DOCSLIB.ORG

A Radiation of Arboreal Basal Eutherian Mammals Beginning in the Late Cretaceous of India

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
A Radiation of Arboreal Basal Eutherian Mammals Beginning in the Late Cretaceous of India A radiation of arboreal basal eutherian mammals beginning in the Late Cretaceous of India Anjali Goswamia,b,1, Guntupalli V. R. Prasadc, Paul Upchurchb, Doug M. Boyerd, Erik R. Seifferte, Omkar Vermaf, Emmanuel Gheerbrantg, and John J. Flynnh aDepartment of Genetics, Evolution, and Environment, bDepartment of Earth Sciences, University College London, London WC1E 6BT, United Kingdom; cDepartment of Geology, Centre for Advanced Studies, University of Delhi, Delhi 110 007, India; dDepartment of Anthropology and Archaeology, Brooklyn College, City University of New York, Brooklyn, NY 11210; eDepartment of Anatomical Sciences, Stony Brook University, Stony Brook, NY 11794-8081; fSchool of Sciences, Indira Gandhi National Open University, New Delhi 110 068, India; gUnité Mixte de Recherche 7207 du Centre National de la Recherche Scientifique (CR2P), Département Histoire de la Terre, Muséum National d’Histoire Naturelle, 75005 Paris, France; and hDivision of Paleontology and Richard Gilder Graduate School, American Museum of Natural History, New York, NY 10024 Edited* by Elwyn L. Simons, Duke University, Durham, NC, and approved August 15, 2011 (received for review June 6, 2011) India’s Late Cretaceous fossil mammals include the only undis- cluding placentals and their stem relatives) are known from the puted pre-Tertiary Gondwanan eutherians, such as Deccanolestes. Late Cretaceous of Laurasia (North America, Europe, and Asia) Recent studies have suggested a relationship between Deccano- (9), and although a few have been suggested as possible pla- lestes and African and European Paleocene adapisoriculids, which centals [e.g., Protungulatum (10)], none are unequivocally sup- have been variably identified as stem euarchontans, stem pri- ported as a Cretaceous placental mammal (2). With over 4,969 mates, lipotyphlan insectivores, or afrosoricids. Support for a close small-mammal fossils recovered from Mesozoic deposits world- relationship between Deccanolestes and any of these placental wide (ref. 9: occurence matrix downloaded using the parameters fi mammal clades would be unique in representing a con rmed Me- taxon = Mammalia, interval = Cretaceous; species data down- sozoic record of a placental mammal. However, some paleogeo- loaded using the parameters: taxon = Eutheria, interval = graphic reconstructions place India at its peak isolation from all Cretaceous), the absence of placentals cannot easily be ascribed other continents during the latest Cretaceous, complicating recon- to unsuitable preservation conditions across such a broad spec- structions of the biogeographic history of the placental radiation. EVOLUTION trum of temporal, geographic, and paleoenvironmental settings Recent fieldwork in India has recovered dozens of better-pre- (11). One possible explanation for the contradiction between the served specimens of Cretaceous eutherians, including several observed record and molecular age estimates is that molecular new species. Here, we incorporate these new specimens into an fl extensive phylogenetic analysis that includes every clade with a clocks for placentals may be awed and inaccurately reconstruct previously hypothesized relationship to Deccanolestes. Our results estimated divergence ages. Alternatively, some of the described support a robust relationship between Deccanolestes and Paleo- Cretaceous eutherians may be stem members of particular pla- cene adapisoriculids, but do not support a close affinity between cental lineages, but had not yet evolved the osteological syna- these taxa and any placental clade, demonstrating that Deccano- pomorphies of their crown clades, the presence of which would lestes is not a Cretaceous placental mammal and reinforcing the be necessary for accurate cladistic placement. Finally, Late sizeable gap between molecular and fossil divergence time esti- Cretaceous placentals may exist, but remain unsampled if pla- mates for the placental mammal radiation. Instead, our expanded centals originated where the fossil record is poor, specifically in data push Adapisoriculidae, including Deccanolestes, into a much the Late Cretaceous of Gondwana (11) [South America, Africa, more basal position than in earlier analyses, strengthening hypoth- Antarctica, Madagascar, India, and Australia: fewer than 5% of eses that scansoriality and arboreality were prevalent early in