one of the oldest and the northernmost record of the genus in the western North Pacific, and it suggests that the diversification of the genus in the western North Pacific was synchronous to the time of their diversification in the eastern North Pacific. Tsai, C.H. and R.E. Fordyce. 2018. A new archaic baleen whale Toihapautea waitaiki (early Late Oligocene, New Zealand) and the origins of crown Mysticeti. Royal Society Open Science 5:172453. https://royalsocietypublishing.org/doi/full/10.1098/rsos.172453 A new genus and species of extinct baleen whale †Toipahautea waitaki (Late Oligocene, New Zealand) is based on a skull and associated bones, from the lower Kokoamu Greensand, about 27.5 Ma (local upper Whaingaroan Stage, early Chattian). The upper jaw includes a thin, elongate and apparently toothless maxilla, with evidence of arterial supply for baleen. Open sutures with the premaxilla suggest a flexible (kinetic) upper jaw. The blowhole is well forward. The mandible is bowed laterally and slightly dorsally; unlike the Eomysticetidae, there are no mandibular alveoli, and the coronoid process is tapered and curved laterally. Jaw structure is consistent with baleen-assisted gulp-feeding. The age of early Chattian makes †Toipahautea a very early, if not the oldest named, toothless and baleen-bearing mysticete, suggesting that the full transition from toothed to baleen-bearing probably occurred in the Early Oligocene. Late Oligocene mysticetes vary considerably in jaw form and kinesis, tooth form and function, and development of baleen, implying a wide range of raptorial, suctorial and filter-feeding behaviour. More study may elucidate the function of jaws, teeth and baleen in terms of opportunist/generalist feeding, as in modern gray whales, versus specialized feeding. We here propose that early mysticetes, when transitioned from toothed to baleen-bearing, were generalists and opportunists instead of specializing in any forms of feeding strategies. In addition, two different phylogenetic analyses placed †Toipahautea either in a polytomy including crown Mysticeti, or immediately basal to the crown, and above †Eomysticetidae in both cases. Because the †Toipahautea waitaki holotype is an immature individual, it may plot more basally in phylogeny than its true position. Velez-Juarbe, J. 2018. New data on the early odobenid Neotherium Kellogg, 1931, and other pinniped remains from the Sharktooth Hill Bonebed, California. Journal of Vertebrate Paleontology. Online Early. https://www.tandfonline.com/doi/abs/10.1080/02724634.2018.1481080?journalCode=ujvp20 Deposited over a short period of time during the Middle Miocene Climatic Optimum, the Sharktooth Hill Bonebed in California is one of the world’s densest marine vertebrate concentrations. Pinnipeds are represented here by odobenids and desmatophocids, but some are still poorly known. Herein, the mandibular morphology of the odobenid Neotherium mirum is described in detail. Its morphology resembles that of early pinnipedimorphs, with postcanine teeth consisting of three or four longitudinally aligned cusps and double-rooted p2–m1, but shows derived characteristics such as reduced metaconid and bilobed canine root. Additionally, Neotherium is represented by two distinct size classes, which is likely the earliest evidence of sexually dimorphic body size in odobenids. Two additional mandibles represent other pinnipeds. One represents an unknown odobenid, with a unique suite of morphological characteristics setting it apart from contemporaneous odobenids such as Neotherium and Pelagiarctos. The other reconfirms the presence of Allodesmus cf. A. sadoensis, a species otherwise known from the middle Miocene of Japan. This species is distinguished from Allodesmus kernensis, based on anteriorly crowded and reduced postcanine dentition. This record adds further support for the presence of this taxon in the middle Miocene of California and represents the earliest evidence of trans-Pacific dispersal in pinnipeds. The Sharktooth Hill pinniped assemblage now consists of five species: the odobenids Neotherium mirum, Pelagiarctos thomasi, an unknown odobenid, and the desmatophocids Allodesmus kernensis and Allodesmus cf. A. sadoensis. Niche partitioning within this sympatric pinniped community was possible due to differences in body size, and feeding and foraging preferences. Velez-Juarbe, J. and F.M. Salinas-Marquez. 