Trachelas acuminus ( Zhu & An, 1988 )

Zhang, Feng, Fu, Jian-Ying & Zhu, Ming-Sheng, 2009, A review of the genus Trachelas (Araneae: Corinnidae) from China, Zootaxa 2235, pp. 40-58 : 43-45

Trachelas acuminus ( Zhu & An, 1988)

( Figs. 1–10 )

Clubiona acumina Zhu & An, 1988: 72 , f. 1–6.

Trachelas coreanus Paik, 1991: 200 , f. 1–11. Namkung, 2002: 456, f. 35.3a. Namkung, 2003: 452, f. 35.3a. Lee et al., 2004: 99.

Trachelas acuminus: Mikhailov, 1995: 100 . Zhu, Song & Kim, 1998: 425, f. 1–7. Kim & Lee, 2008: 1871 .

Trachelas acumina: Song, Zhu & Chen, 1999: 429 , f. 255O–P, 256E–F. Song, Zhu & Chen, 2001: 324, f. 208A–G.

Diagnosis. This species can be easily distinguished from other Chinese Trachelas species by: (1) palpal organ relatively simple, only with short embolus and tegular apophysis distally; (2) male palp without patellar apophysis; (3) male palpal femur without concavity on the distal part ventrally; (4) bursa club-shaped, located laterally of the vulva, almost parallel to the spermathecae; (5) epigynal plate with nearly M-shaped anterior hood. Also this species is closed related to T. maculatus from eastern Europe, but differs from the latter by the pointed and thinner functional conductor, and by the M-shaped anterior hood of the epigynum.

Redescription. Male (‘allotype’). Total length 3.15; cephalothorax 1.45 long, 1.23 wide; abdomen 1.70 long, 1.02 wide. Carapace ( Fig. 1 ) dark red-brown, darker in eye area; longitudinal ovoid, cephalic area relatively broad, thoracic area convex, lacking lateral invagination behind eye region; highest at or anterior to fovea. Entire surface covered with fine granulations, denser in thoracic region. Fovea short and indistinct. Eyes moderately large; eye diameters: AME 0.10, ALE 0.10, PME 0.08, PLE 0.08; eye interdistances: AME– AME 0.08, AME–ALE 0.07, PME–PME 0.10, PME–PLE 0.17; MOA 0.28 long, anterior width 0.30, posterior width 0.25. Clypeal height 0.10, almost equal to the diameter of AME; clypeal margin ( Fig. 4 ) straight and without chilum (= clypeal lobe). Chelicerae ( Fig. 3 ) moderately long, red-brown, covered with numerous long setae, with three promarginal and two retromarginal teeth. Endites and labium ( Fig. 2 ) yellowish brown; endites widest anteriorly, with longitudinal depression on inner part, and a maxillar hair tuft prolaterally; labium long as wide, tip rounded and with several setae. Sternum ( Fig. 2 ) light brown, shieldshaped, with brown markings laterally. Legs light brown and spineless; leg I ( Fig. 5 ) with ventral cusps in the tibia, metatarsus and tarsus. Leg formula: 1423 ( Table 1).

Femur Patella Tibia Metatarsus Tarsus Total I 1.16 0.35 1.15 0.81 0.58 4.05 II 0.95 0.40 0.85 0.70 0.43 3.33 III 0.78 0.35 0.98 0.51 0.35 2.97 IV 1.10 0.45 0.90 0.85 0.46 3.76 Abdomen ( Fig. 1 ) ovoid, yellow brown, slightly brown centrally; dorsum with two pairs of sigilla in the middle part, and several pairs of white chevron markings on its posterior part. Venter of abdomen light brown.

Male palp ( Figs. 6–8 ) without ventral patellar apophysis, with long triangular retrolateral tibial apophysis, pointed at distal end. Genital bulb longitudinal pear-shaped from ventral view ( Fig. 7 ), tegulum rounded at base; enclosing distinctive long loop of sperm duct from embolus to upper part of tegulum; subtegulum visible prolaterally ( Fig. 6 ), darker and small; small and short embolus distally, beak-shaped from ventral view ( Fig. 7 ); a functional conductor distally, behind the embolus, small, short and spine-shaped.

Female (one paratype). Carapace colour, eye arrangement, abdominal colouration as for male. Total length 4.65; cephalothorax 2.05 long, 1.73 wide; abdomen 2.50 long, 1.22 wide. Eye diameters: AME 0.12, ALE 0.12, PME 0.10, PLE 0.10; eye interdistances: AME–AME 0.09, AME–ALE 0.08, PME–PME 0.11, PME–PLE 0.18; MOA 0.30 long, anterior width 0.34, posterior width 0.28. Clypeal height 0.13. Legs without spines and cusps. Leg formula: 1423 ( Table 2).

Femur Patella Tibia Metatarsus Tarsus Total I 1.26 0.40 1.19 0.87 0.56 4.29 II 1.05 0.45 0.95 0.75 0.45 3.65 III 0.87 0.40 1.03 0.56 0.40 3.25 IV 1.11 0.48 0.95 0.87 0.48 3.89 Epigynum as in Figs. 9–10 . Epigynal plate weakly sclerotized, with anterior hood, slightly M-shaped; two copulatory openings concave, located posteromedially near the epigastric furrow. Bursa situated lateral of copulatory openings, short, club-shaped; spermathecae elongate oval, larger and longer than bursa, situated medially, connecting with the copulatory ducts through a thin duct; fertilization ducts short, arising from the posterolateral ends of the spermathecae.

Distribution. China (Shanxi Province); Korea.

Type material. Clubiona acumina Zhu et An, 1988 : the type specimens were deposited in the Museum of Hebei University, examined. Trachelas coreanus Paik, 1991 : the original specimens were presumably lost (according to Kim and Lee, 2008), not examined.

Material examined. CHINA: Shanxi Province, Yicheng County (N25.34°, E 100.13°), female holotype, male ‘allotype’, 132Ƥ paratypes ( MHBU), 17 July 1983, M. S. Zhu leg.

Remarks. Trachelas acuminus ( Zhu & An, 1988) seems to be a special species as it differs from other Trachelas species distributed in China. However, based on the functional conductor and embolus shape, the ventral cusps in males, and arrangement of the spermathecae, it is similar to T. maculatus and T. validus distributed in the Europe, and belongs to the Eurasian T. validus species group ( Bosselaers et al., 2009).

Figures

FIGURES 1 – 10. Trachelas acuminus (Zhu et An, 1988). 1. Male body, dorsal view. 2. Endites, labium and sternum of male, ventral view. 3. Left chelicera of male, posterior view. 4. Carapace and chelicerae of male, front view. 5. Tibia, metatarsus and tarsus of male right leg I, showing cusps. 6. Left male palp, prolateral view. 7. Same, ventral view. 8. Same, retrolateral view. 9. Epigynum, ventral view. 10. Vulva, dorsal view. Scale bars: 1 mm (1, 5); 0.3 mm (3, 9 – 10); 0.4 mm (6 – 8); 0.5 mm (2, 4).