DOCSLIB.ORG

(Microsyopidae, Primates) from the Paleocene-Eocene Thermal Maximum: One Species Or Two?

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
(Microsyopidae, Primates) from the Paleocene-Eocene Thermal Maximum: One Species Or Two? Molar Size and Shape Variation in a Large Sample of Niptomomys (Microsyopidae, Primates) from the Paleocene-Eocene Thermal Maximum: One Species or Two? by Rosa S. Felibert Department of Anthropology University of Florida 2017 ABSTRACT The oldest euprimates first appear during a period of rapid, short-term, global warming ~56 mya known as the Paleocene-Eocene Thermal Maximum (PETM). Plesiadapiform primates of similar size and dental morphology to euprimates were present in North America before the PETM, and may have been affected by the arrival of euprimates as ecological competitors. Screenwashing PETM fossil localities in the Bighorn Basin, Wyoming, has yielded many fossils (N≈600) of the microsyopid plesiadapiform Niptomomys. N. doreenae is known from before and after the PETM and may range through it. A second taxon, N. favorum, characterized by its small size and squarer M2 occlusal outline, was described from the large Castle Gardens locality sample. To better characterize PETM primate diversity, we test the validity of N. favorum against a sample of Niptomomys from Castle Gardens, other PETM localities, and published measurements. M2 occlusal outlines (N=62) revealed a continuous range from square to lingually compressed that encompasses the holotype of N. favorum. Linear measurements of M1 (N=127) and M2 (N=163) indicated M1’s from Castle Gardens are larger than those of later PETM localities (p=0.038), but produced no outliers, suggesting the PETM fauna contains one species of Niptomomys. PETM lower molars are smaller than all other measured Niptomomys teeth, paralleling the response to warming effects recorded in larger-bodied mammal lineages. These results are consistent with either a single lineage of Niptomomys that became smaller during the PETM, or a small immigrant taxon (N. favorum) that was transitionally present in the Bighorn Basin during the PETM. 1 INTRODUCTION The Paleocene-Eocene Thermal Maximum (PETM) was a rapid warming event that occurred about 56 million years ago (mya), during which global temperatures increased ~5-8 degrees C in the span of 20,000 years or less. The entire event lasted 200,000 years and was caused by an increase in the amount of carbon dioxide (CO2) in the atmosphere (McInerney & Wing, 2011). This warming event facilitated the dispersal and dwarfing of mammals in North America, as well as the migration of euprimates, or primates of modern aspect (Bloch, Silcox, Boyer, & Sargis, 2007). The arrival of euprimates to North America may have caused ecological competition with endemic plesiadapiforms, a sister group of euprimates (Bloch, Silcox, Boyer, & Sargis, 2007; Gingerich, 2003). Adaptive changes may have occurred during the PETM to fill new and rapidly shifting ecological niches, and these provide the setting of this paper. One such adaptive change is body size. Many studies (Fleagle, 1978; Hutchinson & MacArthur, 1959; Newell, 1949; Cope, 1887; Gould, 1966; Gingerich & Smith, 1985; Peters, 1986; Maurer, Brown, & Rusler, 1992) have shown that body size is important when studying the ecology of past organisms, as well as when attempting to reconstruct an extinct taxon’s biology and life history. One such group of extinct organisms is the suborder of primitive primate-like mammals, Plesiadapiformes. Plesiadapiforms appear in the fossil record ~65 mya and have been argued to have shared a recent common ancestor with euprimates (Bloch, Silcox, Boyer, & Sargis, 2007). This group of mammals, which flourished during the Paleocene and Early Eocene of North America, shares numerous traits with living primates, even including a species with a nail instead of the more primitive claw (Bloch 2 & Boyer, 2002). Understanding plesiadapiforms is a crucial component to understanding primate evolution, and therefore, our own evolutionary history. The suborder Plesiadapiformes contains 12 families (Bloch, Silcox, Boyer, & Sargis, 2007; Silcox, 2001; Silcox & Gunnell, 2008). One of these is Microsyopidae, a diverse family of over 20 species that ranged from the Late Paleocene through Middle Eocene of North America (Fleagle, 2013; Gunnell, 1989; Silcox & Gunnell, 2008). Fossils of the microsyopid plesiadapiform genus Niptomomys have been found in North America ranging from before, during, and after the PETM. To date, there have