Protoribates sichuanensis, Chen & Chen, 2020

Chen, Shujing Xu Yannan & Chen, Jun, 2020, New species and records of oribatid mites of the genus Protoribates (Acari Oribatida, Haplozetidae) from China, Zootaxa 4772 (3), pp. 469-511 : 481-485

Protoribates sichuanensis sp.nov.

( Figs 7–12 )

urn:lsid:zoobank.org:act:98629198-D701-4BAA-80A8-A4DAE13EF79

Diagnose. Body size: 520–660 × 320–400. Rostrum rounded or slightly protruding. Rostral, lamellar and interlamellar setae long, setiform, barbed. Bothridial setae with long stalk and short, unilaterally dilated, apically pointed, barbed head. Notogastral setae minute. Four pairs of small rounded porose areas. Distance between porose areas A1–A1 shorter than A2–A2. Epimeral setal formula: 3-1-3-2; setae 3c and 1b longest, barbed. Custodium present. Humeral porose areas Ah present. Adanal setae ad 1 and ad 2 of medium size. Five pairs of genital setae. Legs heterotridactylous. Femora II ventroanteriorly rounded.

Description. Measurements. Body length 520 (holotyle, male), 520–660 (six paratypes: four females and two males), width 320 (holotype), 320–400 (six paratypes). Females (585–630 × 365–400) always larger than males (520–530 × 320–325).

Integument. Body color brown. Body surface punctate. Lateral parts of prodorsum between sublamellae and acetabula I, II microgranulate.

Prodorsum ( Figs 7 , 9A ). Rostrum rounded or slightly protruding. Lamellae located dorsolaterally, half as long as prodorsum (measured in lateral view). Sublamellae about half as long as lamellae. Sublamellar porose areas (19– 24 × 14–19) oval, located very near to sublamellae. Rostral (46–63), lamellar (75–111) and interlamellar (102–150) setae setiform, barbed. Lamellar setae inserted on inside lamellar ends. Bothridial setae (114–127) with long stalk and short, unilaterally dilated, apically pointed, barbed head. Exobothridial setae minute. Dorsophragmata comparatively short, longitudinally elongated, directed posteromedially. Tutorium ridge-like.

Notogaster ( Figs 7 , 9 , 12 ). Anterior notogastral margin convex medially. Pteromorphs with distinct hinges. Ten pairs of notogastral setae minute (5–6), thin, smooth. Four pairs of rounded porose areas, Aa (14–25) larger than A1, A2 and A3 (8–12); A1 lost on one side of a specimen (CYN-18-142); A2 lost on one side of a specimen, and A3 on this side larger than that on other side (CYN-18-141-2). Distance between porose areas A1–A1 shorter than A2–A2 (1:2). Setae h 1 and h 2 almost in transverse line (h 1 slightly anterior). All lyrifissures and opisthonotal gland openings clearly visible.

Gnathosoma ( Fig. 8 ). Generally, similar to P. tibetensis sp. nov. Subcapitulum longer than wide (137–150 × 85–92). Subcapitular setae (a, 19–21; h, 33–38; m, 16–18) setiform, h longest, barbed, m thinnest. Adoral setae (15–20) setiform, heavily barbed. Palps (length 87–90) with setation 0-2-1-3-9(+ω). Postpalpal setae (7) spiniform, smooth. Chelicerae (length 154–185) with two setiform, barbed setae (cha, 50–56; chb, 25–33). Trägårdh’s organ of chelicerae elongate triangular.

Epimeral and lateral podosomal regions ( Figs 8 , 9A ). Epimeral setal formula: 3-1-3-2. Epimeral setae setiform, thin, 3c (30–40), 1b (24–35) and 3b (24–27) longer than others (13–17), 3c and 1b barbed, others smooth. Custodium present. Humeral porose areas Ah oval. Circumpedal carinae of medium size, directed to pedotecta II, but not reaching it.

Anogenital region ( Figs 8 , 9 ). Five pairs of genital (g 1, 19–24; g 2 –g 5, 11–16), one pair of aggenital (12–19), two pairs of anal (22–32) and three pairs of adanal (ad 1, 33–76; ad 2, 27–48; ad 3, 16–24) setae setiform, thin, smooth, length of setae ad 1 within a wide range, always longer than ad 2 and ad 3. Adanal setae ad 1 in posterior, ad 2 in lateral, ad 3 in anterior positions. Adanal lyrifissures located close and parallel to anal aperture.

