Cyclocosmia latusicosta, Zhu & Zhang Introduction, 2006

Zhu, M. S. & Zhang Introduction, J. X. Zhang F., 2006, Rare Spiders Of The Genus Cyclocosmia (Arachnida: Araneae: Ctenizidae) From Tropical And Subtropical China, Raffles Bulletin of Zoology 54 (1), pp. 119-124 : 121-123

Cyclocosmia latusicosta , new species

( Figs. 3-6 )

Holotype. – Female , Aidian Village (21°49'N 107°18'E), Ningming County, Guangxi, China, coll. M. S. Zhu, J. X. Zhang and F. Zhang, 25 Aug.2004.

Paratypes. – 4 females, same data as for the holotype .

Diagnosis. – The new species is similar to Cyclocosmia ricketti , especially in the shape of its spermathecae, but differs from the latter by the spermathecae being two times longer than wide ( Figs. 6 F-J), abdominal disc with 20/23 ribs on each side, and each upper muscle impression with an elevated central zone ( Fig. 6B ). It is also similar to Cyclocosmia siamensis Schwendinger, 2005 ( Schwendinger, 2005: 231, figs. 9-30, pl. 1C) in the shape of spermathecae, but differs from the latter in the upper and median pair of muscle impressions on opisthosomal disc separated by one transversal rib, all ribs lacking hairs with dark, short, cylindrical, upright proximal portion and light, long, flat, reclining distal portion, abdominal disc with 20-23 ribs on each side, and each upper muscle impression with an elevated central zone ( Fig. 6B ).

Description. – Female. Holotype total length, including chelicerae, 33.56; chelicerae 4.50 long; carapace 12.78 long, 11.25 wide; abdomen 17.20 long, 16.38 wide.

Carapace black-brown and smooth, with a few hairs and four long bent bristles in longitudinal row running through ocular area. Carapace curved in front and straight behind, widest at coxae III. Ocular area darker in color. Cervical groove and radial furrows distinct. Fovea deep and procurved, U-shaped, its greatest width occupying one fifth of carapace width at that point.

Eyes ( Fig. 6A ) set on low tubercle, ocular area 1.25 long, 3.06 wide anteriorly, 3.09 wide posteriorly, occupying one third of carapace width at that point. Clypeus height 1.80. Anterior eye row straight and posterior eye row slightly recurved, both rows subequal in width. Ratio of eyes, ALE: AME: PLE: PME (0.75: 0.51: 0.54: 0.37). ALE-AME 0.40, AME-AME 0.27, PLE-PME 0.08, PME-PME 1.39. MOA 1.05 long, 1.29 wide at front, 2.19 wide at back.

Chelicerae ( Fig. 6E ) black-brown, inner margin with 10-12 teeth of different size, outer margin with eight or nine large teeth and 23 denticles between them. Rastellum raised on prominent angled projection and consisting of many short black teeth. Labium dark red-brown, 2.16 long, 2.52 wide, with three black cuspules anteriorly. Maxilla dark red-brown, 5.40 long, 3.15 wide, armed with 12-17 cuspules at base and many small cuspules in anterior part. Sternum red-brown, 7.47 long, 7.56 wide, with numerous long black setae, two pairs of small round sigilla near margin opposite coxae I and II, and a pair of large indistinctly outlined posterior sigilla. Palpal patella with one proventral distal spine.

Legs black-brown, short and stout, with erect setae and hairs ventrally. Legs III and IV distinctly thicker and stronger than legs I and II. Tibiae and tarsi of pedipalps and tibiae, metatarsi and tarsi of legs I and II with numerous horn-like spines, metatarsus and tarsus III with a few scattered spines dorsally and ventrally, metatarsus IV with several small spines at tip. Paired claws with a single large tooth, occasionally accompanied by a denticle, unpaired claw lacking tooth. Pedipalp with single claw bearing one tooth. Measurements of legs:I 22.95 (8.55, 4.95, 4.14, 3.60, 1.71), II 21.60 (7.65, 4.50, 3.51, 3.69, 2.25), III 20.88 (6.03, 4.95, 3.42, 3.78, 2.70), IV 27.27 (7.29, 5.58, 4.50, 6.93, 2.97). Leg formula: 3214. Tibia I 2.52 wide, tibia II 2.25 wide, tibia III 2.97 wide, tibia IV 2.88 wide.

Abdomen ( Figs. 6 B-D) dark yellow-brown, with crescentshaped sclerite posterior to spinnerets and anus not connected to ventral median rib angle. Caudal disc convex, with two ribs running dorsoventrally and 20/23 radiating ribs on each side; ribs wide and grooves deep; each rib angle distinctly elevated carrying 46-52 long and smooth bristles and a few bottlebrush-like bristles rising from inner surface of rib angle and bent towards disc center. All ribs with many granular structures in different size ( Fig. 4 ). Abdominal disc with six well-marked muscle impressions, the upper pair with an elevated central zone connected to the outer rim of each of these muscle impressions, and separated from median pair by only one transversal rib, second (lower) transversal rib wide, running into upper portion of ring around median muscle impression. Disc surface with only three pairs of bristles on the rims of muscle impressions. Four spinnerets, with inner pair small and one-segmented, and outer pair much longer and three-segmented. Two sack-like, parallel-sided spermathecae ( Fig. 6F ), each one almost two times longer than wide.

Male. Unknown.

Etymology. – Latin: latus = wide; Latin: costa = rib.

Variation. Measurements and rib counts (females, n=5): Body length: 33.03-33.56, carapace length 12.78-13.50, width 11.25-12.24; rib counts 20-23 (20/21, 21/20, 21/21, 22/21, 20/23). Spination of patellae: One female possesses one proventral spine on its right palpal patella, two proventral spines on the other palpal patella. Another female has one proventral spine on its right palpal patella, and none on the other palpal patella. Other specimens are the same as holotype. Labium with 2-3 cuspules.

Burrow. Burrows found at a sloping earth bank with moist leaf litter were about 16 cm in depth and 22 mm in diameter, narrowed near the bottom. The hinged entrance door was 32 mm in diameter, made of moss, earth and silks. The inside of the burrow was lined with a thin silk layer ( Fig. 3 ).

Distribution. – Known only from the type locality in southeastern China, near the border to Vietnam.

Figures

Fig. 3. Burrow entrance and trapdoor of Cyclocosmia latusicosta, new species.

Fig.4. Abdomen of Cyclocosmia latusicosta, new species, paratype, caudal view.

Fig. 5. Cyclocosmia latusicosta, new species, paratype (SEM micrographs). A, detail of ribs; B, detail of inner side of rib angles showing two kinds of bristles; C, detail of long and smooth bristles; D, detail of bottlebrush-like bristles.

Fig. 6. Cyclocosmia latusicosta, new species. A, ocular area, dorsal view, holotype; B, abdomen, caudal view, holotype; C, same, lateral view, holotype; D, posterior portion of opisthosoma, ventral view, holotype; E, left chelicera, prolateral view, holotype; F-J, spermathecae, dorsal view: F, holotype; G-J, paratypes. Scale bars: A, F-J = 1.0 mm, B-E = 2.0 mm.