Section of Mammals

Pittsburgh, PA, United States

Section of Mammals

Pittsburgh, PA, United States

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Giannini N.P.,CONICET | MacRini T.E.,St. Mary's University | Wible J.R.,Section of Mammals | Rowe T.B.,University of Texas at Austin | Simmons N.B.,American Museum of Natural History
Annals of Carnegie Museum | Year: 2012

The cranial osteology of the megachiropteran Pteropus Brisson, 1762, was the subject of recent study that covered all of the skull bones in significant detail, except for the anatomy of the nasal capsule. Here, we describe and illustrate the internal nasal skeleton of Pteropus lylei K. Andersen, 1908, using histological sections of a fetus and high resolution X-ray computed tomographic (HRXCT) imagery of an adult specimen. The internal nasal skeleton of Pteropus lacks a rostral nasoturbinal and includes a caudal nasoturbinal that corresponds to the ossified crista semicircularis of the fetus; three endoturbinals; one ectoturbinal; the maxilloturbinal; and a low basal crest that may represent a rudimentary element. We describe in detail the structure and connections of these elements in Pteropus. The maxilloturbinal is the largest element. In cross section, the caudal nasoturbinal is unilaminar, the maxilloturbinal is double bilaminar (i.e., each of the basal twin laminae splits further into two secondary laminae), and the other elements range from incipient to asymmetrically double bilaminar (i.e., one branch simple, the other split). All turbinais of the ethmoidal labyrinth contribute to the cribriform plate, creating a specific pattern of cribriform foramina. The elements found in Pteropus are compared with those of other well-known mammals with relatively few turbinai elements, including other bats, primates, canids, and marsupials. We show that, despite terminological discrepancies across studies, homologies are straightforward to establish among these taxa and so comparative or phylogenetic studies may benefit from inclusion of turbinai characters.


Wible J.R.,Section of Mammals | Burrows A.M.,Duquesne University
Palaeontologia Polonica | Year: 2016

Obligate exudativory, including active wounding of bark to acquire gum and/or sap, is rare among extant mammals and does not show a consistent dental signature. A recently described Middle Jurassic docodont Agilodocodon was reconstructed as an exudativore based on proposed similarities of its lower anterior dentition to some extant New World monkeys, specifically marmosets, spider monkeys, and howler monkeys. Oddly enough, of these, only marmosets are exudate-feeders. In our reinvestigation, we did not find any significant resemblance in the lower (and upper) anterior dentition between the Middle Jurassic fossil and these extant New World monkeys. The marmosets, the only obligate platyrrhine exudativores, have lower and upper incisors that are distinguished from Agilodocodon and other New World monkeys by having enamel restricted to the labial surface. Differential wear between the enamel and softer dentine maintains a chisel-like tooth that marmosets use in gouging bark. Additional comparisons of the anterior dentition of Agilodocodon and other extant mammals were conducted. The lower and upper anterior teeth of Agilodocodon were found to be most similar to some elephant shrews and South American marsupials, which have a primarily insectivorous diet. Agilodocodon does not show any dental adaptations found in extant mammals for exudativory. © 2016, Polska Akademia Nauk. All rights reserved.


Hoffmann S.,State University of New York at Stony Brook | O'connor P.M.,Ohio University | O'connor P.M.,Ohio Center for Ecology and Evolutionary Studies | Kirk E.C.,University of Texas at Austin | And 2 more authors.
Journal of Vertebrate Paleontology | Year: 2014

