6932 research outputs found
Sort by
Miocene Tayassuidae and Dromomerycinae
Full text link27 pages : illustrations ; 26 cm.The earliest record of North American mammals in South America is significant for constraining the timing of intercontinental faunal interchange. At present, the oldest securely dated remains of a North American terrestrial mammal in South America pertain to a late Miocene procyonid; a few other North American mammal groups are present in late Miocene and early Pliocene outcrops in South America, but most are not recorded until the late Pliocene or Pleistocene, after the complete emergence of the Panamanian Isthmus. This long-established pattern has recently been called into question by reports of a proboscidean, two tayassuids, and a dromomerycine cervoid in supposed late Miocene deposits of Peruvian Amazon. In this contribution, we analyze the taxonomic identities and stratigraphic provenances of the tayassuid and dromomerycine fossils in detail. We conclude that these specimens are not distinguishable from modern tayassuids (Tayassu pecari and Dicotyles tajacu) and cervids, and that previous taxonomic identifications are based on misinterpretation of characters or inadequate specimens. In addition, there is insufficient evidence to support a late Miocene age for these terrestrial cetartiodactyl fossils; the stratigraphic provenance of the specimens is highly dubious, and the fossils are likely Quaternary in age
A revision of the didelphid marsupial genus Marmosa. Part 4, species of the Alstoni Group (subgenus Micoureus) (American Museum novitates, no. 3983)
Full text link31 pages : color illustrations, map ; 26 cm.In this report, the fourth of a revisionary series on mouse opossums (Marmosa), we treat the members of a monophyletic group of trans-Andean taxa that include M. alstoni (Allen, 1900); M. nicaraguae Thomas, 1905; and M. adleri, a new species. Although cytochrome b sequence divergence values among these species are substantially lower than distances commonly observed among other congeners, members of the Alstoni Group are strikingly unlike one another in morphological traits. We conjecture that rapid phenotypic divergence accompanied the Pleistocene radiation of an ancestral lineage that entered Central America as a late participant in the Great American Biotic Interchange. Additional undescribed species of the Alstoni Group seem likely to exist based on the evidence at hand, and we emphasize the need for renewed collecting in Central America, which has long been neglected by mammalian biodiversity researchers
Supplemental Material for 'Fourteen new, endemic species of shrew (genus Crocidura) from Sulawesi reveal a spectacular island radiation. (Bulletin of the American Museum of Natural History, no. 454)'
No full textSupplemental Material for 'Fourteen new, endemic species of shrew (genus Crocidura) from Sulawesi reveal a spectacular island radiation. (Bulletin of the American Museum of Natural History, no. 454)
Systematic revision of the arboreal Neotropical “thorellii” clade of Centruroides Marx, 1890, bark scorpions (Buthidae C.L. Koch, 1837) with descriptions of six new species (Bulletin of the American Museum of Natural History, no. 452)
Full text link92 pages : illustrations (some color), maps ; 26 cm.The arboreal Neotropical “thorellii” clade of Centruroides Marx, 1890, bark scorpions (Buthidae C.L. Koch, 1837) is revised, using a novel approach to species delimitation. A phylogenetic analysis, based on 112 morphological characters and 1078 aligned DNA nucleotides from the mitochondrial Cytochrome c Oxidase Subunit I (COI) gene, provided the framework for placing singletons from geographically disparate localities (and often with suboptimal preservation) using COI minibarcodes, thereby enlarging the taxon sample for diagnosis and delimitation of morphological species. Six new species are described, tripling the known diversity in the clade to nine: Centruroides berstoni, sp. nov.; Centruroides catemacoensis, sp. nov.; Centruroides chanae, sp. nov.; Centruroides cuauhmapan, sp. nov.; Centruroides hamadryas, sp. nov.; Centruroides yucatanensis, sp. nov. Revised diagnoses are presented for Centruroides hoffmanni Armas, 1996, Centruroides rileyi Sissom, 1995, and Centruroides schmidti Sissom, 1995. Comparative images, a key and distribution maps for all species of the clade are provided, along with a summary of available data for their ecology
