Biantes calyptroideus, Gong & Martens & Zhang, 2018

Gong, Xuyun, Martens, Jochen & Zhang, Chao, 2018, Two new species of Biantes from China and Malaysia (Opiliones: Laniatores: Biantidae), Zootaxa 4461 (4), pp. 587-599: 589-593

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Biantes calyptroideus


BIantes calyptROIdeus  sp. nov.

( Figs 6–7 View Figure , 10–27View FIGURES 10–19View FIGURES 20–27, 47–49 View Figure )

Type material. Holotype: male, CHINA: Xizang Autonomous Region, Muotuo County [N 29°19´, E 95°20´], alt. 1206m, September 21, 2013, Z.Z. Gao leg. (MHBU-Opi-13ZC1106). Paratype: one female (MHBU-Opi- 13ZC1107), same collecting data as holotypeGoogleMaps  .

Diagnosis. Patella of pedipalp unarmed, without a meso-ventral setiferous tubercle, its length shorter than the sum of the length of the tibia and tarsus. Apical portion (pars distalis) of penis shaped like a hat (ventral view). The spongy body distinctly developed, the titillators conical. Conductor with a concave apophysis outside of the frontal border.

Biantes calyptroideus  sp. nov. can be easily distinguished from all seven newar  -group species ( B. newar Martens  , B. gandaki Martens  , B. gandakoides Martens  , B. kathmandicus Martens  , B. sherpa Martens  , B. gurung Martens  , and B. annapurnae Martens  ). Apophyses on the conductors of glans in the new species are laterally situated in the frontal border of the conductor, while apophyses on the conductor in B. gurung  , B. annapurnae  , B. kathmandicus  , and B. sherpa  are situated dorsomedially. Furthermore, the new species differs from B. newar  , B. gandaki  , and B. gandakoides  by the unique spongy body’s sharply keeled projection ( Fig. 24 View Figure ) on the distal truncus area.

Etymology. The specific name is derived from the Latinized Greek word “ calyptroideus  ” meaning “hatshaped”, referring to the shape of the ventral plate and the spongy body of the penis (ventral view).

Description. Male (holotype): habitus as in Figs 6 View Figure , 10 View Figure , 47, 49 View Figure . Coloration ( Figs 47, 49 View Figure ): entire body rusty yellow, with black patches on the dorsum; anterior and lateral area of carapace with black reticulations, the middle reticulations prominent and nearly extending to the inter-eyes space; opisthosomal region of scutum and free tergites with interrupted transverse rows of black stripes, with both lateral ridges of the scutum yellowish brown; coxa with black reticulations; free sternites with black transverse band; chelicerae and pedipalps reticulated on dorsal side; trochanters of all legs with pale black reticulations, tarsus lighter.

Dorsum ( Figs 6 View Figure , 47 View Figure ). Dorsal scutum granular and widely ovoid in shape, the end of abdomen slightly enlarged and rounded. Anterior margin of carapace with a few small tubercles at the lateral portion. Circum-ocular tubercles reduced, except one enlarged one behind the eye. The eyes separated from the anterior margin of the carapace by a distance equal to 2/3 of the length of the scutum; distance between eyes almost equal to the width of scutal area I. The mesotergal sulci inconspicuous. Scutum and free tergites without enlarged tubercles.

Venter. Genital operculum long and narrow ( Fig. 17 View Figure ). Coxae tuberculate, coxa I with conspicuous tubercles with setae on top ( Fig. 16 View Figure ). Coxae II, III and IV with only minute tubercles. Genital operculum with a few setatipped granules. Free sternites with a row of very small tubercles with setae on top. Spiracles clearly visible.

Chelicerae ( Figs 11–13 View Figure ). Basal segment of chelicera with distinct dorso-distal bulla, no prominent armaments except a few small setiferous tubercles. Cheliceral claw unarmed, with sparse setae only. Fingers relatively short, inner edges toothed as illustrated ( Fig. 13 View Figure ): moveable finger and fixed finger each proximally armed with one enlarged tooth, other teeth small or inconspicuous.

Pedipalps ( Fig. 14 View Figure ). Coxa with two dorsal and one ventral setiferous tubercles. Trochanter, femur and patella unarmed. The length of patella shorter than the sum of the length of the tibia and tarsus. Tibia with two ventromesal setiferous tubercles and three ventroectal ones. Tarsus with two setiferous tubercles on each side of ventral surface. Tarsal claw curved, approximately the same length as the tarsus.

Legs ( Fig. 15 View Figure ). All segments smooth, with only scarce short setae. Femur IV slightly curved. Distitarsus I with two tarsomeres, distitarsus II with three tarsomeres. Distitarsi III–IV with scopulae ( Fig. 15 View Figure ). Tarsal claws smooth. Tarsal formula (I–IV): 3/5/5/5.

Penis ( Figs 20–25 View Figure ). The basal third of the shaft (beyond the triangular base) slender and slightly broadened, the pars distalis strongly enlarged but nearly parallel-sided until apical portion. The ventral plate and the spongy body (‘Schwellkörper’ in Martens 1978) of the pars distalis hat-shaped ( Fig. 22 View Figure ). The ventral plate almost trapezoid, with one short lateral seta on each side ( Figs 20, 23 View Figure ). The spongy body ring-shaped around the base of the ventral plate, enclosing its surface ( Fig. 21 View Figure ). The titillators conical, with a blunt, rounded top, forming small digitiform projections ( Fig. 24 View Figure ). Conductors rather complicated, bipartite, long and slender; the two basal thirds spoon-like, the inner side prolonged to a longish, slender outgrowth ending in a rounded hook ( Fig. 23 View Figure ). Stylus slender, hidden between the conductors, free in everted state.

Female paratype: ( Figs 7 View Figure , 18–19 View Figure , 26–27 View Figure , 48 View Figure ). In general appearance similar to the male ( Figs 7 View Figure , 48 View Figure ), with only a slight difference in inner edges of finger of chelicera ( Fig. 19 View Figure ), genital operculum short and broad ( Fig. 18 View Figure ) (versus long and narrow in male holotype, Fig. 17 View Figure ). Ovipositor as illustrated ( Figs 26–27 View Figure ), cylindrical. Ventral surface with four, and dorsal surface with six setae.

Measurements. Male holotype (female paratype): body 2.12 (1.62) long; scutum 1.44 (1.36) long, 1.47(1.41) wide; carapace 0.63 (0.57) long, 1.12 (0.92) wide. Interocular distance 0.70 (0.53) (not including the eye). Pedipalp claw 0.53 (0.46) long. Penis 0.93 long. Measurements of pedipalp and legs as in Table 1.

Habitat. The specimens were collected by leaf litter sifting in dark moist forest patches under dense forest canopy. The altitude of the collecting locality at about 1200 m, subtropical broad leaf forest.

Distribution. Known only from the type locality in Himalayan Southeast Tibet.