Tarrocanus Simon, 1895

Ileperuma Arachchi, Ilesha S. & Benjamin, Suresh P., 2019, The crab spider genus Tarrocanus Simon, 1895 with notes on the genera Alcimochthes Simon, 1895 and Domatha Simon, 1895 (Araneae: Thomisidae), Zootaxa 4613 (3), pp. 587-593 : 588

Genus Tarrocanus Simon, 1895

Type species: Tarrocanus capra Simon, 1895: 979 : fig. 1047.

Diagnosis. Species of Tarrocanus can be readily distinguished from other thomisid genera by the following characteristics: vertical and broad clypeus, elevated ocular area with slightly curved anterior row, enlarged prominent lateral eye tubercles (arrows in Figs 1, 2, 4, 5 ), tubercles of PLE larger than that of the other eyes and are either modified with prominent triangular shaped tooth-like projections (in T. capra ) or without such modifications ( T. jaffnaensis sp. nov) and horseshoe shaped marking on the centre of prosoma starting from the base of PLE tubercles. Tarrocanus can be separated from Alcimochthes and Domatha by the strongly recurved anterior margin and posteriorly broader opisthosoma.

Description. Small spiders, body size 2.5-3.0. Prosoma brown, laterals dark brown, clypeus, ocular area, middle of prosoma light brown with whitish hue, widest at the centre, horseshoe-shaped markings on the centre, outlined by whitish yellow lines ( Figs 1, 2 ), covered with sparsely distributed long setae and sub-erect weak setae. Opisthosoma lighter than prosoma, covered with numerous spots and patches of reddish brown, dark brown and greyish white, anterior half strongly recurved, bell-shaped, covered with sparsely distributed short setae. Eyes with enlarged, yellowish brown, partly jointed tubercles, both eye rows recurved. Eye formula: ALE>PLE>PME>AME, triangular shaped tooth-like projection on PLE (prominent only in T. capra ). Clypeus vertical and broad, chelicerae yellowish brown, legs pale with parsley distributed spines and setae. Palp: tegulum simple and round with no apophyses, VTA with long stem and hook-shaped, embolus either moderately long and slender or short, curved and stout. RTA rudimentary, ITA may or may not be present. Females are unknown.

Composition. Two species: T. capra and T. jaffnaensis sp. nov.

Distribution. Currently known only from Sri Lanka.

Remarks. Close relationship of Tarrocanus and Alcimochthes is confirmed by molecular data (Ileperuma Arachchi & Benjamin, in press). The extent of the relatedness of Domatha to Tarrocanus and Alcimochthes is yet unknown due to unavailability of molecular data for Domatha . A well represented sample, including species of the three genera (both sexes) is essential to evaluate their relationships and to corroborate their generic boundaries in morphological terms.

Figures

FIGURES 1–9. 1 Tarrocanus capra (male), Bowatenna Forest Reserve, dorsal view; 2 Tarrocanus jaffnaensis sp. nov (male), Mundathivu, Jaffna, dorsal view; 3 Domatha vivida (male), type specimen (MNHN 11376), dorsal view; 4 Tarrocanus capra (male), lateral view; 5 Tarrocanus jaffnaensis sp. nov (male), lateral view; 6–7 T.capra, left male palp (6 ventral, 7 retrolateral). 8–9 T. jaffnaensis sp. nov., left male palp (8 ventral, 9 retrolateral).Arrows point to the lateral eye tubercles. Scale bars: 0.2 mm (6–9), 1 mm (1–5).