Reduced sexual dimorphism in a new genus of Heteropachylinae: morphological and biogeographic implications (Opiliones, Gonyleptidae)

Heteropachylinae Kury, 1994 is a diverse group within the Gonyleptidae family in the northeastern Atlantic Rain Forest, in which many new species of harvestmen have been described. This paper presents the description of a new genus and species of the subfamily, Oshumare basitarsale gen. et sp. nov., endemic to the Atlantic Rain Forest of the state of Pernambuco, Bahia and Alagoas, two known areas of endemism for several taxa. This genus differs mainly by the absence of sexually dimorphic characters in leg IV and dorsal shield, by contrast to most Gonyleptidae, as well as the recently described species Oshumare thelydrias (Abreu & Mendes, 2022) gen. et comb. nov. However, the males of the new species described here have an inflated basitarsus I, III and IV. We present a new phylogeny resulting in a new genus for the subfamily, the only one without sexual dimorphism in leg IV, which groups the two species. Furthermore, we also discuss the implications to biogeography and the loss of intrasexual dimorphism. http://zoobank.org/urn:lsid:zoobank.org:pub:EE258BD9-3CE1-420E-893F-04819F73264A