been three species of Niptomomys identified: N. doreenae, N. thelmae, and the more elusive N. favorum. N. favorum from the Castle Gardens locality in the Bighorn Basin, Wyoming, was diagnosed based on an isolated M1/2 (UCMP 212635) as being smaller and squarer in occlusal outline than N. doreenae and N. thelmae, (Strait, 2001). The extant primate literature has shown that there is a high correlation between tooth size, specifically lower cheek teeth, and body size (Gingerich, 1974; Gingerich & Schoeninger, 1979; Gingerich & Smith, 1985; Gingerich, Smith, & Rosenberg, 1982; Pilbeam & Gould, 1974). This study assessed the occlusal outline of upper molars from Castle Gardens and measured a large sample of M1 and M2 Niptomomys specimens to determine whether N. favorum can be identified as a separate species existing alongside N. doreenae during the PETM, or if specimens attributed to N. favorum from Castle Gardens are merely a manifestation of dwarfing with a continuous N. doreenae lineage through the PETM, as has been observed in other PETM lineages (Gingerich, 2003; Secord et al., 2012). 3 LITERATURE REVIEW The Paleocene-Eocene Thermal Maximum The PETM was a massive, rapid global warming event that caused temperatures to rise ~5-8 degrees Celsius at a rapid rate and persist for a span of ~200,000 years. There have been numerous contributions made to the literature about the PETM, its onset, and its ecological consequences for mammals. McInerney and Wing (2011) thoroughly discussed changes in the carbon cycle, precipitation, ecosystems, and temperature during the PETM, and compared its effects to the effects that similar, even more rapid, anthropogenic global warming event could have in the future. Chester and colleagues (2010) determined that rapid morphological change in carnivorous species occurred during the PETM as a way of adapting to the changing climate and the availability of food. This conclusion was based on Rosenzweig’s (1968) study on Actual Evapotranspiration (AE), the amount of water that is evaporated from soil and transpired from plants into the atmosphere, and its relationship with carnivore body size. AE is correlated with the availability of water and solar energy and is therefore a good predictor of mammalian carnivore productivity levels. Rosenzweig found that environments lacking either or both of these resources are scarce in food, which he found limited the body size of mammalian carnivores (Rosenzweig, 1968). Chester and colleagues (2010) interpreted this research and concluded that selective pressures, such as lack of water or increased temperature, could cause smaller body sizes in mammals during the PETM. Gingerich (2003) also related mammal body size to the PETM. His research showed that mammalian body size dwarves in the same strata where the PETM occurred, providing evidence that climate change and faunal size change are related. 4 He posited that two different types of changes in body size occurred: transient and permanent. A transient change in body size is especially interesting to study because evidence shows body size decreasing during the PETM and returning to pre-PETM size after the PETM. Gingerich (2003) posited that these adaptive changes had to happen for immigrant taxa, which could only migrate due to the conditions the PETM caused, to coexist with endemic taxa. Secord and colleagues (2012) related the PETM to mammal body size by discussing the change of body size in equids during and after the PETM. This was determined by examining the isotopic composition of mammal teeth and finding that body size in equids was negatively correlated with the temperatures inferred from the oxygen isotopes in those teeth. At the carbon isotope excursion (CIE) onset, equids had a 30% size decrease compared to a 76% size increase at the end of the CIE. This decrease in body size may have been caused by higher temperatures and increased CO2 concentrations in the atmosphere. This paper also depicts the correlation between the decrease of carbon-13 and the increase of oxygen-18 during the PETM, and suggests that environmental and faunal changes during the PETM occurred extremely rapidly. Importance of Body Size in Ecology Several studies have demonstrated the importance of body size in terms of ecology and macro- and microevolution (Fleagle, 1978; Hutchinson & MacArthur, 1959; Newell, 1949; Cope, 1887; Gould 1966; Speakman, 2005; Peters & Wassenberg, 1983; Schmidt-Nielsen, 1984; Kelt & Van Vuren, 1999; Savage et al., 2007; Duncan, Forsyth, & Hone, 2007; Capellini, Venditti, & Barton, 