Supplemental Material for 'Total evidence phylogenetic analysis supports new morphological synapomorphies for Bovidae (Mammalia, Artiodactyla). (American Museum novitates, no. 3970)'
No full textSupplemental Material for 'Total evidence phylogenetic analysis supports new morphological synapomorphies for Bovidae (Mammalia, Artiodactyla). (American Museum novitates, no. 3970)
Mammalian diversity and Matses ethnomammalogy in Amazonian Peru. Part 4, Bats (Bulletin of the American Museum of Natural History, no. 451)
Full text link199 pages : color illustrations, maps ; 26 cm.In this report, the fourth of our monographic series on mammalian diversity and Matses ethnomammalogyin the Yavarí-Ucayali interfluvial region of northeastern Peru, we document the occurrence of 98 species of bats, including 11 emballonurids, 2 noctilionids, 66 phyllostomids, 1 furipterid, 4 thyropterids, 7 vespertilionids, and 7 molossids. New species based on specimens collected in this region (Peropteryx pallidoptera, Micronycteris matses, Hsunycteris dashe, Sturnira giannae, and Thyropterawynneae) have already been described elsewhere, but noteworthy distributional and taxonomicresults newly reported here include the first specimen of Diclidurus isabella from Peru and the diagnosis of Glossophaga bakeri as a species distinct from G. commissarisi. Lists of examined voucher specimens, identification criteria, essential taxonomic references, and summaries of natural history observations are provided for all species. Original natural history information reported herein includes numerous observations of roosting behavior obtained by indigenous Matses collaborators. We assess the Yavarí-Ucayali bat inventory for completeness and conclude that more species remain to be discovered in the region, where as many as 116 species might be expected. Most of the “missing” species (those expected based on geographic criteria but not actually observed) are aerial insectivores, a guild that is notoriously difficult to sample by mistnetting. Of the 98 species in the observed regional fauna, only 71 are known to occur sympatrically at Jenaro Herrera, by far the best-sampled locality between the Yavarí and Ucayali rivers. Faunal comparisons with extralimital inventories (e.g., from Brazil, Ecuador, and French Guiana) suggest that frugivorous bats are substantially more speciose in western Amazonia than in eastern Amazonia, a result that is consistent with previous suggestions of an east-to-west gradient in the trophic structure of Amazonian mammal faunas. As previously reported, the Matses have only a single name for “bat,” but they recognize the existence of many unnamed local species, which they distinguish on the basis of morphology and behavior. However, by contrast with the well-documented accuracy of Matses observations about primates and other game species, recorded Matses monologs about bat natural history contain numerous factual errors and ambiguities. Linguistic underdifferentiation of bat diversity and inaccurate natural history knowledge are both explained by cultural inattention to small, inedible, and inoffensive nocturnal fauna
A new dromaeosaurid from the Late Cretaceous Khulsan locality of Mongolia (American Museum novitates, no. 3965)
No full text46 pages : color illustrations, map ; 26 cm.A new dromaeosaurid dinosaur, Shri devi, from the Late Cretaceous deposit of the Barun Goyot Formation at Khulsan, Mongolia, is described here. The Barun Goyot Formation (herein referred to as the Barun Goyot) is stratigraphically intermediate between the overlying Nemegt Formation and the underlying Djadokhta Formation, where much of the dromaeosaurid diversity has been reported to date. Sediments of the Barun Goyot are typically considered Upper Campanian in age. Although dromaeosaurid remains have been noted to occur in the Barun Goyot for decades, descriptive and taxonomic work has never been completed for the material. The holotype specimen (IGM 100/980) consists of a partially articulated individual preserving the right hind limb; left tibiotarsus; pelvis; and adjacent cervical, dorsal, and caudal vertebrae. IGM 100/980 is referable to a clade with Velociraptor based on the presence of a distinct ambiens tubercle located proximally on the anterior face of the pubis, a well-developed anterior tuberosity proximally located on the ischium, and a rounded