The crab spider genus Uraarachne Keyserling (Araneae: Thomisidae) in Argentina, Uruguay and Paraguay: a proposal of its senior synonymy over Plancinus Simon, and description of four new species.

GRISMADO, CRISTIAN J.; ACHITTE-SCHMUTZLER, HELGA C.

Revista del Museo Argentino de Ciencias Naturales, n. s.

Museo Argentino de Ciencias Naturales

Lugar: Buenos Aires; Año: 2020 vol. 22 p. 91 - 130

1514-5158

The crab spider genus Uraarachne Keyserling 1880 currently comprises two species: U. longa Keyserling (type species, from Brazil, and herein newly recorded from Paraguay) and U. vittata (Caporiacco) from French Guiana. Uraarachne is herein proposed, on base of somatic and genitalic characters, as a senior synonym of Plancinus Simon 1886, which is known from three species from Uruguay: P. runcinioides Simon (type species), P. cornutus Simon, and P. brevipes Simon (all three transferred here to Uraarachne). Uraarachne runcinioides new comb., (type species of Plancinus), and U. cornuta new comb., are reported for the first time for Argentina and redescribed, based on the type specimens and new material, including the first known males. Four new species are described from Argentina: U. panthera n. sp., and U. ceratophrys n. sp. (from Misiones province, both on base of single male specimens), U. toro n. sp. (from Salta province, female only), and U. kapiity n. sp. (from the argentine provinces of Chaco, Corrientes, and Entre Ríos, and from Paraguay, on base of both sexes). Two additional species are transferred to Uraarachne: Runcinia plana Simon, previously known only from juveniles from Paraguay (adults described here for the first time, and distribution extended to central-eastern Argentina), and Misumenoides variegatus Mello-Leitão, known from the holotype male from Santa Fe (female described here for the first time, and distribution extended to Paraguay and Buenos Aires, Argentina). Platyarachne argentina Mello-Leitão and Erissoides argentinus Mello-Leitão are newly synonymized with Uraarachne runcinioides. The relationships of the genus are breafly discussed, proposing a close relationship with Runcinia Simon.