DOCSLIB.ORG

Protocetid Cetaceans (Mammalia) from the Eocene of India

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Protocetid Cetaceans (Mammalia) from the Eocene of India Palaeontologia Electronica palaeo-electronica.org Protocetid cetaceans (Mammalia) from the Eocene of India Sunil Bajpai and J.G.M. Thewissen ABSTRACT Protocetid cetaceans were first described from the Eocene of India in 1975, but many more specimens have been discovered since then and are described here. All specimens are from District Kutch in the State of Gujarat and were recovered in depos- its approximately 42 million years old. Valid species described in the past include Indocetus ramani, Babiacetus indicus and B. mishrai. We here describe new material for Indocetus, including lower teeth and deciduous premolars. We also describe two new genera and species: Kharodacetus sahnii and Dhedacetus hyaeni. Kharodacetus is mostly based on a very well preserved rostrum and mandibles with teeth, and Dhe- dacetus is based on a partial skull with vertebral column. The Kutch protocetid fauna differs from the protocetid fauna of the Pakistani Sulaiman Range, possibly because the latter is partly older, and/or because it samples a different environment, being located on the trailing edge of the Indian Plate, directly exposed to the Indian Ocean. Sunil Bajpai. Department of Earth Sciences, Indian Institute of Technology, Roorkee 247667, Uttarakhand, India. Current address: Birbal Sahni Institute of Palaeobotany, Lucknow 226007, Uttar Pradesh, India. [email protected]; [email protected]. J.G.M. Thewissen (corresponding author). Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, Ohio 44272, U.S.A. [email protected]. Keywords: Eocene; Mammalia; Cetacea; India; New species; New genus INTRODUCTION 1998, 2000; Thewissen and Hussain, 1998) and many specimens of the remingtonocetine genera The earliest cetaceans, pakicetids and ambu- Remingtonocetus (Bajpai et al., 2011), Dalanistes locetids are only known from the Eocene of India (Thewissen and Bajpai, 2001) and the andrewsi- and Pakistan (reviewed by Thewissen et al., 2009). phiine genera Andrewsiphius and Kutchicetus These families are followed, in time as well as on (Thewissen and Bajpai, 2009) have been recov- the cladogram, by remingtonocetids and proto- ered in Kutch (Gujarat, India). Remingtonocetids cetids. Unambiguous remingtonocetid fossils are had small eyes and large middle ear cavities. Rem- also only known only from India and Pakistan ingtonocetines and andrewsiphiines are both com- (Sahni and Mishra, 1975; Kumar and Sahni, 1986; mon in localities indicative of murky water, but Gingerich et al., 1995b; Bajpai and Thewissen, http://zoobank.org/6A475A48-F702-49BB-8A8F-1B732123348A PE Article Number: 17.3.34A Copyright: Paleontological Society October 2014 Submission: 31 January 2014. Acceptance: 11 September 2014 Bajpai, Sunil and Thewissen, J.G.M. 2014. Protocetid cetaceans (Mammalia) from the Eocene of India. Palaeontologia Electronica Vol. 17, Issue 3;34A; 19p; palaeo-electronica.org/content/2014/914-whales-from-india BAJPAI AND THEWISSEN: WHALES FROM INDIA Remingtonocetus also lived in more clear water Differential diagnosis. Indocetus is a medium-sized localities (Thewissen and Bajpai, 2009). protocetid, with teeth larger than most protocetids Protocetids are found in many continents, from the Indian continent, but smaller than those of including Africa (Kellogg, 1936; Williams, 1998; Kharodacetus, and only slightly larger than teeth of Bianucci and Gingerich, 2011; Gingerich and Cap- Rodhocetus. The orbit is barely elevated above the petta, 2014), North America (Hulbert et al., 1998; palate (unlike Kharodacetus and Dhedacetus). Geisler et al., 2005; Uhen, 2008, 2014a, 2014b), Indocetus has a flat supraorbital shield with large and South America (Uhen et al., 2011). Apparently orbits, similar to all other protocetids and different then, protocetids were the