DOCSLIB.ORG

Mauicetus’ Lophocephalus

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Mauicetus’ Lophocephalus 1 This is a postprint that has been peer reviewed and published in Zoological Journal of 2 the Linnean Society. The final, published version of this article is available online. 3 Please check the final publication record for the latest revisions to this article. 4 [Author's note: one figure, the only known tooth of an eomysticetid, is not present in 5 this postprint because it was added during final revisions. Consult the formally 6 published version of record.] 7 8 Boessenecker, R.W., and R.E. Fordyce. 2015. A new genus and species of 9 eomysticetid (Cetacea: Mysticeti) and a reinterpretation of ‘Mauicetus’ lophocephalus 10 Marples, 1956: transitional baleen whales from the upper Oligocene of New Zealand. 11 Zoological Journal of the Linnean Society 175:607-660. doi: 10.1111/zoj.12297 12 1 1 ABSTRACT 2 The early evolution of toothless baleen whales (Chaeomysticeti) remains elusive 3 despite a robust record of Eocene-Oligocene archaeocetes and toothed mysticetes. 4 Eomysticetids, a group of archaic longirostrine and putatively toothless baleen whales 5 fill in a crucial morphological gap between well-known toothed mysticetes and more 6 crownward Neogene Mysticeti. A historically important but perplexing cetacean is 7 “Mauicetus” lophocephalus (upper Oligocene South Island, New Zealand). The 8 discovery of new skulls and skeletons of eomysticetids from the Oligocene Kokoamu 9 Greensand and Otekaike Limestone permit a redescription and modern 10 reinterpretation of “Mauicetus” lophocephalus, and indicating that this species may 11 have retained adult teeth. A new genus and species, Tokarahia kauaeroa, is erected on 12 the basis of a well-preserved subadult to adult skull with mandibles, tympanoperiotics, 13 and cervical and thoracic vertebrae, ribs, sternum, and forelimbs from the Otekaike 14 Limestone (>25.2 Ma). “Mauicetus” lophocephalus is relatively similar and 15 recombined as Tokarahia lophocephalus. Phylogenetic analysis supports inclusion of 16 Tokarahia within the Eomysticetidae alongside Eomysticetus, Micromysticetus, 17 Yamatocetus, and Tohoraata, and strongly supports monophyly of Eomysticetidae. 18 Tokarahia lacked extreme rostral kinesis of extant Mysticeti and primitively retained 19 a delicate archaeocete-like posterior mandible and synovial temporomandibular joint, 20 suggesting that Tokarahia was capable of at most, limited lunge feeding in contrast to 21 extant Balaenopteridae, and utilized an alternative as-yet unspecified feeding strategy. 22 Baleen whales-Oligocene-Cetacea-Mysticeti-Eomysticetidae 23 24 INTRODUCTION 2 1 Sometime before 1937 an unassuming fragmentary skull was collected from a 2 limestone quarry near Milton in south Otago, South Island, New Zealand. It was 3 formally described by University of Otago zoology Professor W.B. Benham (1937) as 4 Lophocephalus parki, and thought to be a new archaeocete; it is now known to have 5 been collected from the latest Oligocene-earliest Miocene Milburn Limestone (Willett, 6 1946; Waitakian Stage, 25.2-21.7 Ma, Raine et al., 2012). Subsequent correspondence 7 led Benham to realize that the genus name was preoccupied and that Lophocephalus 8 parki was in fact an archaic baleen whale, which he later renamed Mauicetus parki 9 (Benham, 1942). Additional mysticetes collected by Brian J. Marples from North 10 Otago from the somewhat older Kokoamu Greensand (Duntroonian stage). In 1956 he 11 named these Mauicetus lophocephalus (based on a partial braincase, mandible, 12 tympanic bullae, and cervical and thoracic vertebrae), Mauicetus waitakiensis (based 13 on an occipital, tympanic bullae, and cervical vertebrae) and Mauicetus brevicollis 14 (based on a partial vertebral column and scapula). Recently collected material of 15 