Genus Thinobatis Eschscholtz, 1831

(Figs. 1, 5, 7, 9, 11)

Thinobatis Eschscholtz 1831: 8 . Solier 1835: 407; Laporte 1840: 196; Solier 1851: 126; Lacordaire 1859: 65; Gemminger and Harold 1870: 1836 (catalog); Philippi 1887: 722 (catalog); Gebien 1910: 19 (catalog), 1937: 588 (catalog); Blackwelder 1945: 513 (catalog); Kulzer 1956: 903 (revision); Freude 1960: 24; Peña 1966: 405 (catalog), 1974b: 243.

Type species: Thinobatis ferruginea Eschscholtz, 1831, by monotypy.

Description. In addition to the characters stated above: Mandibles thick, base 2X wider than apex, both mandibles with dorsal cusp on basal half, shorter on right than on left mandible (Fig. 5), lacking ventral fossa; labrum exposed, entirely sclerotized; clypeus short, not covering labrum, anterior margin straight or concave, nearly at same level with antennal insertions, lacking row of teeth (Fig. 5); prementum partially sclerotized, base concealed beneath mentum; anterior margin of mentum narrowly notched (Fig. 7); eyes small, not protruding, upper margin lacking carina; length of epicanthus 1.5X length of eye (Fig. 5); antennae reaching posterior margin of pronotum, antennomere 1 as long as 3, emerging from distal half of antennal insertion (Fig. 7), antennomere 3 longer than 2 (Fig. 5), antennomeres 9 and 10 triangular, strongly expanded outwards, wider than long, antennomere 11 equal to or longer than 10 (Fig. 9). Pronotum with anterior angles acute, directed forwards, or rounded sloping towards venter (Fig. 1). Metasternum short, as long as mesosternum. Metacoxae separated by less than half metacoxal width; metacoxal width 3X metacoxal length; distance between meso– and metacoxae equal to metacoxal length (Fig. 11). First tarsomere of hind legs longer than 2+3 combined.

Species Included. T h i n ob a t i s f e r r u g i ne a Eschscholtz, Thinobatis rufipes rufipes Solier, Thinobatis rufipes penai Freude, Thinobatis rotundicollis Waterhouse, Thinobatis intermedia Philippi and Philippi, Thinobatis kuscheli Kulzer, Thinobatis brevicollis Kulzer, Thinobatis calderana Kulzer, Thinobatis melcheri Freude, Thinobatis simplex Peña, Thinobatis punctata Peña, Thinobatis confusa Peña, and Thinobatis arenaria Peña (Peña 1974b) .

Material Examined. Thinobatis intermedia, T. melcheri, T. rufipes rufipes, and T. rufipes penai (IADIZA) . We also examined T. rotundicollis, but it should be classified in a distinct genus because of the shape and proportional length and width of the pronotum, rounded pronotal posterior angles, lack of a dorsal cusp on both mandibles, and clypeus and frons with protuberances.