longitudinal ischial ridge. It is distinguishable from V. mongoliensis based on a weak fourth trochanter (shared with all other dromaeosaurids) and deep anterior pedicular fossae in the cervical vertebrae; epipophyses in the last four cervicals are not raised but are instead represented by rugose circular scars. A suite of axial and appendicular characters are diagnostic for the new species. New discoveries including Shri devi allow for an improved understanding of dromaeosaurid anatomy, as well as the temporal and regional variation of the dromaeosaurid fauna of Mongolia and Inner Mongolia (Nei Mongol Autonomous Region, China), during the Late Cretaceous
The osteology of Haya griva (Dinosauria: Ornithischia) from the Late Cretaceous of Mongolia. (Bulletin of the American Museum of Natural History, no. 445)
Full text link111 pages : illustrations (chiefly color), color map ; 26 cm.Haya griva is an early-diverging neornithischian ("hypsilophodontid") dinosaur known from several well-preserved skulls and articulated postcranial skeletons, in addition to dozens of partial or isolated finds from the Upper Cretaceous Khugenetslavkant and Zos Canyon localities (Javkhlant Formation and equivalent beds) in the Gobi Desert of Mongolia. Collectively, nearly the entire skeletal anatomy of Haya is known, including partial growth series of skulls and femora. Detailed description and comparisons with other ornithischians, including novel anatomical information about the palate and braincase gleaned through high-resolution x-ray microcomputed tomography, reveals a wealth of osteological data for understanding the growth and relationships of this key taxon. Though the Haya specimens span a wide size range, bone histology reveals that all are likely perinatal to subadult individuals, with specimens of intermediate age the most common, and skeletally mature specimens absent. Phylogenetic of Thescelosauridae, an important noncerapodan neornithischian group of the Late Cretaceous.analyses place Haya as one of the few Asian members of Thescelosauridae, an important noncerapodan neornithischian group of the Late Cretaceous
Supplemental Material for 'The osteology of Haya griva (Dinosauria: Ornithischia) from the Late Cretaceous of Mongolia. (Bulletin of the American Museum of Natural History, no. 445)'
No full textSupplemental Material for 'The osteology of Haya griva (Dinosauria: Ornithischia) from the Late Cretaceous of Mongolia. (Bulletin of the American Museum of Natural History, no. 445)
Cephalopods from the Cretaceous-Paleogene (K-Pg) boundary interval on the Brazos River, Texas, and extinction of the ammonites (American Museum novitates, no. 3964)
No full text52 pages : illustrations (some color), map ; 26 cm.We report on new collections of cephalopods (ammonites and nautilids) from the Cretaceous-Paleogene (K-Pg) successions of the Corsicana and Kincaid formations exposed along the Brazos River in Falls County, Texas. An abundant fauna of eight species comprising four genera of ammonites is described from the Corsicana Formation, including Discoscaphites mullinaxorum n. sp. The presence of abundant aptychi (probably lower jaws) of Discoscaphites and Eubaculites, as well as juvenile specimens, indicates a living population that experienced little postmortem drift. The lytoceratid genus Gaudryceras is also reported for the first time from the Brazos River area. Presence of the index taxon Discoscaphites iris (Conrad, 1858) indicates that the fauna belongs to the D. iris Range Zone, the highest ammonite range zone in North America. Correlation with new and existing microfossil data indicates that the fauna represents the uppermost Maastrichtian, and comparison with published records further suggests that this is the most diverse D. iris Zone fauna yet reported from the Gulf and Atlantic Coastal Plains of North America. Three ammonite genera are recorded from the basal units of the K-Pg event deposit at Brazos, which likely represents deposition in the immediate aftermath of the Chicxulub impact event. A single specimen of the nautilid Eutrephoceras is reported from the Danian Kincaid Formation, less than 300 kyr after the K-Pg boundary. These data provide new information on the differing fate of these cephalopod groups during the K-Pg mass extinction and add to the picture of diverse and abundant Maastrichtian ammonite faunas prior to the Chicxulub impact event