first cetaceans able to from pakicetids, ambulocetids and reming- cross oceans, and to colonize tropical and subtrop- tonocetids. ical oceans. Discussion. Gingerich et al. (1994) diagnosed Rod- Several genera of protocetids are known from hocetus as distinct from Indocetus based on the the desert of Kutch in western India and the moun- convexity of the posterior surface of the exoccipital, tains of the Sulaiman Range in Pakistan. From the shorter cervical vertebrae, unfused sacral ver- Kutch, Indocetus ramani Sahni and Mishra, 1975, tebrae and the shorter femur. However, the post- Babiacetus indicus Trivedi and Satsangi, 1984, cranial elements on which the Indocetus Babiacetus mishrai Bajpai and Thewissen, 1998, comparisons are based have been reassigned to and Gaviacetus sahnii Bajpai and Thewissen, other taxa, and these elements are not known for 1998, have been reported. Specimens initially Indocetus. This leaves the exoccipital as the only identified as Protocetus (Sahni and Mishra, 1975) diagnostic feature. It is possible that the exoccipital have been reassigned later to Remingtonocetus shape constitutes a consistent and sharp differ- (Kumar and Sahni, 1986). In the Sulaiman Range, ence between Rodhocetus and Indocetus, but it is there may be nine genera with 10 species of also possible that this difference does not merit dis- Eocene whales: Rodhocetus kasranii Gingerich et tinction of separate genera. The m1 crown of the al., 1994 (spelling amended by Gingerich et al., specimen referred to Indocetus below (IITR-SB 2001a); Babiacetus indicus Trivedi and Satsangi, 2986) is 125% as large, in linear dimensions, as 1984 (reported by Gingerich et al., 1995a), the same tooth of Rodhocetus kasrani (GSP-UM Takracetus simus Gingerich et al., 1995b; Gaviace- 3012, Gingerich et al., 1995b). This size difference tus razai Gingerich et al., 1995b; Artiocetus clavis may merit distinction at the specific level, but is Gingerich et al., 2001b; Rodhocetus balochistan- probably not a diagnostic character at the genus ensis Gingerich et al., 2001b; Qaisracetus arifi Gin- level. Based on the limited amount of available evi- gerich et al., 2001a; Makaracetus bidens, dence, it is likely that Rodhocetus is a junior syn- Gingerich et al., 2005, and Maiacetus inuus Gin- onym of Indocetus, however, we stop short of gerich et al., 2009. Specimens of Indocetus synonymizing these taxa, as a more detailed com- reported from the Sulaiman Range by Gingerich et parison of holotypes and a study of the variability of al. (1993) have now been reassigned to Reming- South Asian protocetids are needed. At present, it tonocetus (Gingerich et al., 1995b). is preferable to maintain the status quo. The Kutch deposits with fossil cetaceans were Gingerich et al. (2001b, supplementary infor- dated to 42 million years ago by Ravikant and mation) showed that there are significant differ- Bajpai (2010). The localities in the Sulaiman ences in the rostrum shape of the Indo-Pakistani Range have some species in common with those protocetids. The shape of the rostrum of Indocetus in Kutch, and it appears clear that some of the fau- matches that of Rodhocetus. The rostrum of nal differences are due to environmental differ- Artiocetus, Takracetus and Maiacetus (Gingerich et ences between the two regions. Here we report al., 2009) is broader, whereas that of Gaviacetus new protocetid cetaceans from Kutch and review and Babiacetus (based on its lower jaws) is nar- the already described species from India. rower. In Makaracetus the rostrum is downturned (Gingerich et al., 2005), unlike any other proto- SYSTEMATIC PALAEONTOLOGY cetid. It is likely that rostrum differences reflect dif- ferences in feeding and quantification of these Class MAMMALIA Linnaeus, 1758 differences based on original, undeformed material Order CETACEA Brisson, 1762 may expose subtle ecological differences among Family PROTOCETIDAE Stromer, 1908 these taxa. Genus Indocetus Sahni and Mishra, 1975 Type species. Indocetus ramani Sahni and Mishra, 1975, by original designation. 