2010) 5 Peters (1983) provided a comprehensive book explaining the ways in which organism body size affects ecology. On a fundamental level, body size affects a number of physiological functions, such as metabolism, heat production and heat loss, rate of energy use, and dynamics of locomotion. He discussed that these effects on physiological function are the reason for the wide range of animal diversity on the planet. Schmidt-Nielsen (1984) also provided a comprehensive introduction to the topic of scaling and its importance in ecology. He described the concept of food extraction, the amount of food resources an animal consumes and how this directly affects population densities
Load more

Recommended publications
  • Paleoenvironment of the Late Eocene Chadronian-Age Whitehead Creek Locality (Northwestern Nebraska)
    St. Cloud State University theRepository at St. Cloud State Culminating Projects in Cultural Resource Management Department of Anthropology 10-2019 Paleoenvironment of the Late Eocene Chadronian-Age Whitehead Creek Locality (Northwestern Nebraska) Samantha Mills Follow this and additional works at: https://repository.stcloudstate.edu/crm_etds Part of the Archaeological Anthropology Commons Recommended Citation Mills, Samantha, "Paleoenvironment of the Late Eocene Chadronian-Age Whitehead Creek Locality (Northwestern Nebraska)" (2019). Culminating Projects in Cultural Resource Management. 28. https://repository.stcloudstate.edu/crm_etds/28 This Thesis is brought to you for free and open access by the Department of Anthropology at theRepository at St. Cloud State. It has been accepted for inclusion in Culminating Projects in Cultural Resource Management by an authorized administrator of theRepository at St. Cloud State. For more information, please contact [email protected]. Paleoenvironment of the Late Eocene Chadronian-Age Whitehead Creek Locality (Northwestern Nebraska) by Samantha M. Mills A Thesis Submitted to the Graduate Faculty of St. Cloud State University in Partial Fulfillment of the Requirements for the Degree of Master of Science in Functional Morphology October, 2019 Thesis Committee: Matthew Tornow, Chairperson Mark Muñiz Bill Cook Tafline Arbor 2 Abstract Toward the end of the Middle Eocene (40-37mya), the environment started to decline on a global scale. It was becoming more arid, the tropical forests were disappearing from the northern latitudes, and there was an increase in seasonality. Research of the Chadronian (37- 33.7mya) in the Great Plains region of North America has documented the persistence of several mammalian taxa (e.g. primates) that are extinct in other parts of North America.
    [Show full text]
  • Palaeontologia Electronica New Data on the Oxyaenidae from the Early
    Palaeontologia Electronica http://palaeo-electronica.org New data on the Oxyaenidae from the Early Eocene of Europe; biostratigraphic, paleobiogeographic and paleoecologic implications Floréal Solé, Emmanuel Gheerbrant and Marc Godinot ABSTRACT The locality of Le Quesnoy (France; MP7) has yielded a diversified mammal fauna including especially large mammals. Oxyaenidae are well documented with two spe- cies identified: Oxyaena woutersi and Palaeonictis gigantea. The Le Quesnoy material illustrates almost the entire dentition of these species. Its study supports the generic attribution of Oxyaena woutersi. Its M2 is more secant than in the primitive Dipsalidictis, but the M1 appears to be slightly less secant than in the earliest species of Oxyaena. Oxyaena woutersi is a morphological intermediate between the Clarkforkian-Wasat- chian Dipsalidictis and the Wasatchian Oxyaena. The M2 of Palaeonictis gigantea is compared to the sole known molar of Dormaalodon woutersi. Dormaalodon is here demonstrated to be a junior synonym of Palaeonictis. Several postcranial elements of Oxyaena woutersi and Palaeonictis gigantea are described: they are the first described for European oxyaenids. The oxyaenid species from Le Quesnoy and Dormaal show a close affinity and support an age very close to MP7 for Le Quesnoy. The Le Quesnoy oxyaenids are morphologically close to the North American species of Wa0, which sup- ports correlation with this level. We revised the European Oxyaenidae previously described from younger localities. Fossils from Meudon, Sinceny and Abbey Wood (MP8+9) are referred to Oxyaena sp. A North American origin of the Oxyaenidae is confirmed. Our study supports a single dispersal event of oxyaenids from North Amer- ica to Europe followed by a short endemic local evolution.