euthe- Cretaceous fossil mammal localities are Gondwanan (9)]. rian evolution. This comprehensive phylogeny indicates that faunal Among Gondwanan landmasses, India has been of particular exchange occurred between India, Africa, and Europe in the Late interest for decades (12), since the discovery of the first un- Cretaceous-Early Paleocene, and suggests a previously unrecognized disputed Cretaceous Gondwanan eutherian, Deccanolestes hislopi ∼30 to 45 Myr “ghost lineage” for these Gondwanan eutherians. (13). The Indian subcontinent’s lengthy northward migration, starting with Gondwanan breakup from the Middle Jurassic (178– placentals | paleobiogeography | phylogenetics | dispersal 161 Mya) to its collision with Asia in the Eocene (14), has fueled discussions about an Indian “Garden of Eden” for placental espite substantial augmentation of the Mesozoic record of mammals (12). To date, five species of eutherians have been Dmammals and improvements in calibration methods for named from India’s Upper Cretaceous (Maastrichtian, 70.6– molecular clock estimators, the age of origin of placental mam- 65.5 Mya) intertrappean beds: D. hislopi (13), Deccanolestes mals remains hotly debated (1, 2). Molecular clock estimates robustus (15), Deccanolestes narmadensis (16), Sahnitherium ran- consistently place the earliest divergences within Placentalia as gapurensis (17), and Kharmerungulatum vanvaleni (18). Sahnithe- falling within the Late Cretaceous (99.6–65.5 Mya) (3), or even rium is known from only a single molar and has been qualitatively – in the Early Cretaceous (145.5 99.6 Mya) (1), but the existence compared with “zhelestids,” but also shares many morphological of placental fossils from pre-Paleocene (older than 65.5 Mya) similarities with Deccanolestes (17) (see Materials and Methods). deposits is highly contentious (2). These ancient molecular di- Kharmerungulatum is also known from a single, heavily worn vergence age estimates and the absence of Cretaceous placentals can be reconciled by proposing that the first 20 to 40 Myr (or 25– ’ 50%) of this group s fossil record is missing entirely. A few re- Author contributions: A.G., G.V.R.P., P.U., and D.M.B. designed research; A.G., G.V.R.P., cent studies using statistical models that incorporate gaps in the D.M.B., E.R.S., O.V., E.G., and J.J.F. performed research; A.G. and P.U. analyzed data; and fossil record to estimate divergence times, either from fossil A.G. wrote the paper. occurrences alone or combined with molecular data, have pro- The authors declare no conflict of interest. duced results more similar to molecular clock dates (81–88 Mya) *This Direct Submission article had a prearranged editor. for the origin of Primates (4, 5), but other quantitative analyses 1To whom correspondence should be addressed. E-mail: [email protected]. based on the fossil record dispute these early divergence esti- This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10. mates (6–8). At least 70 species of eutherians (the clade in- 1073/pnas.1108723108/-/DCSupplemental. www.pnas.org/cgi/doi/10.1073/pnas.1108723108 PNAS Early Edition | 1of6 Downloaded by guest on September 30, 2021 molar, and was described as a possible placental mammal, specifi- cally a “condylarth” (18). D. hislopi is the only Indian Cretaceous eutherian to have been included in a few previous phylogenetic analyses, which have returned mixed results. Analyses based on the first described, heavily worn dental specimens placed Deccanolestes as a stem eutherian, outside of placentals (2), consistent with the “paleo- ryctid-like” dental morphology noted in its original description (13). In contrast, phylogenetic analyses based on tarsal elements, which show arboreal specializations such as an enlarged peroneal tubercle of the calcaneum and confluence of the navicular and sustentacular facets (19) (Fig. S1), have placed Deccanolestes as a stem member of Euarchonta (primates, colugos, and tree shrews), well within Placentalia (20). However, recent qualitative studies have suggested a relationship between Deccanolestes and African and European Paleocene adapisoriculids (16, 21, 22)— which have been variably identified as stem euarchontans (21), stem primates (23), lipotyphlan insectivores (24), or afrosoricids (25)—but this relationship has never been tested with a phylo- genetic analysis. Support for a close relationship between Dec- canolestes and any of these placental mammal clades would be unique in representing a confirmed Mesozoic fossil record of a placental mammal. At present then, Deccanolestes and Khar- merungulatum represent some of the best potential evidence for pre-Tertiary placentals, and thus lie at the heart of resolving the debate over the timing of placental origins. Fig. 1. Relationships of Deccanolestes to other eutherians. Simplified re- Recent discoveries of many more and better-preserved dental, duced strict consensus tree using the Exafroplacentalia crown group con- mandibular (16), and postcranial (22) specimens, the result of straint. Shaded area, Cretaceous period (145.5–65.5 Mya). Positions of years of fieldwork in Central and South India, provide an op- terminal branches indicate the
