Two new species of Lohmanniidae, Papillacarus (Papillacarus) internus sp. nov. from soil in Hainan Province, South China and Papillacarus (Vepracarus) hexagonus sp. nov. from rotten tree and soil in Chongqing City, Southwest China are described and illustrated. Papillacarus (P.) internus sp. nov. is most similar to Papillacarus (P.) lienhardi (Mahunka, 1997), however, it can be distinguished from the latter by the following characters: 29–30 pairs of additional neotrichal setae, seta c1 shorter than c2, all genital setae setiform and smooth. Papillacarus (V.) hexagonus sp. nov. is most similar to Papillacarus (V.) gueyeae (Pérez-Íñigo, 1989), however, it can be distinguished from the latter by the following characters: 38 pairs of additional neotrichal setae, 7 pairs of subcapitula setae, epimeral formula 9-4-3-4.
Introduction
In this paper we describe two new species of Lohmanniidae: Papillacarus (Papillacarus) internus sp. nov. from soil in Hainan Province, South China, and Papillacarus (Vepracarus) hexagonus sp. nov. from rotten tree and soil in Chongqing City, Southwest China.
The oribatid mite genus Papillacarus was proposed by Kunst (1959) with Lohmannia murcioides aciculata Berlese, 1905 as type species. Currently, Papillacarus comprises 37 species in the two subgenera Papillacarus and Vepracarus, which are distributed in tropical regions (Subías 2004, online version 2018). The main generic characters of Papillacarus are the following: genital plates with transverse suture, anal and adanal plates separated, preanal plate narrow, two pairs of adanal setae present, notogastral setae setiform, branched or ciliate. The main subgeneric characters of Papillacarus (P.) are the following: pygidial setae setiform, ciliate; weak additional neotrichal setae, no more than 30 pairs. The main subgeneric characters of Papillacarus (V.) are the following: pygidial setae branched or tree-shaped; strong additional neotrichal setae, more than 20 pairs (Balogh 1961; Wallwork 1962; Aoki 1965; Balogh & Balogh 1987, 1992). Prior to this study, eight species of the genus Papillacarus have been recorded in China (Wang & Hu 1990, Li et al. 1991, Chen et al. 2010a, Chen et al. 2010b, Chen & Yang 2011): Papillacarus (Papillacarus) echinatus Li et al. 1991, Papillacarus (Vepracarus) hirsutus Aoki, 1961, Papillacarus (P.) ondriasi Mahunka, 1974, Papillacarus (P.) undirostratus Aoki, 1965, Papillacarus (V.) cruzae Corpuz-Raros, 1979, Papillacarus (V.) punctatus Wang & Hu, 1990, Papillacarus (V.) jinggangshanensis Chen et al. 2010b, Papillacarus (V.) konglinensis Chen & Yang, 2011. Identification keys for some species of Papillacarus were presented by Balogh and Balogh (1987), Ermilov et al. (2012), Ermilov and Tolstikov (2015).
Material and methods
For the material, see Material examined section of each species. The specimens were mounted in lactic acid on temporary cavity slides for measurement and illustration. The body measurements are presented in micrometers. The body length was measured in lateral view, from the tip of the rostrum to the posterior edge of the ventral plate. Notogastral width refers to the maximum width in dorsal aspect. Lengths of body setae were measured in lateral aspect. Formulae for leg setation are given according to the sequence trochanter-femur-genu-tibia-tarsus (famulus included). Formulae for leg solenidia are given in brackets according to the sequence genu-tibia-tarsus. General terminology used in this paper follows that summarized by Grandjean (1950), Norton (1977) for leg setal nomenclature, and Norton and Behan-Pelletier (2009). Morphological description of both species follows with Ermilov and Deharveng (2016), Ermilov (2017), Ermilov et al. (2017). Drawings were made with a camera lucida using an Olympus transmission light microscope “Olympus CX41”.
Descriptions
Papillacarus
(Papillacarus
) internus
sp. nov.
(Figs 1–10)
Diagnosis
Body size 467-488×227-243. Rostrum rounded. Prodorsum and notogaster surface densely punctate. Prodorsal, notogastral and neotrichal setae setiform, with short cilia, and thin, smooth apex. Five transverse bands present on notogaster surface. Bothridial seta pectinate, with 12 to 13 branches. Epimeral setal formula: 7-4-3-4. Genital seta setiform, smooth. Adanal seta setiform, barbed unilaterally.
Measurements. Body length 472 (holotype), 467–488 (9 paratypes); body width 236 (holotype), 227–243 (9 paratypes).
Integument. Body yellow-brown. Surface of prodorsum, notogaster, subcapitulum, genital, adanal plates and legs densely punctate.
