Plesiadapis ROCK ROCK UNIT COLUMN PERIOD EPOCH AGES MILLIONS of YEARS AGO Common Name: Holocene Oahe .01 Lemur-Like Mammal

Total Page:16

File Type:pdf, Size:1020Kb

Plesiadapis ROCK ROCK UNIT COLUMN PERIOD EPOCH AGES MILLIONS of YEARS AGO Common Name: Holocene Oahe .01 Lemur-Like Mammal North Dakota Stratigraphy Plesiadapis ROCK ROCK UNIT COLUMN PERIOD EPOCH AGES MILLIONS OF YEARS AGO Common Name: Holocene Oahe .01 Lemur-like mammal Coleharbor Pleistocene QUATERNARY Classification: 1.8 Pliocene Unnamed 5 Miocene Class: Mammalia 25 Arikaree Order: Primates Family: Plesiadapidae Brule Oligocene 38 South Heart Chadron Jaw of the lemur-like mammal, Plesiadapis. Bullion Creek Chalky Buttes Camels Butte Formation, Billings County. Width 24 mm. Science Museum of Eocene Golden 55 Valley Bear Den Minnesota Collection. Sentinel Butte TERTIARY Description: Plesiadapis was a lemur-like mammal the size of a modern-day beaver, about 2 ½ feet long. They had long tails, agile limbs with Bullion Paleocene Creek claws rather than nails, and eyes placed on the sides of their heads. Unlike modern primates, the head of Plesiadapis had a long snout Slope with rodentlike jaws and teeth and long, gnawing incisors Cannonball separated by a gap from its molars. It was well-adapted for climbing in trees with its long, clawed fingers and toes. Ludlow 65 Plesiadapis inhabited the vast forests that covered western North Hell Creek Dakota when the climate was subtropical, similar to south Florida today. Fox Hills ACEOUS Pierre CRET 84 Niobrara Carlile Carbonate Calcareous Shale Claystone/Shale Siltstone Sandstone Sand & Gravel Mudstone Lignite Glacial Drift Plesiadapis. Painting courtesy of Simon and Schuster Publishing Company. Locations where fossils have been found ND State Fossil Collection Prehistoric Life of ND Map North Dakota Geological Survey Home Page.
Recommended publications
  • Mammalia, Plesiadapiformes) As Reflected on Selected Parts of the Postcranium
    SHAPE MEETS FUNCTION: STRUCTURAL MODELS IN PRIMATOLOGY Edited by Emiliano Bruner Proceedings of the 20th Congress of the International Primatological Society Torino, Italy, 22-28 August 2004 MORPHOLOGY AND MORPHOMETRICS JASs Journal of Anthropological Sciences Vol. 82 (2004), pp. 103-118 Locomotor adaptations of Plesiadapis tricuspidens and Plesiadapis n. sp. (Mammalia, Plesiadapiformes) as reflected on selected parts of the postcranium Dionisios Youlatos1, Marc Godinot2 1) Aristotle University of Thessaloniki, School of Biology, Department of Zoology, GR-54124 Thessaloniki, Greece. email [email protected] 2) Ecole Pratique des Hautes Etudes, UMR 5143, Case Courrier 38, Museum National d’Histoire Naturelle, Institut de Paleontologie, 8 rue Buffon, F-75005 Paris, France Summary – Plesiadapis is one of the best-known Plesiadapiformes, a group of Archontan mammals from the Late Paleocene-Early Eocene of Europe and North America that are at the core of debates con- cerning primate origins. So far, the reconstruction of its locomotor behavior has varied from terrestrial bounding to semi-arboreal scansoriality and squirrel-like arboreal walking, bounding and claw climbing. In order to elucidate substrate preferences and positional behavior of this extinct archontan, the present study investigates quantitatively selected postcranial characters of the ulna, radius, femur, and ungual pha- langes of P. tricuspidens and P. n .sp. from three sites (Cernay-les-Reims, Berru, Le Quesnoy) in the Paris Basin, France. These species of Plesiadapis was compared to squirrels of different locomotor habits in terms of selected functional indices that were further explored through a Principal Components Analysis (PCA), and a Discriminant Functions Analysis (DFA). The indices treated the relative olecranon height, form of ulnar shaft, shape and depth of radial head, shape of femoral distal end, shape of femoral trochlea, and dis- tal wedging of ungual phalanx, and placed Plesiadapis well within arboreal quadrupedal, clambering, and claw climbing squirrels.
