The first two blind troglobitic spiders of the genus Ochyrocera from caves in Floresta Nacional de Carajás, state of Pará, Brazil (Araneae, Ochyroceratidae)

Abstract

The first two anophthalmic species of spiders of the genus Ochyrocera Simon, 1892, are described for caves located in the iron formation of Floresta Nacional (FLONA) de Carajás in southeastern Pará State, Brazil. The caves are located in the municipalities of Parauapebas and Canaã dos Carajás, in the eastern portion of the Amazon Forest domain. Ochyrocera ritxocosp. nov. and O. ritxoosp. nov. are described based on males and females. The species have similar body characteristics with the total absence of eyes and complete depigmentation, characteristics that indicate possible evolution in subterranean environments , and thus are classified as troglobites. Each species is associated with a single geomorphological unit (mountain range), with Ochyrocera ritxocosp. nov. being restricted to caves of Serra Norte (North Mountain) and O. ritxoosp. nov. to caves of Serra Sul (South Mountain). Both species were collected in aphotic zones of the caves. Small and tangled webs of O. ritxocosp. nov. were observed under blocks of stone in the soil or in cracks of the walls.