Prodorsum (Figs 1–3). Rostrum widely rounded. Rostral seta (ro, 52) setiform. All prodorsal setae setiform, with short cilia, and thin, smooth apex. Lamellar seta (le, 62), interlamellar seta (in, 70) longer than others, posterior exobothridial seta (exp, 65) setiform, smooth. Anterior exobothridial seta (exa, 59) barbed bilaterally. Bothridial seta (bs, 82) pectinate, with 12 to 13 branches on one side, and four barbs on the opposite side. Postbothridial transverse band (Sb) between bothridia.
Notogaster (Figs 1–3). Five transverse bands (S2–S6) present on notogaster, S2 and S4 complete, while S3, S5 and S6 interrupted medially. Sixteen pairs of primary notogastral setae and 29–30 pairs of additional neotrichal setae present, all setiform, with short cilia bilaterally or unilaterally and smooth apex. Setae c1 d1, e1, and f1 never reaching the margin of notogaster, seta c1 shorter than distance c1–d1, setae d1, d2 lie on (d1) resp. inside of a duplication (d2) of the transverse band S4. Neotrichal setae of two types: 3 pairs long (m, 45–48; n, 50–53; r, 58–60) and 26–27 pairs short (21– 33). Lyrifissures ia, im, ip, ih distinct, ia laterally to seta c3, ip anterior laterally to f2, ih laterally to h3, ips not distinct. Notogastral setal lengths: c1≈ h1 = 41 (39-42), c2 ≈ d1 ≈ e1 ≈ f1 = 52 (51-54), c3 ≈ d2 ≈ e2= 57 (56-58) f2 ≈ h2 = 63 (62-64), d3 ≈ h3 ≈ p1 ≈ p2 ≈ p3 = 69 (68-71).
Gnathosoma (Figs 2, 4–6). Subcapitulum longer than wide (116-122×92-97). Setae h, m1 and m2 (11–20) thickened in medio-basal part, barbed bilaterally, represented by four pairs: a (26), h (17), m1 (11), m2 (18). Adoral setae smooth: or1 (23) more or less triangular, wide in proximal part, bluntended; or2 (30) long, setiform, blunt-ended; or3 (25) long, setiform, pointed-ended. Palp (49) with setal formula 0-1-0-1-10(+1ω). Chelicera (139) with two setae, seta cha (17) short, thorn-like, seta chb (27) long, setiform and barbed. Trägårdh's organs (Tg) triangular, tip slightly pointed.
Epimeral region (Fig. 2). Epimeral plates distinct, partly distinct ridges, epimeral setae setiform, setae 1a, 2a, 3a, 4a, 4b and one pair of lateral setae of epimere I smooth (6–9); other setae barbed bilaterally. Epimeral formula 7-4-3-4.
Anogenital region (Figs 2–3). Ten pairs of genital setae, setiform and smooth, four setae in outer row and six setae in inner row, setae g2, g5, g7, g8 longer (17–22), others setae shorter (8–10). Two pairs of anal setae, setiform, barbed unilaterally. Four pairs of adanal setae (ad, 56–72), setiform, barbed unilaterally. Lyrifissure iad distinct.
Legs (Figs 7–10). All legs with one simple claw each of which with small basoventral tooth. Famulus ε conical and short, posterior to solenidion ω1,. Solenidion ω, 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 0-5-3(2)-4(1)-18(2), II 0-6-3(1)-4(1)-13(2), III 2-4-2(1)-3(1)-12(0), IV 2-3-2(1)-3(0)-12(0) (see Table 1).
Material examined
Holotype, Chengmai County (19°63′N, 110°3′E), Haikou City, Hainan Province, 9 Jan. 2016, Guoru Ren, in soil. Nine paratypes, same data as holotype. The holotype and nine paratypes are deposited in the Institute of Entomology, Guizhou University, Guiyang of China (GUGC).
Etymology
The new specific name “internus” is derived from the Latin “internus”, and refers to the notogastral setae d1 and d2 which are situated on and inside of the duplication of the transverse band S4.
Remarks
The new species Papillacarus (P.) internus sp. nov. is most similar to Papillacarus (P.) lienhardi (Mahunka, 1997) from Brunei in having setiform prodorsal and notogastral setae. However, the new species differs from the latter by the following characters: (1) 29–30 pairs of additional neotrichal setae (versus approximately 25 pairs P. lienhardi); (2) seta c1 shorter than c2 (versus seta c1 longer than c2); (3) five transverse bands, S4 complete (versus four transverse bands, S4 interrupted medially); (4) all genital setae setiform and smooth (versus all genital setae ciliate).
The new species Papillacarus (P.) internus sp. nov. is also similar to Papillacarus (P.) gramenicus (Bayartogtokh, 2010) from Mongolia in having setiform prodorsal and notogastral setae. However, the new species differs from the latter by the following characters: (1) 29–30 pairs of additional neotrichal setae (versus 13 pairs); (2) epimeral formula 7-4-3-4 (versus 8-4-4-4); (3) four pairs of subcapitular setae (versus five pairs).
TABLE 1.
Leg setation and solenidia of adult Papillacarus (Papillacarus) internus sp. nov.

