Calommata transvaalica Hewitt, 1916

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 : 11-13

Calommata transvaalica Hewitt, 1916 Figs 7, 818, 1969-72

Calommata transvaalicus Hewitt, 1916: 180, fig. 3, pl. 26, fig. 11 revalidated Calommata simoni Benoit, 1967: 283 synonymy rejected

Type material. Female holotype.

SOUTH AFRICA: Gauteng Province: Pretoria, Roodeplaat [25°38'S, 28°21'E], 3.IV.1915, G. van Dam (TMSA 2999 - examined).

Other material examined.

SOUTH AFRICA: Gauteng Province: 1♂: Groenkloof Nature Reserve [25°47'S, 28°12'E], 21.I.2003, reptile trap, M. Forsythe (NCA 2004/750); 1♀: Pretoria district, Hatfield [25°45'S, 28°15'E], 25.IV.1915, G. van Dam (TMSA 4639); 13♂: Zwartkoppies Farm 364, Portion 2, ca. 21km E of Pretoria, 25°45'23.6"S, 28°24'47.7"E, 1347m a.s.l., 29.X.2010, open pitfall traps, I. Engelbrecht & GDARD Field Staff (TMSA 23875). Limpopo Province: 1♂: Blouberg Nature Reserve, 23°00.065'S, 29°03.855'E, 29.XI.2005, searching below the knee, Philenoptera violaceae ,A. Dawood (NCA 2009/3665); 1♀: Soutpansberg district, Blouberg, Wilhan’s Hohe [not traced], 28.VIII.1923, G. van Dam (TMSA 2772); 1♀: Same data, 29.VIII.1923 (TMSA 2773).

Diagnosis.

The female of this species has an additional row of two to four large prolateral teeth close to the fang base in addition to the main row of teeth, which are larger and more strongly curved than in Calommata simoni . The epigyne comprises a single pair of transversely oval spermathecae, while Calommata simoni possesses two pairs of smaller spermathecae. The male of the species shares with Calommata meridionalis the transversely orientated embolus and conductor, but the conductor of Calommata transvaalica is clearly narrower at the tip and the embolus is straight and not slightly curved as in Calommata meridionalis . The male chelicerae of Calommata transvaalica also lack the one or two large teeth found near the fang base in Calommata meridionalis .

Redescription.

Female from Blouberg Nature Reserve. Measurements: CL 6.72, CW 5.80, AL 13.70, AW 10.50, TL 25.20 (18.60-27.00). Length of leg segments, and total: I 1.85 + 0.60 + 0.74 + 0.85 + 0.60 = 4.64; II 1.60 + 1.05 + 0.69 + 0.90 + 0.72 = 4.96; III 1.45 + 1.28 + 0.60 + 0.80 + 0.55 = 4.68; IV 1.58 + 1.41 + 0.90 + 0.90 + 0.47 = 5.26. Carapace index 1.16; patella-tibia index 0.20.

Robustly built with short legs (Fig. 7), carapace pale creamy brown. Median ocular tubercle raised, narrow, sloping sharply at fovea. Single median line running from front of median ocular tubercle to middle of chilum. Chelicerae orange, darker laterally; chelicerae with a row of two to four large teeth close to fang base, prolateral of promarginal teeth row; teeth row comprising very large teeth curved at tips, interspersed with small teeth, with extensive denticle field retrolateral of teeth row near cheliceral base (Fig. 18). Endites strongly elongated and slender prolaterally, strongly curved upwards. Sternum and legs pale yellow-brown. Legs short and stout, leg formula 4231; legs III and IV more robust than legs I and II; leg I with three to five spines on patellae and two on tibiae; leg II with few spinules on patellae and several spinules on tibiae and metatarsi; legs III and IV with spinules from patellae to tarsi (mainly dorsal and prolateral); legs II to IV covered in bristles. Abdomen globose and pale grey, with indistinct median heart marking anteriorly (Fig. 7). Epigyne forming a broad, weakly sclerotised plate ventrally, in dorsal view with single pair of large, transversely oval spermathecae (Fig. 69). Female palp short, tibiae and tarsi flattened.

