Paktongius suzukii, 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 : 36-40

Paktongius suzukii sp. nov.

( Figs. 1–3 , 11 , 12 ; Tables 1–2 )

Paktongius n. sp. 1, Palmieri et al. 2023

Type material. Holotype. ♂ ( MHNG TH-11/05 ) THAILAND, Surat Thani Prov., Ko Samui, Nathon Distr., Hin Lad Waterfall (9°31’15” N, 99°57’47”E), 100 m, primary forest near stream, 5– 6 VII 2011, leg. P.J. Schwendinger. Genitalia and appendages dissected and mounted for SEM. One leg III extracted for DNA by Palmieri et al. (2023) .

Paratypes. 1 ♂ ( UWZM Y.40170 ) , 1 ♀ ( UWZM Y.40169 ), same collecting data as holotype; appendages dissected and mounted on SEM stubs . 2 ♀ ( MHNG TH-11/05 ), same collecting data as holotype .

Additional material studied. 1 subadult male ( MHNG TH-11/05 ), same collecting data as holotype .

Etymology. The species epithet is a patronymic in honor of the late Seisho Suzuki, who described the genus Paktongius , its type species, P. distinctus , and P. thaiensis (as Mysorea thaiensis ).

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 winged shape with median anterior projection; (3) absence of two distinct lines of pigmentation extending posteriorly from the ocularium (contra P. furculus , P. paritensis ); (4) absence of enlarged spines on the anal plate (contra P. spiculosus , P. thaiensis ); (5) absence of enlarged tubercles along the anterolateral margins of the fourth coxae (contra P. distinctus , P. thaiensis ); (6) tarsal formula 5: 9: 6: 7. Males additionally distinguished from congeners by genitalia with four pairs of lateral setae ( P. spiculosus , P. thaiensis with five pairs; male P. distinctus unknown) and absence of paired cuticular projections dorso-apically (contra P. spiculosus ).

Description

Total length of male holotype (female paratype in parentheses) 2.95 mm (2.92 mm), greatest width of prosoma 1.46 mm (1.44 mm), greatest width of opisthosoma 2.77 mm (2.64 mm); length-to-width ratio 1.06 (1.11). Body either campaniform with rounded posterior margin (holotype) or campaniform with sub-rectangular posterior margin (female) ( Fig. 1a, 1c ). Body reddish brown in color with darker mottling (in alcohol, depending on incidence of light), almost entirely with a dense microgranulate surface microstructure. Eyes present on small, unornamented ocularium that is set back from anterior margin of the carapace. Ocularium 0.29 mm (0.37 mm) long, 0.30 mm (0.35 mm) wide. Anterior margin of carapace with five pegs (two pairs on lateral margins, one at the dorsal midline), typical of Assamiidae . Scutal grooves of mesotergum indistinct. Posterior margin of carapace with two prominent spines flanking midline and projecting posteriorly. Free tergites granulated, unarmed.

Ventral prosoma complex ( Fig. 1b, 1d ) of male and female, with coxae II and III meeting in midline, coxae I not so. Genital operculum subtriangular in male, elliptical in female. Spiracles not apparent. Coxae IV of both male and female massively enlarged (for Grassatores). Anal plate unarmed.

Dorsal pigmentation of male with continuous band of pigment along lateral margins of the carapace; rings of dark pigmentation immediately posterior to ocularium; variable wing-shaped patches of pigmentation on scutal areas I–IV; and dark patches of pigmentation abutting pedipalpal coxae. Ventral pigmentation of male indistinct except along ventral midline of opisthosomal segment II (between coxae IV), lateral margins of coxae IV, and flanking the midline at the posterior of coxae IV. Darker pigmentation flanking midline of anal plate. Female with comparable pigmentation dorsally, but richer patterns of mottling on ventral surface; pigmentation most prominent along midline of opisthosomal segment II and posterior margins of coxae IV.

Chelicerae ( Fig. 2a , 3a ) sexually monomorphic, with prominent bulla on proximal article. Proximal article with denticulate granulation basally and ventrally. Second article not incrassate, free of ornamentation, with dorsal and latero-distal margin bearing several setae. Distal article with delicate dentition, free of ornamentation. Pedipalps ( Fig. 2b–c , 3b–c ) spoon-shaped and folded over chelicerae. Pedipalpal trochanter slender with two setose tubercles at ventro-distal margin. Pedipalpal femur ventrally with eight small tubercles, lacking megaspines and located in proximal half of femur; dorsally with small setose tubercles distally. Pedipalpal tibia with a single, ventrally oriented spine. Spine length 0.20 mm (0.25 mm). Pedipalpal tarsus with two small ventral spines, four megaspines, and unornamented tarsal claw. Legs I–IV ( Fig. 2d–g ) slender, elongate, finely granulated, with small and irregularly distributed setiferous tubercles on femora, patellae, tibiae, and metatarsi. Male leg IV with more prominent setiferous tubercles in the patellae and tibiae, and two prominent spines in distal margin of trochanter. Tarsal claws I–IV smooth, unmodified, double claws on legs III and IV (typical of Grassatores). Legs III and IV with tarsal process ( Fig. 11a ). Tarsal formula 5: 9: 6: 7.

Male genitalia ( Fig. 2h–i ) typical of Assamiidae , with two dorsal setae distally; four pairs of setae on lateral margins of ventral plate; and three pairs of setae on ventral plate.

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

Figures

FIGURE 1. Paktongius suzukii sp. nov. Male holotype, dorsal view (a). Male holotype, ventral view (b). Female paratype, dorsal view (c). Female paratype, ventral view (d). Scale bars: 1.0 mm.

FIGURE 2. Paktongius suzukii sp. nov. Appendages are presented in ectal view unless otherwise indicated. Left chelicera of male holotype (a). Right pedipalp of male holotype, mesal view (b). Left pedipalp of male holotype (c). Left leg I of male holotype (d). Left leg II of male holotype (e). Left leg III of male holotype (f). Left leg IV of male holotype (g). Genitalia of male holotype, dorsal view (h). Genitalia of male holotype, ventral view (i). Scale bars: 500 µm (a–c), 1 mm (d, f), 2 mm (e, g), 100 µm (h–i).

FIGURE 3. Paktongius suzukii sp. nov. Appendages are presented in ectal view unless otherwise indicated. Left chelicera of female paratype (a). Left pedipalp of female paratype (b). Right pedipalp of female paratype, mesal view (c). Left leg I of female paratype (d). Left leg II of female paratype (e). Left leg III of female paratype (f). Left leg IV of female paratype (g). Scale bars: 500 µm (a–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.