2 PALAEO-ELECTRONICA.ORG Indocetus ramani Sahni and Mishra, 1975 ventrally by a deep groove that contained the Figure 1.1-4 nerves to the eye and orbit. The face is low, with Holotype. LUVP 11034, fragments of orbits with the orbit placed only slightly above the palate, palate, interorbital region, and ear region with unlike Kharodacetus (see below). crown for one molar. IITR-SB 2986 (Figure 1.1-2) is a well-pre- Other material. IITR-SB 2000-33, left mandible with served mandible for Indocetus ramani. The caudal dp3 and dp4, Babia Hill; IITR-SB 2986, left mandi- end of dp3 is preserved, and it shows that a small ble with dp3 fragment, dp4, m1, and unerupted m2; cusp is present at the end of the postprotocrista. Rato Nala. IITR-SB 4001, palatal/orbital fragment The dp4 has four cusps that are lined up from ros- with crowns for right P3-M1, Rato Nala; VPL 1014, tral to caudal, and are connected by a sharp crest. right tympanic, Bajpai and Thewissen (1998); VPL The rostral cusp is the lowest, and the second cusp 1017, endocast of cranial cavity, palatal, interorbital the highest, the third and fourth cusp decrease in fragment, Bajpai et al. (1996); VPL 1018, endocast size from the second cusp. The lingual cingulum is of cranial cavity, Bajpai et al. (1996). complete, and the labial cingulum is damaged for Type locality. Rato Nala, 1 km north of the village of as far as it can be studied. The m1 bears two Harudi. cusps, a high protoconid on the trigonid and a low Type stratum. Harudi Formation, Eocene, around hypoconid. The rostral face of the protoconid is 42 million years old. concave, bounded by a sharp lingual crest and a Diagnosis. Same as for genus. much weaker labial crest. Both of these crests Description. IITR-SB 4001 shows alveoli for P2 and ascend the protoconid partially. A sharp crest crowns for P3 to M1 (Figure 1.3-4, Table 1). There descends from the protoconid caudally and is con- are two alveoli for P2, followed by a diastema, tinued over the rostral and caudal aspect of the whereas no diastemata occur between P3 and M1. hypoconid. Only the tip of m2 is erupted. P3 and P4 are similar in shape. They lack a proto- The mandible shows a gently ascending coro- cone, but have a large lingual bulge, similar in size noid process, and a strongly dorso-ventrally con- to that of Babiacetus (Gingerich et al., 1995a).
Load more

Recommended publications
  • SOCIETY of VERTEBRATE PALEONTOLOGY OCTOBER 2015 ABSTRACTS of PAPERS 75Th ANNUAL MEETING
    SOCIETY OF VERTEBRATE PALEONTOLOGY OCTOBER 2015 ABSTRACTS OF PAPERS 75th ANNUAL MEETING Hyatt Regency Dallas Dallas, Texas, USA October 14 – 17, 2015 HOST COMMITTEE Stephen Cohen; Anthony R. Fiorillo; Louis Jacobs; Michael Polcyn; Amy Smith; Christopher Strganac; Ronald S. Tykoski; Diana Vineyard; Dale Winkler EXECUTIVE COMMITTEE John Long, President; P. David Polly, Vice President; Catherine A. Forster, Past-President; Glenn Storrs, Secretary; Ted J. Vlamis, Treasurer; Elizabeth Hadly, Member-at-Large; Xiaoming Wang, Member-at-Large; Paul M. Barrett, Member-at-Large SYMPOSIUM CONVENORS Larisa R. G. DeSantis; Anthony R. Fiorillo; Camille Grohé; Marc E. H. Jones; Joshua H. Miller; Christopher Noto; Emma Sherratt; Michael Spaulding; Z. Jack Tseng; Akinobu Watanabe; Lindsay Zanno PROGRAM COMMITTEE David Evans, Co-Chair; Mary Silcox, Co-Chair; Heather Ahrens; Brian Beatty; Jonathan Bloch; Martin Brazeau; Chris Brochu; Richard Butler; Darin Croft; Ted Daeschler; David Fox; Anjali Goswami; Elizabeth Hadly; Pat Holroyd; Marc Jones; Christian Kammerer; Amber MacKenzie; Erin Maxwell; Josh Miller; Jessica Miller-Camp; Kevin Padian; Lauren Sallan; William Sanders; Michelle Stocker; Paul Upchurch; Aaron Wood EDITORS Amber MacKenzie; Erin Maxwell; Jessica Miller-Camp October 2015 PROGRAM AND ABSTRACTS 1 Grant Information dinosaur-bearing units in the world. Though exposed in Saskatchewan, outcropping is NSF grant #0847777 (EAR) to D.J. Varrichio sparse, widely distributed, and often difficult to access. Despite this, recently, several microfossil sites have been identified throughout southwestern Saskatchewan, Canada. Technical Session VI (Thursday, October 15, 2015, 9:00 AM) The Saskatchewan sites produce a rich vertebrate record, including chondrichthyans, osteichthyans, turtles, champsosaurs, crocodiles, squamates, amphibians, birds, MULTIDENTICULATE TEETH IN TRIASSIC FISH HEMICALYPTERUS WEIRI mammals, and dinosaurs.
