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Research Article
Three new species of the subgenus Otocepheus (Acrotocepheus) (Acari, Oribatida, Otocepheidae) from China
expand article infoLi-Hao Zheng‡§|, Jun Chen‡|
‡ University of Chinese Academy of Sciences, Beijing, China
§ Guang’an Vocational and Technical College, Guang’an, China
| Institute of Zoology, Chinese Academy of Sciences, Beijing, China

Corresponding author: Jun Chen ( chenj@ioz.ac.cn )

Academic editor: Vladimir Pesic
© 2020 Li-Hao Zheng, Jun Chen.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation: Zheng L-H, Chen J (2020) Three new species of the subgenus Otocepheus (Acrotocepheus) (Acari, Oribatida, Otocepheidae) from China. ZooKeys 934: 1-23. https://doi.org/10.3897/zookeys.934.49862
ZooBank: urn:lsid:zoobank.org:pub:84A89C53-939E-41FE-A0E6-37390FE7B7B5
Open Access

Abstract

Three new species of subgenus Otocepheus (Acrotocepheus): O. (A.) digitatus sp. nov., O. (A.) multigranulatus sp. nov., and O. (A.) occultatus sp. nov. are proposed and described based on adult material collected from China, and O. (A.) duplicornutus Aoki, 1965 is reported in China for the first time. A key to Chinese species of the subgenus Acrotocepheus is provided.

Keywords

oribatid mites, new species, new record, taxonomy, key

Introduction

The oribatid mite genus Otocepheus was first proposed by Berlese (1905) as a subgenus of Carobodes with two new species from Java, Carabodes (Otocepheus) longior and C. (O.) crinitus. Later, Berlese (1913) described another new species, Otocepheus damoeoides, and a variety, O. longior var. minor, both from Java, which suggested that the subgenus was promoted to the generic rank. Trägårdh (1931) recognized the generic status of the genus Otocepheus and selected Carabodes (Otocepheus) longior Berlese, 1905 as the type species for the genus. At present, Otocepheus has three subgenera, Otocepheus (Otocepheus) Berlese, 1905, Otocepheus (Aceotocepheus) Aoki, 1965, and Otocepheus (Hexatocepheus) Wen, 1993, and comprises 53 species (Subías 2004, 2020).

The subgenus Otocepheus (Acrotocepheus) was proposed by Aoki (1965), with O. (A.) quateorum Aoki, 1965 as type. The subgeneric characters of Otocepheus (Acrotocepheus) were summarized by Aoki (1965), and identification keys to species from some regions and countries were presented by Aoki (1965) and Corpuz-Raros (2007).

Chen et al. (1992) recorded O. (A.) gracilis (Aoki, 1973) from Anhui, China, which was the first report of genus Otocepheus in China. The following year, Wen (1993) proposed the subgenus Otocepheus (Hexatocepheus) with O. (Hexatocepheus) emeiensis from Sichuan, China as type. Until now, only two subgenera and two species of Otocepheus were recorded in China (Chen et al. 2010). During studies of oribatid mites from China, we discovered three new species of subgenus Otocepheus (Acrotocepheus)–O. (A.) digitatus sp. nov., O. (A.) multigranulatus sp. nov., and O. (A.) occultatus sp. nov.–and the first record in China of O. (A.) duplicornutus Aoki, 1965. All four of these species are described, and an identification key for all known species of this subgenus in China is provided.

Materials and methods

The collection locality and habitat for each new species are given in the “Material examined”.

Specimens were mounted in lactic acid on temporary cavity slides for measurement and illustration, except one specimen of O. (A.) digitatus sp. nov., which was mounted on a permanent slide with Hoyer’s medium. 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. All body measurements are presented in micrometers. Formulas for leg setation are given in parentheses according to the sequence trochanter-femur-genu-tibia-tarsus (famulus included). Formulas for leg solenidia are given in square brackets according to the sequence genu-tibia-tarsus.

General terminology used in this paper follows that of Grandjean (1934), Aoki (1965, 1967), Norton (1977), and Norton and Behan-Pelletier (2009).

Abbreviations and notations

Prodorsum : ro, le, in, bs, ex – rostral, lamellar, interlamellar, bothridial, and exobothridial setae, respectively; cos – costula; tu – tutorium; spa.l – lamelliform expansion; tbd, tbv – dorsal and ventral bothridial plate, respectively; cpm, cpl – medial and lateral prodorsal condyles, respectively; cex – extral condyles.

