Cladistics of the harvestmen of the family Gonyleptidae (Arachnida: Opiliones) based on morphological, behavioral and molecular characters

Abstract

Harvestmen (Arachnida: Opiliones) can be an excellent model for studies on comparative biology. This can be seen when results of studies concerning behavior (in all of its diversity) and distribution patterns are related to available phylogenetic hypotheses. However, only a few phylogenetic hypotheses are presently available and they are somewhat fragmented when higher level taxonomic groups are concerned. Therefore, a better understanding about the phylogenetic relationship within Gonyleptidae (one of the two largest families of harvestmen) could offer important theoretical contributions for several areas of the biological knowledge, such as evolution, biogeography and behavior. Aiming that goal, a first step includes faunal surveys to improve the knowledge about the diversity of Gonyleptidae in Brazil, sampling an area as large as possible involving the larger number of ecosystems as possible. Potential undescribed species collected and recognized at this time will be described, as well as supraspecific taxa may be revised, with the help of information from museum collections. At the same time, live specimens captured during these faunal surveys will be used for behavioral and life history studies, as well as material from museum collections may be used for morphological studies under the microscope (especially SEM - Scanning Electron Microscope). The second step aims at testing the monophyletic status of Gonyleptidae and at proposing a phylogenetic hypothesis about the relationship among its subfamilies and main genera, based on total evidence including morphological, molecular and behavioral data. The increase in knowledge about the phylogenetic relationships among the subfamilies of Gonyleptidae is paramount for studies on comparative biology, since it will allow the use of phylogenetic comparative methods. In addition, the phylogenetic hypothesis obtained in the present study may help in future studies on biogeography. Finally, since this phylogenetic hypothesis will be based on three different sources of characters (morphology, behavior, and molecules), it will be a good opportunity for testing the congruence among the results using each source of information at a time, and also to compare these results to an additional analysis based on the combination of all three datasets. Such study will be developed for the first time focusing on harvestmen, and its theoretical implications may be extended for other taxonomic groups as well. (AU)