Load more

Recommended publications
  • Digital Reconstruction of the Inner Ear of Leptictidium Auderiense
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by RERO DOC Digital Library Published in "Paläontologische Zeitschrift 90(1): 153–171, 2016" which should be cited to refer to this work. Digital reconstruction of the inner ear of Leptictidium auderiense (Leptictida, Mammalia) and North American leptictids reveals new insight into leptictidan locomotor agility Irina Ruf1,2 • Virginie Volpato1,3 • Kenneth D. Rose4 • Guillaume Billet2,5 • Christian de Muizon5 • Thomas Lehmann1 Abstract Leptictida are basal Paleocene to Oligocene semicircular canals than the leptictids under study. Our eutherians from Europe and North America comprising estimations reveal that Leptictidium was a very agile ani- species with highly specialized postcranial features mal with agility score values (4.6 and 5.5, respectively) including elongated hind limbs. Among them, the Euro- comparable to Macroscelidea and extant bipedal saltatory pean Leptictidium was probably a bipedal runner or jum- placentals. Leptictis and Palaeictops have lower agility per. Because the semicircular canals of the inner ear are scores (3.4 to 4.1), which correspond to the more gener- involved in detecting angular acceleration of the head, their alized types of locomotion (e.g., terrestrial, cursorial) of morphometry can be used as a proxy to elucidate the agility most extant mammals. In contrast, the angular velocity in fossil mammals. Here we provide the first insight into magnitude predicted from semicircular canal angles sup- inner ear anatomy and morphometry of Leptictida based on ports a conflicting pattern of agility among leptictidans, but high-resolution computed tomography of a new specimen the significance of these differences might be challenged of Leptictidium auderiense from the middle Eocene Messel when more is known about intraspecific variation and the Pit (Germany) and specimens of the North American pattern of semicircular canal angles in non-primate Leptictis and Palaeictops.
    [Show full text]
  • Stratigraphic Paleobiology of an Evolutionary Radiation: Taphonomy and Facies Distribution of Cetaceans in the Last 23 Million Years
    Fossilia, Volume 2018: 15-17 Stratigraphic paleobiology of an evolutionary radiation: taphonomy and facies distribution of cetaceans in the last 23 million years Stefano Dominici1, Simone Cau2 & Alessandro Freschi2 1 Museo di Storia Naturale, Università degli Studi di Firenze, Firenze, Italy; [email protected] 2 Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale, Università degli Studi di Parma, Parma, Italy; cau.simo- [email protected], [email protected] BULLET-POINTS ABSTRACT KEYWORDS: • The majority of cetacean fossils are in Zanclean and Piacenzian deposits. Neogene; • Cetacean fossils are preferentially found in offshore paleosettings. Pliocene; • Pleistocene findings drop to a minimum, notwithstanding offshore strata are Cetaceans; well represented in the record. Taphonomy. • A taphonomic imprinting on the cetacean fossil record is hypothesised, con- nected with a radiation of whale-bone consumers of modern type. offer a particularly rich cetacean fossil record and an INTRODUCTION area where available studies allow to explore this key The study of the stratigraphy and taphonomy of Neo- time of cetacean evolution at a stratigraphic resolution gene cetaceans is a fundamental step to properly frame finer than the stage. An increase in cetaceans diversity the evolutionary radiation of this megafauna, at the is recorded around 3.2 – 3.0 Ma, in coincidence of top of the pelagic marine ecosystem. Major evolutio- the mid-Piacenzian climatic optimum, and a drastic nary steps have been summarised in recent
    [Show full text]
  • Diversity Partitioning During the Cambrian Radiation
