Bisetocreagris cheni, Ying, Jia, Yong-Wei, Zhao & Ming-Sheng, Zhu, 2010

Ying, Jia, Yong-Wei, Zhao & Ming-Sheng, Zhu, 2010, A new species of the pseudoscorpion genus Bisetocreagris from China (Arachnida: Pseudoscorpiones: Neobisiidae), Zootaxa 2340, pp. 65-68 : 65-68

Bisetocreagris cheni sp. n.

( Figs. 1–13 )

Type material. Male holotype: (Museum ID # Ar.-MHBU-ZJ 070804), China, Zhejiang Province, Tonglu County, Mt Tongjun, 29°48'43ʺN 119°40'54ʺE, CHEN Zhang-Fu leg., 5 April 1987.

Etymology. The specific name is a patronym in honour of Prof. CHEN Zhang-Fu who collected and donated the specimen.

Diagnosis. The new species is very similar to Bisetocreagris silvestrii , but can be distinguished from the latter by its larger size—e.g. in B. cheni the chela (with pedicel) is 2.15 mm long, whereas in B. silvestrii it is 1.86 mm; the length of palpal movable finger is 1.07 times longer than that of the hand (without pedicel) in the new species, as opposed to 0.92 in B. silvestrii (Harvey, 1999) —and the divided galea of the male (undivided in B. silvestrii ).

Description (holotype male). Colour mostly reddish brown, pedipalps and carapace slightly darker. Carapace slightly longer than broad, smooth and slightly contracted posteriorly; four distinct eyes with flattened lenses; 36 setae in total, of which 4 are at anterior and 12 at posterior margin, 3 ocular setae on each side, median and intermedian rows with 7 each; epistome small, rounded ( Figs. 1, 2 ). Tergites and sternites with uniseriate setation; tergal chaetotaxy (I–X): 15: 16: 16: 17: 18: 17: 16: 17: 12:10; sternal chaetotaxy (IV–XI): 21: 20: 20: 18: 18: 14: 8. Male genital area ( Fig. 3 ): sternite II with a median and posterior group of 26 scattered setae; sternite III with an anteromedian bisetose groove and a median group of 19 scattered setae ( Fig. 3 ). Pleural membrane granulostriate.

Chelicera. Palm with 7 setae, movable finger with 1 sub-medial seta; with 1 lyrifissures on the dorsal face of palm; fixed finger with 6 teeth; movable finger with 8 teeth ( Fig. 12 ). Rallum composed of 7 blades, all blades with anteriorlydirected spinules, basalmost blade obviously shorter than others ( Fig. 11 ); galea medium-sized, with major bifurcation about half way, each tine distally four-furcated ( Fig. 10 ).

Pedipalps. Apex of coxa rounded, with 5 setae. Femur, patella and chela smooth. Fixed chelal finger with 8 trichobothria and a pseudo-tactile seta (pts) at the base of the fixed chelal finger ( Fig. 6 ), movable chelal finger with 4 trichobothria: eb and esb situated on lateral margin of hand; ist situated near ib; st slightly closer to t than to sb ( Fig. 5 ). Both chelal fingers bear blunt and contiguous teeth, fixed finger with 61 and movable finger with ca. 68 ( Figs. 7, 8 ), venom duct very short in the tip of fixed finger, nodus ramosus lying about opposite second tooth.

Legs. Junction between femur and patella IV perpendicular; tactile setae distributed as follows: tibia IV with 1 medial seta, TS ratio(Tactile seta ratio) is 0.49, basitarsus IV with 1 sub-proximal seta, TS ratio is 0.23, and telotarsus IV with 1 medial seta in the middle of the podomere, TS ratio is 0.4; subterminal seta forked; arolium smooth, and slightly shorter than claws.

Measurements (length/width in mm, ratios in parentheses). Body length 4.4. Carapace 1.22/1.06 (1.15). Chelicera 0.83/0.43(1.93), movable finger 0.59. Palp femur 1.32/0.46 (2.87), patella 1.19/0.59 (2.02), chela 2.15/0.83 (2.59 with pedicel), palm length 0.99, movable finger length 1.06, the ratio of movable finger/hand (without pedicel) 1.07. Leg IV femur 0.63/0.46 (1.37), patella 0.76/0.46 (1.65), femur + patella IV 1.39/0.46 (3.0), tibia 1.16/0.23 (5.04), basitarsus 0.43/0.17 (2.53), telotarsus 0.53/0.13 (4.08).

Figures

FIGURES 1 – 3. Bisetocreagris cheni new species, holotype male. 1, habitus, dorsal view; 2, anterior margin of carapace; 3, genital area. Scale lines: 1 mm (Fig. 1); 0.1 mm (Figs. 2 – 3).

FIGURES 4 – 13. Bisetocreagris cheni new species, holotype male. 4, right pedipalpal, dorsal view; 5, mesal view of right chela; 6, lateral view of right chelal fingers; 7, tip of fixed chelal finger; 8, tip of movable chelal finger; 9, right chelicera, dorsal view; 10, galea; 11, rallum; 12, telotarsus IV; 13, subterminal seta. Scale lines: 1 mm (Figs. 4 – 5); 0.5 mm (Figs. 6, 9, 12); 0.1 mm (Figs. 7 – 8); 0.05 mm (Figs. 10 – 11, 13).