Chactinae Pocock, 1893

Soleglad, Michael E. & Fet, Victor, 2003, High-level systematics and phylogeny of the extant scorpions (Scorpiones: Orthosterni), Euscorpius 2003 (11), pp. 1-175 : 95-96

Subfamily Chactinae Pocock, 1893

Type Genus. Chactas Gervais, 1844 .

Composition. This subfamily includes two tribes: Chactini (Central and South America; three genera) and Nullibrotheini ( Mexico, one genus). This taxonomic arrangement of four chactid genera, as opposed to subfamily Brotheinae , is proposed here for the first time.

Distribution. North America ( Mexico), Central America ( Panama, Costa Rica), South America.

Biogeographic history. Chactini are found only in the tropical Central and South America ( Table 10), while the tribe Nullibrotheini includes a monotypic desert genus. It is unlikely that Nullibrotheini has a recent South American origin, and therefore it could be a relict of much earlier (Pangean?) distribution of Chactinae . Disjunct distribution of some South American genera of Chactini can be attributed to the recent (Pleistocene) fluctuations of tropical rainforest (Lourenço, 1988, 1994, 1996b).

Diagnosis. Synapomorphies. Chelal trichobothria Db basal, Dt situated at palm midpoint; patellar trichobothria series em 1 –em 2 and esb 1 proximal of segment midpoint; neobothriotaxy Ch1 present on patellar ventral surface; neobothriotaxy Ch1 present on patellar external surface. Important Symplesiomorphies. Hemispermatophore truncal flexure absent; hemispermatophore lamina terminus tenuous, thin, highly tapered; stigma shape small and circular.