    Diversity partitioning during the Cambrian radiation Lin Naa,1 and Wolfgang Kiesslinga,b aGeoZentrum Nordbayern, Paleobiology and Paleoenvironments, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany; and bMuseum für Naturkunde, Leibniz Institute for Research on Evolution and Biodiversity at the Humboldt University Berlin, 10115 Berlin, Germany Edited by Douglas H. Erwin, Smithsonian National Museum of Natural History, Washington, DC, and accepted by the Editorial Board March 10, 2015 (received for review January 2, 2015) The fossil record offers unique insights into the environmental and Results geographic partitioning of biodiversity during global diversifica- Raw gamma diversity exhibits a strong increase in the first three tions. We explored biodiversity patterns during the Cambrian Cambrian stages (informally referred to as early Cambrian in this radiation, the most dramatic radiation in Earth history. We as- work) (Fig. 1A). Gamma diversity dropped in Stage 4 and de- sessed how the overall increase in global diversity was partitioned clined further through the rest of the Cambrian. The pattern is between within-community (alpha) and between-community (beta) robust to sampling standardization (Fig. 1B) and insensitive to components and how beta diversity was partitioned among environ- including or excluding the archaeocyath sponges, which are po- ments and geographic regions. Changes in gamma diversity in the tentially oversplit (16). Alpha and beta diversity increased from Cambrian were chiefly driven by changes in beta diversity. The the Fortunian to Stage 3, and fluctuated erratically through the combined trajectories of alpha and beta diversity during the initial following stages (Fig. 2). Our estimate of alpha (and indirectly diversification suggest low competition and high predation within beta) diversity is based on the number of genera in published communities.
    [Show full text]
  • Classification of Mammals 61
    © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FORCHAPTER SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Classification © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC 4 NOT FORof SALE MammalsOR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. 2ND PAGES 9781284032093_CH04_0060.indd 60 8/28/13 12:08 PM CHAPTER 4: Classification of Mammals 61 © Jones Despite& Bartlett their Learning,remarkable success, LLC mammals are much less© Jones stress & onBartlett the taxonomic Learning, aspect LLCof mammalogy, but rather as diverse than are most invertebrate groups. This is probably an attempt to provide students with sufficient information NOT FOR SALE OR DISTRIBUTION NOT FORattributable SALE OR to theirDISTRIBUTION far greater individual size, to the high on the various kinds of mammals to make the subsequent energy requirements of endothermy, and thus to the inabil- discussions of mammalian biology meaningful.
    [Show full text]
  • The World at the Time of Messel: Conference Volume
    T. Lehmann & S.F.K. Schaal (eds) The World at the Time of Messel - Conference Volume Time at the The World The World at the Time of Messel: Puzzles in Palaeobiology, Palaeoenvironment and the History of Early Primates 22nd International Senckenberg Conference 2011 Frankfurt am Main, 15th - 19th November 2011 ISBN 978-3-929907-86-5 Conference Volume SENCKENBERG Gesellschaft für Naturforschung THOMAS LEHMANN & STEPHAN F.K. SCHAAL (eds) The World at the Time of Messel: Puzzles in Palaeobiology, Palaeoenvironment, and the History of Early Primates 22nd International Senckenberg Conference Frankfurt am Main, 15th – 19th November 2011 Conference Volume Senckenberg Gesellschaft für Naturforschung IMPRINT The World at the Time of Messel: Puzzles in Palaeobiology, Palaeoenvironment, and the History of Early Primates 22nd International Senckenberg Conference 15th – 19th November 2011, Frankfurt am Main, Germany Conference Volume Publisher PROF. DR. DR. H.C. VOLKER MOSBRUGGER Senckenberg Gesellschaft für Naturforschung Senckenberganlage 25, 60325 Frankfurt am Main, Germany Editors DR. THOMAS LEHMANN & DR. STEPHAN F.K. SCHAAL Senckenberg Research Institute and Natural History Museum Frankfurt Senckenberganlage 25, 60325 Frankfurt am Main, Germany [email protected]; [email protected] Language editors JOSEPH E.B. HOGAN & DR. KRISTER T. SMITH Layout JULIANE EBERHARDT & ANIKA VOGEL Cover Illustration EVELINE JUNQUEIRA Print Rhein-Main-Geschäftsdrucke, Hofheim-Wallau, Germany Citation LEHMANN, T. & SCHAAL, S.F.K. (eds) (2011). The World at the Time of Messel: Puzzles in Palaeobiology, Palaeoenvironment, and the History of Early Primates. 22nd International Senckenberg Conference. 15th – 19th November 2011, Frankfurt am Main. Conference Volume. Senckenberg Gesellschaft für Naturforschung, Frankfurt am Main. pp. 203.