Notogaster : c, la, lm, lp, h-row, p-row – notogastral setae; cnm, cnl – medial and lateral notogastral condyles, respectively; vm – vitta marginalis; ia, im, ip – anterior, middle, posterior lyrifissures, respectively; ih, ips – same, associated with setal rows h and p, respectively; gla – opisthonotal gland opening.

Coxisternum and lateral podosoma : 1a, 1b, 1c, 2a, 3a, 3b, 3c, 4a, 4b, 4c – setae of epimeres I–IV; met – mentotectum; cst – carina sterinalis; ap1 – apodeme I; bo1 – epimeral border I; Pd I, Pd II – pedotectum I, II respectively; spd – sub pedotectum; fep – epimeral foramen; dis – discidium; opp – postpodosomal ornamentation.

Anogenital region : g, ag, an, ad – genital, aggenital, anal and adanal setae, respectively; vr – ventral ridge; iag, iad – aggenital, adanal lyrifissure respectively.

Gnathosoma : lir – lower lip ridge of mentum; a, m – anterior, middle seta of gena; h – hypostomal seta of mentum; v, l, d, cm, acm, ul, su, vt, lt, sup, inf – palp setae; ω – palp tarsal solenidion; ep – postpalpal seta; cha, chb – cheliceral setae; cht – tooth on dorsal chelicerae; rbr – rutellar brush; ru – rutellum; Tg – Trägårdh’s organ.

Legs : σ, φ, ω – solenidia of genu, tibia and tarsus, respectively; ɛ – famulus of tarsus I; d, l, v – dorsal, lateral, ventral setae, respectively; ev, bv – basal trochanteral setae; ft, tc, it, p, u, a, s, pv – tarsal setae; Tr, Fe, Ge, Ti, Ta – trochanter, femur, genu, tibia, tarsus of legs, respectively.

Descriptions

Otocepheus (Acrotocepheus) digitatussp. nov.

http://zoobank.org/BA165CB6-E780-4F37-942E-F7A36B42F2AE
Figs 1–4, 5, 6, 7

Diagnosis

Body size: 1020 × 330. Body surface densely foveolate. Bothridial setae with a long fusiform head and a strongly curved peduncle. Lateral notogastral condyles finger-shaped, with wide base. Notogastral setae different in length, setae lm, lp, h1, h2, p2 flagelliform and distinctly longer than the others. Genital plates each with two longitudinal, slant furrows.

Figures 1–4. 

Otocepheus (Acrotocepheus) digitatus sp. nov., adult 1 bothridial setae 2 ventral view (legs not shown) 3 dorsal view 4 genital plate. Scale bars: 100 µm (1, 4), 200 µm (2, 3).

Figures 5, 6. 

Otocepheus (Acrotocepheus) digitatus sp. nov., adult, microscope images 5 dorsal view 6 prodorsal and notogastral condyles, interlamellar and bothridial setae, notogastral setae c. Scale bar: 200 µm (5).

Figure 7. 

Otocepheus (Acrotocepheus) digitatus sp. nov., adult, microscope image, ventral view. Scale bar: 200 µm.

Description

Measurements (holotype: male). Body length: 1020, notogaster width: 330. Setae length and mutual distance: bs 100, in 140, le180, ro 160, ex 25; c, la, h3, p1, p3 range 100–160; lm, lp, h1, h2, p2 range 300–450; c–c 120, la–la 160, lm–lm 190, lp–lp 240, h2–h2 160, h1–h1 170.

Integument. Body color light yellow-brownish. Body surface densely foveolate.

Prodorsum. Rostrum broadly rounded. Rostral seta moderately curved inward, densely barbed outside. Lamellar seta inserted behind tip of costula, curved inward, roughened externally. Interlamellar seta barbed, blunt at tip. Bothridial seta with a long fusiform head and a strongly curved peduncle. Exobothridial seta short. Bothridium opening laterally, dorsal bothridial plate straight or curved outward slightly, ventral bothridial plate broadly triangular in dorsal view. Tutorium well developed. Two pairs of prodorsal condyles present, lateral prodorsal condyles broadly rounded, median prodorsal condyles large and rounded, well separated from each other. Mutual distance between ventral bothridial plates nearly equal with that between lateral prodorsal condyles. Subpedotectum well developed.

Notogaster. L/W of notogaster about 1.8. Surface of notogaster densely punctate. Anterior margin of notogater strait. Lateral notogastral condyles finger-shaped, with wide base. Median notogastral condyles absent. Ten pairs of notogastral setae glabrous, setae c, la, h3, p1, p3 setiform and relatively short in length, while the rest notogastral setae lm, lp, h1, h2, p2 flagelliform and longer in length. Setae c, la, lm nearly located on the same line. All lyrifissures well visible, ip located between setae p2 and p3, ips between setae h3 and p3. Opisthonotal gland opening located anterior and very close to lyrifissure im. Vitta marginalis distinct.

