A cladistic analysis of the Brazilian troglobitic harvestmen genus Iandumoema Pinto-da-Rocha, 1997 (Opiliones: Gonyleptidae) with the description of three new species

Abstract

Iandumoema was the third troglobitic (i.e., ecological-evolutionary concept denoting 16that the organism is restricted to the subterranean environment) genus of Brazilian harvestmen to be described. It is also the only troglobitic genus in Brazil with more than one species, comprising three described species, all from caves in Minas Gerais state, Brazil. Traditionally, testing monophyly of troglobitic groups is difficult because many features shared by them might be result of convergence/parallelism due to the pressure of the cave environment. This issue, as well as comparative studies, is hindered because Iandumoema is also currently placed in the species rich and polyphyletic subfamily Pachylinae. In this work, we test the monophyly of this troglobitic genus and propose the first phylogenetic hypothesis for Iandumoema based on cladistic analysis using morphological data. The analysis included all described species of Iandumoema plus three new troglobitic species: I. cuca, sp. nov.(Itacarambi: Gruta da Água do João Ferreira), I. gollum, sp. nov. (Presidente Juscelino: Lapa D'Água) and I. stygia, sp. nov. (Montes Claros: Gruta do Cedro). The character matrix comprises 79 characters for 28 terminal taxa: six species of Iandumoema, 14 species of Pachylinae, six species from other Gonyleptidae subfamilies, one species of Cosmetidae and one species of Metasarcidae. The cladistic analysis using heuristic search retrieved one most parsimonious tree (339 steps, consistency index = 0.35, retention index = 0.56). Iandumoema is a monophyletic and well-supported genus, nested among Brazilian “Pachylinae”. The present work also provides an identification key and ecological 35remarks for all the six species of the genus Iandumoema.