Mauicetus parki demonstrates that it is Although a reasonable referral at the time 16 owing to the incomplete knowledge of these Oligo-Miocene mysticetes, new 17 discoveries of fossil mysticetes from the South Island of New Zealand and other 18 continents in the past thirty years indicates that at least two of the species of 19 Mauicetus described by Marples (1956) represent fossil mysticetes dramatically 20 different from anything else known to twentieth century paleocetologists, and are not 21 closely related to Mauicetus parki (Fordyce, 2005; 2006; Boessenecker and Fordyce, 22 2014a). 23 In 2002, the strange new longirostrine toothless mysticete Eomysticetus 24 whitmorei was described from the upper Oligocene of South Carolina, U.S.A. 25 (Sanders and Barnes 2002b). Eomysticetus is characterized by a toothless palate, 3 1 kinetic rostrum, delicate frontals, a poorly “telescoped” skull, enormous temporal 2 fossae, elongate and cylindrical zygomatic processes, and basilosaurid-like 3 tympanoperiotics and postcrania (Sanders and Barnes 2002b). While these authors 4 recognized that Mauicetus lophocephalus was another archaic chaeomysticete and 5 similar in some regards to Eomysticetus, albeit not as archaic, they considered it to not 6 be “[included] within the clade containing Eomysticetus whitmorei and [Yamatocetus 7 canaliculatus]”. Their assertion that “Mauicetus” lophocephalus is not an 8 eomysticetid was not tested by cladistic analysis. Regardless, several features are 9 shared between “Mauicetus” lophocephalus and Eomysticetus, including enormous 10 temporal fossae, transversely narrow intertemporal region with a high sagittal crest, 11 elongate and subcylindrical zygomatic processes, all unique features amongst 12 Chaeomysticeti (although primitively present as well in Basilosauridae and certain 13 toothed mysticetes). In recognition of these similarities with Eomysticetus and 14 concomitant differences from Mauicetus parki, the fragmentary “Mauicetus” 15 waitakiensis was transferred to the newly described eomysticetid genus Tohoraata 16 (Boessenecker and Fordyce, 2014a). Unfortunately, the holotype skull and scapulae of 17 “Mauicetus” lophocephalus are missing (Fordyce, 1980:20), likely discarded by 18 university maintenance staff not long before 1962 (J.T. Darby, personal 19 communication to R.E. Fordyce, May 1978). However, the tympanoperiotics, 20 mandible, and much of the postcrania remain, permitting limited reassessment of this 21 critical but poorly understood fossil mysticete. 22 Newly discovered fossil material from the upper Oligocene Otekaike 23 Limestone of New Zealand (Fig. 1, 2) including a spectacularly preserved and nearly 24 complete skull with mandibles, tympanoperiotics, and partial postcranial skeleton 25 (cervical and thoracic vertebrae, ribs, sternum, scapulae, humeri, radius, ulnae) share 4 1 near identical tympanoperiotic morphology with “Mauicetus” lophocephalus, and 2 critically share similar skull morphology with published eomysticetids and 3 “Mauicetus” lophocephalus. The skull and skeleton of this new fossil mysticete is 4 remarkable in its transitional morphology between toothed Mysticeti and Neogene 5 crown Mysticeti (=Balaenomorpha), serving as an exemplar for comparison between 6 the two. Another partial skull and skeleton is tentatively referred to “Mauicetus” 7 lophocephalus, and notably includes an isolated tooth differing in morphology from 8 all other cetaceans and indicates that eomysticetids may have primitively retained 9 non-functional adult teeth (out of convention, “toothed mysticete” hereafter refers to 10 stem Mysticetes not including eomysticetids). The aim of this study is to report the 11 new morphological details preserved in this new genus and species of archaic 12 mysticete and other similar specimens (Fig. 3), provide a new description through 13 which “Mauicetus” lophocephalus may be reinterpreted in light of recent advances in 14 paleocetology, and establish a phylogenetic context for these distinctive fossil 15 cetaceans through cladistic analysis. 