Utivarachna phyllicola Deeleman-Reinhold, 2001

Naven Kumar, R K, Sivalingam, Azhagu Madhavan, Alex, Arockia & Brahma, Neha, 2022, A Record of Utivarachna phyllicola (Araneae, Trachelidae) from Lampi Island, Southern Myanmar, Bulletin of the National Museum of Nature and Science. Series A, Zoology 48 (2), pp. 29-34 : 30-33

Utivarachna phyllicola Deeleman-Reinhold, 2001

Utivarachna phyllicola Deeleman-Reinhold, 2001, pp. 386–388, figs. 604–609. Holotype: male, and one female and one male paratypes from humid evergreen forest near the entrance of tourist center, about 1,000 m alt., in the Khao Yai National Park, Nakhon Ratchasima Province, Thailand, 3–7–III–1986, P. R. and C. L. Deeleman leg., preserved in the Naturalis Biodiversity Center, Leiden (Rijksmuseum van Natuurlijke Historie), not examined.

Diagnosis. ɹThis species is very unique in having an extremely developed, retrolateral tibial apophysis of the male palp ( Fig. 4), and is easily distinguishable from other Utivarachna species. However, we are not sure which species group it belongs to, because the subdivision proposed by Deeleman-Reinhold (2001) should be reviewed. In the key of the article (p. 372), Utivarachna phyllicola was treated as a species group of its own with characteristics including some variable features of the eyes and chelicerae. For instance, the posterior eye row shows different phases by the viewing angle, and the number of teeth on the retromargin of the fang furrow of the chelicera can be variable, as it is four in the present specimen, not three as specified in the key. The com- parison of the palpal organs and female genitalia among species was also insufficient. Focusing on the structure of the male palp among species of the genus, in fact, Utivarachna phyllicola seems to be related to the species of the U. kinabaluensis group established by the same author, namely, U. kinabaluensis Deeleman-Reinhold, 2001 , from Sabah, Borneo and U. bucculenta Deeleman-Reinhold, 2001 , from Khao Yai National Park, Thailand.

Description. ɹBased on a single male specimen from southern Myanmar. Measurements. Body length 3.60 mm; prosoma length 1.65 mm, width 1.33 mm; opisthosoma length 1.95 mm, width 1.20 mm; lengths of legs [total length (femur+patella+tibia+metatarsus+tarsus)]: I 5.04 mm (1.58+0.60+1.23+1.03+0.60), II 4.88 mm (1.47+0.58+1.20+1.03+0.60), III 3.45 mm (1.13+0.38+0.77+0.82+0.35), IV 4.53 mm (1.30+0.45+1.00+1.28+0.50). Leg formula: I–II–IV–III.

Prosoma. Carapace wholly granulated, longer than wide (length/width 1.25), posteriorly narrowed to the width of the pedicel, with a small but distinct fovea ( Fig. 1). Anterior eye row procurved, posterior eye row slightly procurved or straight in dorsal view, differs depending on the viewing angle. AME round, other eyes oval. ALE>PME>PLE>AME (10: 8: 7: 6), AME– AME<AME–ALE (3: 4), PME–PME>PME– PLE (8: 7), ALE and PLE close to each other. Median ocular area as long as wide, wider behind than in front (6: 4). Clypeus narrow, as same as the diameter of AME. Chelicera with three teeth on the promargin of fang furrow, four teeth on the retromargin ( Fig. 2). Maxillae wide and round distally, labium longer than wide (length/width 1.20), sternum slightly longer than wide (length/width 1.06). Legs without spines and strong hairs, coxae of legs I and II remarkably long, as long as tibia of the legs, metatarsi of legs I and II ventrally with rows of thin hairs with granular base, metatarsi of legs III and IV apically with scopula, tarsus with claw tuft and two claws which are small and not pectinate.

Male palp ( Figs. 3–5). The basal part of femur slightly bent downward, without swelling or apophysis, the length of patella one-third of the femur, tibia basally short, the retrolateral tibial apophysis large, its apical part furnished with a sclerotized hook and the surrounding membrane ( Figs. 4–5). Cymbium longer than wide, apically with two strong hairs, palpal organ large and globular, without distinct tegular apophysis and conductor, embolus filiform, long, coiled around the tegulum and visible through the cymbium as shown by the arrow on Fig. 4, the tip of embolus reaches the end of the cymbium.

Opisthosoma. Bullet-shaped, longer than wide (length/width 1.63), covered with an indistinct, thin dorsal plate ( Fig. 1). Pedicel relatively short, cylindrical, basally covered by membranous structure ( Fig. 6). Colulus absent, replaced by a pair of vestigial hairs, all spinnerets without distinct large spigots, anterior-lateral spinnerets semi-cylindrical, thicker than others, median ones small and short, posterior-lateral ones longest ( Fig. 7).

Coloration and markings ( Fig. 1). Prosoma: Carapace brown with three pairs of black dots on both sides; chelicerae, maxillae, labium and sternum brown; coxa, trochanter, the basal two thirds of femur of leg I and the middle part of femur of leg II also brown, other segments of leg I and II yellow; legs III and IV basally light yellowish brown, distally yellow. Opisthosoma: dorsal plate light yellowish brown with indistinct markings; other parts yellowish white; spinnerets yellow.

Distribution ( Fig. 8). Myanmar (Tanintharyi Region); Thailand, Indonesia (Sumatra), Malaysia (Borneo).