Utivarachna rama Chami-Kranon & Likhitrakarn

Chami-Kranon, Thanaphum, Likhitrakarn, Natdanai & Wongsawad, Chalobol, 2007, Utivarachna rama sp. n., a new species of tracheline spiders (Araneae: Corinnidae) from Thailand, Zootaxa 1446, pp. 59-68 : 60-67

Utivarachna rama Chami-Kranon & Likhitrakarn sp. n.

Figs 1–19

Type material. Holotype: ɗ, northern Thailand, Chiang Mai Province, Mae Jam District, Doi Inthanon National Park, Doi Inthanon, evergreen cloud forest near the summit ca. 2550 m, 18°35.361'N 98°29.157'E, pitfall trap, 21.–27.ix.2003, P. Dankittipakul & T. Chami-Kranon leg. [ MHNG, TH /CR 001].

Paratypes: From the type locality, 1 Ψ, pitfall trap, 27.ix.–5.x.2003; P. Dankittipakul & T. Chami-Kranon leg. [ MHNG, TH /CR 002]; 2 Ψ, pitfall trap, 2.–8.vii.2003, P. Dankittipakul & T. Chami-Kranon leg. [ MHNG, TH /CR 003–4]; evergreen cloud forest ca. 1 km from Telecom station, 2430 m: 1 juv., beating, 27.xi.1999, P. Dankittipakul leg. [ MHNG, TH /CR 005]; 1 juv., sweeping, 25.xii.1999, P. Dankittipakul leg. [ MHNG, TH /CR 006]; evergreen cloud forest ca. 1 km above Kiew Mae Pan Trail, 2250 m, 1 juv., soil sample, 15.xii.1999, P. Dankittipakul leg. [ MHNG, TH /CR 007]; Kiew Mae Pan Trail, 18°33.163'N 98°28.8'E, evergreen hill forest near stream, 2090 m: 1 Ψ, 8.–15.vii.2003, pitfall trap, P. Dankittipakul & T. Chami-Kranon leg. [ MHNG, TH / CR 008]; 2 juv., sweeping, 25.xii.1999, P. Dankittipakul leg. [ MHNG, TH /CR 009–10]; 1 juv., sweeping, 25.xii.1999, P. Dankittipakul leg. [ MHNG, TH /CR 011]; 1 juv., soil sample, 25.iii.2000, P. Dankittipakul leg. [ MHNG, TH /CR 012]; 1 juv., sweeping, 25.iii.2000, P. Dankittipakul leg. [ MHNG, TH /CR 013]; evergreen hill forest ca. 2 km from checkpoint to Mae Jam, 1750 m, 1 juv., soil sample, 15.iii.2000, P. Dankittipakul & S. Sonthichai leg. [ MHNG, TH /CR 014]; evergreen hill forest ca. 500 m from checkpoint to Mae Jam, 1610– 1680 m, 18°31.559'N 98°29.941'E: 1 Ψ, pitfall trap, 29.iv.2000, P. Dankittipakul & S. Sonthichai leg. [ TNHM]; 13 ɗ, 5 Ψ, soil sample, 10.–15.ix.2005, T. Chami-Kranon leg. [ MHNG, TNHM]; 1 Ψ, soil sample, 25.iii.2000, P. Dankittipakul leg. [ MHNG, TH /CR 0015]; 2 juv., sweeping, 23.x.1999, P. Dankittipakul leg. [ MHNG, TH /CR 016-17]; 1 juv., beating, 27.xi.1999, P. Dankittipakul leg. [ MHNG, TH /CR 018]; 6 juv., beating, 27.xi.1999, P. Dankittipakul & S. Sonthichai leg. [ MHNG, TH /CR 019-24]; 3 juv., sweeping, 29.vii.2000, P. Dankittipakul leg. [ MHNG, TH /CR 025–27]; 1 juv., soil sample, 27.xi.1999, P. Dankittipakul leg. [ MHNG, TH /CR 028]; 1 juv., sweeping, 25.ix.1999, P. Dankittipakul leg. [ MHNG, TH /CR 029]; 1 juv., sweeping, 26.ii.2000, P. Dankittipakul & S. Sonthichai leg. [ TNHM]; 1 juv., beating, 25.iii.2000, P. Dankittipakul & S. Sonthichai leg. [ MHNG, TH /CR 030]; Doi Inthanon, 1700 m, 18.iv.1987, P. Schwendinger leg. [ MHNG].

