Insights on vulval morphology in Ochyroceratinae with a rediagnosis of the subfamily and description of the first Argentinean species (Araneae: Synspermiata: Ochyroceratidae)

Abstract

We examine the internal morphology of the female genitalia of representatives of the three subfamilies of the spider family Ochyroceratidae (Ochyroceratinae, Psilodercinae and Theotiminae) by means of scanning electron microscope. Ochyroceratines have the uterus externus constricted into a narrow neck at its connection with the uterus internus, which, after comparison with other spider families, is proposed as a synapomorphy of the subfamily. We describe Ochyrocera diablo sp. nov. from Misiones province in northeastern Argentina. The measurements of their eggs and uterus externus indicate that the eggs must squeeze through a small duct 40 times smaller in diameter. The eggs of Ochyrocera diablo sp. nov. are among the smallest reported for spiders. We also propose that another synapomorphy for Ochyroceratinae is the insertion of the male palpal copulatory organ in a projecting pedestal at the base of the cymbium, and update the differential diagnosis of the subfamily. Finally, we recognize that Psilodercinae Deeleman-Reinhold, 1995, is a junior objective synonym and homonym of Psilodercinae Machado, 1951.