    [Show full text]
  • Geology and Vertebrate Paleontology of Western and Southern North America
    OF WESTERN AND SOUTHERN NORTH AMERICA OF WESTERN AND SOUTHERN NORTH PALEONTOLOGY GEOLOGY AND VERTEBRATE Geology and Vertebrate Paleontology of Western and Southern North America Edited By Xiaoming Wang and Lawrence G. Barnes Contributions in Honor of David P. Whistler WANG | BARNES 900 Exposition Boulevard Los Angeles, California 90007 Natural History Museum of Los Angeles County Science Series 41 May 28, 2008 Paleocene primates from the Goler Formation of the Mojave Desert in California Donald L. Lofgren,1 James G. Honey,2 Malcolm C. McKenna,2,{,2 Robert L. Zondervan,3 and Erin E. Smith3 ABSTRACT. Recent collecting efforts in the Goler Formation in California’s Mojave Desert have yielded new records of turtles, rays, lizards, crocodilians, and mammals, including the primates Paromomys depressidens Gidley, 1923; Ignacius frugivorus Matthew and Granger, 1921; Plesiadapis cf. P. anceps; and Plesiadapis cf. P. churchilli. The species of Plesiadapis Gervais, 1877, indicate that Member 4b of the Goler Formation is Tiffanian. In correlation with Tiffanian (Ti) lineage zones, Plesiadapis cf. P. anceps indicates that the Laudate Discovery Site and Edentulous Jaw Site are Ti2–Ti3 and Plesiadapis cf. P. churchilli indicates that Primate Gulch is Ti4. The presence of Paromomys Gidley, 1923, at the Laudate Discovery Site suggests that the Goler Formation occurrence is the youngest known for the genus. Fossils from Member 3 and the lower part of Member 4 indicate a possible marine influence as Goler Formation sediments accumulated. On the basis of these specimens and a previously documented occurrence of marine invertebrates in Member 4d, the Goler Basin probably was in close proximity to the ocean throughout much of its existence.
    [Show full text]
  • Recherches De Mammiferes Paleogenes Dans Les Departements De L'aisne Et De La Marne Pendant La Deuxieme Moitie Du Vingtieme Siecle
    RECHERCHES DE MAMMIFERES PALEOGENES DANS LES DEPARTEMENTS DE L'AISNE ET DE LA MARNE PENDANT LA DEUXIEME MOITIE DU VINGTIEME SIECLE par Pierre LOUIS * SOMMAIRE Page Résumé, Abstract , ' , , , ' , , , , , ' , , , , , , , , , , , ' , , ' , , ' , , ' , , , , , , , , , , ' , , ' , , , ' , , ' , , , ' , , ' , , , , 84 Historique des découvertes jusqu'à la fin de la première moitié du XXème siècle, , , ' , , , ' , , , , , , , 84 Gisements à mammifères exploités depuis 1950 , , , , , , , , , , , , , , , , , , , , , , , , ' , , , , , , , , , , , , , , , , 88 Thanétien ,',',',""',""""',"""',',,",","',",",,""',,",,',,', 88 Les gisements , , , , ' , , ' , , , , , , , , , , , , , ' , , , ' , , ' , , , , , ' , , , ' , , ' , , , ' , , ' , , , ' , , ' , , ' , , 88 Environnement du Pays rémois au Thanétien supérieur, , , , , , , , , , , , , , ' , , ' , , , ' , , ' , , , , 90 Yprésien "',""",",""",",,",,',,",",,',,",,',,',,",",',',,',,', 91 Les gisements du début de l'Yprésien ,,""""""""',',"",',,',',',,',", 91 Environnement de Reims et d'Epernay au début de l'Yprésien, , , " , ' , ' , , , " , , , , , , , , , 95 Les gisements de l'Yprésien supérieur, , , , , , , ' , , ' , , ' , , , , , , , , , ' , , ' , , ' , , , ' , , , , , , ' , 96 Environnement de l'Est du Bassin Parisien à l'Yprésien , , , , , , , , , , , , , , , , , , , , , , , ' , , , , 99 Lutétien "","',",,',,",",,',,",,',',',,',,',',',",,',,",,',,",",,', 99 Bartonien , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , ' , , , , , , , , , , , , , , ' , , , , , , , , , , ,