Diagnosis. Utivarachna rama sp. n. belongs to the kinabaluensis -group, the species of which share the following somatic characteristics: carapace not protruded or forming posterior stalk ( Figs 1–3 , 5 ); lateral margins of carapace vaguely undulated; PER slightly recurved ( Figs 1–5 ); spermathecae constricted ( Fig. 19 ). Utivarachna rama sp. n. is similar to U. bucculenta , known from Khao Yai National Park, from which it can be distinguished by: the retrolateral tibial apophysis gradually tapering towards its tip, bearing a small apical hook ( Figs 11, 13 , 15, 17 ; sigmoid-shaped with blunt apex in U. bucculenta , see Deeleman-Reinhold 2001, fig. 599); by the absence of tibial, metatarsal and tarsal cusps on prolateral side of the anterior legs (present in U. bucculenta , see Deeleman-Reinhold 2001, fig. 601); and by the PER being slightly recurved (strongly recurved in U. bucculenta , see Deeleman-Reinhold 2001, fig. 598). In U. rama sp. n., the spermathecae are in an oblique position, constricted in the middle, forming the anterior margin of the epigynal atrium ( Fig. 19 ) but elongated and abruptly bending downwards, not in contact with the atrium margin in U. bucculenta (see Deeleman-Reinhold 2001, fig. 603). Females of the new species are similar to those of U. kinabaluensis . The latter species can be separated from the new species treated here by the strongly convoluted insemination ducts and the more or less globular spermathecae with mesal constriction.

Etymology. The specific epithet, a noun in apposition, is a patronym in honor of His Majesty King Bhumibol Adulyadej the Great of Thailand, also known as King Rama IX, who has served his country with undying dedication. His Majesty is the longest-ruling monarch in Thailand's history and longest-reigning ruler of the world. This new species is described to commemorate the auspicious celebrations of the 60th anniversary of His Majesty’s ascension to the throne in June 2006.

Description. Male (holotype). Total length 4.96 Carapace 2.73 long, 1.90 wide. Opisthosoma 2.97 long, 1.75 wide.

Prosoma ( Fig. 1 ) with not so strong lateral invagination, highest between the PME and the short longitudinal fovea, widest at the midpoint of coxa II. Carapace dark chestnut-brown, cephalic area distinctly reddishbrown; tegument with fine granulation forming radial lines, each granule provided with a white hair ( Fig. 4 ); a series of transverse ridges present in posterior third. Anterior carapace margin with pointed chitinous area projecting between chelicerae ( Fig. 4 ). Chelicerae black; anterior surface rugose ( Fig. 4 ); groove provided with three promarginal and four retromarginal teeth. Sternum heart-shaped, distinctly elevated, covered by numerous fine hairs, protruding between coxae IV; anterior concavities accommodating labium and maxillae; lateral margins rebordered, distinctly elevated, provided with triangular extensions fitting into coxal and intracoxal concavities.

Eight eyes arranged into two rows: AER slightly procurved; PER slightly recurved; PME facing upwards; MOQ longer than wide, wider behind than in front. Eye sizes and interdistances: AME 0.18, ALE 0.20, PME 0.20, PLE 0.23; AME–AME 0.18, AME–ALE 0.30, PME–PME 0.40, PME–PLE 0.45, ALE–PLE 0.25; MOQ 0.58 long, front width 0.54, back width 0.60. Clypeus 0.15 high.

Legs without strong, erect spines; ventral cusps absent; ventral metatarsal preening brush distinct on legs I & II; 1/3 of anterior tibiae provided with dense group of white hairs. Coxae and trochanters orange-brown; the remaining leg articles of legs I and II brown, legs III and IV yellowish. Leg formula (from longest to shortest) 1–4–2–3.

Leg measurements:

Opisthosoma ( Fig. 1 ) ovate, clothed with sparse black pubescence. Dorsum of opisthosoma with two pairs of sigilla; dorsal scutum diamond-shaped, lightly sclerotized, occupying half of opisthosomal length.

