Research Training ProgramSmithsonian
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| Cristiano Moreira Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil Dr. Richard P. Vari Dr. Stanley H Weitzman Supervising Scientists Department of Vertebrate Zoology, Division of Fishes "It was a great experience working side-by-side excellent professionals in one of the best museums." |
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On the monophyly of the Iguanodectinae (Characiformes: Characidae)
ABSTRACT
The Iguanodectinae is a widespread subfamily of the Characidae, occurring in most of the major neotropical drainages east of the Andes. It is composed of 10 described species, distributed in two genera, Iguanodectes and Piabucus. Knowledge of the group extends back several centuries, with the first iguanodectine species described in the 17th century. Despite the lengthy taxonomic history of the group, the phylogenetic status of the group and of its species remains obscure. The first attempt to determine the monophyly of the group was made by Vari (1977), when three synapomorphies associated with the gas bladder were proposed for the group. Subsequently, two phylogenetic studies of the family Characidae (Lucena, 1993 and Uj, 1990) dealt with Iguanodectinae in their analyses, proposing additional synapomorphies for the group. In the present study specimens of Iguanodectes and Piabucus were analyzed from 30 different localities, comprising a great portion of the range of their distribution. The osteological and soft anatomical features of this material, and of 22 species belonging to other groups of Characiformes, were examined in the search of shared derived characters for the Iguanodectinae. The main goal was to test the hypothesis that the group was monophyletic. New evidence for the monophyly of the group were added and some proposed previously by different authors was shown not to be consistent. During the study, putative synapomorphies for groups within the Iguanodectinae were also found. They will be useful in future studies of the subfamily. In the present study, some populations of Iguanodectes spilurus were examined and it was possible to determine that the present definition in the literature of I. spilurus does not reflect a monophyletic unity. This shows that the group needs not only a phylogenetic study, but also a revision of its component species.
This research was supported by a grant from the Smithsonian Women's Committee.