Pygmarrhopalites trisetosus Vargovitsh, 2025, sp. nov.

Pygmarrhopalites trisetosus sp. nov. urn:lsid:zoobank.org:act: F454BDA0-432C-40DD-8D40-D5FAE6A510AF Figs 7–11, Tables 1–2, 4 Diagnosis. Body length up to 1.4 mm. Diffuse reddish pigmentation. Eyes 1 + 1, indistinct, covered by granulated cuticle and with diffuse reddish pigmentation. Dorsal head setae not spine-like, 3 axial setae present. Antenna 2.8× head length; Ant IV with 6 subsegments and 13 whorls of setae; several intercalary pseudosubsegments without setae inserted between normal subsegments. Trochanters I, II, III with 4, 5, 5 setae, respectively. Femora I, II, III with 11, 13, 12 setae, respectively. Claws slender, without tunica; claw I without inner tooth (or with extremely reduced one), claws II–III with distinct inner tooth. Empodia short, without apical filaments, tips not reaching claw tip; empodia I and II with small corner tooth, empodium III without tooth. Manubrium with 6 + 6 setae. Dens with 15 (rarely 14) posterior setae, including Ie as blunt spine, IIpe as moderate spine with pointed apex, Ii weakly spine-like and setaceous. Mucro with spoon-like broadened tip; ~40–45 small teeth on posterior inner lamella, ~30 on outer lamella. Trichobothria ABC forming ~150° angle, AB <BC. Abd VI in female with regular, not broadened circumanal setae, sometimes weakly denticulate basally; dorsal valve with 10 + 2 axial + 10 setae (ms5 absent); each lateral valve with 18 setae (mi1 absent). Appendices anales palmated in distal quarter. Member of the Pygmarrhopalites principalis species group (sensu Bretfeld 1999). Type material. Holotype: slide C-1076a-6 (Fig. 10A), female, W Caucasus, Abkhazia, Gagra Mt. R., Arabika Massif, 2,266 m a.s.l., Sirota Cave, - 22 m, 6.ix.2017, R.S. Vargovitsh leg. Paratypes (2 males, 6 females on slides): 2 males (C-1081a-7, C-1081a-8), 6 females (C-1081a-2, C-1081a-3, C-1081a-4, C-1081a-5, C-1081a-6; one dissected and mounted in 3 slides: C-1081a-1-1: head and leg I; C-1081a-1- 2: legs and great abdomen; C-1081a-1-3: Abd VI and furca), W Caucasus, Abkhazia, Gagra Mt. R., Arabika Massif, 2,354 m a.s.l., Nadezhda Cave, -20 to - 25 m, on liquid surface of Barber traps, exposed 13.vii.2016 – 08.ix.2017, R.S. Vargovitsh leg. The holotype and 8 paratypes are deposited in the collection of the Schmalhausen Institute of Zoology, National Academy of Sciences of Ukraine, Kyiv. Description. Female: Body measurements and ratios in Tables 1 and 2. Maximum body length without appendages 1.4 mm. Pigmentation in alcohol slightly reddish (Fig. 10A). Head (Figs 7A, 10B). Eyes 1 + 1, relatively large (~16 μm) but indistinct, poorly defined cornea covered by almost typical cuticular granulation (Fig. 10B). Clypeal area with six rows of setae, and median region M with 2 setae; row a: 4 +1 axial + 4 setae; rows b, c, e: 5 + 5; rows d, f: 6 + 6. Interantennal area: row α: 2 + 2; row β: 1 + 1 axial + 1. Frontal area: rows A, D: 2 + 2; row B: 1 + 1 axial + 1; row C: 2 + 1 axial + 2; all setae of frontal area slender; longest (median pair of D -row) slightly thicker (Fig. 8D), ~2× shorter than longest abdominal seta dI-1 (Table 2). Head dorsum with 3 axial setae: A0 (as in Fig. 7A) or C0 (as in Fig. 10B) absent. Chaetotaxy of ventral side as in Fig. 7A (dashed-line setae). Chaetotaxy of mouth region. Labrum (Fig. 7A, C): labral / prelabral chaetotaxy 4, 5, 5 / 6. Labium: basomedian field with 4 setae, basolateral field with 5 setae. Labial palp (Fig. 7B): 5 proximal setae, 5 papillae (A, B, C, D, E) each with long deeply embedded terminal sensillum; 13 guard setae (a1, b1–b4, d1–d4, e1–e4), a1 blunt and Ƨshaped; lateral process (l. p.) in papilla E short, pointed; 3 hypostomal setae (H, h1, h2); papilla B with accessory papilla. Maxillary head as in Fig. 10G. Maxillary outer lobe (Fig. 7C) with 2 setae, including long apical seta with short and thin basal branch, sublobal plate with 3 sublobal hairs. Oral fold with 2 setae. Antenna (Figs 7D, 10C–F) ~2.8× head length, 0.92× total body length. Mean segment length ratio I / II / III / IV = 1 / 3.0 / 5.2 / 12.4. Total number of setae: 166. Ant I with 7 setae, p as microseta (8 μm). Ant II: 15 setae, two anterior setae longer (mean 75 μm). Ant III: 15 simple setae, 5 special setae in apical region (Fig. 10E–F): Api and Ape thinner and shorter than simple setae; 2 sense rods (Ant III organ) (mean 10.2 μm) in shallow pit; Aai as small (7 μm) blunt sensillum. Ant IV subdivided into 6 subsegments. Basal subsegment separated from median by intercalary pseudosubsegment lacking setae as well as 3 median subsegments from each other (Figs 7D, 10C). Three apical subsegments separated from each other by simple suture (Figs 7D, 10C). Subsegmental formula: 1 + 4 + 1. Ant IV with 124 setae in 13 whorls: 4 on apical subsegment (AI–AIII + M1: 33 setae), 4 on median subsegments (M2–M5: 60 setae), 5 on basal subsegment (BA + BM1–BM3 + BB: 31 setae). Each middle subsegment with 12 setae (7 ordinary + 5 thin H -setae or 8 ordinary + 4 H -setae). Chaetotaxy of whorl BA resembles that of M -whorls, with 8 ordinary setae and 4 H -setae. Apical subsegment, besides regular setae, with 4 H -setae, hooked AIIpe seta, knobbed and deeply embedded subapical organite, mossy microseta AIp, and 11 ordinary microsetae at tip (Fig. 7D). Legs. Foreleg (Figs 8A, 10I): precoxae 1, 2 and coxa with 1, 0, 1 setae, respectively (Fig. 9A). Trochanter with 4 setae; i2 strongly curved. Femur with 11 setae; a4 slightly thickened (Fig. 8F), oriented perpendicularly to segment axis; p1 and p3 much thinner than other setae; p1 as microseta about twice shorter than p3. Tibiotarsus with 44 setae; tibiotarsal formula: 9, 8, 8, 8, 7, 4 (from apex to base); Ja of distal whorl I curved, not spine-like; region F with secondary FSa seta present. Pretarsus with single anterior microseta lager than posterior one. Foot complex (Figs 8A, 10I). Claw: slender (max. 80 μm), without tunica, without or with vestigial inner tooth, with two pairs of barely visible lateral teeth; ~5.3× (mean) shorter than tibiotarsus. Empodium: thin, with small corner tooth; ~1.7× shorter than claw (max. 52 μm); tip of empodium far not reaching claw tip. Midleg (Figs 8B, 10J): precoxae 1 and 2 with 1, 1 setae, respectively; precoxal process present; coxa with 3 setae and spine-like microsensillum. Trochanter with 5 setae, a1 as trochanteral organ (Fig. 10H). Femur with 13 setae; p1 and p3 as thin, short microsetae. Tibiotarsus with 44 setae; tibiotarsal formula: 9, 8, 8, 8, 7, 4 (from apex to base); Ja of distal whorl I not modified. Pretarsus with single anterior microseta somewhat larger than posterior one. Foot complex (Figs 8B, 10J). Claw: slightly