Male palp ( Figs 10–17 ): Palpal tibia with retrolateral tibial apophysis (RTA) broad at base, gradually narrowing towards its tip when viewed from retrolateral side ( Figs 13 , 17 ); pointing laterally, with anterior margin slightly concave, the apex bearing a small, sharply pointed apical hook, when viewed from ventral ( Figs 11 , 15 ) and dorsal ( Figs 10 , 14 ) sides. Tegulum (T) longer than wide, distal part membranous, basal part sclerotized ( Figs 11–13 , 15–17 ); sperm duct (SD) one-looped, U-shaped when viewed from ventral side ( Figs 11 , 15 ); subtegulum (ST) strongly sclerotized, elongate oval, clearly visible in prolateral view ( Figs 12 , 16 ). Embolus (E) coiled, originating on top of tegulum, visible as a transverse distal band, filiform embolic tip resting in distal cymbial alveolus ( Figs 11 , 15–17 ).

Female (paratype) ( Figs 2, 3 , 5–9 , 18, 19 ). Total length 6.30 Carapace 3.02 long, 2.15 wide. Opisthosoma 3.28 long, 2.63 wide.

As the male but larger in size ( Figs 2, 3 ); carapace dark chestnut-brown, with orange-brown cephalic area ( Fig. 3 ); legs uniform orange-brown, coxae of anterior legs and proximal part of all femora slightly darker, the remaining leg articles yellow; dorsum of opisthosoma dark green. Palpal tarsus club-shaped ( Fig. 3 ), with a long apical spine.

Eye sizes and interdistances: AME 0.18, ALE 0.20, PME 0.20, PLE 0.22; AME–AME 0.18, AME–ALE 0.30, PME–PME 0.38, PME–PLE 0.42, ALE–PLE 0.24; MOQ 0.56 long, front width 0.52, back width 0.57. Clypeus 0.13 high.

Leg measurements:

Epigyne and its internal structures ( Figs 7–9 , 18, 19 ): Epigyne with posteriorly located atrium (A); copulatory orifices (CO) semi-lunar in shape, connected to rather short insemination ducts (ID) running to anterior portion of bursae, straight and thin, leading to strongly sclerotized, reniform spermathecae (SP), located posteriorly, forming anterior margin of genital atrium; fertilization ducts (FD) thin, branching off a structure outlining lateral borders of atrium.

Natural history. Deeleman-Reinhold (2001) suggested that different color patterns are important in different ecological circumstances and she identified two syntopic eco-morphs: uniformly dark brown species can be found on the ground, while those with a lighter carapace are collected in the foliage. It is interesting to note that we obtained only juveniles (greenish colored specimens) by sweeping and beating bushes. The majority of mature females (dark brown colored specimens) were trapped in pitfalls and another female was collected by sifting decomposing leaf litter. The separation of microhabitats inhabited by U. rama sp. n. is thus quite clear: mature females (also males?) live on the forest floor while immature spiders can be found foraging in the lower foliage layers.

Distribution. Utivarachna rama sp. n. inhabits pristine evergreen forests in the Doi Inthanon National Park (between 1610 and 2550 m). Results from a previous spider survey in the Doi Inthanon National Park showed that the distribution of this new species ranges from 1610 to 2430 m elevations ( Dankittipakul, 2002). The material examined for the present study confirms the broad altitudinal distribution of Utivarachna rama sp. n.

Figures

FIGURES 1 – 4. Utivarachna rama sp. n., male holotype (1, 4) and female paratypes (2, 3). Habitus, dorsal view (1 – 3). Carapace, frontal view showing eye arrangement (4). Scale lines = 1.0 mm.

FIGURES 5 – 9. Utivarachna rama sp. n., female paratypes (5 – 9). Prosoma, dorsal view (5). Ditto, ventral view (6), showing mouth parts, labium and sternum, as well as part of the opisthosoma. Epigynes of three female paratypes (7 – 9). Scale lines = 1.0 mm (5, 6) and 0.25 mm (7 – 9).

FIGURES 10 – 13. Utivarachna rama sp. n., male holotype. Male palp, dorsal (10), ventral (11), prolateral (12) and retrolateral (13) views. Scale line = 0.50 mm.

FIGURES 14 – 19. Utivarachna rama sp. n., male holotype (14 – 17) and female paratype (18, 19). Male palp, dorsal (14), ventral (15), prolateral (16) and retrolateral (17) views. Epigyne, ventral view (18) and its internal structures, dorsal view (19). Abbreviations: A, epigynal atrium; BS, anterior bursa; CO, copulatory orifice; E, embolus; FD, fertilization duct; ID, insemination duct; RTA, retrolateral tibial apophysis; SD, sperm duct; SP, spermatheca; ST, subtegulum; T, tegulum. Scale line = 0.50 mm (14 – 17) and 0.25 mm (18, 19).