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| Author(s): |
Elisandra de Almeida Chiquito
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Piracicaba. |
| Institution: | Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC) |
| Defense date: | 2015-09-11 |
| Examining board members: |
Alexandre Reis Percequillo;
Ana Paula Carmignotto;
Pedro Cordeiro Estrela de Andrade Pinto;
Gilson Evaristo Iack Ximenes;
Gabriel Henrique Marroig Zambonato
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| Advisor: | Alexandre Reis Percequillo |
| Abstract | |
The tribe Oryzomyini holds 34 of 86 sigmodontine genera and presents a wide geographic distribution, occurring in several habitats from Tierra del Fuego to southeast United States ; it includes cursorial, arboreal and semi-acquatic species with distinct food habits, ranging from omnivorous to insectivorous. Systematic studies in Oryzomyini have been based on morphological and morphometric data, as well cytogenetic and molecular information, which is contributing to recognition of new taxa. However, the latest published taxonomic review of the genus Nectomys date from 1940, where was recognized only one species with several subespecies, what increased substantially the amount of names related to the genus. In this way, the main goal of this study was to test the Hershkovitz\'s hypothesis that Nectomys is represented by only one species widely distributed through South America. To test this hypothesis, I gathered information about the nominal taxa and I employed geographical variation analysis based on the transect method, for what I used the South America river basins as a geographic units. To do so, I applied univariated and multivariated analysis for the quantitative data, and character frequency for the qualitative data. The results suggest the genus Nectomys is composed by eight species, which are so named and distributed: N. apicalis, Andean eastern slope, from southern Peru to northern Colombia, and westernmost Amazonas state, in Brazil; N. magdalenae, through Magdalena and Cauca valleys, in Colombia; N. palmipes, Trinidad and Tobago, and northeast Venezuela; N. rattus, central and north region in Brazil, Guyana, Suriname, and French Guyana, Venezuela (except Paria peninsula), and Ucayali and Huallaga rivers in Peru; N. saturatus, Ibarra, Ecuador; N. squamipes, Atlantic Forest, from Pernambuco to Rio Grande do Sul, Minas Gerais and eastern Mato Grosso do Sul in Brazil, Paraguay, and Misiones province, Argentina; Nectomys sp. A, northwestern Bolivia, in the eastern Andean slope; and Nectomys sp. B., western Amazônia, in Purus, Juruá, and Javari rivers. The analysis conducted allowed me to establish that the cytogenetic and morphologic variation is not random: I found marked discontinuities among samples through the geography, and based on the species concept I adopted, I establish that these entities represent eight distinct species. (AU) | |
| FAPESP's process: | 10/18846-5 - Systematics of the genus Nectomys Peters, 1860 (Cricetidae, Sigmodontinae) |
| Grantee: | Elisandra de Almeida Chiquito |
| Support Opportunities: | Scholarships in Brazil - Doctorate |