Papillacarus indistinctus, Ermilov, Sergey G., Anichkin, Alexander E. & Wu, Donghui, 2012

Ermilov, Sergey G., Anichkin, Alexander E. & Wu, Donghui, 2012, Two new species of the genus Papillacarus (Acari: Oribatida: Lohmanniidae) from caves of Southern Vietnam, Zootaxa 3593, pp. 75-88 : 79-83

Papillacarus indistinctus sp. nov.

( Figs. 1–22 )

With characters of Papillacarus as summarized by Balogh (1961), Balogh & Balogh (1992).

Diagnosis. Body size 763–813 × 365–398. Surface of body foveolate. Rostrum weakly concave. Prodorsal, notogastral (except short and smooth c 1, d 1, e 1, f 1), anal and adanal setae long, setiform, ciliate. Sensilli with 13 to 15 branches. One transverse band (S 2) developed on notogaster. Two pairs of neotrichal setae morphlogically similar to lateral notogastral setae; others short, setiform, ciliate. Subcapitulum with five pairs of setae. Palptarsus with 10 setae. Sternal apodeme fused with apodemes III. Epimeral setal formula 7–5–3–4. Transverse genital suture poorly developed. Genital setae heterogenous, all ciliate.

Description. Measurements. Large species. Body length 813 (holotype), 763–813 (mean 785; three paratypes); body width 381 (holotype), 365–398 (mean 381; three paratypes).

Integument ( Figs. 1, 2 , 7). Body color yellow-brownish. Surface of body foveolate. Foveolae of two types: a) large, polygonal, forming polygonal network on prodorsum, notogaster, lateral part of body and anogenital region (length up to 16); b) very small (distinctly visible only under high magnification), polygonal, located on all surfaces of body, also forming polygonal network of very small foveolae on all surfaces of body and legs.

Prodorsum ( Figs. 1, 3–6 ). Roughly triangular in dorsal view, occupying about 2/3 of dorsal length. Rostrum weakly concave in dorsal view. Rostral (ro), lamellar (le), interlamellar (in) and both pairs of exobothridial (exa, exp) setae similar: long (123–131), setiform, thickened, with short cilia. Sensilli (98–106) pectinate, with 13 to 15 branches on one side. Postbothridial transverse band (S b) present, but poorly visible.

Notogaster ( Figs. 1, 2 , 8–11). Anterior border of the notogaster straight. Only one transverse band (S 2) developed, complete. Sixteen pairs of primary notogastral setae and 14–16 pairs of additional neotrichal setae (n) present. Notogastral setae c 1, d 1, e 1, f 1 short (24–32), setiform, smooth; others long (131–153), setiform, thickened, with short cilia. Neotrichal setae of two types: two pairs morphlogically similar to notogastral setae; others short (36–49), setiform, ciliate. Lyrifissures ia and im distinct.

Gnathosoma ( Figs. 18, 19 ). Subcapitulum with one pair of lateral tubercles. Subcapitulum longer than wide (196–209 × 143–151). Subcapitular setae h, m 1, m 2 and m 3 short (32–36), setiform, with cilia; setae a longer (49–57), setiform, smooth. Three pairs of adoral setae present: or 1 36–41, wide, lobe-formed, smooth; or 2 41–45, setiform, thickened, with tooth in distal part, blunt-ended; or 3 32–36, lobe-formed, smooth. Palps (82) with setation 0–1–0–1–10(+1ω). Distal three setae fused basally. Solenidion longer than palptarsus, thick, not fused with acm. Chelicerae 213–225; cheliceral seta chb 65, setiform, smooth; seta cha 8, thorn-like.

Epimeral region ( Figs. 2 , 12, 13). Apodemes III medially fused. Sternal apodeme fused with apodemes III. Epimeral setal formula: 7–5–3–4. Medial setae 1a, 2a, 3a, 4a short (20), setiform, smooth; anteriomost pair longer (45–53), with cilia unilaterally; three pairs of lateral setae on epimeres II (53–61) straight, setiform, ciliate; other setae (28–41) setiform, with cilia unilaterally.

Anogenital region ( Figs. 2 , 14–17). Transverse genital suture present, but poorly developed (visible under high magnification in dissected specimens). Genital setae heterogenous: four lateral pairs longer (45–57), with one to three long cilia; six medial pairs shorter (16–20), ciliate. Two pairs of anal (an 1, an 2 53–57) and four pairs of adanal (ad 1– ad 3 90–106; ad 4 69–77) setae setiform, thickened, with cilia. One pair of ventrolateral bands present. Lyrifissures ih and ip distinct, iad and ips not visible.