    [Show full text]
  • Late Paleocene) of the Eastern Crazy Mountain Basin, Montana
    CONTRIBUTIONS FROM THE MUSEUM OF PALEONTOLOGY THE UNIVERSITY OF MICHIGAN VOL. 26, NO. 9, p. 157-196 December 3 1, 1983 MAMMALIAN FAUNA FROM DOUGLASS QUARRY, EARLIEST TIFFANIAN (LATE PALEOCENE) OF THE EASTERN CRAZY MOUNTAIN BASIN, MONTANA BY DAVID W. KRAUSE AND PHILIP D. GINGERICH MUSEUM OF PALEONTOLOGY THE UNIVERSITY OF MICHIGAN ANN ARBOR CONTRIBUTIONS FROM THE MUSEUM OF PALEONTOLOGY Philip D. Gingerich, Director Gerald R. Smith, Editor This series of contributions from the Museum of Paleontology is a medium for the publication of papers based chiefly upon the collection in the Museum. When the number of pages issued is sufficient to make a volume, a title page and a table of contents will be sent to libraries on the mailing list, and to individuals upon request. A list of the separate papers may also be obtained. Correspondence should be directed to the Museum of Paleontology, The University of Michigan, Ann Arbor, Michigan, 48 109. VOLS. 11-XXVI. Parts of volumes may be obtained if available. Price lists available upon inquiry. MAMMALIAN FAUNA FROM DOUGLASS QUARRY, EARLIEST TIFFANIAN (LATE PALEOCENE) OF THE EASTERN CRAZY MOUNTAIN BASIN, MONTANA BY David W. ~rause'and Philip D. ~in~erich' Abstract.-Douglass Quarry is the fourth major locality to yield fossil mammals in the eastern Crazy Mountain Basin of south-central Montana. It is stratigraphically intermediate between Gidley and Silberling quarries below, which are late Torrejonian (middle Paleocene) in age, and Scarritt Quarry above, which is early Tiffanian (late Paleocene) in age. The stratigraphic position of Douglass Quarry and the presence of primitive species of Plesiadapis, Nannodectes, Phenacodus, and Ectocion (genera first appearing at the Torrejonian-Tiffanian boundary) combine to indicate an earliest Tiffanian age.
    [Show full text]
  • A Note on the Origin of Rodents
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by American Museum of Natural History Scientific... PUBLISHED BY THE AMERICAN MUSEUM OF NATURAL HISTORY CENTRAL PARK WEST AT 79TH STREET, NEW YORK 24, N.Y. NUMBER 2037 JULY 7, I96I A Note on the Origin of Rodents BY MALCOLM C. MCKENNA Knowledge of Paleocene rodents is still restricted to a single species, Paramys atavus, from a single locality, the Eagle Coal Mine at Bear Creek, Montana. The age of this deposit is late Paleocene. Incisors of P. atavus were first described by Simpson (1928, p. 14), but were referred by him to the Multituberculata. Jepsen (1937) recognized the true affinities of the incisors and described a newly found lower molar. No additional material has been reported since 1937. The purpose of the present paper is to place on record the morphology of a recently identified upper cheek tooth of Paramys atavus and to discuss briefly its significance. I am in- debted to Drs. Albert E. Wood and Mary Dawson for helpful comments. Mr. Chester Tarka prepared the figure. ORDER RODENTIA FAMILY PARAMYIDAE GENUS PARAMYS LEIDY, 1871 Paramys atavusJepsen, 1937 MATERIAL: A.M.N.H. No. 22195 (fig. 1), a left P 4, M 1, or M 2, figured by Simpson (1929, p. 10, fig. 2). LOCALITY: Eagle Coal Mine, Bear Creek, Carbon County, Montana. FORMATION: Polecat Bench formation (Fort Union of the United States Geological Survey and others). AGE: Tiffanian (= approximately late, but not latest, Paleocene). DESCRIPTION: Small, tritubercular, rodent upper cheek tooth with 2 AMERICAN MUSEUM NOVITATES NO.
