Paktongius paritensis, Klementz & Sharma, 2023

Klementz, Benjamin C. & Sharma, Prashant P., 2023, New species of Paktongius and convergent evolution of the gonyleptoid-like habitus in Southeast Asian Assamiidae (Opiliones: Laniatores), Zootaxa 5389 (1), pp. 34-54 : 44-47

Paktongius paritensis sp. nov.

( Figs. 7–8 , 11 , 12 ; Table 5 )

Type material. Holotype. ♀ ( MHNG), MALAYSIA, Pahang, Cameron Highlands, Tanah Rata, near Parit Falls , 4°28.52’N, 101°23.02’E, ca. 1500 meters, sitting on leaf litter, 26.iv.2009, leg. P. Banar; four legs extracted for DNA, remaining appendages removed and mounted for SEM imaging.

Etymology. The species epithet is referred to the collection locality near Parit Falls in the Cameron Highlands of West Malaysia.

Diagnosis. Distinguished from congeners by the combination of the following characters: (1) dorsal surface of scutal areas I–IV with rings of dark pigmentation that do not cross the dorsal midline (contra solid patches in P. distinctus , P. spiculosus , P. thaiensis ; rings crossing midline in P. furculus ); (2) ventral pigmentation posterior to the genital operculum constituting three discontinuous patches, as a central arrowhead shape and lateral wings; (3) presence of two distinct lines of pigment stretching posteriorly from the ocularium (see Fig. 7a ; contra P. distinctus , P. spiculosus , P. suzukii , P. thaiensis ); (4) presence of two to three enlarged tubercles along the anterolateral margins of the fourth coxae (contra P. spiculosus , P. suzukii , P. thaiensis ); (5) absence of enlarged tubercles on the anal plate (contra P. thaiensis , male P. spiculosus ); (6) tarsal formula: 5: 10: 6: 6.

Description. Female holotype, total length 2.57 mm, greatest width of prosoma 1.27 mm, greatest width of opisthosoma 1.76 mm; length-to-width ratio 1.46. Body pandurate (fiddle-shaped; Fig. 7a ). Body light-brown in color with mottling, densely microgranulate surface microstructure. Eyes present on small ocularium with a single enlarged tubercle abutting the anterior margin of the carapace. Ocularium 0.34 mm long, 0.23 mm wide. Anterior margin of carapace with five pegs (two pairs on lateral margins with outermost longest, one at dorsal midline), typical of Assamiidae . Posterior margin of scutum with two prominent spines flanking midline and projecting posteriorly.

Ventral prosomal complex ( Fig. 7b ) with coxae II and III meeting in midline, coxae I not so. Genital operculum subtriangular. Spiracles not apparent. Coxae IV highly enlarged (typical of Grassatores) with one enlarged tubercle along anterolateral margin and an enlarged tubercle laterally abutting trochanter IV projecting posteriorly. Cuticular projections span the gap between coxa IV and the anterior margin of sternite I, creating a bridge near the distal end of coxa IV. Free tergites smooth. Anal plate unarmed.

Dorsal pigmentation with continuous band of dark pigment along lateral margin of the carapace; two solid patches of pigment flanking anterior-posterior axis immediately posterior to the ocularium and meeting in the midline; two arcuate patches of pigment toward posterior-lateral margin of the prosoma; prominent and complex arcs of pigmentation on scutal areas I–IV overlapping the midline; pegs at anterior margin of carapace indistinctly mottled; and spines on scutal area V pigmented. Ventral pigmentation prominently flanking ventral midline of opisthosomal segment II and the posterior margins of the leg IV coxae, creating slender and non-contiguous winged shapes with prominent anterior projection. Leg IV coxae also with lighter bands of pigment extending posteriorly to the junction of the leg IV trochanter and at the distal margin of coxae III. Pigmentation of opisthosoma present along ventral midline of sternites and complex wing-shaped pigmentation pattern on segment anterior to anal plate.

Chelicerae ( Fig. 8a ) with prominent bulla on proximal article. Proximal article with denticulate granulation throughout basal territory. Article sparsely setose. Second article not incrassate, smooth, free of ornamentation. Several prominent setae along the length of the dorsal territory and along margin of distal article. Distal article with delicate dentition, free of ornamentation. Pedipalps ( Fig. 8b, 8c ) spoon-shaped and folded over chelicerae. Pedipalpal trochanter slender with two prominent setose tubercles at ventro-distal margin. Femur ventrally with a series of seven small, adjacent tubercles, lacking megaspines, restricted to proximal-most territory, and two additional disjunct tubercles midway along ventral surface. Femur dorsally with small setose tubercles toward distal end. Pedipalpal tibia with two large spines, one ventrally oriented at apex of prominent triangular projection, other dorso-laterally oriented. Pedipalpal tarsus with unornamented tarsal claw and four megaspines. Tarsal claw 0.27 mm long. Tarsus sparsely setose, with four megaspines ventro-distally, two flanking each side of the claw. Legs I–IV ( Fig. 8d–g ) slender, elongate, finely granulated, and with setiferous tubercles roughly arranged into rows along femora, patellae, tibiae, and metatarsi. Tarsal claws I–IV smooth, unmodified, double claws on legs III and IV (typical of Grassatores). Legs III and IV with tarsal process ( Fig. 11c ). Tarsal formula 5: 10: 6: 6.

Male: Unknown.

Distribution. Known only from the type locality ( Fig. 12 ).

Figures

FIGURE 7. Paktongius paritensis sp. nov. Female holotype, dorsal view (a). Female holotype, ventral view (b). Scale bars: 1.0 mm.

FIGURE 8. Paktongius paritensis sp. nov. Appendages are presented in ectal view unless otherwise indicated. Left chelicera of female holotype (a). Left pedipalp of female holotype (b). Right pedipalp of female holotype, mesal view (c). Left leg I of female holotype (d). Left leg II of female holotype (e). Left leg III of female holotype (f). Left leg IV of female holotype (g). Scale bars: 400 µm (a), 500 µm (b–c), 1 mm (d), 2 mm (e–g).

FIGURE 11. Condition of the leg IV tarsal process in all newly described Paktongius species. Paktongius suzukii sp. nov., left leg IV of female paratype (a). Paktongius spiculosus sp. nov., left leg IV of male paratype (b). Paktongius paritensis sp.nov., left leg IV of female holotype (c). Paktongius furculus sp. nov., left leg IV tarsus of female holotype (d). Location of tarsal process indicated by white arrowheads. Scale bars: 100 µm.

FIGURE 12. Distribution of Paktongius species in the Thai-Malay Peninsula. Icons correspond to the following species: star: Paktongius suzukii sp. nov.; circle: Paktongius spiculosus sp. nov.; square: Paktongius paritensis sp. nov.; triangle: Paktongius furculus sp. nov.; pentagon: Paktongius distinctus Suzuki, 1969; ten-pointed star: Paktongius thaiensis (Suzuki, 1985) comb. nov.