Male from Groenkloof Nature Reserve. Measurements: CL 2.10, CW 1.85, AL 2.70, AW 1.70, TL 6.40 (6.20-6.40). Length of leg segments, and total: I 1.66 + 0.60 + 1.10 + 1.43 + 1.28 = 6.07; II 1.67 + 0.70 + 0.95 + 1.50 + 1.47 = 6.29; III 1.45 + 0.70 + 0.70 + 1.55 + 1.95 = 6.35; IV 1.85 + 0.78 + 1.05 + 1.85 + 1.90 = 7.43. Carapace index 1.14; patella-tibia index 0.81.

Carapace and chelicerae dark brown in colour (Fig. 8). Chelicerae with single row of large teeth, gradually decreasing in size from fang base to cheliceral base, without denticles near cheliceral base (Fig. 19). Carapace oval in shape. Median ocular tubercle raised, narrow, darker in colour. Sternum and coxae yellow-brown, femora, patellae and tibiae brown, metatarsi yellow-brown, tarsi yellow. Legs weakly covered with bristles; prolateral side of patellae, tibiae and metatarsi of legs II–IV covered with spinules. Abdomen dark grey, nearly black, with dark orange-brown scutum anteriorly (Fig. 8). Palp with short cymbium, cymbium tip in ventral view tapering to rounded point; embolus and conductor orientated transversely to palpal axis, pointing retrolaterally, distal ends projecting beyond retrolateral cymbial margin; conductor short, slightly broadened distally, with single sharp, curved tooth on its dorsal surface; embolus long and straight (Figs 70-72).

Remarks.

It is clear from the redescriptions of both sexes of Calommata simoni , and the redescription of the female and first description of the male of Calommata transvaalica provided here, that the two species have distinct differences in their somatic and genitalic morphology, most notably regarding their cheliceral dentition, number of spermathecae in the female epigyne and orientation and length of the male embolus and conductor. Consequently, we reject Benoit’s (1967) synonymy of the two species and propose the revalidation of Calommata transvaalica . The specimens collected by Van Dam and Roberts (1917) between Villeria and Derdepoort near Pretoria could not be traced.

The abdomen of the female holotype of Calommata transvaalica is damaged and therefore the specimen was not redescribed. The holotype is the smallest of the known females of this species (18.60mm long). The colour of all available female specimens has likely faded over time in 70 % ethanol.

Distribution.

Limpopo and Gauteng Provinces, South Africa (Fig. 73).

Biology. The biology of Calommata transvaalica was studied by Van Dam and Roberts (1917) at Roodeplaat near Pretoria, South Africa, in the days following heavy rainfall. They first detected a female (the holotype) by kicking up a tuft of grass that disclosed white webbing, which was followed downwards into the ground to locate the spider. They subsequently discovered additional nests on bare ground. They described the nests as slightly raised above the ground at the top, and then from the inner rim they were neatly rounded off, gradually sloping outwards and downwards to the level of the ground with the outer surface covered with earth that resembled the surroundings. The interior of the tube was lined with loose, highly adhesive silky webbing. They suggested that the adhesive webbing may afford the spider some protection against the intrusion of enemies. The nests were deep (22-25cm) and vertical for the greater part of their depth ( Van Dam and Roberts 1917). Hewitt (1916) commented that Calommata transvaalica specimens had a very pronounced and objectionable odour and compared it to decomposing stable manure.

The recently collected series of males from Zwartkoppies Farm (TMSA 23875) was collected in open pitfalls without preservative from a site in open Acacia karroo woodland on red structured clay soils (30-45% clay in A horizon, Shortlands form). The site has a gentle slope and had recently been burned. The activity of the males appears to be related to heavy rainfall that had fallen two days prior to the collection of the males. It thus seems that males do not emerge on the night immediately following a heavy shower, but instead on the night thereafter (Ian Engelbrecht, pers. comm.).