Papillacarus (Papillacarus) retinervius Ren & Yang & Liang & Xie 2018, sp. nov.

Descriptions of Papillacarus (Papillacarus) retinervius sp. nov.

(Figs 1–10)

Diagnosis. Body size: 667–684×328–342. Rostrum truncate in dorsal view, bulging anteriorly in ventral view. Surfaces of prodorsum and notogaster covered with polygonal network sculpture. Prodorsal, notogastral (except short and smooth c 1, c 2, d 1, d 2, e 1, e 2, f 1, h 1, p 1) setae setiform, with short cilia, and thin, smooth apex, neotrichal setae setiform, short and smooth. Transverse bands absent on notogaster surface. Bothridial seta pectinate, with 10 branches. Epimeral setal formula: 10-8-4-3. Genital setae (except smooth g 10), setiform, with short cilia. Anal and adanal seta setiform, barbed bilaterally.

Descriptions. Measurements. Body length 672 (holotype), 667–684 (83 paratypes); body width 332 (holotype), 328–342 (83 paratypes).

Integument. Body yellow-brown. Surfaces of prodorsum and notogaster covered with polygonal network sculpture.

Prodorsum (Figs 1–3). Rostrum truncate in dorsal view. All prodorsal setae setiform, with short cilia, smooth apex. Rostral seta (ro, 83), lamellar seta (le, 90), interlamellar seta (in, 117), posterior exobothridial seta (exp, 146) longer than others, anterior exobothridial seta (exa, 96) barbed bilaterally. Bothridial seta (bs, 130) pectinate, with 10 branches on one side, and four barbs on the opposite side. Postbothridial transverse band (S b) between bothridia.

Notogaster (Figs 1–3). Transverse bands absent on notogaster. Sixteen pairs of primary notogastral setae of two types: 7 pairs long c 3 = d 3 = h 3 = p 2 = p 3, (116–128); f 2 = h 2, (94–102) and 9 pairs short c 1 = c 2, (21–28); d 1 = d 2 = e 1 = e 2 = f 1 = h 1 = p 1, (12–16), and 20–21 pairs of additional neotrichal setae also present, all setiform, short and smooth. Setae c 1, c 2, d 1, e 1, and f 1 not reaching margin of notogaster. Neotrichal lyrifissures ia, im, ip, ih distinct, ia laterally to seta c 3, ip anterolaterally to f 2, ih laterally to h 3, ips not distinct.

Gnathosoma (Figs 2, 4–6). Subcapitulum longer than wide (147–163×104–113). Subcapitular setae h, m 2 and m 3 (12–20) setiform, ciliate; a (33) and m 1 (26) setiform, smooth. Adoral setae smooth: or 1 (23) more or less triangular, wide in proximal part, blunt-ending; or 2 (30) long, setiform, pointed-ending; or 3 (25) long, setiform, pointed-ending. Palp (53) with setal formula 0-1-0-3-10(+1ω). Chelicera (214) with two setae, seta cha (18) short, thorn-like, seta chb (48) long, setiform and smooth.

Epimeral region (Fig. 2). Epimeral plates distinct, with partly distinct ridge; epimeral setae setiform, setae 1a, 2a, 2d, 3a, 4a, and one pair of lateral setae on epimere I smooth; other setae ciliate. Epimeral setal formula 10-8-4-3.

Anogenital region (Figs 2–3). Ten pairs of genital setae, setiform, with short cilia (except smooth g 10), four setae in outer row and six in inner row, setae g 8 longer (35–38) than others (12–24). Two pairs of anal setae (27–39), setiform, barbed bilaterally. Four pairs of adanal setae (41–72), setiform, barbed bilaterally. Lyrifissure iad distinct.

Legs (Figs 7–10). All legs with one simple claw each with small basoventral tooth. Famulus ɛ conical and short, posterior to solenidion ω1. Solenidion ω1 on tarsus I, ω1 and ω2 on tarsus II, φ on tibia III thickened and blunt distally. Other solenidia setiform, with thinner tips. Formulae of leg setation and solenidia: I 0-6-3(2)-4(1)-17(2), II 0-7-3(1)-5(1)-13(2), III 2-4 -2(1)-3(1)-10(0), IV 2-3 -2(1)-3(0)-10(0) (see Table 1).

Note: Roman letters for normal setae, Greek letters for solenidia, except ɛ to famulus, d φ–seta and solenidion coupled. Single prime (′) marks setae on anterior and double prime (″) setae on posterior side of the given leg segment. Parentheses refers to a pair of setae.

Material examined. Holotype, Haikou City (19°44’N, 110°14’E), Hainan Province, 23 Apr. 2017, leg. Yaowen Zhang, in soil. Eighty three paratypes, same data as holotype. No obvious morphological variation detected. No juveniles found.

Type deposition. The holotype and all paratypes are deposited in the Institute of Entomology, Guizhou University, Guiyang of China (GUGC).

Etymology. The new specific name “ retinervius ” is derived from the Latin “ retinervius ”, and refers to the prodorsum and notogaster surface covered with polygonal network sculpture.

Remarks. The new species Papillacarus (P.) retinervius sp. nov. is morphologically most similar to Papillacarus (P.) polygonatus (Ermilov & Anichkin, 2011) from Vietnam in having setiform prodorsal and notogastral setae. However, the new species differs from the latter by the following characterstics: (1) 20–21 pairs of additional neotrichal setae (versus approximately 12–16 pairs in P. polygonatus); (2) seta in shorter than exp (versus seta in longer than exp); (3) setae d 2, e 2, h 1, p 1 shorter, as long as d 1 (versus setae d 2, e 2, h 1, p 1 longer, more than 3 times the length of d 1); (4) epimeral setal formula 10-8-4-3 (versus 8-5-3-4).

The new species Papillacarus (P.) retinervius sp. nov. is morphologically also similar to Papillacarus (P.) indistinctus (Ermilov, Anichkin & Wu 2012), also known from the Oriental region (Vietnam, Cambodia) in having setiform prodorsal and notogastral setae. However, the new species differs from the latter by the following characterstics: (1) 20–21 pairs of additional neotrichal setae (versus 14–16 pairs P. indistinctus); (2) seta c 2 similar in length to c 1 (versus c 2 more than 4 times the length of c 1); (3) setae d 2, e 2, h 1, p 1 shorter, as long as d 1 (versus setae d 2, e 2, h 1, p 1 longer, more than 4 times the length of d 1); (4) epimeral formula 10-8-4-3 (versus 7-5-3-4).