    [Show full text]
  • A New Middle Eocene Protocetid Whale (Mammalia: Cetacea: Archaeoceti) and Associated Biota from Georgia Author(S): Richard C
    A New Middle Eocene Protocetid Whale (Mammalia: Cetacea: Archaeoceti) and Associated Biota from Georgia Author(s): Richard C. Hulbert, Jr., Richard M. Petkewich, Gale A. Bishop, David Bukry and David P. Aleshire Source: Journal of Paleontology , Sep., 1998, Vol. 72, No. 5 (Sep., 1998), pp. 907-927 Published by: Paleontological Society Stable URL: https://www.jstor.org/stable/1306667 REFERENCES Linked references are available on JSTOR for this article: https://www.jstor.org/stable/1306667?seq=1&cid=pdf- reference#references_tab_contents You may need to log in to JSTOR to access the linked references. JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at https://about.jstor.org/terms SEPM Society for Sedimentary Geology and are collaborating with JSTOR to digitize, preserve and extend access to Journal of Paleontology This content downloaded from 131.204.154.192 on Thu, 08 Apr 2021 18:43:05 UTC All use subject to https://about.jstor.org/terms J. Paleont., 72(5), 1998, pp. 907-927 Copyright ? 1998, The Paleontological Society 0022-3360/98/0072-0907$03.00 A NEW MIDDLE EOCENE PROTOCETID WHALE (MAMMALIA: CETACEA: ARCHAEOCETI) AND ASSOCIATED BIOTA FROM GEORGIA RICHARD C. HULBERT, JR.,1 RICHARD M. PETKEWICH,"4 GALE A.
    [Show full text]
  • Intervertebral and Epiphyseal Fusion in the Postnatal Ontogeny of Cetaceans and Terrestrial Mammals
    J Mammal Evol DOI 10.1007/s10914-014-9256-7 ORIGINAL PAPER Intervertebral and Epiphyseal Fusion in the Postnatal Ontogeny of Cetaceans and Terrestrial Mammals Meghan M. Moran & Sunil Bajpai & J. Craig George & Robert Suydam & Sharon Usip & J. G. M. Thewissen # Springer Science+Business Media New York 2014 Abstract In this paper we studied three related aspects of the Introduction ontogeny of the vertebral centrum of cetaceans and terrestrial mammals in an evolutionary context. We determined patterns The vertebral column provides support for the body and of ontogenetic fusion of the vertebral epiphyses in bowhead allows for flexibility and mobility (Gegenbaur and Bell whale (Balaena mysticetus) and beluga whale 1878;Hristovaetal.2011; Bruggeman et al. 2012). To (Delphinapterus leucas), comparing those to terrestrial mam- achieve this mobility, individual vertebrae articulate with each mals and Eocene cetaceans. We found that epiphyseal fusion other through cartilaginous intervertebral joints between the is initiated in the neck and the sacral region of terrestrial centra and synovial joints between the pre- and post- mammals, while in recent aquatic mammals epiphyseal fusion zygapophyses. The mobility of each vertebral joint varies is initiated in the neck and caudal regions, suggesting loco- greatly between species as well as along the vertebral column motor pattern and environment affect fusion pattern. We also within a single species. Vertebral column mobility greatly studied bony fusion of the sacrum and evaluated criteria used impacts locomotor style, whether the animal is terrestrial or to homologize cetacean vertebrae with the fused sacrum of aquatic. In aquatic Cetacea, buoyancy counteracts gravity, and terrestrial mammals. We found that the initial ossification of the tail is the main propulsive organ (Fish 1996;Fishetal.
