Browsing by Author "Emmons, Louise."
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Item The identity of Winge's Lasiuromys villosus and the description of a new genus of echimyid rodent (Rodentia, Echimyidae). American Museum novitates ; no. 3223(New York, NY : American Museum of Natural History, 1998) Emmons, Louise.; Vucetich, MarÃa Guiomar."The painted tree rat, a large, strikingly patterned arboreal echimyid rodent variously identified as Isothrix picta or Echimys pictus, differs in many major cranial characters from other living species of Echimyidae. In addition, a fossil collected by Lund at Lagoa Santa, Brazil, and referred by Winge to the genus now known as Isothrix, is clearly closely allied to it. We propose a new generic name, Callistomys, for these rodents and we describe and compare them to members of the three genera into which they have at one time or another been placed: Nelomys, Isothrix, and Echimys. The fossil may represent an undescribed species, but there is insufficient material to be confident in distinguishing it from C. pictus at this time. Callistomys shows some resemblances to Mid-Miocene and earlier fossil Echimyidae, and it may be more closely related to these than to other extant genera"--P. [1].Item Mammalian diversity in Neotropical lowland rainforests : a preliminary assessment. Bulletin of the AMNH ; no. 230([New York] : American Museum of Natural History, 1996) Voss, Robert S.; Emmons, Louise."Information about the magnitude and geographic distribution of mammalian diversity in Neotropical lowland rainforests is important for evaluating research and conservation priorities in Central and South America. Although relevant inventory data are rapidly accumulating in the literature, real site-to-site diversity differences are hard to identify because many confounding factors can affect the size and composition of faunal lists. Herein we assess the available information about Neotropical rainforest mammal diversity and suggest guidelines for future work by reviewing inventory methods, documenting and discussing faunal lists from ten localities, and summarizing geographic range data to predict diversity patterns that can be tested by field and museum research. All inventory methods are biased because each is suitable for collecting or observing only a fraction of the morphologically and behaviorally diverse mammalian fauna that inhabits Neotropical rainforests. Hence, many methods must be used in combination to census whole communities. Although no combination of methods can be guaranteed to produce complete inventories, the omission or nonintensive application of any of several essential methods probably guarantees incomplete results. We recommend nine methods that, used intensively and in combination, should maximize the efficiency of future inventory fieldwork. Ten rainforest mammal inventories selected as exemplars illustrate several common problems: sampling effort is highly variable from study to study, species accumulation curves are not asymptotic for any fauna, essential field methods were omitted in every case, and some localities were partially defaunated by hunters prior to inventory. Meaningful diversity comparisons are therefore impossible without a major investment in additional fieldwork at each site. Geographic range data provide an essential alternative source of diversity estimates. Comparisons of inventory results with geographic expectations (diversity predictions based on range data) suggest that all existing inventories are incomplete, that the degree of incompleteness is inversely correlated with inventory duration, and that special methods are required to add elusive species to faunal lists. The range data at hand also suggest several geographic patterns that should be tested with carefully focussed fieldwork. (1) Mammalian diversity in Amazonia is probably greatest in the western subregion (between the Rio Negro and the Rio Madeira, where over 200 species might be sympatric at some localities), least in the Guiana subregion (east of the Negro and north of the Amazon), and intermediate in southeastern Amazonia (east of the Madeira and south of the Amazon). (2) Geographic variation in Amazonian diversity chiefly involves marsupials, bats, primates, and rodents; by contrast, xenarthran, carnivore, and ungulate faunas are remarkably uniform across the entire region. (3) In Central American rainforests, a conspicuous and apparently monotonic diversity gradient extends from eastern Panama (where mammalian diversity is within the range of Amazonian values) to southern Mexico (where mammalian diversity may be less than anywhere else on the rainforested Neotropical mainland). Mammalian diversity in coastal Venezuelan and southeastern Brazilian rainforests is difficult to assess with existing literature and collection resources, but neither region is likely to be as diverse as Amazonia. Despite a few dissenting voices, the literature of New World mammalogy provides compelling evidence that mammalian diversity, as measured by sympatric species richness, is greatest in lowland tropical rainforests and decreases along gradients of increasing latitude, elevation, and aridity. Thus, the mammalian faunas of western Amazonia are the most diverse of any in the Americas and perhaps in the world. We briefly discuss the generality and causes of observed diversity patterns in terms of contemporary ecology and historical scenarios. Significant advances in understanding mammalian diversity patterns in Neotropical rainforests will require systematic revisions of many problematic genera and an aggressive program to inventory poorly sampled areas while opportunities to do so yet remain"--P. 3.Item A new genus and species of abrocomid rodent from Peru (Rodentia, Abrocomidae). American Museum novitates ; no. 3279(New York, NY : American Museum of Natural History, 1999) Emmons, Louise."A new specimen of a giant arboreally adapted abrocomid rodent from the northern Vilcabamba Mountains of Cusco, Peru, is here described as a member of a new genus and species. The arboreal nature