FIGURES 3–6.
Papillacarus (Papillacarus) internus sp. nov., adult: 3. lateral view; 4. chelicera, left; 5. subcapitulum, ventral view; 6. palp, left. Scale bar 100 µm (3), 25 µm (4, 5, 6).

FIGURES 7–8.
Papillacarus (Papillacarus) internus sp. nov., adult: legs, femur to tarsus, antiaxial view. 7. leg I, right; 8. leg II, right. Scale bar 50 µm.

FIGURES 9–10.
Papillacarus (Papillacarus) internus sp. nov., adult: legs, femur to tarsus, antiaxial view. 9. leg III, left; 10. leg IV, left. Scale bar 50 µm.

Papillacarus
(Vepracarus
) hexagonus
sp. nov.
(Figs 11–20)
Diagnosis
Body size 455-472×210-228. Rostrum truncate, but medially convex. Prodorsum and the whole surface of notogaster covered with bacilliar papillae. Prodorsal, notogastral and neotrichal setae with branches, tree-shaped. Four transverse bands present on notogaster surface. Bothridial seta pectinate, with 9 to 10 branches. Epimeral setal formula: 9-4-3-4. Genital seta setiform or tree-shaped. Adanal seta branched.
Measurements. Body length 462 (holotype), 455–472 (15 paratypes); body width 213 (holotype), 210–228 (15 paratypes).
Integument. Body yellow-brown. Surface of Prodorsum, notogaster, subcapitulum, genital, adanal plates and legs papilliform.
Prodorsum (Figs 11–13). Rostrum truncate, but medially convex. Rostral seta (ro, 30) bear several long branches on each side. Prodorsal surface papilliform in front of postbothridial transverse band and covered with fine spots posterior of this band. Lamellar seta (le, 26), interlamellar seta (in, 36), anterior exobothridial seta (exa, 32), posterior exobothridial seta (exp, 38) tree-shaped. Bothridial seta (bs, 69) pectinate, with 9 to 10 branches on one side, and three barbs on the opposite side. Postbothridial transverse band (Sb) between bothridia.
Notogaster (Figs 11–13). Four transverse bands (S2–S5) present on notogaster, all interrupted medially. Sixteen pairs of primary notogastral setae and 38 pairs of additional neotrichal setae present, all with 5–7 branches, tree-shaped. Setae c1, c2, d1, e1, h1, and f1 never reaching margin of notogaster, setae d1, e1, looking like hexagram in dorsal view. Lyrifissures ia, im, ip, ih distinct, ia laterally to seta c3, ip laterally to f2, ih anterior laterally to h3, ips not distinct. Lengths of notogastral setae: c1, c2, d1, d2, e1, f1, h1, p1, p2 (13–25); c3, d3, e2, f2, h2, h3, p3 (31–48).
Gnathosoma (Figs 12, 14–16). Subcapitulum longer than wide (98-105×80-84). Surface of subcapitulum papilliform. Seven pairs of subcapitula setae, a (22–24) setiform, smooth, pointedended; m1 and m4 (18–23) setiform, barbed unilaterally; h1, h2, m2, m3 (12–17) setiform, barbed bilaterally. Three pairs of smooth adoral setae: or1 (14) wide m proximal part, tapering up, bluntended; or2 (22) long, setiform, blunt-ended; or3 (17) long, setiform, pointed-ended. Palp (38) with setal formula 0-1-0-3-10(+ 1ω). Chelicera (134) with two setae, seta cha (4) short, thorn-like, seta chb (36) long, setiform and smooth. Trägårdh's organs (Tg) triangular, rounded distally.
Epimeral region (Fig. 12). Epimeral plates distinct, partly distinct ridges, epimeral I and II neotrichous, setae setiform or tree-shaped, epimeral formula 9-4-3-4, setae 1a, 2a, 3a, 4a, and one pair of lateral setae of epimere I setiform and smooth (6–10); other setae tree-shaped (11–26).