Epimeral and lateral podosomal regions. Apodemes I, II and sejugal well developed, apodeme III invisible. Carina sterinalis well developed. Epimeral setal formula 3-1-3-3. Seta 4a inserted between 4b and 4c, and closer to 4c. Epimeral setae 1b, 1c, 3b, 3c, 4a distinctly longer than the rest. Postpodosomal ornamentation invisible.

Anogenital region. Genital plates each with 2 longitudinal, slant furrows. Four pairs of genital setae (mutual distances g1–g1≈g2–g2≈g4–g4<g3–g3). Aggenital lyrifissure located close and anterolateral to genital aperture. One pair of aggenital, two pairs of anal (mutual distances an1–an1<an2–an2) and three pairs of adanal setae similar in length. Setae ad3–ad3 below level of anterior margin of anal opening. Adanal lyrifissure located in diagonal position and close to anal aperture, below level of anterior margin of anal opening.

Legs. Monodactylous. Claw of each leg strong and smooth. Formulae of leg setation and solenidia: I (1-4-3-4-16) [1-2-2], II (1-4-3-3-15) [1-1-2], III (2-3-1-2-15) [1-1-0], IV (1-2-2-2-12) [0-1-0]. Leg seta u setiform (L-type) on tarsi I, thorn-like (S-type) on tarsi II–IV. Homology of setae and solenidia indicated in Table 1.

Table 1.
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Leg setation and solenidia of adult Otocepheus (Acrotocepheus) digitatus sp. nov., Otocepheus (Acrotocepheus) multigranulatus sp. nov., Otocepheus (Acrotocepheus) occultatus sp. nov., and Otocepheus (Acrotocepheus) duplicornutus Aoki, 1965.

Leg Tr Fe Ge Ti Ta
I v' d, (l), bv" (l), v', σ (l), (v), φ1, φ2 (ft), (tc), (it), (p), (u), (a), s, (pv), ε, ω1, ω2
II v' d, (l), bv" (l), v', σ l', (v), φ (ft), (tc), (it), (p), (u), (a), s, (pv), ω1, ω2
III v', l' d, l', ev' l', σ (v), φ (ft), (tc), (it), (p), (u), (a), s, (pv)
IV v' d, ev' d, l' (v), φ ft", (tc), (p), (u), (a), s, (pv)

Note: Roman letters refer to normal setae, Greek letters to solenidia (except ɛ = famulus). Single prime (') marks setae on the anterior and double prime (") setae on the posterior side of a given leg segment. Parentheses refer to a pair of setae.

Material examined

Holotype (male, LD-07-117): China, Hainan Province, Qiongzhong City, Limu Mountain, 19°6'18"N, 109°26'42"E, 616 m a.s.l., in soil and debris under reeds, 20 July 2007, collected by Dong Liu.

Type deposition. The holotype is deposited in the collection of the Zoological Museum of China, Institute of Zoology, Chinese Academy of Sciences, Beijing (IZAS) (Zhang 2018).

Etymology

The specific name “digitatus” is from Latin for “finger-like” refers to the finger-shaped lateral notogastral condyles.

Remarks

The new species is similar to O. (A.) duplicornutus discrepans (Balogh & Mahunka, 1967) from Vietnam and O. (A.) bajau Mahunka, 2000 from Malaysia in having similar shape of lateral notogastral condyles. However, it differs from O. (A.) duplicornutus discrepans by the flagelliform setae lm, lp, h1, h2, p2 (versus blunt at tips), different length in notogastral setae (versus nearly same length), postpodosomal ornamentation invisible (versus markedly developed), bothridial setae with a long fusiform head (versus flattened distally); it differs from O. (A.) bajau by the flagelliform setae lm, lp, h1, h2, p2 (versus setiform), setae c, la, h3, p1, p3 shorter than the other notogastral setae (versus length increasing toward the posterior part of notogaster), lyrifissure ips located between h3 and p3 (versus between p3 and p2), surface of notogaster densely foveolate (versus granulate).

