Oribatula kumayaensis, 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 : 461-463

Oribatula kumayaensis sp. nov.

[Japanese name: Kumaya-koitadani] ( Figs. 15 and 16 )

Diagnosis — Body length 314 µm; width 193 µm. Rostral tip rounded, weakly protruding. Sensilli conspicuously verrucose club-shaped head. Four pairs of porose areas like deep cavity, surrounded by clearly sclerotized areas. Fourteen pairs of notogastral setae. Porose areas Aa situated posterior to c 1 and lateral to c 2; da posterior to c 2. Genito-anal setal formula 4-1-2-3. Epimeral setal formula: 3-1-3-3. Heterotridactylous.

Material examined — Holotype (Male) (NSMT- Ac 13595) from point D.

Etymology — After the name of sampling point, Kumaya Cave.

Measurements and body appearance — Body length 314 µm; width 193 µm. Body colour light yellowish brown. Whole integument smooth.

Prodorsum — Rostral tip rounded, weakly protruding, bearing setae ro (47 µm) thick, ciliate, setiform, at lateral margins, extending anterior of rostrum for distance equal to half of their length ( Fig. 15A ). Lamellae convergent, extending from bothridia to about half-way along length of prodorsum, setae le (51 µm) arising at base of short extention, without cusp nor translamella. Setae le and in (54 µm) thick spiniform, ciliate throughout length, extending for short distance anterior of insertions of setae ro and le, respectively. Relative distances, (in – in) (52 µm)>(ro – ro) (41 µm)> (le – le) (40 µm). Bothridia opened antero-laterally. Sensilli (ss) (34 µm) consisting of conspicuously verrucose club-shaped head and smooth thin long stem. Setae ex thin setiform, roughened throughout length.

Notogaster — Oval, bearing four pairs of porose areas like deep cavity (about 4 µm in depth, 9 µm in diameter), surrounded by clearly sclerotized areas ( Fig. 16A ). Fourteen pairs of notogastral setae present; c 1 (23 µm) barbed spiniform, thicker than the remainder; other setae thin, smooth setiform. Porose areas Aa situated posterior to c 1 and lateral to c 2; da posterior to c 2. Lyrifissures ia aligned obliquely lateral to c 1; im obliquely immediately anterior to A1; ih and ips obliquely to notogastral outline; ip obliquely behind h 1. A number of light spots arranged peripherally on notogaster.

Ventral region — Genital (42 µm) and anal (54 µm) apertures roughly circular; distance (78 µm) between them about 1.9x and 1.5x as long as length of genital and anal apertures, respectively ( Fig. 16B ). Genito-anal setal formula 4-1-2-3; all setae smooth setiform. Setae g 1 (12 µm) inserted at anterior margin of plates; setae g 3 near lateral margins. Setae ag (17 µm) inserted latero-posteriorly to genital aperture. Setae an 1 (12 µm) inserted almost middistance along plates. Setae ad 1 (15 µm) aligned in postanal position; ad 2 in adanal; ad 3 in preanal. Lyrifissures iad located postero-laterally to ad 3, at anterior margin of anal aperture. Sternal ridge indistinct. Epimeral borders bo. 1, sj distinct. Epimeral setal formula: 3-1-3-3; setae thin, smooth setiform. Diarthric subcapitulum bearing 3 pairs of setae: a (15 µm), m (19 µm) and h (19 µm); setae thin, smooth setiform ( Fig. 15B ).

Legs — Heterotridactylous. Setal formula: I (1- 5-2-3-17), II (1-5-2-3-14), III (2-3-1-3-12), IV (1-2-2-3- 12). On tarsus I, famulus ε setiform situated immediately posterior to solenidion ω 2; ω 2 posterior to ω 1. Solenidion ω 1 bacilliform and ω 2 setiform. Solenidion ’ 1 on tibia I originating from apophysis; ’ 2 situated laterally at base of apophysis ( Fig. 15C ).

Remarks — The new species resembles in some respects of Oribatula (Oribatula) sakamorii Aoki, 1970 ( Fujikawa, 1983; Bayartogtokh and Aoki, 2000). However, the new species differs from this latter species in having short lamellar setae, porose areas like deep cavity, sensilli with club-shaped head, long custodium, and mutual distances, (1 a – 1 a) ≈ (2 a – 2 a). As far as the authors know, form of porose areas such as found in the new species, was also, recorded in O. magniporosa Hammer, 1958 , O. exsudans TravØ, 1961, and Zygoribatula dubita Coetzer, 1967 -1968. However, the new species has different insertion of lp, h 2 and h 3 than the ones of O. magniporosa , different form of humeral region, length of le, insertion of c 2 and direction of im than those of O. exsudans , and different form of rostral anterior margin and lamellae than those of Z. dubita . Sensilli and lamellar tips of the new species are similar in appearance to those of O. parisi TravØ, 1961 and O. interrupta ( Willmann, 1939) . However, the new species can be distinguished from them by relative distances between their mutual distances of ro, le and in, and from O. interrupta by situation of porose areas Aa.

Figures

FIGURE 15: Oribatula kumayaensis sp. nov. A, Prodorsum; B, Anterior half of ventral region; C, Solenidial region on tarsus and tibia of leg I.

FIGURE 16: Oribatula kumayaensis sp. nov. A, Right half of notogaster; B, Genito-anal region.