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| Author(s): |
Natália Rossi
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Ribeirão Preto. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (PCARP/BC) |
| Defense date: | 2012-04-12 |
| Examining board members: |
Fernando Luis Medina Mantelatto;
Alexandre Oliveira de Almeida;
Mariana Terossi Rodrigues
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| Advisor: | Fernando Luis Medina Mantelatto |
| Abstract | |
Studies on systematic and taxonomy of freshwater shrimp of the genus Macrobrachium Bate, 1868 are still unclear for some of its members, such as Macrobrachium olfersii Wiegmann, 1836). This species occurs from the southeastern United States to southern Brazil and is commonly mistaken with species that occur mainly in Central America (M. faustinum (de Saussure, 1857), M. digueti (Bouvier, 1895), M. crenulatum Holthuis, 1950, M. hancocki Holthuis, 1950 e M. acanthochirus Villalobos, 1967). In 1969 these species have been designated as a species-complex by Villalobos, because they share morphological characteristics, particularly in the second pair of pereiopod. This strong affinity and proposed some synonyms species is pointed by other authors. Faced with this problem, the validity of these species and the evolutionary relationships between them were verified by a wide taxonomic and molecular data. The phylogenetic hypotheses were based on partial sequences of 16S rDNA, COI mtDNA, 18S and H3 nDNA using analysis of Maximum Likelihood and Inference Bayesian. The diagnoses of the species were detailed, highlighting the differences between them. Nevertheless the morphological analysis were not enough to infer the phylogeny of this group because of the presence of plastic and variables characters among individuals of the same species and other preserved characters among different species of the genus. However, all identities were supported with additional molecular analysis based on four markers, rejecting the existence of synonymy. These species are evolutionarily related to M. zariqueyi Holthuis, 1949, from the west coast of Africa and share morphological character. The latter species could also belong to the M. olfersii complex because has philogenetic closeness, but before this afirmation it may be verified by morphological and molecular analysis. The mitochondrial genes (COI and 16S) showed a broad phylogenetic signal allowing a good resolution of the dendrograms. The nuclear genes (H3 and 18S) showed the recent divergence between some members of the group. (AU) | |
| FAPESP's process: | 09/12409-5 - Revision of Macrobrachium species belonging to the olfersi complex (Crustacea, Palaemonidae): morphological and molecular analysis |
| Grantee: | Natália Rossi |
| Support Opportunities: | Scholarships in Brazil - Master |