Otocepheus (Acrotocepheus) multigranulatussp. nov.

http://zoobank.org/72F9B5C4-CEBC-49DC-9EFD-2D0D053C6CFA
Figs 8–12, 13–15, 16–18, 19–22

Diagnosis

Body size (n = 3): 1150–1240 × 530–609. Bothridial setae with a fusiform head. Lateral notogastral condyles wide, like staircase with two to three layers mainly. An extra pair of condyles (cex) located posterior to lateral prodorsal condyles, covered by lateral notogastral condyles. Bothridial seta with a fusiform head. Body surface densely granulate.

Figures 8–12. 

Otocepheus (Acrotocepheus) multigranulatus sp. nov., adult 8 seta ro 9 seta le 10 ventral view (legs not shown) 11 dorsal view 12 bothridial seta. Scale bars: 100 µm (8, 9, 12), 200 µm (10, 11).

Description

Measurements. Body length: 1240 (holotype: female), 1150–1230 (two paratypes: all males); notogaster width: 609 (holotype), 530–600 (paratypes). Setae length and mutual distance (holotype): bs 160, in 200, le 210, ro 160, ex 35; c, la, lm, lp, h1, h2, h3, p1, p2, p3 range 170–200; c–c 199, la–la 290, lm–lm 240, lp–lp 390, h2–h2 260, h1–h1 240.

Integument. Body color light yellow-brownish. Body surface densely granulate.

Prodorsum. Rostrum rounded. Rostral seta moderately curved inward, densely barbed outside. Lamellar seta inserted behind tip of costula, curved inward, roughened outside. Interlamellar seta barbed, setiform. Bothridial seta with a fusiform head. Exobothridial seta short. Bothridium opening laterally, dorsal bothridial plate straight, ventral bothridial plate broadly rounded in dorsal view. Tutorium well developed. Two pairs of prodorsal condyles present, lateral prodorsal condyles earlobe-shaped, median prodorsal condyles rounded, well separated from each other. An extra pair of condyles located posterior to lateral prodorsal condyles, covered by lateral notogastral condyles. Mutual distance between ventral bothridial plates larger than that between lateral prodorsal condyles. Subpedotectum well developed.

Figures 13–15. 

Otocepheus (Acrotocepheus) multigranulatus sp. nov., adult, microscope images 13 dorsal view 14 ventral view 15 lateral view. Scale bars: 200 µm.

Notogaster. L/W of notogaster about 1.2. Surface of notogaster densely and obviously granulate. Anterior margin of notogaster straight. The largest width of notogaster medially, near level of seta lp. Lateral notogastral condyles wide, like a lateral view of staircase with two to three steps mainly. Median notogastral condyles absent. Ten pairs of notogastral setae nearly same in length, barbed. A faint, short ridge present lateral to insertion of seta c. Mutual distance between setae p1 lager than that between p1 and p2. Seta lm and lyriffissure im nearly on same line. Five pairs of lyrifissures visible, ip located between setae p2 and p3, ips between setae h3 and p3. Opisthonotal gland opening located anterior to lyriffissure im. Vitta marginalis well developed, fainted anteriorly.

Figures 16–18. 

Otocepheus (Acrotocepheus) multigranulatus sp. nov., adult 16 subcapitulum, ventral view 17 right palp (without trochanter), abaxial view 18 right chelicera, adaxial view. Scale bars: 50 μm.

Epimeral and lateral podosomal regions. Apodemes I, II and sejugal well developed, apodeme III invisible. Carina sterinalis well developed. Epimeral setal formula 3-1-3-3. Seta 4a inserted between 4b and 4c, and closer to 4c. Postpodosomal ornamentation invisible.

Anogenital region. A pair of longitudinal ridges posterior to epimeral seta 4a. Genital plates smooth. Four pairs of genital setae (mutual distances g1–g1≈g2–g2<g4–g4<g3–g3). Aggenital lyrifissure located close and anterolateral to genital aperture. One pair of aggenital, two pairs of anal (mutual distances an1–an1<an2–an2) and three pairs of adanal setae. Anal and adanal setae barbed like notogastral setae. Setae ad3–ad3 below level of anterior margin of anal opening. Adanal lyrifissure situated anterior to level of seta ad3.

Gnathosoma. Subcapitular setae fistulous, barbed. Adoral setae and their alveoli absent. Rutellum pantelobasic, with typical dentition and rutellar brush. Chelicera chelate-dentate; with a minute denticle proximal to seta cha; cha longer than chb, both of them setiform, barbed; Trägårdh’s organ narrowly triangular. Palp with usual setal formula: 0–2–1–3–8 (+ω); setae of femur to tibia barbed. Tarsus with four short, blunt distal eupathidia–acm, su, (ul); other tarsal setae smooth or with sparse, inconspicuous barbs; solenidion ω connected with seta ul’, seta ul” medioanteriorly. Postpalpal seta erect, smooth.