of the external morphology of the holotype differs strikingly from that of all other know Abrocomidae, which are terrestrial. A species known only from remains found in Inca tombs, Abrocoma oblativa Eaton, 1916, is placed in the new genus"--P. [1].Item A new species of the rodent genus Oecomys (Cricetidae, Sigmodontinae, Oryzomyini) from eastern Bolivia, with emended definitions of O. concolor (Wagner) and O. mamorae (Thomas). (American Museum novitates, no. 3661)(New York, NY : American Museum of Natural History., 2009) Carleton, Michael D.; Emmons, Louise.; Musser, Guy G.We describe a new species of Oecomys, O. sydandersoni (Cricetidae: Sigmodontinae), from the Parque Nacional Noel Kempff Mercado in eastern Bolivia. One of its diagnostic traits, a derived carotid circulatory plan, provides morphological evidence for its close relationship to O. concolor and O. mamorae among the 15 species of Oecomys currently recognized. Notwithstanding this shared trait, other morphological contrasts and morphometric analyses demonstrate the sharp differentiation of the eastern Bolivian form from both of those species. Oecomys sydandersoni, n. sp., is arboreal and was encountered above ground on limbs and woody vines only in densely wooded hummocks scattered through grassland, in contrast to adjacent closed tropical deciduous forest where three other species of Oecomys (O. bicolor, O. roberti, O. trinitatis) were obtained. The new species represents the fourth sigmodontine rodent to be named from this restricted region within eastern Bolivia since 1999. Its documentation served as a platform to summarize the nomenclatural history, morphological recognition, and geographic distribution of O. concolor (Wagner, 1845) and O. mamorae (Thomas, 1906) based on fresh examination of all type material and museum specimens.Item A review of the genus Isothrix (Rodentia, Echimyidae). American Museum novitates ; no. 2817(New York, N.Y. : American Museum of Natural History, 1985) Patton, James L.; Emmons, Louise."Two species of the echimyid rodent genus Isothrix are recognized within the Amazon and upper Orinoco basins of South America based on color and color pattern, bacular morphology, cranial morphometrics, and karyotype. These represent significant departures in the previously recognized name combinations: I. bistriata Wagner, with two geographic races (bistriata (including villosa Deville, negrensis Thomas, molliae Thomas, and boliviensis Petter and Cuenca Aguirre) and orinoci Thomas), and I. pagurus Wagner. No localities of sympatric contact between these two species are known, although their ranges come very close in the general vicinity of Manaus in central Brazil"--P. [1].Item A review of the named forms of Phyllomys (Rodentia, Echimyidae), with the description of a new species from coastal Brazil. American Museum novitates ; no. 3380(New York, NY : American Museum of Natural History, 2002) Emmons, Louise.; Leite, Yuri L. R.; Kock, Dieter.; Costa, Leonora Pires.To clarify the taxonomy and serve as a foundation for future systematic studies, we searched for the type material associated with all named forms of Brazilian Atlantic tree rats of the genus Phyllomys. For the following ten taxa we found either the originally designated holotypes, syntype series, or contemporary specimens likely to have been seen by the authors: P. blainvilii, P. brasiliensis, P. fossilis, P. nigrispinus, P. unicolor, P. dasythrix, P. lamarum, P. medius, P. thomasi, and P. kerri. For five species the holotype was unambiguously identified. For five other named forms no holotype was originally designated but we found several candidate specimens and for all of these we designate lectotypes. We identify the type localities for all named Phyllomys species and amend those which are ambiguous. We review the taxonomy, diagnosing and redescribing all the named forms of the genus. After examining the type material, we concluded that the rusty-sided tree rat from coastal Brazil, usually identified in the literature as P. brasiliensis, belongs to an unnamed species. We describe and name it here.Item A review of the Pattonomys/Toromys clade (Rodentia, Echimyidae), with descriptions of a new Toromys species and a new genus. (American Museum novitates, no. 3894)(American Museum of Natural History., 2018-03-09) Emmons, Louise.; Fabre, Pierre-Henri.New phylogenomic analyses of South American arboreal echimyids show that there are three species within the genus Toromys (T. grandis, T. rhipidurus, and T. sp. nov.) and that the genera Pattonomys and Toromys form a clade that is the sister group to the other three genera of arboreal Echimyini (Echimys, Makalata, and Phyllomys). The arboreal echimyid species Pattonomys occasius is deeply divergent from other species of Pattonomys and from members of other extant named genera, although it shares a sister relationship with Toromys. We erect a new genus, Leiuromys, for it. To clarify the relationships among the species within these three genera, we describe them with molecular and morphological characters. Because most members of these genera have never been reviewed or diagnosed at the species level, we do so now, and we describe a new species, Toromys albiventris, from the upper Ucayali basin of Peru. We illustrate taxa and morphological features not before figured in publications.Item Two new species of Juscelinomys (Rodentia, Muridae) from Bolivia. American Museum novitates ; no. 3280(New York, NY : American Museum of Natural History, 1999) Emmons, Louise.Juscelinomys, a genus of akodontine rodents allied to Oxymycterus, has been known only from the nine individuals of the type series of J. candango. Two rats recently collected in eastern Bolivia are herein described as new species of the genus. Molecular evidence from sequences of the cytochrome gene confirms the morphological evidence that Juscelinomys is a closely related sister group to Oxymycterus. From its literature account, the newly described genus Brucepattersonius Hershkovitz, 1998, seems more distantly related to Juscelinomys than Oxymycterus does"--P. [1].