    [Show full text]
  • SMC 136 Gazin 1958 1 1-112.Pdf
    SMITHSONIAN MISCELLANEOUS COLLECTIONS VOLUME 136, NUMBER 1 Cftarlesi 3B, anb JKarp "^aux OTalcott 3^es(earcf) Jf unb A REVIEW OF THE MIDDLE AND UPPER EOCENE PRIMATES OF NORTH AMERICA (With 14 Plates) By C. LEWIS GAZIN Curator, Division of Vertebrate Paleontology United States National Museum Smithsonian Institution (Publication 4340) CITY OF WASHINGTON PUBLISHED BY THE SMITHSONIAN INSTITUTION JULY 7, 1958 THE LORD BALTIMORE PRESS, INC. BALTIMORE, MD., U. S. A. CONTENTS Page Introduction i Acknowledgments 2 History of investigation 4 Geographic and geologic occurrence 14 Environment I7 Revision of certain lower Eocene primates and description of three new upper Wasatchian genera 24 Classification of middle and upper Eocene forms 30 Systematic revision of middle and upper Eocene primates 31 Notharctidae 31 Comparison of the skulls of Notharctus and Smilodectcs z:^ Omomyidae 47 Anaptomorphidae 7Z Apatemyidae 86 Summary of relationships of North American fossil primates 91 Discussion of platyrrhine relationships 98 References 100 Explanation of plates 108 ILLUSTRATIONS Plates (All plates follow page 112) 1. Notharctus and Smilodectes from the Bridger middle Eocene. 2. Notharctus and Smilodectes from the Bridger middle Eocene. 3. Notharctus and Smilodectcs from the Bridger middle Eocene. 4. Notharctus and Hemiacodon from the Bridger middle Eocene. 5. Notharctus and Smilodectcs from the Bridger middle Eocene. 6. Omomys from the middle and lower Eocene. 7. Omomys from the middle and lower Eocene. 8. Hemiacodon from the Bridger middle Eocene. 9. Washakius from the Bridger middle Eocene. 10. Anaptomorphus and Uintanius from the Bridger middle Eocene. 11. Trogolemur, Uintasorex, and Apatcmys from the Bridger middle Eocene. 12. Apatemys from the Bridger middle Eocene.
    [Show full text]
  • Hyaenodontidae (Creodonta, Mammalia) and the Position of Systematics in Evolutionary Biology
    Hyaenodontidae (Creodonta, Mammalia) and the Position of Systematics in Evolutionary Biology by Paul David Polly B.A. (University of Texas at Austin) 1987 A dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Paleontology in the GRADUATE DIVISION of the UNIVERSITY of CALIFORNIA at BERKELEY Committee in charge: Professor William A. Clemens, Chair Professor Kevin Padian Professor James L. Patton Professor F. Clark Howell 1993 Hyaenodontidae (Creodonta, Mammalia) and the Position of Systematics in Evolutionary Biology © 1993 by Paul David Polly To P. Reid Hamilton, in memory. iii TABLE OF CONTENTS Introduction ix Acknowledgments xi Chapter One--Revolution and Evolution in Taxonomy: Mammalian Classification Before and After Darwin 1 Introduction 2 The Beginning of Modern Taxonomy: Linnaeus and his Predecessors 5 Cuvier's Classification 10 Owen's Classification 18 Post-Darwinian Taxonomy: Revolution and Evolution in Classification 24 Kovalevskii's Classification 25 Huxley's Classification 28 Cope's Classification 33 Early 20th Century Taxonomy 42 Simpson and the Evolutionary Synthesis 46 A Box Model of Classification 48 The Content of Simpson's 1945 Classification 50 Conclusion 52 Acknowledgments 56 Bibliography 56 Figures 69 Chapter Two: Hyaenodontidae (Creodonta, Mammalia) from the Early Eocene Four Mile Fauna and Their Biostratigraphic Implications 78 Abstract 79 Introduction 79 Materials and Methods 80 iv Systematic Paleontology 80 The Four Mile Fauna and Wasatchian Biostratigraphic Zonation 84 Conclusion 86 Acknowledgments 86 Bibliography 86 Figures 87 Chapter Three: A New Genus Eurotherium (Creodonta, Mammalia) in Reference to Taxonomic Problems with Some Eocene Hyaenodontids from Eurasia (With B. Lange-Badré) 89 Résumé 90 Abstract 90 Version française abrégéé 90 Introduction 93 Acknowledgments 96 Bibliography 96 Table 3.1: Original and Current Usages of Genera and Species 99 Table 3.2: Species Currently Included in Genera Discussed in Text 101 Chapter Four: The skeleton of Gazinocyon vulpeculus n.