Legs ( Figs. 21, 22 ). Morphology of leg segments, setae and solenidia typical for Papillacarus ( Ermilov & Anichkin 2011 f, Ermilov et al. 2011). All legs with one claw, with small tooth on ventral side. Femora with large ventral ridge. Formulae of leg setation and solenidia: leg I (0–6(5)– 3–4–18) [2–1–2], leg II (0– 6 –3–4–13) [1–1–2], leg III (2–4–2–3–12) [1–1–0], leg IV (2–3–2–3–11) [1–0–0]; homology of setae and solenidia indicated in Table 1. Majority of setae ciliate. Setae it on tarsi II, III short, thin, smooth. Famulus conical, small, thickened. Solenidia ω1 on tarsi I, ω1 and ω2 on tarsi II, φ on tibiae III thickened, blunt-ended; other solenidia longer, setiform, with thinner tips.

FIGURES 7–17. Papillacarus indistinctus sp. nov., adult: 7—foveolae of notogaster; 8—notogastral seta d 1; 9—notogastral seta d 3; 10, 11—neotrichal setae; 12—epimeral seta 2a; 13—epimeral seta 2b; 14—genital plate, left; 15, 16—genital setae; 17—anal and adanal plates, left. Scale bar (7, 9) 20 μm; scale bar (8, 10–13, 15, 16) 10 μm; scale bar (14, 17) 50 μm.

I - d, (l 1), l 2 ''*, bv'', v'' (l'), σ', d σ'' (l 1), l 2 '', v', φ (ft), (tc), (it), (p), (u), (a), s, (pv), m, n, e, ω1, ω 2 II - d, (l), bv'', v'' (l), d σ (l 1), l 2 '', v', φ (ft), (tc), (it), (u), (a), s, (pv), ω1, ω 2 III l', v' d, l 1 ', l 2 ', ev' l', d σ d, l', v', φ (ft), (tc), (it), (u), a’, s, (pv)

IV l', v' d, l', ev' l', d σ d, l', v' (ft), (tc), p’, (u), a’, s, (pv)

Roman letters refer to normal setae (e to famulus), Greek letters to solenidia, d σ —seta and solenidion coupled. Single prime (') marks setae on anterior and double prime (") setae on posterior side of the given leg segment. Parentheses refer to a pair of setae.

*—Seta absent in two specimens of Papillacarus indistinctus sp. nov.

Material examined. Collection data for holotype and three paratypes: VC-3.

Type deposition. The holotype (in alcohol) is deposited in the collection of the Zoological Institute of the Russian Academy of Sciences, St. Petersburg, Russia; one paratype (in alcohol) is deposited in the collection of the Siberian Zoological Museum, Novosibirsk, Russia; two paratypes (dissected) are in the personal collection of the first author.

Etymology. The specific name “ indistinctus ” refers to the poorly developed (indistinct) transverse suture on the genital plates.

Remarks. In having the combination of foveolate body surface, absence of body papillae, setiform prodorsal, notogastral and neotrichal setae, few neotrichal setae, and poorly visible transverse suture on genital plates, Papillacarus indistinctus sp. nov. is very similar to Papillacarus polygonatus Ermilov & Anichkin, 2011 (see Ermilov & Anichkin 2011 f) from Vietnam. However, it clearly differs from the latter by two types of neotrichal setae (versus three types in P. polygonatus ), long notogastral setae c 2, which are slightly shorter than c 3 (versus considerably shorter than c 3 in P. polygonatus ), notogastral setae e 1 and f 1 similar in length to c 1 and d 1 (versus shorter in P. polygonatus ), presence of four pairs of long genital setae, all with cilia (versus three pairs present, all smooth in P. polygonatus ), epimeral setal formula 7–5–3–4 (versus 8–5– 3–4 in P. polygonatus ), presence of three pairs of subcapitular setae m (versus two pairs in P. polygonatus ), palptarsus with 10 setae (versus nine setae in P. polygonatus ).

Figures

FIGURES 1 – 6. Papillacarus indistinctus sp. nov., adult: 1 — dorsal view; 2 — ventral view, gnathosoma and legs not shown; 3 — rostrum; 4 — rostral seta; 5 — sensillus; 6 — exobothridial seta exp. Scale bar (1, 2) 200 μm; scale bar (3 – 6) 20 μm.

FIGURES 18 – 22. Papillacarus indistinctus sp. nov., adult: 18 — subcapitulum, left half; 19 — palp; 20 — anterior part of chelicera; 21 — leg I, right, antiaxial view; 22 — leg IV, left, antiaxial view. Scale bar (18, 19) 20 μm; scale bar (20 – 22) 50 μm.