16 17 MATERIALS AND METHODS 18 Preparation, Anatomical Description, and Illustration: Fossil material in OU 19 collections was mechanically prepared with pneumatic air scribes. Fine preparation 20 was performed under a Zeiss binocular microscope. Anatomical terminology follows 21 Mead and Fordyce (2009), Oishi and Hasegawa (1995) and Ekdale et al. (2011). 22 Tympanoperiotic orientation follows Mead and Fordyce (2009) using anatomical 23 structures (e.g. anterior process, posterior process, lateral tuberosity) to dictate 24 orientation of tympanoperiotics when in isolation from the skull (in contrast to 25 orientation in situ) to facilitate comparisons between taxa. 5 1 Osteohistology: Histologic sections were taken from rib fragments of OU 22235 2 (Tokarahia kauaeroa holotype) and OU 22081 (Tokarahia sp., cf. T. lophocephalus). 3 Sections were embedded in epoxy and thin sections were prepared by University of 4 Otago Petrology Technician B. Pooley. Photomicrographs were captured under non- 5 polarized light. 6 Cladistic Methodology: A cladistic analysis was executed in order to assess the 7 phylogenetic relationships of Tokarahia spp. in addition to the previously described 8 Tohoraata raekohao. This analysis includes 74 terminal taxa (Archaeoceti, n=3; 9 Odontoceti, n=2, Mysticeti, n=69; 12 extant mysticetes and one extant odontocete) 10 and a total of 363 morphological characters including cranial (n=251; 104 characters 11 for the tympanoperiotic complex), mandibular (n=27), dental (n=15), postcranial 12 (n=46), and soft tissue characters (n=24). Character inclusion began with the matrix 13 of Marx (2011) and included 101 characters modified from Fitzgerald (2010), 142 14 characters modified from Fordyce and Marx (2013), and
Load more

Recommended publications
  • How to Cite Complete Issue More Information About This Article
    Boletín de la Sociedad Geológica Mexicana ISSN: 1405-3322 Sociedad Geológica Mexicana, A.C. Hernández Cisneros, Atzcalli Ehécatl; González Barba, Gerardo; Fordyce, Robert Ewan Oligocene cetaceans from Baja California Sur, Mexico Boletín de la Sociedad Geológica Mexicana, vol. 69, no. 1, January-April, 2017, pp. 149-173 Sociedad Geológica Mexicana, A.C. Available in: http://www.redalyc.org/articulo.oa?id=94350664007 How to cite Complete issue Scientific Information System Redalyc More information about this article Network of Scientific Journals from Latin America and the Caribbean, Spain and Portugal Journal's homepage in redalyc.org Project academic non-profit, developed under the open access initiative Boletín de la Sociedad Geológica Mexicana / 2017 / 149 Oligocene cetaceans from Baja California Sur, Mexico Atzcalli Ehécatl Hernández Cisneros, Gerardo González Barba, Robert Ewan Fordyce ABSTRACT Atzcalli Ehecatl Hernández Cisneros ABSTRACT RESUMEN [email protected] Museo de Historia Natural de la Universidad Autónoma de Baja California Sur, Univer- Baja California Sur has an import- Baja California Sur tiene un importante re- sidad Autónoma de Baja California Sur, ant Cenozoic marine fossil record gistro de fósiles marinos del Cenozoico que Carretera al Sur Km 5.5, Apartado Postal which includes diverse but poorly incluye los restos poco conocidos de cetáceos 19-B, C.P. 23080, La Paz, Baja California Sur, México. known Oligocene cetaceans from del Oligoceno de México. En este estudio Instituto Politécnico Nacional, Centro Inter- Mexico. Here we review the cetacean ofrecemos más detalles sobre estos fósiles de disciplinario de Ciencias Marinas (CICMAR), fossil record including new observa- cetáceos, incluyendo nuevas observaciones Av. Instituto Politécnico Nacional s/n, Col.