    [Show full text]
  • Mammalian Faunal Turnover Across the Paleocene-Eocene Boundary in NW Europe: the Roles of Displacement, Com- Munity Evolution and Environment______
    of CLIMATE & BIOTA the EARLY PALEOGENE Austrian Journal of Earth Sciences Volume 105/1 Vienna 2012 Mammalian faunal turnover across the Paleocene-Eocene boundary in NW Europe: the roles of displacement, com- munity evolution and environment__________________________ Jerry J. HOOKER1)*) & Margaret E. COLLINSON2) KEYWORDS Ecological diversity 1) Department of Palaeontology, Natural History Museum, Cromwell Road, London, SW7 5BD, UK; plant fossils 2) Department of Earth Sciences, Royal Holloway University of London, Egham, Surrey, TW20 0EX, UK; understorey extinction *) Corresponding author, [email protected] predation Abstract Improved knowledge of the diversity of Late Paleocene mammal faunas of NW Europe indicates a higher level of turnover at the Paleocene-Eocene boundary than previously recognized. Possible causes of the large number of extinctions in Europe are inves- tigated through ecological diversity analysis of the mammals and the plant fossil record. Predation by incoming ground- and tree- dwelling specialized carnivores has been previously considered the main cause of the extinctions. However, the preferential extinc- tion of small terrestrial and semiterrestrial insectivore-frugivores, (mainly stem macroscelideans and multituberculates), which are inferred to have inhabited forests with dense understorey in the Paleocene, is also linked to the arrival in Europe of a new ecolo- gical type, the large terrestrial browsing herbivore, namely the pantodont Coryphodon, which would have reduced understorey by feeding and physical disturbance. It is suggested that there was a delay in community evolution in Europe, which in North America had previously produced large herbivorous and specialized carnivorous types. The cause of the delay may have been the persis- tence throughout the Paleocene in Europe of thermophilic evergreen forests despite the cooling in the middle of the epoch.
    [Show full text]
  • Eocene Plesiadapiform Shows Affinities with Flying Lemurs Not
    =% LETTERS TO NATURE Eocene plesiadapiform shows branous in primitive eutherians12'13, the presence of an entotym. panic bulla in Ignatius would be a derived character that rules affinities with flying lemurs Ignatius and other Plesiadapiformes out of the ancestry 0f Primates. Bullar entotympanics have evolved in many mam- not primates malian groups10. However, an unusual similarity in the entotym- panics of Ignatius and the living dermopteran Cynocephalus is Richard F. Kay*, Richard W. Thorington Jrt that the entotympanic contacts the basioccipital ven- 14 & Peter Houdet tromedially . This is a distinction from the entotympanics of tree shrews, for example, in which the only bony contact * Department of Biological Anthropology and Anatomy, medially is with the petrosal. Duke University Medical Center, Durham, Previous proposals of a significant intracranial blood supply North Carolina 27710, USA for paromomyids by way of either the internal carotid artery3,5 t Department of Vertebrate Zoology, or the ascending pharyngeal artery6 are ruled out by the follow- National Museum of Natural History, Smithsonian Institution, Washington, DC 20560, USA ing observations. (1) The carotid foramen is too small to have % Department of Biological Sciences, Princeton University, Princeton, conducted an internal carotid artery of significant size. The New Jersey 08544, USA diameter of the carotid foramen in Ignatius is comparable to. that of lorises, in which the internal carotid artery involutes PLESIADAPIFORMES, of the North American and European during development and only the internal carotid nerve passes Paleogene, is often identified as a sister group of primates. This through15'16. (2) There are no grooves or tubes for the promon- hypothesis is based on several proposed anatomical synapo- tory division of the internal carotid artery on the promontorium.
    [Show full text]
  • Plesiadapis (Plesiadapiformes) from the Brisbane, Judson, and Wannagan Creek Quarry Local Faunas
    CONTRIBUTIONS TO THE MARSHALL LAMBERT SYMPOSIUM LATE PALEOCENE MAMMALIAN BIOCHRONOLOGY OF THE FORT UNION GROUP IN NORTH DAKOTA: PLESIADAPIS (PLESIADAPIFORMES) FROM THE BRISBANE, JUDSON, AND WANNAGAN CREEK QUARRY LOCAL FAUNAS Allen J. Kihm Department of Earth Science, Minot State University, Minot, ND 58702 This study focuses on Plesiadapis because it has been used to define the subdivisions of the Tiffanian (Ti) Mammal Age in North America. A reevaluation of previously described (Holtzman, 1978) Plesiadapis material from the Brisbane Locality (Slope Formation, Grant County), and Judson Localities (uppermost Slope Formation or lowermost Bullion Creek Formation, Morton County), together with new observations from the Wannagan Creek Quarry (upper Bullion Creek Formation, Billings County), provide the basis for a revised interpretation of the Ti3-Ti4 boundary in North Dakota. Erickson (1991) reported the presence of Plesiadapis cf. P. fodinatus Jepsen and Plesiadapis sp. from Wannagan Creek Quarry. These identifications were based on preliminary analysis and are not supported by more detailed investigation. Plesiadapis fodinatus has curved and crested entoconids on M1 and M2, and talonids on P3 and P4 with distinct entoconids. None of the Wannagan Creek Quarry specimens show these characteristics, and there is no compelling evidence to suggest more than a single species is represented. Plesiadapis specimens from the Wannagan Creek Quarry are most similar to P. rex (Gidley) and P. churchilli Gingerich. Plesiadapis churchilli is larger than P. rex, has the P2 variably present, a significant diastema 1 between the P3 and Il, and almost always has mesostyles on the M . The Wannagan Creek Quarry sample has six specimens that preserve the mandible immediately anterior to the P3.
