Browsing by Author "Giarla, Thomas C."
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Item DNA sequence data from the holotype of Marmosa elegans coquimbensis Tate, 1931 (Mammalia, Didelphidae) resolve its disputed relationships. (American Museum novitates, no. 3946)(American Museum of Natural History., 2020-02-28) Giarla, Thomas C.; Voss, Robert S.DNA sequence data obtained from the 96 year old holotype of Marmosa elegans coquimbensis Tate, 1931, support the hypothesis that this nominal taxon is a synonym or subspecies of Thylamys elegans (Waterhouse, 1839) and is not conspecific with T. pallidior (Thomas, 1902).Item 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)(American Museum of Natural History., 2021-12-15) Esselstyn, Jacob A.; Setiawan Achmadi, Anang; Handika, Heru; Swanson, Mark T.; Giarla, Thomas C.; Rowe, Kevin C.After nearly a decade of field inventories in which we preserved voucher specimens of the small terrestrial mammals of Sulawesi, we combined qualitative and quantitative analyses of morphological traits with molecular phylogenetics to better understand the diversity of shrews (Soricidae: Crocidura) on the island. We examined the morphology of 1368 specimens and obtained extensive molecular data from many of them, including mitochondrial DNA sequences from 851 specimens, up to five nuclear exons from 657 specimens, and thousands of ultraconserved elements from 90 specimens. By iteratively testing species limits using distinct character datasets and appropriate taxon sampling, we found clear, mostly consistent evidence for the existence of 21 species of shrews on Sulawesi, only seven of which were previously recognized. We divide these 21 species into five morphogroups, provide emended diagnoses of the seven previously named species, and describe 14 new species. The Long-Tailed Group contains Crocidura caudipilosa, C. elongata, C. microelongata, new species, and C. quasielongata, new species; the Rhoditis Group contains C. rhoditis, C. pseudorhoditis, new species, C. australis, new species, and C. pallida, new species; the Small-Bodied Group contains C. lea, C. levicula, C. baletei, new species, C. mediocris, new species, C. parva, new species, and C. tenebrosa, new species; the Thick-Tailed Group contains C. brevicauda, new species and C. caudicrassa, new species; and the Ordinary Group contains C. musseri, C. nigripes, C. normalis, new species, C. ordinaria, new species, and C. solita, new species. Documenting these endemic species reveals a local radiation (20 of the 21 species are members of an endemic clade) in which elevational gradients played a prominent role in either promoting speciation, or at a minimum, fostering the cooccurrence of phenotypically similar species. As now understood, the species-level diversity of Crocidura on Sulawesi is nearly three times the known diversity of any other insular shrew fauna. This study highlights the fact that if we wish to understand the true extent of biodiversity on Earth, large-scale, vouchered organismal inventories followed up with thorough examinations of genetic, morphological, and geographic traits are sorely needed in montane tropical regions, even for purportedly well-studied groups such as mammals.Item Mammalian diversity and Matses ethnomammalogy in Amazonian Peru. Part 5, Rodents. (Bulletin of the American Museum of Natural History, no. 466)(American Museum of Natural History., 2024-04-18) Voss, Robert S.; Fleck, David W. (David William), 1969-; Giarla, Thomas C.In this report, the fifth and last of our monographic series on mammalian diversity and ethnomammalogy in the Yavarí-Ucayali interfluvial region of northeastern Peru, we document the local occurrence of 40 species of rodents, including 5 sciurids, 17 cricetids, 1 caviid, 1 cuniculid, 2 dasyproctids, 1 dinomyid, 2 erethizontids, and 11 echimyids. The following substantive taxonomic results, among others, are reported: (1) We discuss current issues of sciurid classification and treat all New World tree squirrels (Sciurini), except North American Tamiasciurus, as members of the genus Sciurus; the proposed subgeneric classification is monophyletic, and it conserves longstanding binomial usage for most species. (2) We describe a new species of squirrel, Sciurus (Hadrosciurus) pachecoi, which had previously been identified as a distinct lineage by molecular analyses. (3) We discuss the nominal taxa currently synonymized with S. (H.) pyrrhinus and comment on the application of names to phenotypes and mitochondrial haplogroups. (4) The currently accepted type locality of S. (H.) spadiceus (Cuiabá) cannot be correct; instead, documentary evidence suggests that the holotype must have been collected near Santarém. (5) Sciurus flaviventer appears to be the only valid species of Microsciurus (sensu lato) that occurs in the Amazonian