    [Show full text]
  • Mammal and Plant Localities of the Fort Union, Willwood, and Iktman Formations, Southern Bighorn Basin* Wyoming
    Distribution and Stratigraphip Correlation of Upper:UB_ • Ju Paleocene and Lower Eocene Fossil Mammal and Plant Localities of the Fort Union, Willwood, and Iktman Formations, Southern Bighorn Basin* Wyoming U,S. GEOLOGICAL SURVEY PROFESS IONAL PAPER 1540 Cover. A member of the American Museum of Natural History 1896 expedition enter­ ing the badlands of the Willwood Formation on Dorsey Creek, Wyoming, near what is now U.S. Geological Survey fossil vertebrate locality D1691 (Wardel Reservoir quadran­ gle). View to the southwest. Photograph by Walter Granger, courtesy of the Department of Library Services, American Museum of Natural History, New York, negative no. 35957. DISTRIBUTION AND STRATIGRAPHIC CORRELATION OF UPPER PALEOCENE AND LOWER EOCENE FOSSIL MAMMAL AND PLANT LOCALITIES OF THE FORT UNION, WILLWOOD, AND TATMAN FORMATIONS, SOUTHERN BIGHORN BASIN, WYOMING Upper part of the Will wood Formation on East Ridge, Middle Fork of Fifteenmile Creek, southern Bighorn Basin, Wyoming. The Kirwin intrusive complex of the Absaroka Range is in the background. View to the west. Distribution and Stratigraphic Correlation of Upper Paleocene and Lower Eocene Fossil Mammal and Plant Localities of the Fort Union, Willwood, and Tatman Formations, Southern Bighorn Basin, Wyoming By Thomas M. Down, Kenneth D. Rose, Elwyn L. Simons, and Scott L. Wing U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1540 UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1994 U.S. DEPARTMENT OF THE INTERIOR BRUCE BABBITT, Secretary U.S. GEOLOGICAL SURVEY Robert M. Hirsch, Acting Director For sale by U.S. Geological Survey, Map Distribution Box 25286, MS 306, Federal Center Denver, CO 80225 Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S.
    [Show full text]
  • Attachment J Assessment of Existing Paleontologic Data Along with Field Survey Results for the Jonah Field
    Attachment J Assessment of Existing Paleontologic Data Along with Field Survey Results for the Jonah Field June 12, 2007 ABSTRACT This is compilation of a technical analysis of existing paleontological data and a limited, selective paleontological field survey of the geologic bedrock formations that will be impacted on Federal lands by construction associated with energy development in the Jonah Field, Sublette County, Wyoming. The field survey was done on approximately 20% of the field, primarily where good bedrock was exposed or where there were existing, debris piles from recent construction. Some potentially rich areas were inaccessible due to biological restrictions. Heavily vegetated areas were not examined. All locality data are compiled in the separate confidential appendix D. Uinta Paleontological Associates Inc. was contracted to do this work through EnCana Oil & Gas Inc. In addition BP and Ultra Resources are partners in this project as they also have holdings in the Jonah Field. For this project, we reviewed a variety of geologic maps for the area (approximately 47 sections); none of maps have a scale better than 1:100,000. The Wyoming 1:500,000 geology map (Love and Christiansen, 1985) reveals two Eocene geologic formations with four members mapped within or near the Jonah Field (Wasatch – Alkali Creek and Main Body; Green River – Laney and Wilkins Peak members). In addition, Winterfeld’s 1997 paleontology report for the proposed Jonah Field II Project was reviewed carefully. After considerable review of the literature and museum data, it became obvious that the portion of the mapped Alkali Creek Member in the Jonah Field is probably misinterpreted.