    [Show full text]
  • The Taxonomic and Evolutionary History of Fossil and Modern Balaenopteroid Mysticetes
    Journal of Mammalian Evolution, Vol. 12, Nos. 1/2, June 2005 (C 2005) DOI: 10.1007/s10914-005-6944-3 The Taxonomic and Evolutionary History of Fossil and Modern Balaenopteroid Mysticetes Thomas A. Demer´ e,´ 1,4 Annalisa Berta,2 and Michael R. McGowen2,3 Balaenopteroids (Balaenopteridae + Eschrichtiidae) are a diverse lineage of living mysticetes, with seven to ten species divided between three genera (Megaptera, Balaenoptera and Eschrichtius). Extant members of the Balaenopteridae (Balaenoptera and Megaptera) are characterized by their engulfment feeding behavior, which is associated with a number of unique cranial, mandibular, and soft anatomical characters. The Eschrichtiidae employ suction feeding, which is associated with arched rostra and short, coarse baleen. The recognition of these and other characters in fossil balaenopteroids, when viewed in a phylogenetic framework, provides a means for assessing the evolutionary history of this clade, including its origin and diversification. The earliest fossil balaenopterids include incomplete crania from the early late Miocene (7–10 Ma) of the North Pacific Ocean Basin. Our preliminary phylogenetic results indicate that the basal taxon, “Megaptera” miocaena should be reassigned to a new genus based on its possession of primitive and derived characters. The late late Miocene (5–7 Ma) balaenopterid record, except for Parabalaenoptera baulinensis and Balaenoptera siberi, is largely undescribed and consists of fossil specimens from the North and South Pacific and North Atlantic Ocean basins. The Pliocene record (2–5 Ma) is very diverse and consists of numerous named, but problematic, taxa from Italy and Belgium, as well as unnamed taxa from the North and South Pacific and eastern North Atlantic Ocean basins.
    [Show full text]
  • The Biology of Marine Mammals
    Romero, A. 2009. The Biology of Marine Mammals. The Biology of Marine Mammals Aldemaro Romero, Ph.D. Arkansas State University Jonesboro, AR 2009 2 INTRODUCTION Dear students, 3 Chapter 1 Introduction to Marine Mammals 1.1. Overture Humans have always been fascinated with marine mammals. These creatures have been the basis of mythical tales since Antiquity. For centuries naturalists classified them as fish. Today they are symbols of the environmental movement as well as the source of heated controversies: whether we are dealing with the clubbing pub seals in the Arctic or whaling by industrialized nations, marine mammals continue to be a hot issue in science, politics, economics, and ethics. But if we want to better understand these issues, we need to learn more about marine mammal biology. The problem is that, despite increased research efforts, only in the last two decades we have made significant progress in learning about these creatures. And yet, that knowledge is largely limited to a handful of species because they are either relatively easy to observe in nature or because they can be studied in captivity. Still, because of television documentaries, ‘coffee-table’ books, displays in many aquaria around the world, and a growing whale and dolphin watching industry, people believe that they have a certain familiarity with many species of marine mammals (for more on the relationship between humans and marine mammals such as whales, see Ellis 1991, Forestell 2002). As late as 2002, a new species of beaked whale was being reported (Delbout et al. 2002), in 2003 a new species of baleen whale was described (Wada et al.
    [Show full text]
  • This Is a Postprint That Has Been Peer Reviewed and Published in Naturwissenschaften. the Final, Published Version of This Artic
    This is a postprint that has been peer reviewed and published in Naturwissenschaften. The final, published version of this article is available online. Please check the final publication record for the latest revisions to this article. Boessenecker, R.W. 2013. Pleistocene survival of an archaic dwarf baleen whale (Mysticeti: Cetotheriidae). Naturwissenschaften 100:4:365-371. Pleistocene survival of an archaic dwarf baleen whale (Mysticeti: Cetotheriidae) Robert W. Boessenecker1,2 1Department of Geology, University of Otago, 360 Leith Walk, Dunedin, New Zealand 2 University of California Museum of Paleontology, University of California, Berkeley, California, U.S.A. *[email protected] Abstract Pliocene baleen whale assemblages are characterized by a mix of early records of extant mysticetes, extinct genera within modern families, and late surviving members of the extinct family Cetotheriidae. Although Pleistocene baleen whales are poorly known, thus far they include only fossils of extant genera, indicating late Pliocene extinctions of numerous mysticetes alongside other marine mammals. Here, a new fossil of the late Neogene cetotheriid mysticete Herpetocetus is reported from the Lower to Middle Pleistocene Falor Formation of Northern California. This find demonstrates that at least one archaic mysticete survived well into the Quaternary Period, indicating a recent loss of a unique niche and a more complex pattern of Plio-Pleistocene faunal overturn for marine mammals than has been previously acknowledged. This discovery also lends indirect support to the hypothesis that the pygmy right whale (Caperea marginata) is an extant cetotheriid, as it documents another cetotheriid nearly surviving to modern times. Keywords Cetacea; Mysticeti; Cetotheriidae; Pleistocene; California Introduction The four modern baleen whale (Cetacea: Mysticeti) families include fifteen gigantic filter-feeding species.
