Systematics and phylogeography of the Brazilian Atlantic Forest endemic harvestmen Neosadocus Mello-Leitão, 1926 (Arachnida: Opiliones: Gonyleptidae).

Feng ZHANG,Elen A. Peres,Daniel Castro-Pereira,Ricardo Pinto-da-Rocha

doi:10.1371/journal.pone.0249746

Abstract

Neosadocus harvestmen are endemic to the Southern Brazilian Atlantic Forest. Although they are conspicuous and display great morphological variation, their evolutionary history and the biogeographical events underlying their diversification and distribution are still unknown. This contribution about Neosadocus includes the following: a taxonomic revision; a molecular phylogenetic analysis using mitochondrial and nuclear markers; an investigation of the genetic structure and species’ diversity in a phylogeographical framework. Our results show that Neosadocus is a monophyletic group and comprises four species: N. bufo, N. maximus, N. robustus and N. misandrus (which we did not find on fieldwork and only studied the female holotype). There is astonishing male polymorphism in N. robustus, mostly related to reproductive strategies. The following synonymies have resulted from this work: “Bunoweyhia” variabilis Mello-Leitão, 1935 = Neosadocus bufo (Mello-Leitão, 1926); and “Bunoweyhia” minor Mello-Leitão, 1935 = Neosadocus maximus (Giltay, 1928). Most divergences occurred during the Miocene, a geological epoch marked by intense orogenic and climatic events in the Brazilian Atlantic Forest. Intraspecific analyses indicate strong population structure, a pattern congruent with the general behavior and physiological constraints of Neotropical harvestmen.

Highlights

Harvestmen (Opiliones) constitute one of the largest orders within Arachnida, with more than 6500 species around the world [1]
Our morphological observations confirmed the validity of four Neosadocus species: N. bufo, N. robustus, N. maximus and N. misandrus
We provide a complete diagnosis for the female holotype of N. misandrus, which is sufficient to distinguish it from the other Neosadocus females

Summary

Introduction

Harvestmen (Opiliones) constitute one of the largest orders within Arachnida, with more than 6500 species around the world [1]. Neotropical harvestmen present low vagility (excepting some species of suborder Eupnoi), are very dependent on high levels of humidity and display limited tolerance to temperature variation [3, 5, 6]. These characteristics have resulted in their generally poor dispersal abilities and narrow species distribution.

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