Eriauchenius ratsirarsoni
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Ordo: Araneae
Familia: Archaeidae
Genus: Eriauchenius
Name
Eriauchenius ratsirarsoni (Lotz, 2003) – Wikispecies link – Pensoft Profile
- Archaea ratsirarsoni Lotz, 2003: 226, fig. 2A–C.
Type material
Male holotype: as Archaea ratsirarsoni (Lotz, 2003), from MADAGASCAR, Toamasina, Forêt Clasée Sandranantitra, 18°2.9'S, 49°5.5'E, 450 m, 18–21 Jan 1999, rainforest, sifted litter, H.J. Ratsirarson (examined, deposited in CAS; CASENT9012339).
Other material examined
MADAGASCAR, Toamasina: female paratype and 1juv, Ambatovy, 12.4 km NE Moramanga, 18°50'22"S, 48°18'30"E, 1080 m, 4–7 Mar 2007, montane rainforest, sifted litter, B.L. Fisher et al. (CASENT9028378); 1F,1juv, Parc National Mantadia, 18°47.5'S, 48°25.6'E, 895 m, 28 Nov – 1 Dec 1998, rainforest, sifted litter, H.J. Ratsirarson (CASENT9012338); 1M, Station Forestier Analamazaotra, administered by Mitsinjo, 0.75 km N Andasibe, 18°55.783’S, 48°24.696’E, 964m, 2 Feb 2009, primary montane rainforest, sifting litter around logs, dead fern fronds, and at base of traveler’s palm, H. Wood (USNMENT01377174); 1M,1F, Corridor Forestier Analamay-Mantadia, Ambohibolakely, 18°45'41"S, 48°21'52"E, 983m, 23-28 Nov 2012, rainforest, sifting litter, B.L. Fisher et al. (CASENT9062876).
Diagnosis
Males and females are distinguished from other Eriauchenius, except E. mahariraensis and E. sama sp. n., by the presence of 4 small spines on the cephalon crown, and the cheliceral spine pointing perpendicular. Males of E. ratsirarsoni are distinguished from E. sama sp. n. and E. mahariraensis by lacking membranous tissue close to the conductor tip (Fig. 15D–L) and having a long conductor and conductor process that extends past the embolus tip (Fig. 19F, I). Females are distinguished by the presence of two lateral bulges on the FSGP and translucent “wings” (Fig. 19B, arrows).
Description
Male holotype (CASENT9012339, from Forêt Clasée Sandranantitra, Madagascar). Total length 1.67, carapace 0.80 long, 0.74 wide. Abdomen 0.81 long, 0.87 high. Carapace tilt angle 67.5°, tilt height (CtH) 1.35, constriction 0.46, head length 0.75, neck length 0.64. CtH divided by carapace length 1.69. Cephalon with AME on a very small bulge, and with 4 small post-ocular spines (anterior two are broken off, rudimentary or missing) on the crown of the cephalon, and 1 spine between the LE and median eyes (on each lateral side, for a total of 2; broken off on the right side). Chelicerae 1.34 long, and with a long spine 0.20 from base of chelicerae that projects perpendicular. Femur I 1.58 long. Sternum 0.55 long, 0.37 wide. Carapace, chelicerae, sternum, and legs reddish brown with white setae; patellas I–IV, legs II–III, tarsi and metatarsi I–IV pale yellow. Abdomen mostly dark brown with light circular patches, but with several light-yellow patches; abdomen with white and brown setae. Pedipalpal bulb with a membraneous sac above the base of the embolus, with a greatly exposed embolus that is encircled by the conductor (Fig. 19D–L). Conductor swirls around the broad, dark embolus and has a large, long process on the prolateral side (Fig. 19D–I, c1); conductor and process extend past the tip of the embolus (Fig. 19F, I).
Female paratype (CASENT9028378). Total length 1.89, carapace 0.86 long, 0.76 wide. Abdomen 0.87 long, 1.07 high. Carapace tilt angle 69.8°, tilt height (CtH) 1.44, constriction 0.54, head length 0.73, neck length 0.67. CtH divided by carapace length 1.68. Cephalon with AME on a small bulge, and with 4 small spines (anterior pair is rudimentary) on the crown of the cephalon, and missing spine between the LE and median eyes. Chelicerae 1.41 long, and with small spine 0.19 from base of chelicerae projecting perpendicular. Femur I 1.44 long. Sternum 0.56 long, 0.39 wide. Carapace and sternum orangeish brown; legs and chelicerae pale yellow. Abdomen mostly light yellow but with several dark brown areas with light circular patches; abdomen with white and brown setae. Female genitalia FSGP with two large lateral bulges (Fig. 19B, arrows), and nearly translucent “wings”, with PB present (Fig. 19B); one group of poreplates on each side of the bursa anterior; poreplates heavily sclerotized and raised, forming a bulge on the bursa (Fig. 19C).
Variation
Total length 1.67–1.70 (males; n=3), 1.70–2.47 (females; n=3); Carapace length 0.75–0.80 (males; n=3), 0.82–0.87 (females; n=3); Femur I 1.82–1.98 times the length of carapace in males (n=3), 1.63–1.75 in females (n=3); CtH divided by carapace length 1.65–1.69 in males (n=3), 1.68–1.70 in females (n=3). Average femur I length 1.47 in males (n=3) and 1.43 in females (n= 3). In all males the anterior pair of spines on the cephalon are either rudimentary or broken off; in females, one with anterior pair rudimentary, one with all 4 spines present, one with one anterior spine present and the other absent.
Natural history
In montane and primary rainforest from 450–1080 m in elevation, collected by sifting litter.
Distribution
Known only from central-eastern Madagascar (Fig. 31).
Nomenclatural remarks
One male specimen (CASENT9062876) has a pedipalpal bulb that is more heavily sclerotized than the other specimens, and also has a blunt conductor tip (Fig. 19K–L, arrows) rather than the tapering tips in the other two specimens (Fig. 19J, arrow). All three male specimens occur in close proximity so this is likely not a case of geographic variation. This specimen may be a new species and future molecular work as well as additional collection of specimens from more localities can 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
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