Molinaranea, Mello-Leitao, 1940

Saupe, Erin E., Selden, Paul A. & Penney, David, 2010, First fossil Molinaranea Mello-Leitão, 1940 (Araneae: Araneidae), from middle Miocene Dominican amber, with a phylogenetic and palaeobiogeographical analysis of the genus, Zoological Journal of the Linnean Society 158 (4), pp. 711-725 : 715

MOLINARANEA MELLO- LEITÃO, 1940

Type species: Molinaranea molinai Mello-Leitão, 1940

Diagnosis: See Levi (2001).

Distribution: Recent species are found in Chile, Argentina, the Falkland Islands, and Juan Fernandez Island. The fossil species is found in Dominican Republic amber (this paper).

Remarks: Molinaranea was created as a monotypic genus by Mello-Leitão in 1940; the gender is feminine. Levi (2001) used the paramedian apophysis to help distinguish amongst genera of Araneidae , a structure that is unfortunately not discernable in our specimen. A filiform (thread-like) embolus is visible adjacent to the conductor, however, and distinguishes our specimen from members of Parawixia Pickard- Cambridge 1904 and Ocrepeira Marx 1883 , which have robust emboli. Furthermore, our specimen can be placed with confidence within Molinaranea for the following reasons: the median apophysis is prominent, forked, and projects away from the palpal bulb. Although this morphology occurs in other genera, such as Parawixia , Spilasma Simon, 1897 , and Ocrepeira ( Levi, 1992, 1993, 1995), the details differ from those in our specimen. For example, our specimen and members of Molinaranea have prongs that do not re-curve as prominently as those in members of Ocrepeira . In those members of Ocrepeira that do have median apophysis prongs, the prongs are usually of unequal thickness, differing from the quasi-equal prong widths in Molinaranea and our specimen ( Levi, 1993). Members of both Ocrepeira and Parawixia have median apophyses that typically thicken distally, whereas members of Molinaranea and our specimen thin distally ( Levi, 1992, 1993). Members of these same genera also possess many processes, bumps and/or indentations on the median apophysis, unlike the smoother median apophyses present in Molinaranea and our specimen. Additionally, many Parawixia species with forked prongs on the median apophysis possess numerous (more than three) tubercles on the opisthosoma (more than the two present in our specimen). In Spilasma , the median apophysis is commonly trifid distally, with relatively short prong lengths, unlike the bi-forked prongs in Molinaranea . Male members of Spilasma also possess a ventral, sclerotized area extending from the sides of the pedicel to the genital groove ( Levi, 1995), a feature lacking in our specimen.