Legs. Monodactylous. Claw of each leg strong and smooth. Formulae of leg setation and solenidia: I (1-4-3-4-16) [1-2-2], II (1-4-3-3-15) [1-1-2], III (2-3-1-2-15) [1-1-0], IV (1-2-2-2-12) [0-1-0]. Leg seta u setiform (L-type) on tarsi I, thorn-like (S-type) on tarsi II–IV. Homology of setae and solenidia indicated in Table 1.

Figures 19–22. 

Otocepheus (Acrotocepheus) multigranulatus sp. nov., adult: leg I–IV, right, antiaxial view. Scale bars: 100 µm (19–22).

Material examined

Holotype (female, LD-08-10): China, Hunan Province, Yanling County, Taoyuan Dong, 26°17'42"N, 114°1'15"E, 1065 m a.s.l., in soil and debris under trees, 6 July 2008, collected by Dong Liu. Two paratypes (males, LD-08-49): China, Hunan Province, Guidong County, Xinlong Village, 26°4'29"N, 113°46'53"E, 1525 m a.s.l., in soil and debris under trees, 12 July 2008, collected by Dong Liu.

Type deposition

All type specimens are deposited in the collection of IZAS.

Etymology

The specific name “multigranulatus” is from Latin for “granulate” and is in reference to the uneven, granular body surface.

Remarks

The new species is similar to O. (A.) lienhardorum Mahunka, 2000 from Malaysia, O. (A.) macrodentatus Hammer, 1981 from Java, and O. (A.) holtmanni Aoki, 1965 from New Guinea in having similar shaped lateral notogastral condyles. However, it differs from O. (A.) lienhardorum by the granulate ventral plate (versus foveolate), notogastral setae nearly same in length (versus setae p1–p3 and h3 long), bothridial seta with a fusiform head (versus markedly developed), and seta 1a well visible (versus minute or absent). It differs from O. (A.) macrodentatus by the epimeral setal formula 3-1-3-3 (versus 3-1-2-3), normal seta h3 (versus much smaller and thinner than the other notogasral setae), surface of notogaster densely, and obviously granulate (versus punctate). It differs from O. (A.) holtmanni by the granulate notogastral surface (versus minutely and densely punctured), lyrifissure ips located between setae h3 and p3 (versus anterior to seta h3), the largest width of notogaster medially, near level of seta lp (versus the largest width rather anteriorly, near level of seta lm), vitta marginalis well developed, faint anteriorly (versus vitta marginalis visible only on anterior half of notogaster).

Otocepheus (Acrotocepheus) occultatussp. nov.

http://zoobank.org/16C79F8A-145D-40B4-9204-E2D6DC7124A0
Figs 23–26, 27, 28–29

Diagnosis

Body size (n = 4): 1240–1410 × 560–670. Bothridial seta with a long fusiform head and a short peduncle. Lateral prodorsal condyles on prodorsum small, rounded, lateral prodorsal condyles markedly anterior to medial prodorsal condyles. An extra pair of condyles located posterior to lateral prodorsal condyles, covered by lateral notogastral condyles. Lateral notogastral condyles large, width nearly equal with their mutual distance, tips markedly anterior to medial prodorsal condyles. Anterior median part of mentum with a lower lip ridge.

Figures 23–26. 

Otocepheus (Acrotocepheus) occultatus sp. nov., adult 23 bothridial seta 24 ventral view (legs not shown) 25 dorsal view 26 lateral lamelliform expansion. Scale bars: 100 µm (23, 26), 200 µm (24, 25).

Description

Measurements. Body length: 1280 (holotype: female), 1240–1410 (three paratypes: one female and two males); notogaster width: 530 (holotype), 560–670 (paratypes). Setae length and mutual distance (holotype): bs 85, in 220, le 235, ro 175, ex 19; c, la, lm, lp, h1, h2, h3, p1, p2, p3 range 150–300; c–c 200, la–la 300, lm–lm 230, lp–lp 350, h2–h2 225, h1–h1 230.

Integument. Body color light yellow-brownish. Body surface densely foveolate.