lowlands; Amazonian records of taxa previously reported in the literature as M. sabanillae and M. "species 2" appear to be based on erroneous geographic coordinates and unexplained genotype/ phenotype discordance, respectively. (6) We discuss and illustrate the diagnostic morphological characters of Nectomys apicalis and N. rattus, which have broadly overlapping distributions in northern Peru. (7) We analyze cytochrome b sequence data from 143 specimens of Oecomys from western Amazonia and summarize evidence for multiple unnamed lineages; of these, three from the Yavarí-Ucayali interfluve are described as new species. (8) We question the recognition of O. tapajinus as a species distinct from O. roberti due to the lack of unambiguously diagnostic characters and the doubtful identity of the holotype of tapajinus. (9) We confirm sympatry between two species of Scolomys and provide revised diagnostic criteria for S. melanops and S. ucayalensis. (10) We report the only specimen of Dinomys branickii accompanied by definite locality data from Loreto department. (11) Proechimys quadruplicatus and P. steerei, closely related species previously thought to occur on opposite banks of the Peruvian Amazon, are both present in the Yavarí-Ucayali interfluve; diagnostic characters are tabulated for the six species of Proechimys now known to occur in our region. Despite intensive and methodologically complementary faunal-sampling efforts, our rodent inventory is probably incomplete; at least four additional species could be expected to occur in our region based on geographic range data. If all four do occur there, then our inventory is about 90% complete. Documented sympatric species richness at intensively sampled sites in our region is substantially less than the regional total, but because of methodological omissions, no site is believed to have been completely inventoried for rodents. In the absence of known barriers to mammalian dispersal within the Yavarí-Ucayali interfluve, however, local (sympatric) species richness is probably constrained only by habitat availability. Matses knowledge of rodents is richly detailed for primary game species (Cuniculus paca and Dasyprocta fuliginosa) but is less detailed for less culturally important subsets of the fauna. As previously documented for other mammals (e.g., primates, xenarthrans, and ungulates), important game species are known by multiple names (including synonyms and hyponyms), whereas less culturally important but still salient species (e.g., squirrels) have single names, and many inconspicuous (e.g., small, nocturnal, and morphologically indistinguishable) species do not have unique identifiers. With the rodents treated in this report, the mammalian fauna of the Yavarí-Ucayali interfluve is now known to include at least 201 species, but >20 additional species (mostly bats) could still be expected in the region based on geographic range data. Despite the probable incompleteness of our inventory, the Yavarí-Ucayali interfluve is the only part of western Amazonia with an extensively documented mammal fauna. Therefore, the completion of this monographic series provides nomic resource for urgently needed mammalogical research in this ecologically intact but increasingly vulnerable region.Item A revision of Philander (Marsupialia: Didelphidae). Part 2, phylogenetic relationships and morphological diagnosis of P. nigratus Thomas, 1923. (American Museum novitates, no. 3955)(American Museum of Natural History., 2020-06-24) Voss, Robert S.; Giarla, Thomas C.Newly available molecular sequences and morphological data suggest that Philander nigratus Thomas, 1923, is a valid species. Currently known from just eight specimens collected in the Peruvian departments of Junín and Ayacucho, P. nigratus does not appear to be closely related to either of the congeneric taxa with which it was previously synonymized.Item A revision of the didelphid marsupial genus Marmosa. Part 2, Species of the rapposa group (subgenus Micoureus). (Bulletin of the American Museum of Natural History, no. 439)(American Museum of Natural History., 2020-06-01) Voss, Robert S.; Giarla, Thomas C.; Díaz-Nieto, Juan F.; Jansa, Sharon A.In this report, the second of a revisionary series on mouse opossums (Marmosa), we analyze cytochrome b sequence data from 166 specimens of the subgenus Micoureus and delimit putative species using the multirate Poisson Tree Processes (mPTP) method. That analysis identifies 21 putative species, many of which can be matched with available names, including alstoni, constantiae, demerarae, limae, germana, meridae, paraguayana, parda, perplexa, phaea, rapposa, and rutteri. However, some of these nominal taxa are not morphologically diagnosable, and in the absence of other corroborating evidence, we do not recommend that they all be recognized as valid. Phylogenetic