Calommata Lucas, 1837

Rene, Fourie, Charles R., Haddad & Rudy, Jocque, 2011, A revision of the purse-web spider genus Calommata Lucas, 1837 (Araneae, Atypidae) in the Afrotropical Region, ZooKeys 95, pp. 1-28 : 2-5

Genus Calommata Lucas, 1837

Type species.

Pachyloscelis fulvipes Lucas, 1835 from Java and Sumatra

Diagnosis.

Calommata can be distinguished from Atypus and Sphodros by three main characteristics: 1) Spermathecal structure. In Atypus , there are two broad plates each bearing two or more small receptacula ( Schwendinger 1990: figs 14-25), in Sphodros the four spermathecae are each highly coiled and without distinct receptacula (e.g. Gertsch and Platnick 1980: fig. 29), whereas in Calommata there are four spermathecae (Fig. 62), each bearing several closely packed terminal receptacula positioned in a cauliflower-like arrangement,). However, the latter definition was based only on the spermathecal structure of three of the seven Calommata species ( Gertsch and Platnick 1980), and variation does indeed occur within the spermathecal structure of the genus. The female genitalia of Calommata transvaalica only bear one pair of oval spermathecae (Fig. 69). 2) Male palpal cymbium structure. In Calommata the palpal cymbium is short and truncate (Fig. 48), while in Atypus and Sphodros it is short and acuminate ( Gertsch and Platnick 1980: figs 15, 25; Raven 1985). 3) Labiosternal suture. In Calommata the labiosternal suture is positioned anteriorly on the sternum ( Levy 2007: fig. 8), but is considered by Gertsch and Platnick (1980) to be absent and by Raven (1985) to have migrated posteriorly in Atypus and Sphodros (see Gertsch and Platnick 1980: figs 14, 22). Further morphological characters unique to Calommata ( Gertsch and Platnick 1980) include the bipartite, longitudinal thoracic groove (fovea) (Figs 1-9); basal ledge on the outer surface of the fangs of both sexes, the posteriorly positioned ocular tubercle, enormously elongated endites and dorsally expanded chelicerae (Figs 10, 11); short leg I, particularly the femur, and flattened palpal tibia and tarsus of females (Figs 4, 7); and the greatly elongate tarsi of legs III and IV of males, which are clearly pseudosegmented (e.g. Figs 3, 5, 30).

Description.

Medium to large sexually dimorphic spiders (Figs 1-9), females 18.60-33.40 in length and males 5.10-9.35 in length. Carapace with an anterior, strongly elevated median ocular tubercle (Figs 10, 11), with a flattened posterior part traversed by a longitudinal thoracic furrow with a small deep pit in the middle (Figs 1-8). Three faint lines run from the ocular tubercle, converging at the fovea. Chelicerae massive, dorsally expanded with flattened sides, bearing sharp teeth usually in one (rarely two) rows, and a long arched fang with a slit-like distal opening and distinctive basal ledge along its outer margin (Figs 10-19, 20, 21, 26, 29). Cheliceral dentition of both sexes often variable between specimens and even between opposing chelicerae of a specimen. The general dentition pattern of each species and sex is indicated in Figs 12-19. Chelicerae of females have larger, more numerous teeth and an extensive field of tiny denticles retrolateral of the teeth row near the cheliceral base (Figs 15, 18). Chilum single, large, varying in shape, oval, rectangular or pentagonal (Figs 1-8). Endites strongly elongated and curved upwards on the prolateral side (Figs 10, 11, 22). Sternum with a distinctive labio-sternal suture anteriorly. Legs of females short and stout, leg formula of females 4231. Legs of males of normal size, with the tarsi pseudosegmented (Figs 23, 24, 30) and tarsi of legs III and IV distinctly longer (Figs 1-3, 5, 6, 8, 9); leg formula of male s usually 4321, rarely 4132. Tarsi with three claws, paired claws of males with single row of teeth and unpaired claw without teeth (Figs 23, 27), contra Raven (1985: 123). Tarsi ventrally scopulate, consisting of pointed setae (Figs 25, 31) or setae with a rounded tip (Fig. 28). Abdomen of male with small, distinctive anterior dorsal scutum, absent in females (Figs 1-8). Venter with three pairs of spinnerets, examined in detail in males (Figs 32-40) but not females; ALS small and finger-like, single-segmented, with a single short, stout distal fused spigot (Figs 32-34); PMS small and subtriangular, single-segmented, with several fused and articulated spigots in distal half of segment (Figs 32, 35, 36, 39); PLS large, elongate, three segmented, distal segment digitiform, with several fused and articulated spigots in distal half of second and entire ventral surface of third segment (Figs 32, 37, 38, 40). Anal tubercle widely separated from the spinnerets. Female palp short, with flattened tibia and tarsus (Fig. 7). Female epigyne forming broad, weakly sclerotised plate in ventral view; epigyne with two pairs of spermathecae, median pair subrectangular and rounded anteriorly, and lateral pair subtriangular (Fig. 62), or with single pair of transversely oval spermathecae (Fig. 69). Male palp with swollen tibia, bearing a retrolateral ventral row of several trichobothria, the bases of which are raised to one side; palpal tegulum with curved broad conductor with tooth on its dorsal surface, embolus straight, tapering towards tip (Figs 41-52).

Key to the Afrotropical Calommata

[females of Calommata megae sp. n., Calommata meridionalis sp. n., Calommata namibica sp. n. and Calommata tibialis sp. n. unknown]