    [Show full text]
  • Mammals from the Earliest Uintan (Middle Eocene) Turtle Bluff Member, Bridger Formation, Southwestern Wyoming, USA, Part 1: Primates and Rodentia
    Palaeontologia Electronica palaeo-electronica.org Mammals from the earliest Uintan (middle Eocene) Turtle Bluff Member, Bridger Formation, southwestern Wyoming, USA, Part 1: Primates and Rodentia Thomas S. Kelly and Paul C. Murphey ABSTRACT The Turtle Bluff Member (TBM) is the stratotype section for the earliest Uintan bio- chron, Ui1a, of the middle Eocene Uintan North American Land Mammal age. For more than a century, the TBM had yielded only a few fragmentary specimens. As the result of many years of field work, numerous mammal fossils have now been recov- ered and provide an unprecedented opportunity to better define this poorly known interval. This is the first in a series of papers that provide detailed descriptions and tax- onomic revisions of the fauna of the TBM. Here we document the occurrence of the fol- lowing taxa in the TBM: Uintasorex parvulus; Microsyops annectans; Notharctus robustior; Omomys carteri; Trogolemur myodes; Washakius insignis; Thisbemys corru- gatus; Microparamys minutus; Microparamys sp.; Sciuravus nitidus; Tillomys senex; Tillomys? parvidens; Taxymys lucaris; Pauromys sp., cf. P. perdit us ; three informal sci- uravid species (sp. A, B and C); cf. Pareumys sp.; Metanoiamys sp.; and Elymys? emryi new species. Except for the previously described Hemiacodon engardae, all of the primates from the TBM are holdover taxa from the earlier Bridgerian Land Mammal age, whereas the rodents exhibit a modest diversification during the earliest Uintan. Elymys? emryi and four additional informal rodent species (Microparamys sp., sci- uravid sp. A, cf. Pareumys sp., and Metanoiamys sp.) make their appearances in the TBM and, as such, can be added to the list of index species characterizing biochron Ui1a.
    [Show full text]
  • Rapid and Early Post-Flood Mammalian Diversification Videncede in the Green River Formation
    The Proceedings of the International Conference on Creationism Volume 6 Print Reference: Pages 449-457 Article 36 2008 Rapid and Early Post-Flood Mammalian Diversification videncedE in the Green River Formation John H. Whitmore Cedarville University Kurt P. Wise Southern Baptist Theological Seminary Follow this and additional works at: https://digitalcommons.cedarville.edu/icc_proceedings DigitalCommons@Cedarville provides a publication platform for fully open access journals, which means that all articles are available on the Internet to all users immediately upon publication. However, the opinions and sentiments expressed by the authors of articles published in our journals do not necessarily indicate the endorsement or reflect the views of DigitalCommons@Cedarville, the Centennial Library, or Cedarville University and its employees. The authors are solely responsible for the content of their work. Please address questions to [email protected]. Browse the contents of this volume of The Proceedings of the International Conference on Creationism. Recommended Citation Whitmore, John H. and Wise, Kurt P. (2008) "Rapid and Early Post-Flood Mammalian Diversification Evidenced in the Green River Formation," The Proceedings of the International Conference on Creationism: Vol. 6 , Article 36. Available at: https://digitalcommons.cedarville.edu/icc_proceedings/vol6/iss1/36 In A. A. Snelling (Ed.) (2008). Proceedings of the Sixth International Conference on Creationism (pp. 449–457). Pittsburgh, PA: Creation Science Fellowship and Dallas, TX: Institute for Creation Research. Rapid and Early Post-Flood Mammalian Diversification Evidenced in the Green River Formation John H. Whitmore, Ph.D., Cedarville University, 251 N. Main Street, Cedarville, OH 45314 Kurt P. Wise, Ph.D., Southern Baptist Theological Seminary, 2825 Lexington Road.
