Zygoribatula iheyaensis, Nakamura & Fukumori & Fujikawa, 2010

Nakamura, Y. - N., Fukumori, S. & Fujikawa, T., 2010, Oribatid Fauna (Acari, Oribatida) From The Kumaya Cave Of Iheya Village In Central Ryukyu Arc, South Japan, With A Description Of Several New Species, Acarologia 50 (4), pp. 439-477 : 463-464

Zygoribatula iheyaensis sp. nov.

[Japanese name: Iheya-koitadani] ( Figs.17 and 18 )

Diagnosis — Body length 336 µm; width 214 µm. Sensilli with spiculate clavate head not terminating in fine point. Relative lengths le ≈ in> ss> ro> ex. Thirteen pairs notogastral setae. Four pairs of porose areas: Aa at a short distance from la; A1 posterior to lp; A3 near to h 1. Genito-anal setal formula: 4-1-2-3. Epimeral setal formula: 3-1-3-3. Heterotridactylous.

Material examined — Holotype (Male) (NSMT- Ac 13596) from point B.

Etymology — After the name of sampling area, Iheya Village.

Measurements and body appearance — Body length 336 µm; width 214 µm. Body colour light yellowish brown. Whole integument smooth.

Prodorsum — Rostral tip rounded, weakly protruding, bearing setae ro (38 µm) at lateral margins, extending anterior of rostrum for distance equal to half of their length ( Fig. 17A ). Lamellae convergent, extending from bothridia to about halfway along length of prodorsum, connected by thick translamella, arising setae le (58 µm) at apices; le extending anterior of rostrum for distance equal to one-third of their length Setae in (58 µm) extending for short distance in front of translamella. Relative distances (ro – ro) (48 µm) ≈ (in – in)> (le – le) (21 µm). Bothridia opened antero-laterally. Sensilli (ss) (56 µm) with spiculate clavate head not terminating in fine point (17B). Setae ex (6 µm) short, thick. Relative lengths le ≈ in> ss> ro> ex.

Notogaster — Oval, medially weakly protruding at anterior margin, bearing thirteen pairs notogastral setae and four pairs of porose areas. All notogastral setae thin, smooth setiform; setae p 2 absent. Porose areas Aa located lateral to setae la; A1 just behind lp; A2 postero-laterally to h 3; A3 anterolaterally to h 1. Lyrifissures ia aligned longitudinally postero-laterally to c 1 (19 µm); im obliquely anterior to lp; ih obliquely lateral to lp; ips obliquely posterior to ih; ip obliquely behind h 1. Opening gla situated postero-laterally to im.

Ventral region — Genital (48 µm) and anal (77 µm) apertures roughly circular; distance (77 µm) between them nearly as long as length of anal aperture ( Fig. 18B ). Genito-anal setal formula: 4-1-2-3; all setae smooth setiform. Setae g 1 (10 µm) inserted at anterior margin of plates. Setae ag (10 µm) inserted latero-posteriorly to genital aperture. Setae ad 1 (10 µm) aligned in postanal position; ad 2 in adanal; ad 3 in preanal. Lyrifissures iad located lateral to ad 3, in preanal position variable in direction. Epimeral borders bo. 1-3, sj interrupted medially. Sternal ridge

Nakamura Y.-N. et al.

and bo 4 indistinct. Epimeral setal formula: 3-1-3-3; setae barbed setiform; setae 1 a -c, 3 b and 3 c longer than other setae ( Fig. 18A ). Diarthric subcapitulum bearing 3 pairs of setae: a (4 µm), m (9 µm) and h (22 µm); a, m thin, smooth setiform; h barbed longer than a and m.

Legs — Heterotridactylous. Setal formula: I (1- 5-3-4-18), II (1-5-2-4-15), III (2-4-1-3-13), IV (1-2-2-3- 12). On tarsus I, famulus ε bacilliform situated posterior to solenidia ω 2; ω 2 setiform, sharply bending. Solenidion ω 1 bacilliform inserted latero-anterior to ω 2. Solenidion ’ 2 on tibia I lateral to ’ 1 ( Fig. 17C ).

Remarks — The new species resembles in some respects Zygoribatula truncata Aoki, 1961 , however, it differs from this latter species by long interlamellar setae, rounded tip of head of sensilli, protruding anterior medial margin of notogaster, and different situation of porose areas Aa, A1 and A3: Aa at a short distance from la, A1 posterior to lp, A3 near to h 1. Notogastral setae p 2 of the new species is absent as it is in Z. connexa substriata Grobler et Kok, 1993 . However, the new species is different from Z. connexa substriata in notogastral surface without faint yellow striations. Situation of notogaster setae and porose areas of the new species are very similar in appearance to those of Z. glabra ( Michael, 1890) and Z. propinguus ( Oudemans, 1902) . However, the new species differs from them because of a rounded rostrum.

Figures

FIGURE 17: Zygoribatula iheyaensis sp. nov. A, Dorsal view; B, Bothridial region; C, Solenidial region on tarsus and tibia of leg I.

FIGURE 18: Zygoribatula iheyaensis sp. nov. A, Anterior half of left ventral region; B, Genito-anal region.