We present the first digital reconstruction of the endocranial cavity and endosseous labyrinth of the Late Cretaceous gondwanatherian mammal Vintana sertichi from the Maevarano Formation of Madagascar. The Malagasy specimen is exceptionally well preserved and represents the only described cranium known for Gondwanatheria, an enigmatic clade from the Late Cretaceous and Paleogene of Gondwana. The endocranial cast of Vintana is relatively small for an animal of its estimated body mass. Its encephalization quotient is 0.28-0.56 for a range of body mass estimates, which is similar to that of basal mammaliaforms. The olfactory bulbs are very large, occupying over 14% of the endocranial volume. The cerebral hemispheres are only slightly expanded, more similar to the condition in Morganucodon than to that in multituberculates and monotremes. Unlike the condition in other Mesozoic mammaliaforms, the endocast is greatly flexed at the circular fissure. The osseous labyrinth displays a mixture of derived and primitive features. The cochlear canal is only slightly curved and short compared with that of extant therians. The ratio between total cochlear canal length and maximum cranial length is smaller than in basal mammaliaforms and approximates that of non-mammaliaform cynodonts. By contrast, the presence of both primary and secondary osseous laminae, the tractus foraminosus, and Rosenthal's canal represent derived characteristics of the mammalian inner ear typical of cladotherians. A modern innervation of the cochlea has either evolved independently in Vintana and cladotherians or was already present in the last common ancestor of both clades. © 2014 by the Society of Vertebrate Paleontology.


Krause D.W.,State University of New York at Stony Brook | Wible J.R.,Section of Mammals | Hoffmann S.,State University of New York at Stony Brook | Groenke J.R.,State University of New York at Stony Brook | And 3 more authors.
Journal of Vertebrate Paleontology | Year: 2014

The Gondwanatheria are an enigmatic clade of Cretaceous and Paleogene mammals known from South America, Africa, Madagascar, India, and the Antarctic Peninsula. The eight valid species-each belonging to a monotypic genus and the first of which was described only 30 years ago-are represented almost exclusively by isolated teeth, in addition to fragmentary dentaries attributed to Sudamerica, Gondwanatherium, Ferugliotherium, and an unnamed taxon from Tanzania. No cranial (skull exclusive of lower jaw) or postcranial material has heretofore been assigned to the Gondwanatheria, a severe limitation that has precluded a comprehensive assessment of phylogenetic affinities. Here we describe, in detail, the first cranial specimen of a gondwanatherian mammal. This material consists of a complete and wellpreserved cranium of the sudamericid Vintana sertichi, recovered from the Upper Cretaceous (Maastrichtian) Maevarano Formation in the Mahajanga Basin of northwestern Madagascar. Salient features of the cranium include elongate, scimitarlike jugal flanges, huge orbits, strong klinorhynchy, and a vaulted nuchal region. Micro-computed tomography greatly facilitated the delineation of sutures and the description of internal morphology. The cranial features of Vintana are compared with those of a broad range of synapsids, with particular concentration on other Mesozoic mammaliaforms. The cranium of Vintana exhibits a mosaic of extremely primitive and extremely derived features. It is the second largest known for a Mesozoic mammaliaform, superseded only by that of the eutriconodontan Repenomamus giganticus from the Early Cretaceous of China. Vintana is the largest known Late Cretaceous mammaliaform; it is also the largest known Mesozoic mammaliaform from Gondwana. © 2014 by the Society of Vertebrate Paleontology.


Krause D.W.,State University of New York at Stony Brook | Hoffmann S.,State University of New York at Stony Brook | Wible J.R.,Section of Mammals | Kirk E.C.,University of Texas at Austin | And 12 more authors.
Nature | Year: 2014

Previously known only from isolated teeth and lower jaw fragments recovered from the Cretaceous and Palaeogene of the Southern Hemisphere, the Gondwanatheria constitute the most poorly known of all major mammaliaform radiations. Here we report the discovery of the first skull material of a gondwanatherian, a complete and well-preserved cranium from Upper Cretaceous strata in Madagascar that we assign to a new genus and species. Phylogenetic analysis strongly supports its placement within Gondwanatheria, which are recognized as monophyletic and closely related to multituberculates, an evolutionarily successful clade of Mesozoic mammals known almost exclusively from the Northern Hemisphere. The new taxon is the largest known mammaliaform from the Mesozoic of Gondwana. Its craniofacial anatomy reveals that it was herbivorous, large-eyed and agile, with well-developed high-frequency hearing and a keen sense of smell. The cranium exhibits a mosaic of primitive and derived features, the disparity of which is extreme and probably reflective of a long evolutionary history in geographic isolation.