Anogenital region (Figs 12–13). Ten pairs of genital setae, setiform or tree-shaped, four setae in outer row and six setae in inner row, g7, g8, g10 setiform and smooth (17–19), other setae tree-shaped (11–14). Two pairs of anal setae bearing several long branches unilaterally (an, 31–34). Four pairs of adanal setae with several long branches (ad, 33–42). Lyrifissure iad distinct.
Legs (Figs 17–20). Surface of leg femur papilliform. All legs with one simple claw each of which with small basoventral tooth. Famulus ε conical 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 0-5-3(2)-4(1)-17(2), II 0-6-3(1)-4(1)-11(2), III 2-4-2(1)-3(1)-11(0), IV 2-3-2(1)-3(0)-12(0) (see Table 2).
Material examined
Holotype, Simian Mountain (28°34′N, 106°20′E), Chongqing City, 23 Sept. 2017, Guoru Ren, in rotten tree and soil. Fifteen paratypes, same data as holotype. The holotype and fifteen paratypes are deposited in the Institute of Entomology, Guizhou University, Guiyang of China (GUGC).
Etymology
The new specific name “hexagonus” is derived from the Latin “hexagonus”, and refers to the notogastral setae d1 and e1, which look like a hexagram in dorsal view.
Remarks
The new species Papillacarus (V.) hexagonus sp. nov. is most similar to Papillacarus (V.) gueyeae (Pérez-Íñigo, 1989) described from Senegal, in having tree-shaped prodorsum and notogastral setae. However, the new species differs from the latter by the following characters: (1) 38 pairs of additional neotrichal setae (versus 46–50 pairs in Papillacarus (V.) gueyeae); (2) bothridial seta with 9 to 10 branches (versus 13 to 15 branches); (3) epimeral formula 9-4-3-4 (versus 8-5-3-3); (4) seven pairs of subcapitular setae (versus six pairs); (5) genital setae g4–g6 tree-shaped; g10 setiform and smooth (versus g4–g6 setiform, smooth; g10 tree-shaped).
The new species Papillacarus (V.) hexagonus sp. nov. is also similar to Papillacarus (V.) cornutus (Sarkar & Subías, 1984) described from India in having tree-shaped prodorsal and notogastral setae. However, the new species differs from the latter by the following characters: (1) body size 455-472×210-228 (versus 342-349×134-141 in Papillacarus (V.) cornutus); (2) body surface covered with polygonal network sculpture (versus without); (3) 38 pairs of additional neotrichal setae (versus 18 pairs); (4) genital setae g4–g6 tree-shaped; g10 setiform and smooth (versus all genital setae bilaterally barbed).
FIGURES 13–16.
Papillacarus (Vepracarus) hexagonus sp. nov., adult: 13. lateral view; 14. palp, right; 15. subcapitulum, ventral view; 16. chelicera, left. Scale bar 50 µm (13), 25 µm (14, 15, 16).

FIGURES 17–18.
Papillacarus (Vepracarus) hexagonus sp. nov., adult: legs, femur to tarsus, antiaxial view. 17. leg I, right; 18. leg II, right; Scale bar 50 µm.

FIGURES 19–20.
Papillacarus (Vepracarus) hexagonus sp. nov., adult: legs, femur to tarsus, antiaxial view. 19. leg III, left; 20. leg IV, left. Scale bar 50 µm.

TABLE 2.
Leg setation and solenidia of adult Papillacarus (Vepracarus) hexagonus sp. nov.

Acknowledgements
We would like to express our gratitude to Dr. Yong Chen (Institute of Entomology, Guizhou University, Guiyang, China) and Professor Roy A. Norton (State University of New York, Syracuse, U.S.A.) for providing literature. This project was supported by the Program of Ministry of Science and Technology of the People's Republic of China (2015FY210300); the Program of Excellent Innovation Talents, Guizhou Province, China (No. 20164022); the Funds for National Natural Sciences Foundation of China (No. 31501847), the key research and development program of Shandong Province (2016GNC110012).