Prodorsum. Rostrum rounded. Rostral seta curved inward, densely barbed outside. Lamellar seta inserted behind tip of costula, moderately curved inward, roughened outside. Interlamellar seta barbed, setiform. Bothridial seta with a long fusiform head and a short peduncle. Exobothridial seta short. Costula straight, nearly paralleled. Bothridium opening laterally, dorsal bothridial plate straight, ventral bothridial plate broadly rounded in dorsal view. Lamelliform expansion pointing to bottom of seta ro. Two pairs of prodorsal condyles present. Lateral prodorsal condyles small, rounded, markedly anterior to medial prodorsal condyle. Median prodorsal condyles small, rounded, well separated from each other. An extra pair of condyles located posterior to lateral prodorsal condyles, covered by lateral notogastral condyles. Mutual distance between ventral bothridial plates larger than that between lateral prodorsal condyles. Subpedotectum well developed.

Notogaster. L/W of notogaster about 1.3. Surface of notogaster densely punctate. Lateral notogastral condyles large, triangular and rounded distally, inner part with a narrow base, anteromedial margins distinctly excavated, width nearly equal with their mutual distance, tips markedly anterior to medial prodorsal condyles. Medial notogastral condyles absent. Ten pairs of notogastral setae, slightly barbed, setae located posteriorly tend whip-like at tips. All lyrifissures well visible, ip located between setae p2 and p3, ips between setae h3 and p3. Opisthonotal gland opening located posterior to lyrifissure im. Vitta marginalis distinct.

Figure 27. 

Otocepheus (Acrotocepheus) occultatus sp. nov., adult: lateral view (legs not shown). Scale bar: 200 µm.

Epimeral and lateral podosomal regions. Surface punctured. Apodemes II and sejugal well developed, apodeme III invisible. Carina sterinalis short. Epimeral setal formula 3-1-3-3. Seta 4a inserted between 4b and 4c, and closer to 4c. Postpodosomal ornamentation invisible.

Anogenital region. A pair of longitudinal ridges posterior to epimeral setae 4a. Genital plates with two or three longitudinal ridges on both sides. Four pairs of genital setae smooth (mutual distances g1–g1≈g2–g2≈g4–g4<g3–g3). Aggenital lyrifissure located close and anterolateral to genital aperture. One pair of aggenital, two pairs of anal (mutual distances an1–an1<an2–an2), and three pairs of adanal setae. Anal setae barbed and blunt at tips, adanal setae barbed and whip-like at tips. Seta an2 well separated from outer margin of anal plate. Location of adanal setae normal, inside external margin of ventral plate. Setae ad3–ad3 below level of anterior margin of anal opening. Adanal lyrifissure located in diagonal position and close to anal aperture.

Gnathosoma. Anterior median part of mentum with a lower lip ridge. Subcapitular setae relatively smooth. Adoral setae and their alveoli absent. Rutellum pantelobasic, with typical dentition and rutellar brush. Chelicera chelate-dentate; with a minute denticle proximal to seta cha; cha longer than chb, both of them setiform, barbed; Trägårdh’s organ narrowly triangular. Palp with usual setal formula: 0–2–1–3–8 (+ω); setae of femur to tibia barbed. Tarsus with four short, blunt distal eupathidia–acm, su, (ul); other tarsal setae smooth or with sparse, inconspicuous barbs; solenidion ω connected with seta ul’, seta ul” medioanteriorly. Postpalpal seta erect, smooth.

Legs. Monodactylous. Claw of each leg strong and smooth. Formulae of leg setation and solenidia: I (1-4-3-4-16) [1-2-2], II (1-4-3-3-15) [1-1-2], III (2-3-1-2-14) [1-1-0], IV (1-2-2-2-12) [0-1-0]. Leg seta u setiform (L-type) on tarsi I, thorn-like (S-type) on tarsi II–IV. Homology of setae and solenidia indicated in Table 1.

Material examined

Holotype (male, ZLH-12-34): China, Guangxi Province, Wuming County, Daming Mountain, 23°29'42"N, 108°26'17"E, 1223 m a.s.l., in soil and debris under bush, 17 July 2012, collected by Lihao Zheng. Three paratypes (one female and two males, ZLH-12-37): same locality as holotype, 23°28'51"N, 108°27'18"E, 1410 m a.s.l., in soil and debris under tree, 20 July 2012, collected by Lihao Zheng.

Type deposition

All type specimens are deposited in the collection of IZAS.

Etymology

The specific name “occultatus” is from Latin for “hiding”, in reference to the extra condyles which are covered by the large lateral notogastral condyles.

