A New Species of Typhlochactas (Scorpiones, Typhlochactinae) from Eastern Mexico

Abstract

Typhlochactas sissomi, a new species of troglomorphic scorpion in the subfamily Typhlochactinae Mitchell, 1971, is described, based on a single subadult male collected under a stone in a mesophilous forest in the mountains of the state of Queretaro, Mexico. This is the seventh species in the genus Typhlochactas Mitchell, 1971. Although all seven species are troglomorphic, four are troglobitic and two are humicolous. The new species described here is probably also humicolous. A key to the identification of Typhlochactas species is presented.

Troglomorphism, trichobothriotaxy and typhlochactid phylogeny (Scorpiones, Chactoidea): more evidence that troglobitism is not an evolutionary dead‐end

“…Sissom and Cokendolpher (1998, p. 286) considered Typhlochactas granulosus Sissom and Cokendolpher, 1998“most similar to T. rhodesi and T. reddelli ”, which conflicts with Francke’s (1982) hypothesis. A phylogenetic position was not proposed for Typhlochactas sissomi Francke et al., 2009. These species are therefore placed in a polytomy at the base of Typhlochactas .…”

“…(E) Stygochactas granulosus (Sissom and Cokendolpher, 1998). (F) Typhlochactas sissomi Francke et al., 2009. (G) Typhlochactas cavicola Francke, 1986.…”

“…(B) Stygochactas granulosus (Sissom and Cokendolpher, 1998), juv. ♂ holotype (AMNH) (C) Typhlochactas sissomi Francke et al., 2009, subadult ♂ holotype (IBUNAM). (D) Typhlochactas rhodesi Mitchell, 1968, holotype ♀ (AMNH).…”

“…(A) Known localities of Alacraninae Vignoli and Prendini, 2009: Type locality of Alacran tartarus Francke, 1982 on the Huautla Plateau, Oaxaca (1); Te Cimutaá, Oaxaca, a new record for the genus possibly representing a new species of Alacran Francke, 1982 (2). (B) Type localities of Typhlochactinae Mitchell, 1971: Sotanochactas elliotti (Mitchell, 1971), El Sótano de Yerbaniz, San Luis Potosí (1); Stygochactas granulosus (Sissom and Cokendolpher, 1998), Sótano de Poncho, Veracruz (2); Typhlochactas cavicola Francke, 1986, Cueva del Vandalismo, Tamaulipas (3); Typhlochactas mitchelli Sissom, 1988, Cerro Ocote, Oaxaca (4); Typhlochactas reddelli Mitchell, 1968, La Cueva del Ojo de Agua de Tlilapan, Veracruz (5); Typhlochactas rhodesi Mitchell, 1968, La Cueva de la Mina, Tamaulipas (6); Typhlochactas sissomi Francke et al., 2009, Cañada de La Joya, Queretaro (7); Typhlochactas sylvestris Mitchell and Peck, 1977, 25 km S Valle Nacional, Oaxaca (8).…”

“…As with other obligate cavernicoles, the six hypogean (troglobitic) species of Typhlochactidae are greatly specialized for life in the cave environment (Mitchell, 1968, 1971; Francke, 1982, 1986; Sissom and Cokendolpher, 1998), whereas their three endogean (humicolous) relatives are relatively less specialized (Mitchell and Peck, 1977; Sissom, 1988; Francke et al., 2009). The family therefore provides a model for testing the hypotheses that ecological specialists (stenotopes) evolve from generalist ancestors (eurytopes) and that specialization (in this case to the cavernicolous habitat) is an irreversible evolutionary dead‐end that ultimately leads to extinction (Dollo, 1893, 1903, 1922; Cope, 1896; Huxley, 1942; Mayr, 1942, 1988; Simpson, 1944, 1953; Rensch, 1959; Gould, 1970; Sugihara, 1980; Wagner, 1982; Laurent, 1983; Bull and Charnov, 1985; Futuyma and Moreno, 1988; Futuyma, 1998).…”