    [Show full text]
  • Primates, Adapiformes) Skull from the Uintan (Middle Eocene) of San Diego County, California
    AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 98:447-470 (1995 New Notharctine (Primates, Adapiformes) Skull From the Uintan (Middle Eocene) of San Diego County, California GREGG F. GUNNELL Museum of Paleontology, University of Michigan, Ann Arbor, Michigan 481 09-1079 KEY WORDS Californian primates, Cranial morphology, Haplorhine-strepsirhine dichotomy ABSTRACT A new genus and species of notharctine primate, Hespero- lemur actius, is described from Uintan (middle Eocene) aged rocks of San Diego County, California. Hesperolemur differs from all previously described adapiforms in having the anterior third of the ectotympanic anulus fused to the internal lateral wall of the auditory bulla. In this feature Hesperolemur superficially resembles extant cheirogaleids. Hesperolemur also differs from previously known adapiforms in lacking bony canals that transmit the inter- nal carotid artery through the tympanic cavity. Hesperolemur, like the later occurring North American cercamoniine Mahgarita steuensi, appears to have lacked a stapedial artery. Evidence from newly discovered skulls ofNotharctus and Smilodectes, along with Hesperolemur, Mahgarita, and Adapis, indicates that the tympanic arterial circulatory pattern of these adapiforms is charac- terized by stapedial arteries that are smaller than promontory arteries, a feature shared with extant tarsiers and anthropoids and one of the character- istics often used to support the existence of a haplorhine-strepsirhine dichot- omy among extant primates. The existence of such a dichotomy among Eocene primates is not supported by any compelling evidence. Hesperolemur is the latest occurring notharctine primate known from North America and is the only notharctine represented among a relatively diverse primate fauna from southern California. The coastal lowlands of southern California presumably served as a refuge area for primates during the middle and later Eocene as climates deteriorated in the continental interior.
    [Show full text]
  • Paleoenvironmental Implications of Small-Animal Fossils from the Black Mountain Turtle Layer and Associated Layers, Eocene of Wyoming
    Andrews University Digital Commons @ Andrews University Master's Theses Graduate Research 2020 Paleoenvironmental Implications of Small-Animal Fossils from the Black Mountain Turtle Layer and Associated Layers, Eocene of Wyoming Jeremy McLarty [email protected] Follow this and additional works at: https://digitalcommons.andrews.edu/theses Part of the Biology Commons Recommended Citation McLarty, Jeremy, "Paleoenvironmental Implications of Small-Animal Fossils from the Black Mountain Turtle Layer and Associated Layers, Eocene of Wyoming" (2020). Master's Theses. 145. https://digitalcommons.andrews.edu/theses/145 This Thesis is brought to you for free and open access by the Graduate Research at Digital Commons @ Andrews University. It has been accepted for inclusion in Master's Theses by an authorized administrator of Digital Commons @ Andrews University. For more information, please contact [email protected]. ABSTRACT PALEOENVIRONMENTAL IMPLICATIONS OF SMALL-ANIMAL FOSSILS FROM THE BLACK MOUNTIAN TURTLE LAYER AND ASSOCIATED LAYERS, EOCENE OF WYOMING By JEREMY MCLARTY Chair: H. Thomas Goodwin, Ph.D. ABSTRACT OF GRADUATE STUDENT RESEARCH Thesis Andrews University College of Arts and Sciences Title: PALEOENVIRONMENTAL IMPLICATIONS OF SMALL-ANIMAL FOSSILS FROM THE BLACK MOUNTAIN TURTLE LAYER AND ASSOCIATED LAYERS, EOCENE OF WYOMING Name of researcher: Jeremy A. McLarty Name and degree of faculty chair: H. Thomas Goodwin, Ph.D. Date completed: March 2020 The Bridger Formation is an Early Middle Eocene deposit in southwestern Wyoming that preserves a rich record of life from North America. Some horizons within the Bridger Formation contain abundant fossil turtle shells, but turtle skulls are rarely found. Previous research focused on one of these fossil-rich horizons, the Black Mountain turtle layer, to develop a model for the abundance and taphonomic condition of the fossil turtles.