Missoup A.D.,University of Douala | Missoup A.D.,French Natural History Museum | Missoup A.D.,University of Yaounde I | Nicolas V.,French Natural History Museum | And 7 more authors.
Zoologica Scripta | Year: 2012

Our integrative approach combines two mitochondrial genes (16S and cyt b gene), two nuclear genes (exon 10 GHR and exon 1 IRBP) and craniometrical data to test the status and to infer phylogenetic relationships of the three Praomys Cameroon Volcanic Line endemics (P. hartwigi, P. morio and P. obscurus). The taxonomic rank of the principal genus group is assessed and the mode of diversification of species of the P. tullbergi complex in Afrotropical forests is discussed based on estimates of times to the most recent common ancestors and on tree topologies. This study documents for the first time the molecular and morphometrical distinctiveness of P. hartwigi and P. morio within the P. tullbergi species complex. Further studies including specimens of P. hartwigi from all its distribution range are needed to conclude on the status of P. obscurus. The monophyly of the genus Praomys is refuted. Times to the most recent common ancestors of major clades within the P. tullbergi species complex are estimated for the last 2.5Mya and during the last 1 or 2Mya for different species or forms. The lowland forest refuge hypothesis might well explain the diversification of P. misonnei, P. rostratus and P. tullbergi in the guineo-congolese forest block. The isolation of montane forests could have facilitated the divergence between the two montane forest forms P. hartwigi and P. obscurus and between populations of P. morio from the continent and those from the island of Bioko. Praomys populations (species) that inhabit the Cameroon Volcanic Line Praomys probably originated as lowland forms subsequently specialized to highland conditions. © 2012 The Authors. Zoologica Scripta © 2012 The Norwegian Academy of Science and Letters.


PubMed | University of Texas at Austin, Section of Mammals, University of Antananarivo, Ohio University and 4 more.
Type: Journal Article | Journal: Nature | Year: 2014

Previously known only from isolated teeth and lower jaw fragments recovered from the Cretaceous and Palaeogene of the Southern Hemisphere, the Gondwanatheria constitute the most poorly known of all major mammaliaform radiations. Here we report the discovery of the first skull material of a gondwanatherian, a complete and well-preserved cranium from Upper Cretaceous strata in Madagascar that we assign to a new genus and species. Phylogenetic analysis strongly supports its placement within Gondwanatheria, which are recognized as monophyletic and closely related to multituberculates, an evolutionarily successful clade of Mesozoic mammals known almost exclusively from the Northern Hemisphere. The new taxon is the largest known mammaliaform from the Mesozoic of Gondwana. Its craniofacial anatomy reveals that it was herbivorous, large-eyed and agile, with well-developed high-frequency hearing and a keen sense of smell. The cranium exhibits a mosaic of primitive and derived features, the disparity of which is extreme and probably reflective of a long evolutionary history in geographic isolation.


Wible J.R.,Section of Mammals | Spaulding M.,Section of Mammals
PLoS ONE | Year: 2012

Authoritative anatomical references depict domestic dogs and cats as having a malleus with a short rostral (anterior) process that is connected via a ligament to the ectotympanic of the auditory bulla. Similar mallei have been reported for representatives of each of the 15 extant families of Carnivora, the placental order containing dogs and cats. This morphology is in contrast to a malleus with a long rostral process anchored to the ectotympanic that is considered to be primitive for mammals. Our reexamination of extant carnivorans found representatives from 12 families that possess an elongate rostral process anchored to the ectotympanic. Consequently, the malleus also is a component of the bulla. In a subset of our carnivoran sample, we confirmed that the elongate rostral process on the ectotympanic is continuous with the rest of the malleus through a thin osseous lamina. This morphology is reconstructed as primitive for Carnivora. Prior inaccurate descriptions of the taxa in our sample having mallei continuous with the bulla were based on damaged mallei. In addition to coupling to the ectotympanic, the rostral process of the malleus was found to have a hook-like process that fits in a facet on the skull base in representatives from seven families (felids, nandiniids, viverrids, canids, ursids, procyonids, and mustelids); its occurrence in the remaining families could not be ascertained. This feature is named herein the mallear hook and is likewise reconstructed to be primitive for Carnivora. We also investigated mallei in one additional placental order reported to have mallei not connected to the ectotympanic, Pholidota (pangolins), the extant sister group of Carnivora. We found pholidotans to also have anchored mallei with long rostral processes, but lacking mallear hooks. In light of our results, other mammals previously reported to have short rostral processes should be reexamined. © 2012 Wible, Spaulding.