Remarks

The new species is most similar to O. (A.) bajau Mahunka, 2000 from Malaysia and O. (A.) consimilis (Balogh, 1970) from Ceylon in having large lateral prodorsal condyles. However, it differs from O. (A.) bajau by the extra condyles on prodorsum covered by lateral notogastral condyles (versus none), bothridial seta with a long fusiform head (versus with a lanceolate head), tarsus I normal (versus with triangular teeth), and it differs from O. (A.) consimilis by the lateral prodorsal condyles markedly anterior to medial prodorsal condyles (versus lateral prodorsal condyles nearly in same line with median prodorsal condyles), seta an2 well separated from outer margin of anal plate (versus very close to outer margin of anal plate), notogastral setae located posteriorly tend whip-like at tips (versus not), normal location of adanal setae, and inside external margin of ventral plate (versus arising on and parallel with external margin of ventral plate).

Figures 28–30. 

Otocepheus (Acrotocepheus) occultatus sp. nov., adult. 28 subcapitulum, ventral view 29 right palp, abaxial view 30 right chelicera, adaxial view. Scale bars: 50 μm.

Otocepheus (Acrotocepheus) duplicornutus Aoki, 1965: new record in China

Figs 31–33, 34–36, 37–39

Otocepheus (Acrotocepheus) duplicornutus Aoki 1965: 303.

Otocepheus (Acrotocepheus) duplicornutus discrepans (A.): Balogh & Mahunka 1967: 49.

Diagnosis

Body size (n = 4): 1150–1400 × 480–600. Body ratio (length/width): 2.3–2.4. Lateral notogastral condyles appears to be double-structured, the outer portion of lateral notogastral condyles triangular anteriorly. Medial notogastral condyles absent. Postpodosomal ornamentation well developed. A pair of longitudinal ridges posterior to epimeral setae 4a present.

Description

Measurements. Body length: 1150–1400 (four males), notogaster width: 480–600 (four males). Setae length and mutual distance (one male, ZLH-12-73): bs 150, in 215, le 190, ro 150, ex 35; c, la, lm, lp, h1, h2, h3, p1, p2, p3 range 250–300; c–c 110, la–la 190, lm–lm 160, lp–lp 260, h2–h2 180, h1–h1 190.

Integument. Body color light brown, but genital plates and legs dark brown. Body surface densely foveolate.

Prodorsum. Rostrum rounded. Seta ro moderately curved inward, densely barbed outside. Seta le removed backward from tip of costula, curved inward, roughened externally. Setae le and in slightly barbed, with blunt tips. Bothridium opening laterally, dorsal bothridial plate nearly straight, ventral bothridial plate broadly triangular in dorsal view. Bothridial seta with lanceolate head, slightly roughened. Seta ex short, setiform. Tutorium developed. Lamelliform expansion pointing to bottom of seta ro. Costula well developed. Prodorsal condyles broadly rounded, well separated from each other. Subpedotectum well developed. Extra condyles posterior to lateral prodorsal condyles invisible.

Figures 31–33. 

Otocepheus (Acrotocepheus) duplicornutus Aoki, 1965, adult 31 Dorsal view 32 bothridial seta 33 ventral view (legs not shown). Scale bars: 200 µm (31, 33), 100 µm (32).

Notogaster. Anterior margin of notogater weakly concaved. Lateral notogastral condyles appears to be double-structured, the outer portion of lateral notogastral condyles triangular anteriorly. Medial notogastral condyles absent. Notogaster with ten pairs of setae, setiform, slightly barbed. Lyrifissures distinct, ip between setae p2 and p3, ips between setae h3 and p3, ih anterior to seta h3, im interiorly to opisthonotal gland opening.

Epimeral and lateral podosomal regions. Apodemes II and sejugal well-developed, apodeme III invisible, epimeral foramen small and rounded. Epimeral setal formula: 3-1-3-3. Setae setiform, 4a inserted between 4b and 4c, and closer to 4c. Postpodosomal ornamentation well developed.

Figures 34–36. 

Otocepheus (Acrotocepheus) duplicornutus Aoki, 1965, adult, microscope images 34 dorsal view 35 ventral view 36 lateral view. Scale bars: 200 µm.

Anogenital region. Aggenital lyrifissure located close and anterolateral to genital aperture. A pair of longitudinal ridges posterior to epimeral seta 4a present. Genital plates smooth. Four pairs of genital setae (mutual distances g1–g1≈g2–g2≈g4–g4<g3–g3) and one pair of aggenital setae present, setiform and slightly barbed. Three pairs of adanal and two pairs of anal setae (mutual distance an1–an1<an2–an2) slightly barbed. Setae ad3–ad3 below level of anterior margin of anal opening. Adanal lyrifissure located in diagonal position and close to anal aperture (in some specimens one of the adanal lyrifissures aligned transversely while the other one aligned diagonally), below level of anterior margin of anal opening.

