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| Author(s): |
Mauricio da Cruz Forlani
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Instituto de Biociências (IBIOC/SB) |
| Defense date: | 2010-12-03 |
| Examining board members: |
Hussam El Dine Zaher;
Miguel Trefaut Urbano Rodrigues;
Hélio Ricardo da Silva
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| Advisor: | Hussam El Dine Zaher |
| Abstract | |
Among the 20 recognized genera of the New World Microhylidae, Chiasmocleis is the most diverse, containing 25 species widely distributed throughout South America east of the Andes and south of Central America. The genus lacks a robust hypothesis of relationship between its species, and its monophyly has never been adequately tested. In this work a phylogenetic analysis is employed to specifically address those issues and to position Chiasmocleis among American microhylids. Comparative analysis of the morphology of 18 species of Chiasmocleis, and 19 species from 15 genera of Neotropical microhylids resulted in a matrix of 116 characters, 48 concerning the external morphology and 68 osteological. This matrix was analyzed in a cladistic framework with the program TNT, resulting in a single most parsimonious tree with 490 steps, consistency index 0.308 and retention index 0.562. The monophyly of the genus Chiasmocleis is rejected, with the genus Syncope rooting at the apex line formed by species of the genus Chiasmocleis. In addition, C. panamensis did not group with other species in the genus, and is positioned as the sister group to the clade formed by Relictivomer, Elachistocleis, Dasypops, Synapturanus, Myersiella , this clade being the sister group of the other species of Chiasmocleis plus Syncope. The topology found positioned the smaller species in the more derived branches, suggesting an evolutionary trend of reduction of body size in the new world microhylid lineage. Although the present work has not drawn a general profile of the consequences of miniaturization in the group, characteristics of the shoulder girdle suggest the retention of paedomorphic states in smaller species. (AU) | |