Calommata tibialis Fourie, Haddad & Jocque

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

Calommata tibialis Fourie, Haddad & Jocque sp. n. Figs 6, 917293150 –5266– 68

Type material.

Holotype male. TOGO: Between Bassari and Sokodé, 09°15'N, 00°47'E, V–VII.1984, pitfalls, wooded savanna, P. Douben (MRAC 169501).

Paratypes.

1♂: together with holotype. CÔTE D’IVOIRE: 1♂: Kossou, 06°57'N, 04°58'W, 28.IV.1975, pitfalls, wooded savanna, R. Jocqué (MRAC 169500).

Other material examined.

CÔTE D’IVOIRE: 1 subadult ♀: Lamto, 06°12'N, 05°20'W, 6.III.1968, savanna with Borassus aethiopum , C. Girard (MRAC 232547); 1♂: Same locality, 11.II.1974, dirt road near biological station, P. Blandin (MRAC 232548).

Diagnosis.

The male of the species can be recognised by the carapace that is subequal in length and width (Fig. 6), the short, swollen palpal tibia, and the narrow conductor ending in a thick prominent tooth (Figs 51, 52).

Etymology.

The specific epithet refers to the palpal tibia of the male, which is distinctly shorter and more swollen compared to that of other African congeners.

Description.

Male holotype. Measurements: CL 2.13, CW 1.95, AL 3.45, AW 2.02, TL 6.65 (6.00-6.65). Length of leg segments, and total: I 1.98 + 0.65 + 1.35 + 1.71 + 1.63 = 7.32; II 1.80 + 0.75 + 1.10 + 1.60 + 1.80 = 7.05; III 1.49 + 0.80 + 0.75 + 1.70 + 2.45 = 7.19; IV 1.94 + 0.90 + 1.03 + 2.00 + 3.03 = 8.90. Carapace index 1.10; patella-tibia index 0.94.

Carapace and chelicerae orange brown (Fig. 6). Chelicerae with single row of alternating small and medium sized teeth, gradually decreasing in size from fang base to cheliceral base, with several denticles retrolateral of teeth row near cheliceral base (Fig. 17). Eye area raised, narrow, darker in colour. Sternum and coxae yellow, remainder of legs orange, fading to pale yellow at tarsi. Legs weakly covered with bristles; prolateral side of patellae, tibiae and metatarsi of legs II–IV covered with spinules. Abdomen grey, with pale orange-brown scutum anteriorly (Fig. 6). Palp with short cymbium, with rounded distal margin; tibia shorter and broader than in the other five species, slightly longer than wide; embolus and conductor orientated obliquely, pointing retrolaterally and distally, not projecting beyond retrolateral cymbial margin; conductor narrow with a thick prominent tooth distally on its dorsal surface; embolus short and slightly curved (Figs 51, 52, 66-68).

Female. Unknown.

Remark.

The specimens may possibly have faded over time in 70% ethanol, which can only be confirmed should fresh material become available. Although a subadult female is available it will not be described as the genitalic structure cannot be studied.

Distribution.

Central Côte d’Ivoire and northern Togo (Fig. 73).

Biology.

Present data indicates that Calommata tibialis sp. n. occurs in woodland savannah habitats and avoids forests, where Calommata simoni has been collected. This may indicate some degree of ecological separation between the species but requires further study. Taking this into account we consider the studies of Blandin (1971) and Charpentier (1995) to relate to Calommata tibialis sp. n. and not Calommata simoni , as indicated by them.

Charpentier (1995) located more than 50 nests of Calommata tibialis sp. n. at four localities in southern Benin with quite contrasting habitat structures, including grassland, patches of subsistence agriculture, in close proximity to rivers, and open ground near palm forests. He did not indicate the occurrence of the species in forests. In one of the habitats that he found Calommata , the soil was described as sandy, of poor quality and relatively acidic, and covered in ‘grassland’ vegetation, similar to the habitat characteristics described by Blandin (1971) for the Lamto area, from where Calommata tibialis sp. n. specimens are available.

The burrow of Calommata tibialis sp. n. slants obliquely downwards into the soil, and was estimated to be 25-30cm deep by Blandin (1971), while Charpentier (1995) indicated a maximum depth of 21cm in a female specimen, although generally shallower in other specimens (12-19cm). The top 1-2cm of the burrow is expanded to form a chamber covered by silk webbing that is camouflaged with soil, and the spider lies in wait hanging upside-down from the web for wandering prey ( Charpentier 1995). Egg sacs are suspected to hatch in May; during incubation the female spins a silk veil at the base of the chamber that is suspected to firstly allow the spider access to the chamber to capture potential prey, and secondly hide the spider and its eggs from potential parasites once they have entered the chamber ( Charpentier 1995).