    [Show full text]
  • Ecological Causes of Uneven Diversification and Richness in the Mammal Tree of Life
    bioRxiv preprint doi: https://doi.org/10.1101/504803; this version posted March 28, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. 1 Ecological causes of uneven diversification and richness in the mammal tree of life 2 Short title: Ecological causes of diversification in mammals 3 4 Nathan S. Upham1*, Jacob A. Esselstyn2, and Walter Jetz1* 5 6 Author affiliations: 1Department of Ecology & Evolutionary Biology, Yale University, New 7 Haven, CT 06511 USA. 2Department of Biological Sciences and Museum of Natural Science, 8 Louisiana State University, Baton Rouge, LA 70803 USA. 9 10 *Corresponding authors: 165 Prospect St., OML 122, New Haven, CT 06511 USA; 11 [email protected]; [email protected] 12 bioRxiv preprint doi: https://doi.org/10.1101/504803; this version posted March 28, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. 13 Abstract 14 The uneven distribution of species in the tree of life is rooted in unequal speciation and 15 extinction among groups. Yet the causes of differential diversification are little known despite 16 their relevance for sustaining biodiversity into the future. Here we investigate rates of species 17 diversification across extant Mammalia, a compelling system that includes our own closest 18 relatives.
    [Show full text]
  • Evolutionary and Functional Implications of Incisor Enamel Microstructure Diversity in Notoungulata (Placentalia, Mammalia)
    Journal of Mammalian Evolution https://doi.org/10.1007/s10914-019-09462-z ORIGINAL PAPER Evolutionary and Functional Implications of Incisor Enamel Microstructure Diversity in Notoungulata (Placentalia, Mammalia) Andréa Filippo1 & Daniela C. Kalthoff2 & Guillaume Billet1 & Helder Gomes Rodrigues1,3,4 # The Author(s) 2019 Abstract Notoungulates are an extinct clade of South American mammals, comprising a large diversity of body sizes and skeletal morphologies, and including taxa with highly specialized dentitions. The evolutionary history of notoungulates is characterized by numerous dental convergences, such as continuous growth of both molars and incisors, which repeatedly occurred in late- diverging families to counter the effects of abrasion. The main goal of this study is to determine if the acquisition of high-crowned incisors in different notoungulate families was accompanied by significant and repeated changes in their enamel microstructure. More generally, it aims at identifying evolutionary patterns of incisor enamel microstructure in notoungulates. Fifty-eight samples of incisors encompassing 21 genera of notoungulates were sectioned to study the enamel microstructure using a scanning electron microscope. We showed that most Eocene taxa were characterized by an incisor schmelzmuster involving only radial enamel. Interestingly, derived schmelzmusters involving the presence of Hunter-Schreger bands (HSB) and of modified radial enamel occurred in all four late-diverging families, mostly in parallel with morphological specializations, such as crown height increase. Despite a high degree of homoplasy, some characters detected at different levels of enamel complexity (e.g., labial versus lingual sides, upper versus lower incisors) might also be useful for phylogenetic reconstructions. Comparisons with perissodactyls showed that notoungulates paralleled equids in some aspects related to abrasion resistance, in having evolved transverse to oblique HSB combined with modified radial enamel and high-crowned incisors.
    [Show full text]
  • Learning About Mammals
    Learning About Mammals The mammals (Class Mammalia) includes everything from mice to elephants, bats to whales and, of course, man. The amazing diversity of mammals is what has allowed them to live in any habitat from desert to arctic to the deep ocean. They live in trees, they live on the ground, they live underground, and in caves. Some are active during the day (diurnal), while some are active at night (nocturnal) and some are just active at dawn and dusk (crepuscular). They live alone (solitary) or in great herds (gregarious). They mate for life (monogamous) or form harems (polygamous). They eat meat (carnivores), they eat plants (herbivores) and they eat both (omnivores). They fill every niche imaginable. Mammals come in all shapes and sizes from the tiny pygmy shrew, weighing 1/10 of an ounce (2.8 grams), to the blue whale, weighing more than 300,000 pounds! They have a huge variation in life span from a small rodent living one year to an elephant living 70 years. Generally, the bigger the mammal, the longer the life span, except for bats, which are as small as rodents, but can live for up to 20 years. Though huge variation exists in mammals, there are a few physical traits that unite them. 1) Mammals are covered with body hair (fur). Though marine mammals, like dolphins and whales, have traded the benefits of body hair for better aerodynamics for traveling in water, they do still have some bristly hair on their faces (and embryonically - before birth). Hair is important for keeping mammals warm in cold climates, protecting them from sunburn and scratches, and used to warn off others, like when a dog raises the hair on its neck.
