Difference between revisions of "Eriauchenius fisheri"

Latest revision as of 14:26, 8 January 2018

Taxonavigation

Ordo: Araneae
Familia: Archaeidae
Genus: Eriauchenius

Name

Eriauchenius fisheri (Lotz, 2003) comb. n. – Wikispecies link – Pensoft Profile

• Afrarchaea fisheri Lotz, 2003: 234, fig. 6A–C.

Type material

Female holotype: Afrarchaea fisheri Lotz, 2003, from Fianarantsoa, Reserve Andringitra, 8.5 km SE Antanitotsy, 22°10'S, 46°58'E, 1990 m, 6 Mar 1997, rainforest, sifted litter, B.L. Fisher (examined, deposited in CAS, CASENT9012340).
Other material examined: MADAGASCAR: 1M, Fianarantsoa, Reserve Andringitra, 38 km S Ambalavo, 22°12'S, 46°58'E, 1680 m, 23 Oct 1993, rainforest, sifted litter, B.L. Fisher (CASENT9018939); 1F, Fianarantsoa, Res. Special Ivohibe, 8.0 km E Ivohibe, 22°29.0'S, 46°58.1'E, 1200 m, 15–21 Oct 1997, forest, leaf litter, B.L. Fisher (CASENT9012344).

Diagnosis

Males are distinguished from other “bourgini group” species except E. harveyi sp. n., E. goodmani sp. n., and E. wunderlichi sp. n., by having the pedipalpal tegulum of the “workmani group” form, with the apical conductor encircling a pit-like cavity (Fig. 9D–L). Males are distinguished from E. goodmani sp. n., E. harveyi sp. n. and E. wunderlichi sp. n. by having an s-shaped embolus (Fig. 9E, H, K–L). Females are distinguished from the “bourgini group” except for E. goodmani sp. n. and E. wunderlichi sp. n. by having a bursa with two large groups of poreplates on a sclerotized plate that covers the ventral side of the bursa (Fig. 9C). In contrast, in other “bourgini group” species the poreplates are in smaller clusters on the anterior side of the bursa. Females are distinguished from E. goodmani sp. n. by having a thinner posterior bar (Fig. 11C), and from E. wunderlichi sp. n. by lacking the large bulge in the center of the posterior bar (Fig. 12B). Females are indistinguishable from E. harveyi sp. n.

Description

Female holotype (CASENT9012340, from Reserve Andringitra, Madagascar). This specimen was damaged during shipping so that the “head” is broken off from the “neck,” rendering some measurements impossible. Total length 2.38, carapace 1.11 long, 0.98 wide. Abdomen 1.16 long, 1.17 high. Carapace tilt height (CtH) 1.61, head length 0.98, carapace tilt angle, carapace constriction, and neck length unknown due to damage. CtH divided by carapace length 1.45. Cephalon with AME virtually flush with surrounding cuticle, and with a single pair of short modified spines at the apex (Fig. 9A). Chelicerae 1.86 long, and with a long spine 0.21 from base of chelicerae and projecting perpendicular to the cheliceral cuticle. Femur I 1.73 long. Sternum 0.72 long, 0.47 wide. Carapace, chelicerae, sternum and legs reddish brown with white setae, but reduced numbers compared to other Eriauchenius. All patella lighter in color, being more yellowish white. Abdomen mottled brown and beige, with tufts of white setae, although reduced in number compared to other Eriauchenius (Fig. 9A). Genitalia with a noncomplex FSGP, with posterior bar (not visible in Fig. 9B, but similar to Fig. 11B–C), and with “wings” reduced and nearly transparent, with poreplates in two large groups, divided down the middle and on a sclerotized plate that covers the ventral side of the bursa (Fig. 9C, similar to Fig. 11C).
Male paratype (CASENT9018939). Total length 2.18, carapace 1.01 long, 0.92 wide. Abdomen 1.13 long, 1.16 high. Carapace tilt angle 79.9°, tilt height (CtH) 1.53, constriction 0.65, head length 0.91, neck length 0.72 . CtH divided by carapace length 1.51. Cephalon as in female. Chelicerae 1.58 long, and with long spine 0.20 from base of chelicerae and projecting perpendicular. Femur I 1.64 long. Sternum 0.65 long, 0.44 wide. Colors as in female. Pedipalpal tegulum of the “workmani group” form, with apical conductor encircling a pit-like cavity (Fig. 9D–L). Conductor tip tapering off into a sharp point (Fig. 9F,I,L). MA trifurcating into three prongs (Fig. 9E, H, L), and with a sclerite (SC) that may be part of the conductor, thicker and more sclerotized than the transluscent thin structure seen in the “workmani group” (Fig. 9E, H). Embolus dark, wire-like and with two curves making an “s” shape (Fig. 9E, H, K–L).

Variation

Total length 2.69–2.38 (females; n=2); Carapace length 1.11–1.17 (females; n=2); Femur I 1.48–1.55 times the length of carapace in females (n=2). CtH divided by carapace length 1.45–1.52 in females (n=2). Average femur I length 1.69 (females; n=2). For female CASENT9012344, carapace tilt angle 80.4, carapace constriction 0.83, and neck length 0.87.

Natural history

Specimens were collected in rainforest in the leaf litter from 1200–1990 m in elevation.

Distribution

Known only from around Andringitra Massif in southeast Madagascar (Fig. 31).

Nomenclatural remarks

Distributions of E. fisheri and E. harveyi sp. n. are in close proximity, however, E. fisheri seems to occur at higher elevations than E. harveyi sp. n. Furthermore, E. fisheri is slightly larger than E. harveyi sp. n. Male and female conspecifics were associated based on these factors, but due to the small number of specimens available, this association may be incorrect. Future molecular work as well as additional collection of specimens from more localities can help resolve this issue.

Taxon Treatment

• Wood, H; Scharff, N; 2017: A review of the Madagascan pelican spiders of the genera Eriauchenius O. Pickard-Cambridge, 1881 and Madagascarchaea gen. n. (Araneae, Archaeidae) ZooKeys, (727): 1-96. doi

Images

Figure 9. Eriauchenius fisheri (Lotz, 2003). A male (CASENT9018939) habitus, lateral view, image reversed B–C female (holotype, CASENT9012340) internal genitalia B dorsal view C anterior view D–L male pedipalpal bulbs (CASENT9018939) D–F, L right bulb, image reversed G–K left bulb D, G, J prolateral view E, H, K ventral view F, I retrolateral view K close-up, ventral view. Scale bars: 1 mm (A); 0.25 mm (B, D).  Figure 11. Eriauchenius harveyi sp. n. A male (holotype, CASENT9012110) habitus, lateral view, image reversed B–C female (CASENT9012342) genitalia B dorsal view C ventral view D–K male pedipalpal bulbs (CASENT9012109) D–F right bulb, image reversed G–K left bulb D, G, J prolateral view E, H, K ventral view F, I retrolateral view L male (CASENT9012109), arrow showing the long cheliceral seta that projects perpendicularly from the chelieral cuticle, lateral view. Scale bars: 1 mm (A); 0.25 mm (B, D).  Figure 12. Eriauchenius wunderlichi sp. n. A female (CASENT9062648) habitus, lateral view, image reversed B–C female (CASENT9062648) genitalia B dorsal view, arrow showing the large bulge on the posterior bar C ventral view D–F male left pedipalpal bulb (holotype, CASENT9062702) D prolateral view E ventral view F retrolateral view. Scale bars: 1 mm (A); 0.25 mm (B, D).  Figure 31. Distribution map for Eriauchenius species.