    [Show full text]
  • Functional Morphology of the Vertebral Column in Remingtonocetus (Mammalia, Cetacea) and the Evolution of Aquatic Locomotion in Early Archaeocetes
    Functional Morphology of the Vertebral Column in Remingtonocetus (Mammalia, Cetacea) and the Evolution of Aquatic Locomotion in Early Archaeocetes by Ryan Matthew Bebej A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Ecology and Evolutionary Biology) in The University of Michigan 2011 Doctoral Committee: Professor Philip D. Gingerich, Co-Chair Professor Philip Myers, Co-Chair Professor Daniel C. Fisher Professor Paul W. Webb © Ryan Matthew Bebej 2011 To my wonderful wife Melissa, for her infinite love and support ii Acknowledgments First, I would like to thank each of my committee members. I will be forever grateful to my primary mentor, Philip D. Gingerich, for providing me the opportunity of a lifetime, studying the very organisms that sparked my interest in evolution and paleontology in the first place. His encouragement, patience, instruction, and advice have been instrumental in my development as a scholar, and his dedication to his craft has instilled in me the importance of doing careful and solid research. I am extremely grateful to Philip Myers, who graciously consented to be my co-advisor and co-chair early in my career and guided me through some of the most stressful aspects of life as a Ph.D. student (e.g., preliminary examinations). I also thank Paul W. Webb, for his novel thoughts about living in and moving through water, and Daniel C. Fisher, for his insights into functional morphology, 3D modeling, and mammalian paleobiology. My research was almost entirely predicated on cetacean fossils collected through a collaboration of the University of Michigan and the Geological Survey of Pakistan before my arrival in Ann Arbor.
    [Show full text]
  • Thewissen Et Al. Reply Replying To: J
    NATURE | Vol 458 | 19 March 2009 BRIEF COMMUNICATIONS ARISING Hippopotamus and whale phylogeny Arising from: J. G. M. Thewissen, L. N. Cooper, M. T. Clementz, S. Bajpai & B. N. Tiwari Nature 450, 1190–1194 (2007) Thewissen etal.1 describe new fossils from India that apparentlysupport fossils, Raoellidae or the raoellid Indohyus is more closely related to a phylogeny that places Cetacea (that is, whales, dolphins, porpoises) as Cetacea than is Hippopotamidae (Fig. 1). Hippopotamidae is the the sister group to the extinct family Raoellidae, and Hippopotamidae exclusive sister group to Cetacea plus Raoellidae in the analysis that as more closely related to pigs and peccaries (that is, Suina) than to down-weights homoplastic characters, althoughin the equallyweighted cetaceans. However, our reanalysis of a modified version of the data set analysis, another topology was equally parsimonious. In that topology, they used2 differs in retaining molecular characters and demonstrates Hippopotamidae moved one node out, being the sister group to an that Hippopotamidae is the closest extant family to Cetacea and that Andrewsarchus, Raoellidae and Cetacea clade. In neither analysis is raoellids are the closest extinct group, consistent with previous phylo- Hippopotamidae closer to the pigs and peccaries than to Cetacea, the genetic studies2,3. This topology supports the view that the aquatic result obtained by Thewissen et al.1. In all our analyses, pachyostosis adaptations in hippopotamids and cetaceans are inherited from their (thickening) of limb bones and bottom walking, which occur in hippo- common ancestor4. potamids9,10, are interpreted to have evolved before the pachyostosis of To conduct our analyses, we started with the same published matrix the auditory bulla, as seen in raoellids and cetaceans1.