    [Show full text]
  • Filtration Area Scaling and Evolution in Mysticetes: Trophic Niche Partitioning and the Curious Cases of Sei and Pygmy Right Whales
    Biological Journal of the Linnean Society, 2018, XX, 1–16. With 7 figures. Filtration area scaling and evolution in mysticetes: trophic niche partitioning and the curious cases of sei and pygmy right whales ALEXANDER J. WERTH1* , JEAN POTVIN2, ROBERT E. SHADWICK3, MEGAN M. JENSEN4, DAVID E. CADE4 and JEREMY A. GOLDBOGEN4 1Department of Biology, Hampden-Sydney College, Hampden-Sydney, VA 23943, USA 2Department of Physics, Saint Louis University, St. Louis, MO 63103, USA 3Department of Zoology, University of British Columbia, Vancouver, B.C., Canada V6T 1Z4 4Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA Received 16 May 2018; revised 22 July 2018; accepted for publication 23 July 2018 applyparastyle "body/p[1]" parastyle "Text_First" We analysed the functional morphology and hydrodynamics of the filtering apparatus in ten species of baleen whales (Mysticeti). Our results demonstrate a clear demarcation in baleen scaling of continuous ram filter feeders (Balaenidae; right and bowhead whales) and intermittent lunge/suction feeders: rorquals (Balaenopteridae) and the grey whale (Eschrichtiidae). In addition to different scaling trajectories, filter area varies widely among taxa. Balaenid baleen has four to five times the area of that of similarly sized rorquals (by body length and mass). Filter areas correlate with morphology; lineages evidently evolved to exploit different types of patchy prey. Feeding perfor- mance data from hydrodynamic modelling and tagged whales suggest that drag forces limit balaenids, whereas time required to purge and filter engulfed water appears to limit rorquals. Because scaling of engulfment volume outpaces increases in baleen area, large rorquals must devote greater proportions of dive time to filtration.
    [Show full text]
  • How Modern Baleen Whales Arose from a Fossil “Dark Age”
    Editors' choice Like phoenix from the ashes: How modern baleen whales arose from a fossil “dark age” FELIX G. MARX, ERICH M.G. FITZGERALD, and R. EWAN FORDYCE Marx, F.G., Fitzgerald, E.M.G., and Fordyce, R.E. 2019. Like phoenix from the ashes: How modern baleen whales arose from a fossil “dark age”. Acta Palaeontologica Polonica 64 (2): 231–238. The evolution of baleen whales (Mysticeti), the largest animals on Earth, was punctuated by a pivotal turnover event. Following their emergence around 36 million years (Ma), mysticetes diversified into a disparate range of toothed and toothless species until 23 Ma, but then nearly vanished from the global fossil record for the next five million years. Following this early Miocene “dark age”, toothless mysticetes spectacularly reappeared around 18–17 Ma, whereas toothed mysticetes had gone entirely extinct. Here, we suggest that this turnover event reflects a change in mysticete habitat occupancy. Using the well-sampled record of Australasia as a case study, we show that Oligocene pre-“dark age” mysticetes formed distinct coastal and offshore assemblages, dominated by small (2–4 m), ecologically disparate toothed species, and larger (5–6 m) toothless filter feeders, respectively. Environmental change around the Oligocene–Miocene boundary led to the decline of the endemic coastal assemblages, leaving nearshore deposits virtually devoid of mys- ticetes. Filter feeders persisted offshore and subsequently re-invaded coastal habitats during the mid-Miocene Climatic Optimum, thus establishing the modern, cosmopolitan mysticete fauna. Key words: Mammalia, Mysticeti, evolution, Oligocene, Miocene, Zealandia, Australia. Felix G. Marx [[email protected]], Directorate Earth and History of Life, Royal Belgian Institute of Natural Sciences, Rue Vautier 29, Brussels 1000, Belgium; Department of Geology, University of Liège, Belgium; School of Biological Sciences, Monash University, Clayton, Vic., Australia; Museums Victoria, Melbourne, Vic., Australia.
