Tityus (Atreus) obscurus ( Gervais, 1843 )

Lourenço, Wilson R. & Leguin, Elise-Anne, 2008, The true identity of Scorpio (Atreus) obscurus Gervais, 1843 (Scorpiones, Buthidae), Euscorpius 75 (75), pp. 1-9 : 8

Tityus (Atreus) obscurus ( Gervais, 1843)

Large scorpions, from 85 to 100 mm in total length. General coloration uniformly blackish, with only some pale zones on the sternites. In most cases the juvenile instars of these large blackish species of Tityus are yellowish or reddish-yellow, with very numerous variegated spots. These spots are not visible in the adults as a result of the very marked sclerification of the cuticle ( Lourenço, 1983b; Lourenço & Cloudsley-Thompson, 1996).

Metasomal segments I to V and telson uniformily blackish; with 10-10-8-8-5 carinae. Dentate margins of pedipalp-chela fixed and movable fingers with 15 − 17 oblique rows of granules. A strong spinoid subaculear tooth present. This can be moderate in size or almost totally absent in very large specimens. Pectines with 18 to 22 teeth; the basal middle lamellae strongly dilated in females. Tityus obscurus shows very strong sexual dimorphism. Male pedipalps are longer and more slender than those of the females ( Lourenço, 1983a, 2002a, 2002b).

For more detailed description and keys, see Lourenço (1983, 2002a, 2002b).

Distribution: Suriname, French Guiana, and the States of Amapá and Pará in Brazil. Reported or suggested distribution in Ecuador, Guyana, Panama, and Venezuela (Fet & Lowe, 2000: 254) is not confirmed by reliable specimens. The presence of this species in Guyana could yet be confirmed; however, references to Ecuador, Colombia, and Panama most certainly correspond to misidentifications of Tityus asthenes Pocock, 1893 ( Lourenço, 1988). The reference to Venezuela certainly is a misidentification of an unclear related species of the subgenus Atreus ( Lourenço, 2006) .