    [Show full text]
  • Whale Evolution: a Whale of a Tale
    Creation Research Society Quarterly 2012. 49:122–134. 122 Creation Research Society Quarterly Whale Evolution: A Whale of a Tale Jerry Bergman* Abstract review of the evolution of whales from terrestrial land animals finds A that the evidence used to support the current theory is either wrong or very questionable. A focus is on the hip bone and fetal teeth evidence because they are commonly used as proof for the land mammal-to-whale evolution theory. The putative fossil evidence for whale evolution from terrestrial animals is also evaluated, concluding that the examples used are likely all extinct mammals and not transitional forms. Introduction be only about 20 feet long, but baleen A major problem has been deter- The term “whale” is a common noun and blue whales can grow up to 100 feet mining which terrestrial animal whales that can refer to all marine mammals long. Toothed whales are, on average, evolved from. Charles Darwin proposed called cetaceans (members of order smaller then baleen whales, ranging one of the first theories of whale evolu- cetacea), including dolphins and por- from 3 to 32 feet long, although most tion, suggesting they evolved from bears. poises. In this paper the term “whales” are from 10 to 30 feet long. Blue whales He wrote, “I can see no difficulty in a excludes both dolphins and porpoises. can weigh up to 150 tons. race of bears being rendered, by natural Classification of whales divides them selection, more and more aquatic in into two groups; toothed whales and their structure and habits, with larger baleen whales, the latter of which use The Origin of Whales and larger mouths, till a creature was large brush-like structures to filter food The evolution of whales is one of the produced as monstrous as a whale” from the ocean.
    [Show full text]
  • Currently Zygorhiza Kochii; Mammalia, Cetacea): Proposed Replacement of the Holotype by a Neotype
    Case 3611Basilosaurus kochii Reichenbach, 1847 (currently Zygorhiza kochii; Mammalia, Cetacea): proposed replacement of the holotype by a neotype Author: Uhen, Mark D. Source: The Bulletin of Zoological Nomenclature, 70(2) : 103-107 Published By: International Commission on Zoological Nomenclature URL: https://doi.org/10.21805/bzn.v70i2.a14 BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses. Your use of this PDF, the BioOne Complete website, and all posted and associated content indicates your acceptance of BioOne’s Terms of Use, available at www.bioone.org/terms-of-use. Usage of BioOne Complete content is strictly limited to personal, educational, and non - commercial use. Commercial inquiries or rights and permissions requests should be directed to the individual publisher as copyright holder. BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers, academic institutions, research libraries, and research funders in the common goal of maximizing access to critical research. Downloaded From: https://bioone.org/journals/The-Bulletin-of-Zoological-Nomenclature on 08 Apr 2021 Terms of Use: https://bioone.org/terms-of-use Access provided by Auburn University Bulletin of Zoological Nomenclature 70(2) June 2013 103 Case 3611 Basilosaurus kochii Reichenbach, 1847 (currently Zygorhiza kochii; Mammalia, Cetacea): proposed replacement of the holotype by a neotype Mark D. Uhen Department of Atmospheric, Oceanic, and Earth Sciences, George Mason University, MS 5F2, Fairfax, VA 22030, U.S.A. (e-mail: [email protected]) Abstract.