    [Show full text]
  • University of Michigan University Library
    CONTRIBUTIONS FROM THE MUSEUM OF PALEONTOLOGY THE UNTVERSITY OF MICHIGAN VOL.30, NO. 4, PP. 131-162 December 31,1998 CARPOLESTES SZMPSONZ, NEW SPECIES (MAMMALIA, PROPRIMATES) FROM THE LATE PALEOCENE OF THE CLARKS FORK BASIN, WYOMING JONATHAN I. BLOCH AND PHnIP D. GINGERICH MUSEUM OF PALEONTOLOGY THE UNIVERSITY OF MICHIGAN ANN ARBOR CONTRIBUTIONS FROM THE MUSEUM OF PALEONTOLOGY Philip D. Gingerich, Director This series of contributions from the Museum of Paleontology is a medium for publication of papers based chiefly on collections in the Museum. When the number of pages issued is sufficient to make a volume, a title page plus a table of contents will be sent to libraries on the Museum's mailing list. This will be sent to individuals on request. A list of the separate issues may also be obtained by request. Correspondence should be directed to the Publications Secretary, Museum of Paleontology, The University of Michigan, Ann Arbor, Michigan 48 109- 1079. VOLS. 2-29 Parts of volumes may be obtained if available. Price lists are available upon inquiry. Text and illustrations 01998 by the Museum of Paleontology, University of Michigan CARPOLESTES SZMPSONZ, NEW SPECIES (MAMMALIA, PROPRIMATES) FROM THE LATE PALEOCENE OF THE CLARKS FORK BASIN, WYOMING BY JONATHAN I. BLOCH AND PHILIP D. GINGERICH Abstract - Carpolestes is a small North American late Paleocene mammal with distinctively specialized premolar teeth. P3 is polycuspate with a distinct anteroexternal extension, and P4 is high-crowned, bladelike, and multicuspate. Carpolestes is now known from at least 180 specimens representing four mor- phologically and stratigraphically distinct species. Fossils from freshwater lime- stones of the Clarks Fork Basin include complete dentitions of a new species, Carpolestes simpsoni, from Clarkforkian faunal zones Cf-2 and earliest Cf-3.
    [Show full text]
  • Preliminary Assessment of an Early Eocene NW European Tropical Coastal Environment from Molluscs and Vertebrate Fossils
    Cainozoic Research, 15(1-2), pp. 155-180, October 2015 155 Pourcy (Paris Basin, France): preliminary assessment of an early Eocene NW European tropical coastal environment from molluscs and vertebrate fossils E. Spijkerman1,5, F.A.D. van Nieulande2, F.P. Wesselingh3, S. Reich3 & S. Tracey4,5 1 Zonnelaan 50, 1561 ES Krommenie, The Netherlands, E-mail: [email protected] 2 Scheldepoortstraat 56, 4339 BN Nieuw-en-St.-Joosland, The Netherlands; e-mail: [email protected] 3 Naturalis Biodiversity Center, P.O. box 9517, 2300 RA Leiden, The Netherlands; e-mail: frank.wesselingh@natu- ralis.nl; [email protected] 4 ICZN Secretariat, Natural History Museum, London SW7 5BD, England; e-mail: [email protected] 5 corresponding authors Received 3 November 2014, revised version accepted 1 September 2015 We have studied the fossil fauna from the locality of Pourcy (Marne) in the northeast of the Paris Basin, France, housed in various collections, in order to assess the nature and diversity of the fauna and gain an insight into the nature of the conditions that could have produced this assemblage. The mollusc fauna is strongly indicative of varied tropical estuarine environments probably vegetated with mangroves, but may also contain material derived from underlying mangrove facies. Both coastal marine and terrestrial mollusc and vertebrate faunas are also represented. The terrestrial community contained indicators of subtropical rainforest lowland with broad river banks and lakes, but some reworking of materials seems likely. The early-middle Ypresian Falun de Pourcy probably reflected ongoing estuarine/mangrove conditions that characterised the late Sparnacian period. Preliminary species lists of mollusc and vertebrate fossils are given, together with a comparison of mollusc feeding guilds to those of a modern Indo-Pacific estuary system.
