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Pittsburgh, PA, United States

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

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. Source

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

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. Source

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

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. Source

Giannini N.P.,CONICET | MacRini T.E.,St. Marys 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

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. Source

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

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. Source

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