    [Show full text]
  • A New Skull of an Early Diverging Rorqual (Balaenopteridae, Mysticeti, Cetacea) from the Late Miocene to Early Pliocene of Yamagata, Northeastern Japan
    Palaeontologia Electronica palaeo-electronica.org A new skull of an early diverging rorqual (Balaenopteridae, Mysticeti, Cetacea) from the late Miocene to early Pliocene of Yamagata, northeastern Japan Yoshihiro Tanaka, Kazuo Nagasawa, and Yojiro Taketani ABSTRACT The family of rorquals and humpback whales, Balaenopteridae includes the larg- est living animal on Earth, the blue whale Balaenoptera musculus. Many new taxa have been named, but not many from the western Pacific, except Miobalaenoptera numataensis from Japan. Here we describe an early balaenopterid, cf. M. numataensis from a late Miocene to early Pliocene sediment in Yamagata Prefecture, northeastern Japan. The species has a straight and sharp lateral ridge of the fovea epitubaria at the ventral surface of the periotic, and a dorsoventrally thin pars cochlearis. The new spec- imen provides knowledge of supposed ontogenetic variation and periotic morphology in poorly known fossil balaenopterids. Yoshihiro Tanaka. Osaka Museum of Natural History, Nagai Park 1-23, Higashi-Sumiyoshi-ku, Osaka, 546- 0034, Japan. [email protected] Hokkaido University Museum, Kita 10, Nishi 8, Kita-ku, Sapporo, Hokkaido 060-0810 Japan, Numata Fossil Museum, 2-7-49, Minami 1, Numata town, Hokkaido 078-2225 Japan Kazuo Nagasawa. Yamagata Prefectural Touohgakkan Junior and Senior High School. 1-7-1 Chuo- Minami, Higashine City, Yamagata Prefecture, Japan 999-3730. [email protected] Yojiro Taketani. Aizuwakamatsu City, Fukushima Prefecture, Japan. [email protected] Keywords: rorquals; Balaenopteridae; Noguchi Formation; Furukuchi Formation; Miobalaenoptera numataensis; ontogenetic variation Submission: 25 May 2019. Acceptance: 20 February 2020. INTRODUCTION (Van Beneden, 1880; Strobel, 1881; Sacco, 1890; Bisconti, 2007a, 2007b, 2010; Bosselaers and The family of rorquals and humpback whales, Post, 2010; Bisconti and Bosselaers, 2016) and Balaenopteridae includes the largest living animal the East Coast of the U.S.
    [Show full text]
  • Mysticetes Baring Their Teeth: a New Fossil Whale, Mammalodon Hakataramea, from the Southwest Pacific
    Memoirs of Museum Victoria 74: 107–116 (2016) Published 2016 ISSN 1447-2546 (Print) 1447-2554 (On-line) http://museumvictoria.com.au/about/books-and-journals/journals/memoirs-of-museum-victoria/ Mysticetes baring their teeth: a new fossil whale, Mammalodon hakataramea, from the Southwest Pacific R. EWAN FORDYCE1,2,* (http://zoobank.org/urn:lsid:zoobank.org:author:311048BF-4642-412E-B5DA-E01B8C03B802) AND FELIX G. MARX1,3 (http://zoobank.org/urn:lsid:zoobank.org:author:1791C478-33A7-4C75-8104-4C98C7B22125) 1 Department of Geology, University of Otago, PO Box 56, Dunedin 9054, New Zealand ([email protected]) 2 Departments of Vertebrate Zoology and Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington DC 20560, USA 3 Department of Geology and Palaeontology, National Museum of Nature and Science, Tsukuba, Japan (felix.marx@ otago.ac.nz) * To whom correspondence should be addressed. E-mail: [email protected] http://zoobank.org/urn:lsid:zoobank.org:pub:7A2CAF55-70DC-4561-AA3D-86FA72C721E6 Abstract Fordyce, R.E. and Marx, F.G. 2016. Mysticetes baring their teeth: a new fossil whale, Mammalodon hakataramea, from the Southwest Pacific. Memoirs of Museum Victoria 74: 107–116. A small, toothed fossil cetacean from Hakataramea Valley (South Canterbury, New Zealand) represents a new Late Oligocene species, Mammalodon hakataramea. The new material is from the Kokoamu Greensand (Duntroonian Stage, about 27 Ma, early to middle Chattian) of the Canterbury Basin, and thus about 2 Ma older than the only other species included in this genus, Mammalodon colliveri (Late Oligocene, Victoria, Australia). The anterior pedicle of the tympanic bulla is not fused to the periotic and resembles that of Delphinidae in basic structure.