broader and subequal in length to foreclaw (max. 80 μm), without tunica, with distinct inner tooth and two pairs of lateral teeth; ~5.4× (mean) shorter than tibiotarsus. Empodium: broader and shorter than in foreleg, with corner tooth; ~1.7× shorter than claw (max. 48 μm); empodial filament not developed, empodial tip far from reaching claw tip. Hindleg (Figs 8C, 10K): precoxae 1 and 2 each with 1 seta; process on precoxa 1 present, coxa with 3 setae and spine-like microsensillum. Trochanter with 5 setae; a1 as trochanteral organ. Femur with 12 setae; p1 and p3 very thin, short microsetae. Tibiotarsus with 45 setae; tibiotarsal formula: 9, 8, 8, 8, 8, 4 (from apex to base); Ja of whorl I slightly thickened. Pretarsus with 1 anterior microseta somewhat larger than posterior one. Foot complex (Figs 8C, 10K). Claw: shorter and broader than in fore- and midlegs (max. 69 μm), without tunica, with distinct inner tooth and two pairs of lateral teeth; ~7.4× (mean) shorter than tibiotarsus. Empodium: broad, untoothed, shaped as in Fig. 10K; 1.5–1.6 × shorter than claw (max. 44 μm); lacking apical filament, with tip far from reaching claw tip. Length ratio of tibiotarsi I / II / III = 1 / 1/ 1.17. Length of tibiotarsus I subequal to head. Ventral tube (Fig. 9A) with 1 + 1 subapical microsetae (9 μm) on lateral flaps. Tenaculum (Figs 9C, 11I): each ramus with 3 teeth and basal process; anterior lobe with 2 apical setae. Furca (Figs 9B, 11C–H). Manubrium with 6 + 6 posterior setae. Dens with 22(21) setae: 15(14) posterior (IIIpi variable); 7 anterior, formula (apex to base): 3, 2, 1,…1. Posterior side: Ie as blunt spine on projection (Figs 8M, 11G); IIpe as moderate spine with sharply pointed setaceous apex (Fig. 8N); Ii basally thickened (Figs 8O, 11H); others unmodified (Fig. 9B); IIIpi variable, absent in 50% of individual dentes; IVpi absent. Mucro (Figs 9B, 11C– F): inner posterior lamella with 40–45 teeth, outer with 30–35 teeth; anterior lamella smooth, moderately developed; tip spoon-like, distinctly broadened. Dens 1.9–2× mucro length, ~1.3× (rarely 1.2×) manubrium length. Great abdomen (Figs 9A, 11A). Th II with single small sensillum (7 μm) in row a; 3 setae in row m, with m1 unmodified (Fig. 8E), ~3× shorter than most posterior setae of posterior dorsal complex (Fig. 8G). Th III with sensillum in row a (17.5 μm) and 3 setae in row m. Anterior part of abdomen: row a with 5 short setae followed by row m with 4 short setae anterior to trichobothrial complex. Trichobothrial complex (Figs 9A, 11A): ABC forming very obtuse angle (~150°); AB ~1.5× shorter than BC; seta p located below level of B; b1 on line BC, midway between B and C; c1 as ordinary seta (~28 μm, not microseta), in front of C; c2 below C. Posterior lateral complex with 5 setae in two rows (2 + 3). Furca base complex with 9 setae in two rows (5 + 4); neosminthuroid seta absent. Central dorsal complex with seta 2 little longer than 1 and 3. Posterior dorsal complex with ~20 long setae in 3 longitudinal rows (dI: 8, dII: 7, dIII: 5); longest (posteriormost in rows dI–dIII) = 87–105 μm (Fig. 8G), ~1.5× longer than hind claw (Table 2). Ventral complex with 2 or 3 setae. Small abdomen. Abd V (Fig. 9A) with 2 setae and trichobothrium D in row a (a2 distinctly thinner and shorter than a1), and 2 setae in row p. Genital field with 4 + 4