    [Show full text]
  • New Large Leptictid Insectivore from the Late Paleogene of South Dakota, USA
    New large leptictid insectivore from the Late Paleogene of South Dakota, USA TJ MEEHAN and LARRY D. MARTIN Meehan, T.J. and Martin, L.D. 2012. New large leptictid insectivore from the Late Paleogene of South Dakota, USA. Acta Palaeontologica Polonica 57 (3): 509–518. From a skull and mandible, we describe a new genus and species of a primitive insectivore (Mammalia: Insectivora: Leptictida: Leptictidae). Its large body size and higher−crowned teeth indicate a different feeding ecology from other leptictid insectivores. With evidence of some heavy, flat wear on the molariform teeth, its shift in diet was likely to greater herbivory. Unlike the narrow snout of Blacktops, this new leptictid retains a broad snout, suggesting that small verte− brates were still important dietary components. The specimen was collected from the floodplain deposits of the lower or middle White River Group of South Dakota, which represent the latest Eocene to earliest Oligocene (Chadronian and Orellan North American Land Mammal “Ages”). Key words: Mammalia, Leptictidae, Leptictis, Megaleptictis, Eocene, Oligocene, White River Group, South Dakota, North America. TJ Meehan [[email protected]], Research Associate, Section of Vertebrate Paleontology, Carnegie Museum of Natural History, 4400 Forbes Avenue, Pittsburgh, PA 15213, USA; Larry D. Martin [[email protected]], Division of Vertebrate Paleontology, Natural History Museum and Biodiversity Re− search Center, University of Kansas, Lawrence, KS 66045, USA. Received 4 April 2011, accepted 25 July 2011, available online 17 August 2011. Introduction molariform teeth. A fossa in this region at least suggests in− creased snout mobility, but no definitive anatomical argument Leptictida is a primitive order of placental, insectivorous has been made to support a highly mobile cartilaginous snout mammals convergent to extant sengis or elephant “shrews” tip, as in sengis.
    [Show full text]
  • Mammalian Evolution May Not Be Strictly Bifurcating Open Access
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE Mammalian Evolution May not Be Strictly Bifurcating provided by PubMed Central Bjo¨rn M. Hallstro¨m1 and Axel Janke*,2 1Department of Cell and Organism Biology, Division of Evolutionary Molecular Systematics, University of Lund, Lund, Sweden 2LOEWE—Biodiversita¨t und Klima Forschungszentrum BiK-F, Frankfurt, Germany *Corresponding author: E-mail: [email protected]. Associate editor: Arndt von Haeseler Abstract The massive amount of genomic sequence data that is now available for analyzing evolutionary relationships among 31 placental mammals reduces the stochastic error in phylogenetic analyses to virtually zero. One would expect that this would make it possible to finally resolve controversial branches in the placental mammalian tree. We analyzed a 2,863,797 nucleotide- Research article long alignment (3,364 genes) from 31 placental mammals for reconstructing their evolution. Most placental mammalian relationships were resolved, and a consensus of their evolution is emerging. However, certain branches remain difficult or virtually impossible to resolve. These branches are characterized by short divergence times in the order of 1–4 million years. Computer simulations based on parameters from the real data show that as little as about 12,500 amino acid sites could be sufficient to confidently resolve short branches as old as about 90 million years ago (Ma). Thus, the amount of sequence data should no longer be a limiting factor in resolving the relationships among placental mammals. The timing of the early radiation of placental mammals coincides with a period of climate warming some 100–80 Ma and with continental fragmentation.
