Eriauchenius bourgini (Millot, 1948)

Wood, Hannah M. & Scharff, Nikolaj, 2017, A review of the Madagascan pelican spiders of the genera Eriauchenius O. Pickard-Cambridge, 1881 and Madagascarchaea gen. n. (Araneae, Archaeidae), ZooKeys 727, pp. 1-96 : 1

Eriauchenius bourgini (Millot, 1948) Figs 13, 31

Archaea bourgini Millot, 1948: 10, figs 1C,2C,3B,3E.

Archaea bourgini Legendre, 1970: 26, figs 10-11,14C.

Type material.

As Archaea bourgini Millot, 1948: 6M, 3F, Madagascar, La Mandraka (examined, deposited in MNHN; MNHN 13/1970).

Material described and other material examined: 3M,5F,4Juvs, MADAGASCAR: Antananarivo, Réserve Spéciale d’Ambohitantely, Forêt d’Ambohitantely, 20.9 km 72° NE Ankazobe, 18°13'31"S, 47°17'13"E, 1410 m, 17-22 Apr 2001, montane rainforest, EB17 beating low vegetation, Fisher, Griswold et al. (CASENT9001207)

Diagnosis.

Males and females are distinguished from other Eriauchenius by having pointed extensions on coxae I (Fig. 13L, arrows). Males and females of E. bourgini and E. zirafy sp. n. are also distinguished by having two large protrusions on the crown of the cephalon (Fig. 13A). Females of E. bourgini and E. zirafy sp. n. are indistinguishable but are different from all other Eriauchenius by having two sclerotized invaginations on the bursa (Figs 13B, 22B, arrows). In E. bourgini males the conductor has four elaborate processes (Fig. 13 D–K), and in and E. zirafy sp. n. males, five elaborate processes (Fig. 22 D–K).

Description.

Male (based on CASENT9001207, from Réserve Spéciale d’Ambohitantely, Madagascar). Total length 1.94, carapace 0.79 long, 0.74 wide. Abdomen 1.09 long, 0.97 high. Carapace tilt angle 72.1°, tilt height (CtH) 1.80, constriction 0.33, head length 0.89, neck length 0.93. CtH divided by carapace length 2.28. Cephalon with AME on a large bulge and 4 post-ocular spines on the crown of the cephalon, with the posterior pair on large protrusions and the anterior pair not on protrusions, and with 1 small spine between the LE and median eyes (on each side, for a total of 2). Chelicerae 1.68 long, and with a short spine 0.70 from base of chelicerae, projecting downward. Femur I 2.13 long. Sternum 0.51 long, 0.36 wide. Carapace, chelicerae, and sternum dark reddish brown with white setae. Coxae and legs lighter brown, with darker annulations on tibiae and metatarsi. Coxae I with posterior extensions (Fig. 13L). Abdomen mottled brown and beige, with a bright white patch on each lateral side, with tufts of white setae (as in Fig. 22A from E. zirafy sp. n.). Pedipalpal bulb with a small membraneous sac on the retrolateral side, with the base of the conductor small and triangular (labeled “c” in Fig. 13D, F–G), and with the remainder of the conductor wrapping around the embolus and with four long processes (Fig. 13 D–F). The embolus is thick and contains several processes.

Female (based on CASENT9001207, from Réserve Spéciale d’Ambohitantely, Madagascar). Total length 1.89, carapace 0.74 long, 0.72 wide. Abdomen 1.09 long, 1.98 high. Carapace tilt angle 63.0°, tilt height (CtH) 1.85, constriction 0.36, head length 0.92, neck length 0.97. CtH divided by carapace length 2.50. Cephalon as in male. Chelicerae 1.73 long, and with small spine 0.84 from base of chelicerae. Femur I 2.03 long. Sternum 0.49 long, 0.33 wide. Colors as in male, except abdomen lacking the bright white lateral patches (Fig. 13A). Female genitalia with a small and simple FSGP, and posterior bar highly reduced (Fig. 13B). Bursa lacking poreplates and instead having a sclerotized invagination on each lateral side of the anterior side of the bursa (Fig. 13C, arrows).

Variation.

Total length 1.76-1.94 (males; n=5), 1.89-2.15 (females; n=5); Carapace length 0.73-0.79 (males; n=5), 0.74-0.81 (females; n=5); Femur I 2.54-2.71 times the length of carapace in males (n=5) and 2.45-2.75 times the length of carapace in females (n=5). CtH divided by carapace length 2.20-2.39 in males (n=5), 2.37-2.54 in females (n=5). Average femur I length 2.09 (males; n=5), 2.05 (females; n=5).

Natural history.

Specimens were collected at 1410 m in elevation in montane rainforest by beating vegetation.

Distribution.

Known only from central-eastern Madagascar (Fig. 31).