    [Show full text]
  • Transition of Eocene Whales from Land to Sea: Evidence from Bone Microstructure
    RESEARCH ARTICLE Transition of Eocene Whales from Land to Sea: Evidence from Bone Microstructure Alexandra Houssaye1,2*, Paul Tafforeau3, Christian de Muizon4, Philip D. Gingerich5 1 UMR 7179 CNRS/Muséum National d’Histoire Naturelle, Département Ecologie et Gestion de la Biodiversité, Paris, France, 2 Steinmann Institut für Geologie, Paläontologie und Mineralogie, Universität Bonn, Bonn, Germany, 3 European Synchrotron Radiation Facility, Grenoble, France, 4 Sorbonne Universités, CR2P—CNRS, MNHN, UPMC-Paris 6, Département Histoire de la Terre, Muséum National d’Histoire Naturelle, Paris, France, 5 Department of Earth and Environmental Sciences and Museum of Paleontology, University of Michigan, Ann Arbor, Michigan, United States of America a11111 * [email protected] Abstract Cetacea are secondarily aquatic amniotes that underwent their land-to-sea transition during OPEN ACCESS the Eocene. Primitive forms, called archaeocetes, include five families with distinct degrees Citation: Houssaye A, Tafforeau P, de Muizon C, of adaptation to an aquatic life, swimming mode and abilities that remain difficult to estimate. Gingerich PD (2015) Transition of Eocene Whales The lifestyle of early cetaceans is investigated by analysis of microanatomical features in from Land to Sea: Evidence from Bone postcranial elements of archaeocetes. We document the internal structure of long bones, Microstructure. PLoS ONE 10(2): e0118409. ribs and vertebrae in fifteen specimens belonging to the three more derived archaeocete doi:10.1371/journal.pone.0118409 families — Remingtonocetidae, Protocetidae, and Basilosauridae — using microtomogra- Academic Editor: Brian Lee Beatty, New York phy and virtual thin-sectioning. This enables us to discuss the osseous specializations ob- Institute of Technology College of Osteopathic Medicine, UNITED STATES served in these taxa and to comment on their possible swimming behavior.
    [Show full text]
  • WHALE HUNT: SEARCHING for WHALE FOSSILS: a SHORTER NARRATIVE More Suitable for Teacher-Directed “Whale Hunt”
    WHALE HUNT: SEARCHING FOR WHALE FOSSILS: a SHORTER NARRATIVE More Suitable for Teacher-Directed “Whale Hunt” 1. We have NO fossils of modern whales earlier than about 25 million years ago (mya). However, for many years, we have been finding a number of fossils of various primitive whales (archaeocetes) between 25 and 45 million years old, and somewhat different from modern whales, e.g. with very distinctive teeth An example of these early whales would be Dorudon. Place the fossil picture strip of Dorudon at about 36 mya on your timeline (actual range about 39-36 mya); (“mya”= millions of years ago). 2. As more fossils have been discovered from the early Eocene (55 to 34 mya), we searched for a land mammal from which whales most likely evolved. The group of animals that had features like those distinctive teeth that are also found in the earliest primitive whales, was called the Mesonychids. A typical example of these animals was Pachyaena. Mesonychids also had hooves, suggesting that whales may be related to other animals with hooves, like cows, horses, deer and pigs. Place the Pachyaena strip at about the 55 mya level on your timeline. Mesonychids lived from 58-34 mya. 3. In 1983, all we had were these primitive whales and mesonychids, with a big gap in between. This year, paleontologist Philip Gingerich was searching in Eocene deposits in Pakistan, and found the skull of an amazing fossil. It had teeth like the Dorudon whale, with whale-like ear bones and other features, but it was much older (50 mya), and there were indications that it had four legs.