    [Show full text]
  • Borealodon Osedax, a New Stem Mysticete (Mammalia, Royalsocietypublishing.Org/Journal/Rsos Cetacea) from the Oligocene of Washington State and Its Research
    Borealodon osedax, a new stem mysticete (Mammalia, royalsocietypublishing.org/journal/rsos Cetacea) from the Oligocene of Washington State and its Research Cite this article: Shipps BK, Peredo CM, implications for fossil Pyenson ND. 2019 Borealodon osedax, a new stem mysticete (Mammalia, Cetacea) from the whale-fall communities Oligocene of Washington State and its implications for fossil whale-fall communities. 1,2 2,3 R. Soc. open sci. 6: 182168. B. K. Shipps , Carlos Mauricio Peredo http://dx.doi.org/10.1098/rsos.182168 and Nicholas D. Pyenson2,4 1Department of Atmospheric, Oceanic, and Earth Sciences, George Mason University, Fairfax, VA, USA Received: 15 January 2019 2Department of Paleobiology, National Museum of Natural History, Washington, DC, USA Accepted: 30 May 2019 3Department of Earth and Environmental Science, University of Michigan, Ann Arbor, MI, USA 4Department of Paleontology and Geology, Burke Museum of Natural History and Culture, Seattle, WA, USA BKS, 0000-0003-2339-9504; CMP, 0000-0002-7217-9850; NDP, 0000-0003-4678-5782 Subject Category: Biology (whole organism) Baleen whales (mysticetes) lack teeth as adults and instead filter feed using keratinous baleen plates. They do not Subject Areas: echolocate with ultrasonic frequencies like toothed whales palaeontology but are instead known for infrasonic acoustics. Both baleen and infrasonic hearing are separately considered key Keywords: innovations linked to their gigantism, evolutionary success baleen, Cetacea, Mysticeti, Oligocene, and ecological diversity. The earliest mysticetes had teeth, and the phylogenetic position of many so-called toothed Pysht Formation mysticetes remains debated, including those belonging to the nominal taxonomic groups Llanocetidae, Mammalodontidae and Aetiocetidae. Here, we report a new stem mysticete, Author for correspondence: Borealodon osedax gen.
    [Show full text]
  • A Large Late Miocene Cetotheriid (Cetacea, Mysticeti) from the Netherlands Clarifies the Status of Tranatocetidae
    A large Late Miocene cetotheriid (Cetacea, Mysticeti) from the Netherlands clarifies the status of Tranatocetidae Felix G. Marx1,2,3,4, Klaas Post5, Mark Bosselaers2,6 and Dirk K. Munsterman7 1 Department of Geology, Université de Liège, Liège, Belgium 2 Directorate of Earth and History of Life, Royal Belgian Institute of Natural Sciences, Brussels, Belgium 3 Palaeontology, Museums Victoria, Melbourne, Victoria, Australia 4 School of Biological Sciences, Monash University, Clayton, Victoria, Australia 5 Natuurhistorisch Museum, Rotterdam, The Netherlands 6 Zeeland Royal Society of Sciences, Middelburg, The Netherlands 7 Netherlands Institute of Applied Geoscience TNO - National Geological Survey, Utrecht, The Netherlands ABSTRACT Cetotheriidae are a group of small baleen whales (Mysticeti) that evolved alongside modern rorquals. They once enjoyed a nearly global distribution, but then largely went extinct during the Plio-Pleistocene. After languishing as a wastebasket taxon for more than a century, the concept of Cetotheriidae is now well established. Nevertheless, the clade remains notable for its variability, and its scope remains in flux. In particular, the recent referral of several traditional cetotheriids to a new and seemingly unrelated family, Tranatocetidae, has created major phylogenetic uncertainty. Here, we describe a new species of Tranatocetus, the type of Tranatocetidae, from the Late Miocene of the Netherlands. Tranatocetus maregermanicum sp. nov. clarifies several of the traits previously ascribed to this genus, and reveals distinctive auditory and mandibular morphologies suggesting cetotheriid affinities. This interpretation is supported by a large phylogenetic analysis, which mingles cetotheriids and tranatocetids within a unified clade. As a result, we suggest that both groups should be reintegrated into the single family Cetotheriidae.