Gnathosoma. Subcapitular setae fistulous, barbed. Adoral setae and their alveoli absent. Rutellum pantelobasic, with typical dentition and rutellar brush. Chelicera chelate-dentate; with a minute denticle proximal to seta cha; cha longer than chb, both of them setiform, barbed; Trägårdh’s organ narrowly triangular. Palp with usual setal formula: 0–2–1–3–8 (+ω); setae of femur to tibia barbed. Tarsus with four short, blunt distal eupathidia – acm, su, (ul); other tarsal setae smooth or with sparse, inconspicuous barbs; solenidion ω connected with seta ul’, seta ul” medioanteriorly. Postpalpal seta erect, smooth.

Figures 37–39. 

Otocepheus (Acrotocepheus) duplicornutus Aoki, 1965, adult 37 subcapitulum, ventral view 38 right palp, abaxial view 39 left chelicera, adaxial view. Scale bars: 50 μm.

Legs. Claw of each leg strong and smooth. Formulae of leg setation and solenidia: I (1-4-3-4-16) [1-2-2], II (1-4-3-3-15) [1-1-2], III (2-3-1-2-15) [1-1-0], IV (1-2-2-2-12) [0-1-0]. Leg seta u setiform (L-type) on tarsi I, thorn-like (S-type) on tarsi II–IV. Homology of setae and solenidia indicated in Table 1.

Material examined

One male (ZLH-12-72): China, Guangxi Province, Longzhou County, 22°25'19"N, 106°58'12"E, 149 m a.s.l., in soil and debris beside deadwood, 3 August 2012; one male (ZLH-12-73): same locality as ZLH-12-72, 22°25'11"N, 106°58'6"E, 154 m a.s.l., in soil and debris beside deadwood, 3 August 2012; one male (ZLH-12-74): same locality as ZLH-12-72, 22°25'7"N, 106°58'2"E, 166 m a.s.l., in soil and debris under liana, 3 August 2012; one male (ZLH-12-77): China, Guangxi Province, Fusui County, 22°27'36"N, 107°53'24"E, 100 m a.s.l., in soil and debris under leaf wood, 8 August 2012. All specimens were collected by Lihao Zheng.

Specimen deposition

Specimens are deposited in the collection of IZAS.

Remarks

The morphological characters of specimens checked in this study are almost coincident with the original description of this species by Aoki (1965), which was based on material collected from Sara Buri, Thailand, except for the following delicate differences: arc degrees of prodorsal condyles (broadly rounded versus semicircular) and alignment of adanal lyrrifissure (located in diagonal position versus generally aligned transversely). Though these characters are relatively constant in our limited specimens, the shape of prodorsal or notogastral condyles, as well as the alignment of adanal lyrrifissure, sometimes vary. So, we temporarily treat these minor differences as normal individual variation.

Key to known species of Otocepheus (Acrotocepheus) from China

1 Notogastral setae not longer than distance from nearest one O . (A .) gracilis Aoki, 1973
– Notogastral setae distinctly longer than distance from nearest one 2
2 Surface of notogaster with densely small convex granules, lateral notogastral condyles wide, like a lateral view of staircase with two to three steps mainly O . (A .) multigranulatus sp. nov.
– Surface of notogaster densely foveolate, lateral notogastral condyles not as above 3
3 Lateral notogastral condyles finger-shaped with wide base, notogastral setae c, la, h3, p1, p3 setiform and relatively short in length, while the rest flagelliform and distinctly longer in length O . (A .) digitatus sp. nov.
– Lateral notogastral condyles portion triangulate, notogastral setae nearly equal in length 4
4 A pair of extra condyles covered by lateral notogastral condyles , anterior median part of mentum with a lower lip ridge, notogastral setae located posteriorly tend whip-like at tips O . (A .) occultatus sp. nov.
– No extra condyles under lateral notogastral condyles present, anterior median part of mentum relatively flat, all notogastral setae setiform, without whip-like tipes O . (A .) duplicornutus Aoki, 1965

Acknowledgements

We cordially thank all the collectors of the specimens that we studied for this paper. Many thanks go to the anonymous reviewers and the subject editor, Dr Vladimir Pešić, for their thorough reviews of this manuscript and their many valuable suggestions. This work was supported by the National Natural Science Foundation of China (no. 31372155), the Ministry of Science and Technology of the People’s Republic of China (MOST grant no. 2016YFE0203100, 2005DKA21402), and the Second Tibetan Plateau Scientific Expedition and Research (STEP) program (grant no. 2019QZKK0501).

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