analyses of a multigene dataset suggest that putative species of Micoureus belong to several well-supported clades, one of which (the “Rapposa Group”) is revised in this report. As defined herein, the Rapposa Group includes at least three valid species: M. rapposa Thomas, 1899 (including budini Thomas, 1920); M. parda Tate, 1931; and M. rutteri Thomas, 1924. Herein we document their ecogeographic distributions and diagnostic traits, comment on their taxonomic histories, and list the specimens we examined (including all relevant type material).Item A revision of the didelphid marsupial genus Marmosa. Part 3, A new species from western Amazonia, with redescriptions of M. perplexa Anthony, 1922, and M. germana Thomas, 1904. (American Museum novitates, no. 3969)(New York, NY : American Museum of Natural History, 2021-04-01) Voss, Robert S.; Giarla, Thomas C.We describe a new species of woolly mouse opossum from northwestern Amazonia, Marmosa jansae, based on museum specimens previously misidentified either as M. germana Thomas, 1904, or as M. regina Thomas, 1898. Instead of being closely related to either of those species, M. jansae appears to be the sister taxon of M. perplexa Anthony, 1922, a trans-Andean species previously synonymized with M. phaea Thomas, 1899. We redescribe M. perplexa, which inhabits critically endangered evergreen and semideciduous forests in southwestern Ecuador and northwestern Peru. We also redescribe M. germana, an Amazonian species that has long been synonymized with M. regina, but which molecular analyses now suggest is the sister taxon of a trans-Andean species complex that includes M. alstoni (Allen, 1900). These results substantially clarify the long-confused taxonomy of woolly mouse opossums (subgenus Micoureus), provide new examples of sister-group relationships between upper-Amazonian and trans-Andean taxa, and raise interesting questions about congeneric diversity in northwestern Amazonia, where as many as six species of Marmosa might occur sympatrically.Item A revision of the didelphid marsupial genus Marmosa. Part 4, species of the Alstoni Group (subgenus Micoureus) (American Museum novitates, no. 3983)(American Museum of Natural History., 2021-12-08) Voss, Robert S.; Giarla, Thomas C.; Jansa, Sharon A.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.Item Species limits and phylogenetic relationships in the didelphid marsupial genus Thylamys based on mitochondrial DNA sequences and morphology. (Bulletin of the American Museum of Natural History, no. 346)(American Museum of Natural History., 2010) Giarla, Thomas C.; Voss, Robert S.; Jansa, Sharon A.Species of the didelphid marsupial genus Thylamys, commonly known as fat-tailed mouse opossums, are broadly distributed in the open habitats of central and southern South America. In this report we examine species limits in the genus and infer phylogenetic relationships among Thylamys species using both molecular phylogenetic and morphological methods. We assessed species limits using a broad geographic sample of DNA sequences from the mitochondrial gene cytochrome b in conjunction with morphological character analysis, and we inferred phylogenetic relationships among species using the cytochrome-b dataset in addition to sequences from the mitochondrial genes cytochrome c oxidase subunit II and NADH dehydrogenase 2 for a representative subset of individuals. Based on the results of these analyses, we recognize Xerodelphys (new subgenus) for T. karimii and T. velutinus, and we recognize seven valid species in the nominotypical subgenus. The latter includes T. macrurus, T. pusillus, and two monophyletic species groups: the Elegans Group (T. elegans, T. pallidior, T. tatei) and the Venustus Group (T. sponsorius, T. venustus). Analysis of cytochrome-b sequences additionally reveals deep phylogeographic structuring in three species (T. pallidior, T. pusillus, T. venustus), each of which contains two or three robustly supported allopatric haplogroups. The existence of undescribed Peruvian forms of the Elegans Group is also plausibly indicated. We provide morphological diagnoses of all species recognized as valid in this report, summarize information about geographic distributions, comment on previous misidentifications, and briefly consider historical-biogeographic scenarios with a focus on dispersal events across the Andes.Item Supplemental Material for 'A revision of Philander (Marsupialia: Didelphidae). Part 2, phylogenetic relationships and morphological diagnosis of P. nigratus Thomas, 1923. (American Museum novitates, no. 3955)'(2020-06-24) Voss, Robert S.; Giarla, Thomas C.Supplemental Material for 'A revision of Philander (Marsupialia: Didelphidae). Part 2, phylogenetic relationships and morphological diagnosis of P. nigratus Thomas, 1923. (American Museum novitates, no. 3955)'