    [Show full text]
  • Genus/Species Skull Ht Lt Wt Stage Range Abacinonyx See Acinonyx Abathomodon See Speothos A
    Genus/Species Skull Ht Lt Wt Stage Range Abacinonyx see Acinonyx Abathomodon see Speothos A. fossilis see Icticyon pacivorus? Pleistocene Brazil Abelia U.Miocene Europe Absonodaphoenus see Pseudarctos L.Miocene USA A. bathygenus see Cynelos caroniavorus Acarictis L.Eocene W USA cf. A. ryani Wasatchian Colorado(US) A. ryani Wasatchian Wyoming, Colorado(US) Acinomyx see Acinonyx Acinonyx M.Pliocene-Recent Europe,Asia,Africa,N America A. aicha 2.3 m U.Pliocene Morocco A. brachygnathus Pliocene India A. expectata see Miracinonyx expectatus? Or Felis expectata? A. intermedius M.Pleistocene A. jubatus living Cheetah M.Pliocene-Recent Algeria,Europe,India,China A. pardinensis 91 cm 3 m 60 kg Astian-Biharian Italy,India,China,Germany,France A. sp. L.Pleistocene Tanzania,Ethiopia A. sp. Cf. Inexpectatus Blancan-Irvingtonian California(US) A. studeri see Miracinonyx studeri Blancan Texas(US) A. trumani see Miracinonyx trumani Rancholabrean Wyoming,Nevada(US) Acionyx possibly Acinonyx? A. cf. Crassidens Hadar(Ethiopia) Acrophoca 1.5 m U.Miocene-L.Pliocene Peru,Chile A. longirostris U.Miocene-L.Pliocene Peru A. sp. U.Miocene-L.Pliocene Chile Actiocyon M-U.Miocene W USA A. leardi Clarendonian California(US) A. sp. M.Miocene Oregon(US) Adcrocuta 82 cm 1.5 m U.Miocene Europe,Asia A. advena A. eximia 80 cm 1.5 m Vallesian-Turolian Europe(widespread),Asia(widespread) Adelphailurus U.Miocene-L.Pliocene W USA, Mexico,Europe A. kansensis Hemphillian Arizona,Kansas(US),Chihuahua(Mexico) Adelpharctos M.Oligocene Europe Adilophontes L.Miocene W USA A. brachykolos Arikareean Wyoming(US) Adracodon probably Adracon Eocene France A. quercyi probably Adracon quercyi Eocene France Adracon U.Eocene-L.Oligocene France A.
    [Show full text]
  • Mammalian Faunal Change During the Early Eocene Climatic
    MAMMALIAN FAUNAL CHANGE DURING THE EARLY EOCENE CLIMATIC OPTIMUM (WASATCHIAN AND BRIDGERIAN) AT RAVEN RIDGE IN THE NORTHEASTERN UINTA BASIN, COLORADO AND UTAH by ALEXANDER R. DUTCHAK B.Sc., University of Alberta, 2002 M.Sc., University of Alberta, 2005 A thesis submitted to the Faculty of the Graduate School of the University of Colorado in partial fulfillment of the requirements for the degree of Doctor of Philosophy Department of Geological Sciences 2010 This thesis entitled: Mammalian faunal change during the Early Eocene Climatic Optimum (Wasatchian and Bridgerian) at Raven Ridge in the northeastern Uinta Basin, Colorado and Utah written by Alexander R. Dutchak has been approved for the Department of Geological Sciences ______________________________ Jaelyn J. Eberle (Supervisor) ______________________________ John Humphrey ______________________________ Mary Kraus ______________________________ Tom Marchitto ______________________________ Richard Stucky Date: ________________________ The final copy of this thesis has been examined by the signatories, and we find that both the content and the form meet acceptable presentation standards of scholarly work in the above mentioned discipline. ABSTRACT Dutchak, Alexander R. (Ph.D., Geological Sciences, Department of Geological Sciences) Mammalian faunal change during the Early Eocene Climatic Optimum (Wasatchian and Bridgerian) at Raven Ridge in the northeastern Uinta Basin, Colorado and Utah Thesis directed by Assistant Professor Jaelyn J. Eberle This project investigated patterns of mammalian faunal change at Raven Ridge, which straddles the Colorado-Utah border on the northeastern edge of the Uinta Basin and consists of intertonguing units of the fluvial Colton and lacustrine Green River Formations. Fossil vertebrate localities comprising >9,000 fossil mammal specimens from 62 genera in 34 families were identified and described.
    [Show full text]