Otocepheus (Acrotocepheus) digitatus, Zheng & Chen, 2020

Zheng, Li-Hao & Chen, Jun, 2020, Three new species of the subgenus Otocepheus (Acrotocepheus) (Acari, Oribatida, Otocepheidae) from China, ZooKeys 934, pp. 1-23 : 1

Otocepheus (Acrotocepheus) digitatus sp. nov. 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, h 1, h 2, p 2 flagelliform and distinctly longer than the others. Genital plates each with two longitudinal, slant furrows.

Description.

Measurements (holotype: male). Body length: 1020, notogaster width: 330. Setae length and mutual distance: bs 100, in 140, le 180, ro 160, ex 25; c, la, h 3, p 1, p 3 range 100-160; lm, lp, h 1, h 2, p 2 range 300-450; c - c 120, la - la 160, lm - lm 190, lp - lp 240, h 2- h 2 160, h 1- h 1 170.

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, h 3, p 1, p 3 setiform and relatively short in length, while the rest notogastral setae lm, lp, h 1, h 2, p 2 flagelliform and longer in length. Setae c, la, lm nearly located on the same line. All lyrifissures well visible, ip located between setae p 2 and p 3, ips between setae h 3 and p 3. 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 g 1- g 1≈ g 2- g 2≈ g 4- g 4<g 3- g 3). Aggenital lyrifissure located close and anterolateral to genital aperture. One pair of aggenital, two pairs of anal (mutual distances an 1- an 1<an 2- an 2) and three pairs of adanal setae similar in length. Setae ad 3- ad 3 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 .

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, h 1, h 2, p 2 (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, h 1, h 2, p 2 (versus setiform), setae c, la, h 3, p 1, p 3 shorter than the other notogastral setae (versus length increasing toward the posterior part of notogaster), lyrifissure ips located between h 3 and p 3 (versus between p 3 and p 2), surface of notogaster densely foveolate (versus granulate).

Figures

Figure 7. Otocepheus (Acrotocepheus) digitatus sp. nov., adult, microscope image, ventral view. Scale bar: 200 µm.

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).