Homolophus tibetanus ( Roewer, 1911 )

Snegovaya, Nataly Yu. & Cokendolpher, James C., 2021, Further studies on harvestman genus Homolophus (Opiliones: Phalangiidae), with descriptions of two new species, Zootaxa 4908 (3), pp. 301-353 : 346-348

Homolophus tibetanus ( Roewer, 1911)

Figures 7 , 32–33

Egaenus tibetanus Roewer, 1911: 16 , 20–22; Roewer 1912: 200; Roewer 1923: 817–818

Euphalangium trinkleri Roewer, 1956: 261 , figs. 42–44 [junior subjective synonym of Egaenus tibetanus Roewer 1911 by Staręga (2003: 96)].

Opilio insolitus Roewer, 1956: 288 , figs. 125–127 [junior subjective synonym of Egaenus tibetanus Roewer 1911 by Staręga (2003)]

Euphalangium tibetanum — Staręga 1978: 225

Homolophus tibetanus — Cokendolpher 1987: 92; Li & Song 1993: 239; Staręga 2003: 95–96, figs. 19–23

Diagnosis. The species differs from all species, including the most closely related, H. gobiensis Tsurusaki, Tchemeris & Logunov, 2000 , by the following: legs short, Fe I and II about half as long as body length; penis with wide quadrangular glans (seen in lateral view) and uniformly wide truncus (dorsal view), abruptly constricted at distal end.

Type localities. China: Xîzàng (Tibet): Yagntse, and “Tal des Indus bei Nirda + Rongo”; Turkmenistan: Kustri, for Egaenus tibetanus (a single locality was not designated from the 3 localities of the syntypes in the original description; likewise no type locality restrictions have been made since and a lectotype has not been designated and should not be without a study of all the syntypes); Afghanistan, “̂stl. Kabul ” for Euphalangium trinkleri ; and Xîzàng (Tibet), Kashgar Prefecture (= Turkestan, Kaschgar) for Opilio insolitus .

Distribution. Afghanistan, N. Pakistan, China: Xîzàng (Tibet), India: Assam, Turkmenistan, and Uzbekistan ( Fig. 7 ).

Specimens Examined. CHINA, Xîzàng (Tibet), Central Asia, Burhan Buddha Range ( Burkhanboda Range ), Khatu Gorge , 3352–3657 m a.s.l, July 1901 (1 male, 75 females, 2 juv., ZIN) ; Xîzàng (Tibet), tract Ram-da on the river Kam, Makons pool, August 1900 (1 male, ZIN) ; Xîzàng (Tibet), Mokchun Delta, Kam ( East Tibet), 3657 m a.s.l., September 1900 (1 female, ZIN) ; Central Asia, Dulan-Kitsch , 3352 m a.s.l., August 1901 (12 males, 2 females, ZIN) ; Du-Chu valley , 3657 m a.s.l., 1 July 1900 (1 male, 1 female, ZIN) ; headwaters of Dzharchyne River , 4267 m a.s.l., July 1900 (1 female, 15 juv., ZIN) ; headwaters of River Dzhagin-gol, 4267 m a.s.l. headwaters of river Jarchyn , 4267 m a.s.l., July 1900 (4 males, 2 females, 4 juv., ZIN) ; Lake Rhombo Mzo , 3962 m a.s.l., August 1900 (1 male, ZIN) ; Left tributary of Bi-chu River ( Blue River basin), 4267 m a.s.l. Left tributary of Bog-gyu River ( Blue River basin), 4267 m a.s.l., July 1900 (1 male, 2 females, ZIN) ; Ndou Chi, valley of Blue River at KumSogon-Gombi , 3657 m a.s.l., July 1900 (3 males, ZIN) ; Neamtsu river , 4115 m a.s.l., July 1900 (1 female, 1 juv., ZIN) ; upper River Dzhagin-gol [upper river Jargyn], 4267 m a.s.l., July 1900 (5 males, 3 females, ZIN) ; watershed of Yellow and Blue rivers, 4267 m a.s.l., 1 July 1900 (2 females, ZIN) .

Description. Medium-sized harvestmen; male body rectangular, with rounded corners; heavily sclerotized body cuticle, less slender, 1.68 times longer than wide; length 4.7 mm, width 2.8 mm; dark brown with small round specks of light and dark color. Junction between cephalothorax and abdomen light in color. Body with very faint longitudinal, light-colored, indistinct dashed stripe running length of body. Dorsum with fine denticles located along borders of tergites. Ocularium low, round, not large, 1.6 times its length from anterior margin of cephalothorax, with 6–8 denticles on each side. Preocular area with about 15 black-tipped denticles; many other black-tipped denticles over rest of cephalothorax. Legs short, angular in cross-section, Fe I and III thickened, segments of legs are longitudinally with rows of denticles and setae. Leg lengths (mm): I 2.0 + 1.0 + 3.4 + 1.5 + 3.1 = 11.0, II 2.4 + 1.0 + 2.3 + 2.2 + 6.0 = 13.9, III 2.1 + 2.0 + 1.6 + 3.0 + 5.2 = 13.9, IV 2.7 + 1.0 + 2.1 + 3.0 + 5.2 = 14.0. Pedipalp segment lengths (mm): 1.0 + 0.6 + 0.7 + 1.3 = 3.6. Pedipalps not large with various kinds of setae, Fe dorsally and ventral with denticles, Pa and Ti dorsally with denticles, Ta ventrally densely covered with microdenticles. Chelicerae enlarged thickened (sexually dimorphic) with some tabby marks, basal segment dorsally with some smaller denticles; distal segment anteriorly densely covered by smaller denticles. Cheliceral basal segment ventrally smooth without bulge, length 1.7 mm, distal segment length 1.9 mm. Penis short, dorsoventrally flattened, bowed, recurved in lateral view, length (mm): truncus 2.8, glans 0.3, stylus 0.2.

Female differs from male in larger size, more distinctively defined light colored stripe, and light-colored saddle on abdomen. Fe of all legs not thickened, on female’s pedipalp only Fe dorsally with several denticles, all other parts with setae. Body rectangular, with rounded corners; less slender, 2.08 times longer than wide. Preocular area with about 20 black-tipped denticles, placed more thickly on female. Female body length 7.3 mm, width 3.5 mm. Leg lengths (mm): I 2.3 + 1.1 + 2.0 + 2.1 + 4.8 = 12.3, II missing, III 2.5 + 1.1 + 2.1 + 2.7 + 6.0 = 14.4, IV 3.8 + 1.2 + 2.7 + 4.0 + 8.0 = 19.7. Pedipalp segment lengths (mm): 1.0 + 0.6 + 0.8 + 1.3 = 3.7. Cheliceral basal segment length 1.5 mm, distal segment length 1.5 mm.

Comments. Specimens over 100 years old. Colors likely faded.

Figures

FIGURE 7. Distribution of some Homolophus species in the Palearctic: Central and Inner Asia. Data for pale colored symbols taken from literature; identifications not verified.

FIGURE 32. Homolophus tibetanus (Roewer, 1911): A, male body, dorsal; B, male ocularium, dorsal; C, female body, dorsal; D, female ocularium, dorsal; E, male right pedipalp, mesal; F, male right pedipalp, ectal; G, male right chelicera, ectal; H, male right chelicera, mesal; I, female right chelicera, ectal; J, female right chelicera, mesal; K, female right pedipalp, ectal; L, female right pedipalp, mesal.

FIGURE 33. Homolophus tibetanus (Roewer, 1911), male: A, femur I, dorsal; B, penis, lateral; C, penis glans, lateral; D, penis, dorsal; E, penis glans, dorsal.