    [Show full text]
  • Vestibular Evidence for the Evolution of Aquatic Behaviour in Early
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Publications of the IAS Fellows letters to nature .............................................................. cetacean evolution, leading to full independence from life on land. Vestibular evidence for the Early cetacean evolution, marked by the emergence of obligate evolution of aquatic behaviour aquatic behaviour, represents one of the major morphological shifts in the radiation of mammals. Modifications to the postcranial in early cetaceans skeleton during this process are increasingly well-documented3–9. Pakicetids, early Eocene basal cetaceans, were terrestrial quadrupeds 9 F. Spoor*, S. Bajpai†, S. T. Hussain‡, K. Kumar§ & J. G. M. Thewissenk with a long neck and cursorial limb morphology . By the late middle Eocene, obligate aquatic dorudontids approached modern ceta- * Department of Anatomy & Developmental Biology, University College London, ceans in body form, having a tail fluke, a strongly shortened neck, Rockefeller Building, University Street, London WC1E 6JJ, UK and near-absent hindlimbs10. Taxa which represent bridging nodes † Department of Earth Sciences, Indian Institute of Technology, Roorkee 247 667, on the cladogram show intermediate morphologies, which have India been inferred to correspond with otter-like swimming combined ‡ Department of Anatomy, College of Medicine, Howard University, with varying degrees of terrestrial capability4–8,11. Our knowledge of Washington DC 20059, USA § Wadia Institute of Himalayan Geology, Dehradun 248 001, India the behavioural changes that crucially must have driven the post- k Department of Anatomy, Northeastern Ohio Universities College of Medicine, cranial adaptations is based on functional analysis of the affected Rootstown, Ohio 44272, USA morphology itself. This approach is marred by the difficulty of ............................................................................................................................................................................
    [Show full text]
  • Chapter 26 Cenozoic Life
    236 Chapter 26 Cenozoic Life GUIDED STUDY The text chapter should be studied one section at a time. Life on Land (pp. 552-560) Before you read, preview each section by skimming it, noting headings and boldface items. Then read the 5. Describe the adaptations of grasses and herbaceous appropriate section objectives from the following plants that caused their spectacular radiation in the outline. Keep these objectives in mind and, as you read Cenozoic. the chapter section, search for the information that will enable you to meet each objective. Once you have finished a section, write out answers for its objectives. Cenozoic Marine Life (pp. 550-552) 1. List examples of major invertebrate groups that were missing from Cenozoic seas. 6. Discuss the diversification of birds in the Cenozoic, and the dominant roles they played. 2. Describe the diversification of foraminifera during the early Cenozoic. 7. Marsupial mammals developed in both South America and Australia. Why did those in South America suffer greatly from extinction in the Pliocene Epoch, but those in Australia have survived untouched until modern times? 3. Which marine invertebrates seemed little affected by the Cretaceous-Tertiary extinction event? 8. Describe the different stages in the development of the modern horse. What features underwent the most change, and why? 4. Describe the various forms that led to the evolution of whales from original land-based predators. Copyright © Houghton Mifflin Company. All rights reserved. 237 Quaternary Extinctions (pp. 560-562) CHAPTER REVIEW 9. Describe the kinds of animals, both mammal and When you have finished reading the chapter, work bird, that were lost in the late Quaternary extinction through the material that follows to review it.
    [Show full text]
  • Name of Presenter: Tamara Yankovich
    Welcome! Dear Conference Participant: Welcome to Saskatoon and to our conference Applications of Stable Isotope Techniques to Ecological Studies! This meeting involves a unique blend of researchers and students associated with universities, government and industry who share a common interest in learning more about how stable isotope techniques can increase our understanding of ecological processes. Our decision to host this meeting was based on both an appreciation for just how rapidly this field is developing and a realization that presentations of work in this field were typically embedded as workshops within other, larger meetings. With the advent of continuous flow isotope ratio mass spectrometry and several other technological advances, applications of stable isotope analyses to ecological studies are increasing at a tremendous rate. Never before has the need for a dedicated meeting, dealing specifically with both the intricacies of the analytical side and applications involving single organisms through global processes been so great! It is our hope that this meeting will form the basis of a regular event, perhaps every few years, with the venue changing to other centers of isotopic and ecological research. Our program is an exciting one. We are particularly fortunate to have Dr. Marilyn L. Fogel as our keynote speaker. Dr. Fogel's work truly epitomizes the multidisciplinary nature of research involving naturally occurring stable isotopes. We have several theme sessions in our regular program and an extensive poster session. Finally, we look forward to a wrap-up open forum where you can discuss any aspect of topics covered in the conference. We hope that you enjoy your stay in Saskatoon, take time to enjoy the Canadian Prairies in spring, and moreover have a productive and rewarding meeting.
    [Show full text]