2018. A dwarf walrus from the Miocene of Baja California Sur, Mexico. Royal Society Open Science 5:180423. https://royalsocietypublishing.org/doi/full/10.1098/rsos.180423 Here, we describe the odobenid Nanodobenus arandai gen. et sp. nov., based on a nearly complete left mandible from the mid to late Miocene Tortugas Formation in Baja California Sur. Nanodobenus is distinguished among odobenids by displaying a unique combination of plesiomorphic and derived characters, such as narrow mandibular symphysis, well-developed genial tuberosity, bilobed canine and p2 roots, bulbous post-canine teeth with the paraconid, protoconid and hypoconid, and smooth lingual cingula. Moreover, it is characterized by its small adult body length, which is estimated at about 1.65 m. Throughout the Miocene–Pliocene odobenids are characterized by an increase in body size, especially after the extinction of desmatophocids in the late Miocene. The small size of Nanodobenus departs from this trend, demonstrating that there was greater size disparity among odobenids in the mid–late Miocene than previously thought. It is hypothesized that Nanodobenus occupied a niche that was later on occupied by similar-sized otariids, such as Thalassoleon mexicanus, which occurs sympatrically with large odobenids in the overlying Almejas Formation. Viglino, M., M.R. Buono, R.E. Fordyce, et al. 2018. Anatomy and phylogeny of the large shark-toothed dolphin Phoberodon arctirostris Cabrera, 1926 (Cetacea: Odontoceti) from the early Miocene of Patagonia (Argentina). Zoological Journal of the Linnean Society. Online early. https://academic.oup.com/zoolinnean/advance-article-abstract/doi/10.1093/zoolinnean/zly053/5086400?redirectedFrom=fulltext The early Miocene of Patagonia (Argentina) provides one of the best-known records of odontocetes for an age interval with scarce fossils. Most of these taxa are historically old and briefly described, which has contributed, in part, to their controversial taxonomic position. The shark-toothed dolphin Phoberodon arctirostris was described almost 100 years ago and suggested as a member of Platanistoidea and Squalodontidae. However, it has not been analysed recently and has never been included in a phylogenetic analysis. Recent fieldwork in the early Miocene sediments in Patagonia yielded a new specimen referred to this species, allowing for its modern and detailed description and the first phylogenetic analyses. Analyses recovered P. arctirostris as a stem Odontoceti or an early-diverging platanistoid, more closely related to an unnamed Oligocene specimen from New Zealand and not in a clade with Squalodon calvertensis (i.e. Squalodontidae). The reconstructed body length of P. arctirostris indicates that it is one of the largest stem Odontoceti. Our results suggest that during the early Miocene of Patagonia, archaic odontocete forms (i.e. P. arctirostris) cohabited with archaic and more crownward platanistoids (i.e. Aondelphis talen and Notocetus vanbenedeni), helping to characterize the early Miocene cetacean communities of Patagonia. Viglino, M., M.R. Buono, C.S. Gutstein, et al. 2018. A new dolphin from the early Miocene of Patagonia, Argentina: insights into the evolution of Platanistoidea in the southern hemisphere. Acta Palaeontologica Polonica 63:261-277. https://www.app.pan.pl/article/item/app004412017.html The contents of the superfamily Platanistoidea, an early-diverging lineage comprising extinct species and a single extant representative of South Asian river dolphin (Platanista gangetica), remain controversial. We describe here a partial skull and associated tympano-periotic bones identified as a new genus and species, Aondelphis talen gen. et sp. nov., collected in the lower levels of the Gaiman Formation (early Miocene), in Patagonia (Chubut Province, Argentina). Aondelphis is the first Patagonian platanistoid species named in almost a century. Phylogenetic analyses suggest Aondelphis talen gen. et sp. nov. and a taxon from New Zealand (cf. Papahu ZMT-73) are basal Platanistoidea sensu lato. Unambiguous synapomorphies related to the ear bones allowed us to determine its phylogenetic position. Aondelphis talen markedly differs from the other well-known early Miocene Patagonian platanistoid Notocetus, suggesting the coexistence of at least two different morphotypes that may have occupied different ecological niches at that time. The putative close relationship with a species from New Zealand indicates there was a rapid diversification and widespread distribution of the group in the Southern Hemisphere during the early Miocene. The description of new species and revision of historical records of Patagonian platanistoids can help shedding light on cetacean assemblages of the Patagonian sea during this epoch.
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