    [Show full text]
  • Vertical Support Use and Primate Origins Gabriel S
    www.nature.com/scientificreports OPEN Vertical support use and primate origins Gabriel S. Yapuncich 1, Henry J. Feng1, Rachel H. Dunn2, Erik R. Seifert 3 & Doug M. Boyer1 Adaptive scenarios of crown primate origins remain contentious due to uncertain order of acquisition Received: 1 May 2019 and functional signifcance of the clade’s diagnostic traits. A feature of the talus bone in the ankle, Accepted: 6 August 2019 known as the posterior trochlear shelf (PTS), is well-regarded as a derived crown primate trait, but Published: xx xx xxxx its adaptive signifcance has been obscured by poorly understood function. Here we propose a novel biomechanical function for the PTS and model the talus as a cam mechanism. By surveying a large sample of primates and their closest relatives, we demonstrate that the PTS is most strongly developed in extant taxa that habitually grasp vertical supports with strongly dorsifexed feet. Tali of the earliest fossils likely to represent crown primates exhibit more strongly developed PTS cam mechanisms than extant primates. As a cam, the PTS may increase grasping efciency in dorsifexed foot postures by increasing the path length of the fexor fbularis tendon, and thus improve the muscle’s ability to maintain fexed digits without increasing energetic demands. Comparisons are made to other passive digital fexion mechanisms suggested to exist in other vertebrates. These results provide robust anatomical evidence that the habitual vertical support use exerted a strong selective pressure during crown primate origins. Te talus is an important element for reconstructing positional behavior throughout primate evolution because the bone’s morphology correlates well with locomotor and postural behaviors of living euarchontans (the mam- malian clade including Primates, Scandentia, Dermoptera) and it is frequently preserved in fossil assemblages1–4.
    [Show full text]
  • Frontal Fusion: Collapse of Another Anthropoid Synapomorphy
    THE ANATOMICAL RECORD 291:308–317 (2008) Frontal Fusion: Collapse of Another Anthropoid Synapomorphy 1,2,3 3 ALFRED L. ROSENBERGER AND ANTHONY S. PAGANO * 1Department of Anthropology and Archaeology, Brooklyn College, CUNY, Brooklyn, New York 2American Museum of Natural History, New York, New York 3Department of Anthropology, City University of New York Graduate Center, New York Consortium in Evolutionary Primatology (NYCEP), New York, New York ABSTRACT We test the hypothesis that the fused interfrontal suture of anthro- poids is a uniquely distinguishing feature and a derived characteristic indicative of their monophyletic origin. Our survey of nonanthropoid primates and several archontan families indicates frontal fusion is wide- spread. It is most variable (fused, open or partially fused) inter- and intra-specifically among strepsirhines. The frontal bone is more commonly fused in living lemuroids and indrioids than among lorisoids. It appears to be fused regularly among Eocene adapids. Among nonanthropoid haplorhines, the interfrontal is fused in Tarsius, even in neonates and invariably in adults, probably also in all fossil tarsiiforms preserving the frontal bone, and in the late Eocene protoanthropoid Rooneyia. The plesiadapiform pattern remains uncertain, but fusion is ubiquitous among living tree shrews, colugos and bats. Distributional evidence implies that interfrontal fusion was present in the last common ancestor (LCA) of haplorhine primates and possibly in the LCA of euprimates as well. Anthropoids, therefore, cannot be defined cladistically by interfrontal fusion, not out of concern for homoplasy but because it is probably a primitive feature inherited from other taxa related to anthropoids. Fusion of the large anthropoid frontal bone, which was extended anteriorly to roof the orbits and expanded laterally in connection with a wide forebrain in the LCA of anthropoids and protoanthropoids, may have been preadap- tive to the evolution of the postorbital septum.
    [Show full text]