Utivarachna fukasawana Kishida, 1940

Yamasaki, Takeshi, Hashimoto, Yoshiaki, Endo, Tomoji, Hyodo, Fujio, Itioka, Takao, Mohamed, Maryati & Meleng, Paulus, 2023, Taxonomic study of Bornean species of Utivarachna Kishida, 1940 (Araneae: Trachelidae), with the description of a new species, Zootaxa 5343 (1), pp. 55-73 : 66-68

Utivarachna fukasawana Kishida, 1940

Figs 16–19

Utivarachna fukasawana Kishida, 1940: 142 ; Deeleman-Reinhold, 2001: 373, figs 575–580; Dankittipakul, Tavano & Singtripop, 2011: 137, fig. 6.

Material examined. 1 ♀ ( RMNH.ARA. 15300), Brunei , Kuala Belalong, West Ridge , 8.II.1992, leg. R. Snazell (label data shown in Fig. 18E and F are the same as those of the neotype). 1 ♁ (LCo20070821_O1; MNHAH), Lambir Hills National Park, Sarawak .

Diagnosis. In the fukasawana -group, U. fukasawana and U. ichneumon are easily recognizable by the long stalk projection of the posterior carapace, especially in males. In males, U. fukasawana can be distinguished from U. ichneumon by the wide cymbium and bulb. In females, U. fukasawana has short bursae, whereas U. ichneumon has long, tube-like bursae.

Measurements (♁/ ♀). Carapace length 3.35/2.86; cephalic width 1.45/1.33; thoracic width 1.77/1.62. Diameter of eyes: AME 0.18/0.17; ALE 0.17/0.17; PME 0.15/0.13; PLE 0.13/0.16. Interdistances between eyes: AME–AME 0.06/0.05; AME–ALE 0.07/0.06; ALE–ALE 0.58/0.50; PME–PME 0.17/0.16; PME–PLE 0.35/0.27; PLE–PLE 1.11/0.97; ALE–PLE 0.22/0.20; AME–PME 0.07/0.05. MOA: length 0.35/0.28; anterior width 0.41/0.36; posterior width 0.46/0.43. Clypeus height 0.40/0.33. Abdomen length 2.76/2.73; width 1.27/1.76. Legs: I 10.56 (2.80, 1.10, 2.70, 2.80, 1.16)/8.73 (2.45, 0.86, 2.25, 2.15, 1.02); II 8.92 (2.46, 0.90, 2.20, 2.33, 1.03)/7.90 (2.25, 0.73, 2.02, 1.97, 0.93); III 5.36 (1.50, 0.62, 1.17, 1.50, 0.57)/5.04 (1.43, 0.58, 1.11, 1.35, 0.57); IV 7.15 (2.00, 0.70, 1.57, 2.12, 0.76)/7.13 (2.00, 0.63, 1.65, 2.10, 0.75).

Male ( Fig. 16A–D ). Carapace oval, entirely granulated; posterior stalk almost as long as 1/4 carapace length; PER slightly recurved in dorsal view; ocular tubercle accompanied with PLE; thoracic lateral margins undulating. Chelicerae granulated, with five prolateral and five retrolateral teeth. Ventral clypeus margin with small wedge-shaped projection between chelicerae. Pedicel short. Abdomen elongate oval; anterior two-thirds with weakly sclerotized dorsal scutum. Leg I and II elongated, covered with fine spherical granulation; ventral sides of tibia, metatarsus, and tarsus bearing small tooth-like cusps.

Palp ( Fig. 17A–D ). Cymbium strongly convex in retrolateral margin. Bulb inverted pear-shaped, tapering posteriorly; anterior half membranous, and prolateral half weakly sclerotized with subtegulum. Embolus coiled in horizontal plane, inclining dorsally, and plane completely covered by cymbium. Sperm duct U-curved in posterior part of bulb. RTA strongly extended, apically developed into semi-transparent plate with apical claw; base of claw well-sclerotized and developed; claw slender, strongly curved dorsally.

Coloration and setation ( Fig. 16A–D ). Carapace and chelicerae brown, covered with fine setae. Abdomen cream, entirely covered with short setae. All legs brownish cream, except for femora I–II and trochanters I–II brown to light brown.

Female ( Fig. 18A–D ). Somatic characters almost identical to males, except for abdomen shape and shorter posterior stalk; posterior stalk almost as long as 1/5 carapace length. Chelicerae granulated, with six prolateral and five retrolateral teeth. Abdomen oval, without dorsal scutum.

Copulatory organs ( Fig. 19A–C ). Copulatory atrium square. Copulatory openings located at anterior corner of atrium, extending anteriorly with several coils and connected to slender bursae. Spermathecae globular.

Coloration and setation ( Fig. 18A–D ). Almost same as in male.

Distribution. Brunei, Sarawak

Figures

FIGURE 16. Utivarachna fukasawana Kishida, 1940, male (LCo20070821_O1). A habitus, dorsal view; B same, ventral view; C cephalic part and chelicerae, frontal view; D leg I, left, prolateral view. Scale bars: 1 mm.

FIGURE 17. Utivarachna fukasawana, male (LCo20070821_O1). A left palp, prolateral view; B same, ventral view; C same, retrolateral view; D same, dorsal view. Scale bars: 0.50 mm. E—embolus, Sd—sperm duct, St—subtegulum.

FIGURE 18. Utivarachna fukasawana Kishida, 1940, female (RNMH.ARA.15300). A habitus, dorsal view; B same, ventral view; C cephalic part and chelicerae, frontal view; D leg I, left, prolateral view; E label; F label, opposite side. Scale bars A–D: 1 mm.

FIGURE 19. Utivarachna fukasawana, female (RNMH.ARA.15300). A epigyne, ventral view; B internal organs, ventral view; C same, dorsal view. Scale bars: 0.50 mm. Br—bursa, Fd—fertilization duct, S—spermatheca.