    [Show full text]
  • New Mammals from the Marine Selandian of Maret, Belgium, and Their Implications for the Age of the Paleocene Continental Deposits of Walbeek, Germany
    GEOLOGICA BELGICA (2013) 16/4: 236-244 New mammals from the marine Selandian of Maret, Belgium, and their implications for the age of the Paleocene continental deposits of Walbeek, Germany Eric DE BAST, Etienne STEURBAUT & Thierry SMITH O.D. Earth and History ofLife, Royal Belgian Institute for Natural Sciences, Rue lautier 29, 1000 Brussels, Belgium ABSTRACT. The early to middle Selandian fossiliferous Orp Sand Member of the Heers Fonnation in Belgium has regularly been excavated at its type-locality Maret for its rich and diversified selachian fauna. Among the abundant vertebrate remains, extremely rare mammal specimens have been found. Three isolated teeth have been published previously, all with uncertain affinities. The purpose of this study is to present new specimens from the same deposits, including a small well-preserved dentary of an adapisoriculid attributable to “Afrodon” germanicus, a fragmentary upper molar, referred to Berndestes sp., and a premolar of a large arctocyonid. Among the previous specimens we identified Arctocyonides cf. weigeld. The adapisoriculid dentary offers new clues that allow transferring “Afrodon’ germanicus to tile genus Bustylus. The five mammal taxa from Maret indicate an age intermediate between reference-levels MP1-5 of Hainin, Belgium and MP6 of Cemay, France and present the greatest correlation with the rich Walbeek fauna in Germany. The deposits from Walbeek were usually thought to be slightly older than the late Thanetian deposits of Cemay. We infer here that the age of Walbeek is likely to be Selandian. The strong differences observed between Hainin on the one hand, and Walbeek and Cemay on tile other hand, document a dispersal event from North America to Europe around the Danian-Selandian boundary.
    [Show full text]
  • 71St Annual Meeting Society of Vertebrate Paleontology Paris Las Vegas Las Vegas, Nevada, USA November 2 – 5, 2011 SESSION CONCURRENT SESSION CONCURRENT
    ISSN 1937-2809 online Journal of Supplement to the November 2011 Vertebrate Paleontology Vertebrate Society of Vertebrate Paleontology Society of Vertebrate 71st Annual Meeting Paleontology Society of Vertebrate Las Vegas Paris Nevada, USA Las Vegas, November 2 – 5, 2011 Program and Abstracts Society of Vertebrate Paleontology 71st Annual Meeting Program and Abstracts COMMITTEE MEETING ROOM POSTER SESSION/ CONCURRENT CONCURRENT SESSION EXHIBITS SESSION COMMITTEE MEETING ROOMS AUCTION EVENT REGISTRATION, CONCURRENT MERCHANDISE SESSION LOUNGE, EDUCATION & OUTREACH SPEAKER READY COMMITTEE MEETING POSTER SESSION ROOM ROOM SOCIETY OF VERTEBRATE PALEONTOLOGY ABSTRACTS OF PAPERS SEVENTY-FIRST ANNUAL MEETING PARIS LAS VEGAS HOTEL LAS VEGAS, NV, USA NOVEMBER 2–5, 2011 HOST COMMITTEE Stephen Rowland, Co-Chair; Aubrey Bonde, Co-Chair; Joshua Bonde; David Elliott; Lee Hall; Jerry Harris; Andrew Milner; Eric Roberts EXECUTIVE COMMITTEE Philip Currie, President; Blaire Van Valkenburgh, Past President; Catherine Forster, Vice President; Christopher Bell, Secretary; Ted Vlamis, Treasurer; Julia Clarke, Member at Large; Kristina Curry Rogers, Member at Large; Lars Werdelin, Member at Large SYMPOSIUM CONVENORS Roger B.J. Benson, Richard J. Butler, Nadia B. Fröbisch, Hans C.E. Larsson, Mark A. Loewen, Philip D. Mannion, Jim I. Mead, Eric M. Roberts, Scott D. Sampson, Eric D. Scott, Kathleen Springer PROGRAM COMMITTEE Jonathan Bloch, Co-Chair; Anjali Goswami, Co-Chair; Jason Anderson; Paul Barrett; Brian Beatty; Kerin Claeson; Kristina Curry Rogers; Ted Daeschler; David Evans; David Fox; Nadia B. Fröbisch; Christian Kammerer; Johannes Müller; Emily Rayfield; William Sanders; Bruce Shockey; Mary Silcox; Michelle Stocker; Rebecca Terry November 2011—PROGRAM AND ABSTRACTS 1 Members and Friends of the Society of Vertebrate Paleontology, The Host Committee cordially welcomes you to the 71st Annual Meeting of the Society of Vertebrate Paleontology in Las Vegas.
    [Show full text]