Legs ( Figs 10 , 11 ). Heterotridactylous, median claw thicker than laterals, barbed on dorsal side. Tibiae I, II with ventrobasal tooth. Femora II ventroanteriorly rounded. Femora I–IV and trochanters III, IV with distinctly developed dorsoparaxial porose area. Formulas of leg setation and solenidia: I (1-5-3-4-19) [1-2-2], II (1-5-3-4-15) [1-1-2], III (2-3-1-3-15) [1-1-0], IV (1-2-2-3-12) [0-1-0], setae number on tibiae I six on one specimen, one pair of setae on lateral added (CYN-18-141-3); homology of setae and solenidia indicated in Table 1.

Material examined. Holotype (male in alcohol, CYN-18-141-1): China, Sichuan, Pengzhou, Dabaoshan Town, Longcaogou , 31°22′67.57″N, 103°75′50.89″E, 1123 m a.s.l., litter under arbor, 11.VIII.2018; four paratypes (two males, one in alcohol and one on permanent slide; two females, one in alcohol and one on permanent slide, CYN- 18-141); one paratype (female on permanent slide, CYN-18-142): same place as holotype, mosses, 11.VIII.2018; one paratype (female on permanent slide, CYN-18-181): China, Sichuan, Pengzhou , Baoshan Second Road , 31°26′32.33″N, 103°78′30.95″E, 1121 m a.s.l., litter under arbor, 17.VIII.2018. All specimens were collected by Yannan Chen.

Etymology. The species is named after the region, Sichuan in China, from where the type specimens were collected.

Remarks. Protoribates sichuanensis sp. nov. is morphologically similar to the species Protoribates magnus ( Aoki, 1982) from the Eastern Palaearctic and India in having convex anterior notogastral margin, bothridial setae long, with unilaterally dilated, apically pointed, barbed head, long adanal setae ad 1 and ad 2, similar location of setae h and heterotridactylous legs. However, the new species differs from the latter by smaller body size (520–660 × 320– 400 vs. 660–872 × 440–620); ventroanteriorly rounded femora II (vs. ventroanteriorly pointed femora II); adanal setae ad 1 less than 1 × the distance between ad 1 –ad 1 (adanal setae ad 1 1.3–1.6 × the distance between ad 1 –ad 1); single porose area A1 (vs. A1 occasionally divided into two closely situated pores on both sides or on one side).

Protoribates sichuanensis sp. nov. is also morphologically similar to P. gruezoi Corpuz-Raros, 2014 from Philippines; P. seminudus ( Hammer, 1971) from Australian and Oriental (northeast India (frequent) and Philippines); P. shaldybinae Ermilov & Starý, 2017 from Vietnam; and P. punctatus ( Grobler, 1991) from Ethiopic and northeast India, in having long ad 1 and heterotridactylous legs. But it differs from P. gruezoi by body surface punctate (vs. body surface granulate); lamellar setae inserted on lamellar ends (vs. lamellar setae inserted on the prodorsal surface, close to the lamellar ends); h 1 and h 2 almost in transverse line (h 1 slightly anterior) (vs. h 2 aligned with h 1, h 3). It differs from P. seminudus by convex anterior notogastral margin (vs. straight anterior notogastral margin); h 1 and h 2 almost in transverse line (h 1 slightly anterior) (vs. h 2 aligned with h 1, h 3); no line between the tips of the lamellar (a line not a real translamellae between the tips of the lamellae). It differs from P. shaldybinae by adanal setae ad 1 and ad 2 smooth (vs. adanal setae ad 1 and ad 2 barbed); pedotecta II not dentate (vs. pedotecta II dentate); without dorsal teeth on tarsi I and II (vs. with dorsal teeth on tarsi I and II). After comparing the descriptions and illustrations of P. seminudus and P. punctatus , we did not find any differences between them, and also by the fact that both are distributed in northeast India. Protoribates punctatus may be a synonym of P. seminudus , but additional research is necessary.

Figures

FIGURE 7. Protoribates sichuanensis sp. nov., adult. dorsal view. Scale bar 100 μm.

FIGURE 8. Protoribates sichuanensis sp. nov., adult. ventral view. Scale bar 100 μm.

FIGURE 9. Protoribates sichuanensis sp. nov., adult. A. anterior part of body, lateral view; B. posterior part of body, lateral view. Scale bar 100 μm.

FIGURE 10. Protoribates sichuanensis sp. nov., adult. A. leg I, right, antiaxial view; B. genu, femur and part of trochanter of leg II, right, antiaxial view. Scale bar 30 μm.

FIGURE 11. Protoribates sichuanensis sp. nov., adult. A. tarsus of leg II, right, antiaxial view; B. genu, femur and trochanter of leg III, left, antiaxial view; C. leg IV, left, antiaxial view. Scale bar 30 μm.

FIGURE 12. Protoribates sichuanensis sp. nov., adult. dorsal view (A2 lost on left side, A3 on left side large, CYN-18-141-2, male). Scale bar 50 μm.