Alocobisium rahmi Beier, 1976

Hu, Junfang & Zhang, Feng, 2013, Description of Alocobisium tibetense sp. nov., representing the first record of the pseudoscorpion family Syarinidae (Arachnida: Pseudoscorpiones) from China, Zootaxa 3641 (1), pp. 49-56 : 50-52

Alocobisium rahmi Beier, 1976

( Figs 1–9 )

Alocobisium rahmi Beier, 1976: 98 –99, fig. 4; Schawaller, 1983: 108–110, figs 8–11; Schawaller, 1987: 209; Harvey, 1991: 418; Schawaller, 1991: 779, fig. 1.

Type material examined. Two females (holotype and paratype, NMB-PSEU00034a), Phuntsholing, Bhutan, 600 m alt., 15 April 1972, NMB Bhutan Expedition.

Diagnosis. Carapace smooth and without basal furrow; eyeless; trichobothrium ib situated near the base of hand, st nearer to t than to sb.

Description. Carapace and tergites pale yellow, pedipalps brown ( Fig. 1 ).

Carapace smooth and longer than broad ( Fig. 2 ), with a total of 22–23 setae, including 4 on anterior margin and 6–7 on posterior margin; epistome rounded; eyeless; without basal furrow on carapace. Pleural membrane with longitudinal striate and medially weakly granulated.

Tergites I and II each with 8 marginal setae; anterior genital operculum with 4 setae; posterior parts damaged.

Pedipalps ( Fig. 5 ) smooth. Apex of coxa with 2 setae. Trochanter without tubercle. Femur with a stout pedicel, proximal half wider than distal half. Patella stout. Fixed chelal finger ( Fig. 7 ) with 30 blunt teeth, movable finger with 28 teeth, all teeth contiguous. Trichobothrium ib near base of hand, trichobothria eb and esb on distal portion of hand, ist on sub-basal of fixed finger, eb, esb and isb situated in a straight line, 4 antiaxial feather-shaped setae ( Fig. 9 ) clustered between it and est; st nearer to t than to sb, trichobothrium t short and acuminate, situated near middle of movable finger.

Cheliceral palm with 5 setae ( Fig. 3 ), movable finger with 1 seta; fixed finger with 8–9 teeth; movable finger with 5–6 teeth; galea ( Fig. 4 ) long, simple, without branchlets; rallum and serrulae not examined.

Legs ( Figs 6, 8 ); junction between femur and patella of leg IV perpendicular, leg IV basitarsus with one subbasal tactile seta (TS 0.30), telotarsus with one tactile seta (TS 0.22); subterminal seta bifurcate distally, arolium shorter than the thin and smooth claws.

Dimensions (in mm, length/breadth or depth ratios in parentheses). Body length indeterminable. Carapace 0.34–0.35/0.28 (1.21–1.25). Pedipalps: trochanter 0.16–0.17/0.09 (1.78–1.89), femur 0.30/0.10 (3.00), patella 0.25/ 0.12 (2.08), chela (with pedicel) 0.50–0.51/0.16–0.17 (3.00–3.13), chela (without pedicel) 0.47–0.48 (2.82–2.94), hand length (without pedicel) 0.20 (1.18–1.25), movable finger length 0.26–0.27 (1.30–1.35 times longer than hand without pedicel). Chelicera 0.15/0.10 (1.50), movable finger length 0.13. Leg I: femur 0.13/0.06 (2.17), patella 0.11–0.12/0.05 (2.20–2.40), tibia 0.13/0.04 (3.25), basitarsus 0.07–0.08/0.03 (2.33–2.67), telotarsus 0.10– 0.11/0.02 (5.00–5.50). Leg IV: femur + patella 0.20/0.08 (2.50), tibia 0.20/0.06 (3.33), basitarsus 0.07–0.08/0.04 (1.75–2.00), telotarsus 0.12/0.03 (4.00).

Distribution. This species is known only from Bhutan.

Remarks. The two types of Alocobisium rahmi were in the same vial when they were sent to us and the holotype was not designated distinctly. Beier (1976) noted that the paratype of A. rahmi was badly damaged, from which we infer that the specimen shown on the right in Fig. 1 is the holotype. We found that the holotype had a damaged abdomen and that the paratype’s abdomen was lost. The right chelae of both types were detached, but still present in the vial. Legs were partly fragmentary and the detached parts were lost. The carapace of the holotype was cracked anteriorly. Fortunately, the carapace of the paratype was in good condition.

The description given by Beier (1976) is generally accurate, except that the number of setae on carapacal posterior margin was found to be 7 in paratype and 6 in holotype (as opposed to 8 in Beier’s description), no basal furrow could be seen on the carapace (Beier mentions an indistinct and nearly flat furrow), and the carapace is 1.21–1.25 times as long as broad (almost 1.40 times according to Beier).

Figures

FIGURE 1. Alocobisium rahmi Beier, 1976, holotype female (right) and paratype female (left), habitus, dorsal view.

FIGURES 2 – 9. Alocobisium rahmi Beier, 1976, holotype (3 – 9) and paratype (2). 2, carapace, dorsal view; 3, right chelicera, dorsal view (teeth magnified); 4, galea; 5, left pedipalp (without trochanter), dorsal view; 6, left leg IV; 7, right chela, lateral view (with details of teeth); 8, right leg I; 9, feather-shaped setae on right chelal finger, lateral view. Scale lines: 0.4 mm (Figs 2 – 3, 5 – 8), 0.05 mm (Figs 4, 9).