    [Show full text]
  • Skull Anatomy of the Oligocene Toothed Mysticete Aetioceus Weltoni (Mammalia; Cetacea): Implications for Mysticete Evolution and Functional Anatomy
    Zoological Journal of the Linnean Society, 2008, 154, 308–352. With 11 figures Skull anatomy of the Oligocene toothed mysticete Aetioceus weltoni (Mammalia; Cetacea): implications for mysticete evolution and functional anatomy THOMAS A. DEMÉRÉ1* and ANNALISA BERTA2 1Department of Paleontology, San Diego Natural History Museum, PO Box 121390, San Diego, CA 92112, USA 2Department of Biology, San Diego State University, San Diego, CA 92182, USA Received 20 September 2007; accepted for publication 25 September 2007 Toothed mysticetes of the family Aetiocetidae from Oligocene rocks of the North Pacific play a key role in interpretations of cetacean evolution because they are transitional in grade between dorudontine archaeocetes and edentulous mysticetes. The holotype skull of Aetiocetus weltoni from the late Oligocene (28–24 Ma) of Oregon, USA, has been further prepared, revealing additional morphological features of the basicranium, rostrum and dentary that have important implications for mysticete evolution and functional anatomy. The palate of Aetiocetus weltoni preserves diminutive lateral palatal foramina and associated delicate sulci which appear to be homologous with the prominent palatal foramina and sulci that occur along the lateral portion of the palate in extant mysticetes. In modern baleen whales these foramina allow passage of branches of the superior alveolar artery, which supplies blood to the epithelia of the developing baleen racks. As homologous structures, the lateral palatal foramina of A. weltoni suggest that baleen was present in this Oligocene toothed mysticete. Cladistic analysis of 46 cranial and dental characters supports monophyly of the Aetiocetidae, with toothed mysticetes Janjucetus and Mammalodon positioned as successive sister taxa. Morawanacetus is the earliest diverging aetiocetid with Chonecetus as sister taxon to Aetiocetus species.
    [Show full text]
  • Mysticetes, Evolution 749
    Mysticetes, Evolution 749 Figure 2 The full-size model of a blue whale that was mounted at the National Museum of Natural History in Washington, DC. References from the late Oligocene coincident with the radiation of toothed forms, but are not diverse until the Miocene. Although contested, it Conover , A. ( 1996 ). The object at hand . Smithsonian 27 ( 7 ) , 28 , 30, 31 . is likely that most, if not all, archaic mysticetes possessed some form Dalebout , M. L. , van Helden , A. , van Waerebeek , K. , and Baker , C. S. of baleen in the upper jaw. This key fi lter feeding innovation permit- ( 1998 ). Molecular genetic identifi cation of southern henmisphere beaked whales (Cetacea: Ziphiidae) . Mol. Ecol. 7 , 687 – 694 . ted exploitation of a new niche and heralded the evolution of mod- Fraser, F. C. (1974). “Report on Cetacea Stranded on the British Coasts ern baleen whales, the largest animals on Earth. from 1948 to 1966.” British Museum (Natural History), London. M II. Toothed Mysticetes As currently understood, toothed mysticetes are grouped into four families: Llanocetidae, Mammalodontidae, and Janjucetidae from the Southern Ocean and Aetiocetidae, from the North Pacifi c. To date no toothed mysticetes are known from the Atlantic Mysticetes, Evolution region. The retention of an adult dentition in toothed mysticetes is the primitive condition seen in basilosaurid “ archaeocetes ” and ANNALISA BERTA AND THOMAS A. DEMÉRÉ stem odontocetes. The degree of telescoping of the skull is also primitive with little interdigitation of rostral and cranial elements. Consequently, there is a long intertemporal exposure of the frontal I. Introduction and parietal on the cranial vertex.
    [Show full text]