Jacquet F.,French Natural History Museum | Hutterer R.,Section of Mammals | Nicolas V.,French Natural History Museum | Decher J.,University of Vermont | And 3 more authors.
African Zoology | Year: 2013

Crocidura goliath nimbasivanus Hutterer, 2003 (replacement name for C. odorata guineensis Heim de Balsac, 1968) from West Africa (Guinea, Liberia, Ivory Coast) and Crocidura goliath goliath Thomas, 1906 from Central Africa (Cameroon, Central African Republic, Gabon, Republic of Congo, Democratic Republic of Congo) were regarded as members of a single species until recently. A phylogenetic analysis including three mitochondrial (16S, cytb and COI) and one nuclear marker (BRCA) shows that C. g. nimbasilvanus is the sister taxon of C. nimbae, a species also endemic to West Africa. Crocidura g. goliath is part of the C. olivieri group and closely related to C. olivieri, C. viaria and C. fulvastra. Calculation of genetic distances between cytb sequences confirms this pattern (divergence of 13.5% between C. g. nimbasilvanus and C. g. goliath). An analysis of 112 skulls using morphometric geometrics provides evidence of marked shape differences between the two taxa. Despite close external morphological resemblances, we found diagnostic external and craniodental characters between these two forms. We therefore propose to treat C. nimbasilvanus and C. goliath as distinct species. Similar morphological features exhibited by these two African giant forest shrews, especially their large size, may be the result of homoplasy due to convergent evolutionary pressure. We also investigated the phenotypic diversification in size and skull shape within C. goliath and discovered strong intraspecific variability.


Woodman N.,Smithsonian Institution | Matson J.O.,San Jose State University | Mccarthy T.J.,Section of Mammals | Eckerlin R.P.,Northern Virginia Community College | And 2 more authors.
Annals of Carnegie Museum | Year: 2012

Short term surveys for small mammals in Guatemala and Honduras during 19922009 provided important new records for 12 taxa of shrews from 24 localities. These locality records expand the known geographic distributions for five species and for the genus Sorex Linnaeus, 1758: the geographic range of Cryptotis goodwini Jackson, 1933, now includes the Sierra de las Minas, Guatemala, and several isolated highlands in western Honduras; the known distribution of Cryptotis mayensis (Merriam, 1901) is increased with the first definite modern record for this shrew from Guatemala; Cryptotis merriami Choate, 1970, is now known to occur in the Sierra de las Minas and the Sierra del Merendn, Guatemala, as well as the isolated Sierra de Omoa and Montana de La Muralla in Honduras, and its documented elevational range (6001720 m) is expanded; records of Sorex veraepacis Alston, 1877, expand the known distribution of this species to include the Sierra de Yalijux, Guatemala; and discovery of Sorex salvini Merriam, 1897, at Celaque, Honduras (18253110 m), represents a considerable extension of the geographic range of the species, and it is the first record of the genus Sorex from Honduras. In addition, the first record of potential syntopy among C. goodwini, C merriami, and Cryptotis orophilus (J.A. Allen, 1895), is reported at an elevation of 1430 m in the Sierra de Celaque, Honduras. Information associated with these records contributes substantially to knowledge of habitat use, elevational distributions, reproductive patterns, diet, and parasites of the species encountered. General patterns include the first evidence that Neotropical species of soricids have smaller litters than their temperate congeners.

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