RESUMO
BACKGROUND: Since 1996, when Vivo questioned how many species of mammals occur in Brazil, there has been a huge effort to assess this biodiversity. In this contribution, we present new records for rare species of the sigmodontine rodent genera Rhagomys and Neusticomys previously unknown to Brazilian Amazon. We provided detailed information on the morphologic variation to allow the proper identification of these species. We also furnished updated information on their collection, aiming to establish hypothesis of their geographic distribution, based on SDM's, aiming to hypothesize potential occurrence areas for these species. METHODS: Rodent specimens were sampled in separate inventories in two sites of Rondônia State (Hydroelectric Dam Jirau and Parque Nacional de Pacaás Novos) and one site in Pará State (Pacajá), Brazil, and were compared to specimens from museum collections to apply appropriate names. The SDM were conducted using two algorithms for rare species, MaxEnt and randomForest (RF), and were based on seven localities for Rhagomys, and 10 for Neusticomys. RESULTS: All specimens were collected with pitfall traps. One specimen of genus Rhagomys was trapped in the Hydroelectric Dam Jirau. We identified this specimen as R. longilingua, and the SDM species indicates suitable areas for its occurrence at high elevations near on the Andes and lowlands of Amazon Basin to the South of the Rio Amazonas. Two specimens of Neusticomys were recorded, and we identified the specimen from Pacaás Novos as N. peruviensis, with SDM suggesting main areas of occurrence on Western Amazon. We applied the name N. ferreirai to the specimen from Pacajá, with SDM recovering suitable areas in Eastern Amazon. DISCUSSION: We reinforced the importance of pitfall traps on the study of Neotropical rodents. We described morphologic variation within and among all species that do not invalidate their specific status, but in the near future a re-evaluation will be mandatory. The new records extended the species distribution considerably. SDM was successful to predict their distributions, as the two algorithms presented important differences in range size recovered by the models that can be explained by differences in the thresholds used for the construction of the models. Most suitable areas coincide with the areas facing most of the deforestation in Amazon. We added two rare species of sigmodontine rodents to the list of Brazilian Mammals, which now comprises 722 species (or 775 valid nominal taxa). Although more information is available than in 1996, it is essential that mammal experts maintain inventory and revisionary programs to update and revise this information. This is even more important, as changes in Brazilian environmental legislation are being discussed, suggesting reduced need for environmental impact reports prior to beginning commercial enterprises, resulting in the loss of information about native biodiversity in the affected areas.
RESUMO
En el presente trabajo se documenta la diversidad de mamíferos pequeños en la Zona Reservada Sierra del Divisor (ZRSD). Se evaluaron seis localidades entre 2011 y 2013 utilizando técnicas de captura estándar (trampas Víctor, Tomahawk, Pitfall y redes de niebla). Se registró un total de 67 especies (cinco marsupiales, 10 roedores y 52 murciélagos), 32 de las cuales son nuevos registros para la ZRSD y dos son especies de roedores raras y endémicas del Perú, la rata acuática peruana Neusticomys peruviensis (Cricetidae: Ichthyomyini) y el Ratón acuático de Ucayali Amphinectomys savamis (Cricetidae: Oryzomyini). El marsupial Marmosops bishopi; los roedores Neacomys minutus, Euryoryzomys macconnelli, Scolomys melanops y Proechimys kulinae; y los murciélagos Artibeus planirostris y Rhinophylla pumilio fueron las especies más abundantes. Nuestros hallazgos demuestran la importancia de la re-categorización de la Zona Reservada al estatus de Parque Nacional, como una contribución significativa para la conservación de los mamíferos del Perú.
This study documents the small mammalian diversity in the Zona Reservada Sierra del Divisor (ZRSD). Six sites were evaluated between 2011 and 2013 with capture techniques (Victor snap traps, Tomahawk traps, Pitfall traps and mist nets). 67 species of small mammals were recorded (five marsupials, 10 rodents and 52 bats), 32 of which are new records for the ZRSD and two are species of the most rare and endemic rodents of Peru, the Peruvian Aquatic Rat Neusticomys peruviensis (Cricetidae: Ichthyomyini) and Ucayali´s Aquatic Mouse Amphinectomys savamis (Cricetidae: Oryzomyini). On the other hand, the marsupial Marmosops bishopi; rodents Neacomys minutus, Euryoryzomys macconnelli, Scolomys melanops and Proechimys kulinae; and the bats Artibeus planirostris and Rhinophylla pumilio were the most plenty. Our finding showed the importance of the re-categorization of Reserved Zone to National Park like as a significant contribution to the conservation of the Peruvian mammals.
RESUMO
BACKGROUND: Inthis study, the genetic substructure and morphology of the species Neusticomysmonticolus was evaluated. A nuclear marker and mitochondrial maker were used to examine phylogeographic structure and to estimategenetic distances. Two statistical measurement analyses were applied to morphological data. RESULTS: These data recovered two morphologically distinct phylogeographic groups corresponding to populations on the eastern and western slopes of the Andes. Further, these eastern and western Andean slope populations of N. monticolus are 8.5 % divergent using sequence data from cytochrome-b (0.8 % divergent in the interphotoreceptor retinoid-binding protein gene). CONCLUSIONS: Populationscurrently assigned to N.monticolus constitutea species complex. The name N.monticolus is here restricted to western Andean slope populations. Populations on the eastern slope of the Andes are assigned to a new species, to which the authors assign the name Neusticomys vossi sp.nov.