Oribatella vicinus ( Ryabinin, 1975 )

Ermilov, Sergey G. & Behan-Pelletier, Valerie M., 2014, Revision of Fenestrobates (Acari, Oribatellidae) with description of F. marauni sp. nov., from South America, and new diagnosis for Oribatellidae, Zootaxa 3827 (2), pp. 258-272 : 267-268

Oribatella vicinus ( Ryabinin, 1975)

Fenestrobates vicinus Ryabinin, 1975 p. 540

Material examined. Holotype male, kindly loaned from the Zoological Institute of the Russian Academy of Sciences, St. Petersburg, Russia.

Diagnosis. Total length of adult male about 576. Integument of prodorsum, notogaster, venter and mentum micropunctate. Integument of lenticulus and coxisternum with distinct striae, as in Oribatella jacoti Behan- Pelletier 2011. Rostrum medially rounded with pair of small lateral teeth on margin, as in O. brevicornuta Jacot, 1934 (see Fig. 2D, E, F in Behan-Pelletier 2011). Lamella (with cusp) about 162 long, cusp about 108 long, 62 wide at level of insertion of seta le. Lamellar cusps diverging anteromedially; separated posteromedially, leaving prodorsum visible through oval opening about 14 at widest. Medial dens of lamellar cusps about 52 – 55 µm, subequal to length lateral dens; medial dens smooth; lateral dens with about three small teeth on lateral edge. Long striae extending longitudinally along outer margin of lamella. Translamella without tooth, about 14 at greatest width, about 26 deep. Setae ro strongly barbed along length, acuminate, strongly directed medially. Setae le about 79 long, thick, heavily barbed, tapered. Setae in 172 long, thick (less so than le), heavily barbed, tapered; mutual distance of pair about 81 µm. Sensillus 141 long, subequal in width to seta le, except head slightly fusiform, tapered, stalk with small barbs distally; head directed slightly anteromedially, as in O. brevicornuta (see Fig. 3 , insert in Behan-Pelletier 2011). Exobothridial seta not visible. Genal tooth broad, subtriangular, rounded distally, without dens ventrodistally, with longitudinal ridge ventrally. Tutorium including cusp about 168 long, rectangular, distal margin with eight to 10 dentes. Ventral depression between pedotectum I and the lateral body wall less defined than that in O. brevicornuta . Custodium about 58 long, extending to anterior margin of pedotectum II. Anterior margin of notogaster undulating, convex lateral of bothridium, with about 10 transverse ridges. Pteromorph with dens anteroventrally. Four pairs of porose areas present, Aa circular about 12 at widest. Ten pairs of long, barbed notogastral setae present; setae barbed, acuminate, almost flagellate 52 – 79 long ( Fig. 4 of Ryabinin 1975). Setae h 1 directed posteriorly and parallel as in O. jacoti ( Behan-Pelletier, 2011) . Distance h 1 –h 1 and p 1 –p 1 subequal, about 23 – 26. Lenticulus subtriangular. Epimeral setation 3(?) – 1 – 3 – 3; barbed, tapered, length not established except 3b, about 72, 4a, 4b about 29 – 36, long, spinous. Setae 3b, 4a, 4b, strongly directed anteriorly ( Fig. 5 of Ryabinin 1975). Genital setae 6 pairs, two seta on anterior of genital plate. Mentum with anterior tectum covering base of gena, reflexed anteriorly, similar in size and shape to that for Oribatella yukonensis Behan- Pelletier and Walter, 2012 (their Fig. 14G ). Seta l” of tibia I about 53. Tarsi heterotridactylous.

Remarks. The description of this species by Ryabinin (1975) is brief and lacks measurements. We redescribe this species based on the slide mounted holotype male. This is a dorsal mount which precludes evaluation of ventral and lateral characters. Ryabinin (1975) assigned this species to Fenestrobates on the basis of its similarity to O. rossicus . He stated “The new species is similar to F. rossicus from Primorye territory ( Krivolutsky 1974)”. The species are similar but can be easily separated by the long, acuminate notogastral seta in O. vicinus vs. the short notogastral setae of O. rossicus ; the very long epimeral seta 3b (96) in O. rossicus vs. shorter seta (72) in O. vicinus ; setae h 1 directed posteriorly and parallel in O. vicinus vs. curved h 1 in O. rossicus . We were unable to verify whether O. rossicus had 11 pairs of notogastral setae vs. the 10 pairs found in O. vicinus .

Figures

FIGURES 1–3. Fenestrobates marauni sp. nov., adult: 1—dorsal view; 2—ventral view (legs not illustrated); 3—lateral view. Scale bar 100 µm.

FIGURES 4–11. Fenestrobates marauni sp. nov., adult: 4—rostrum, dorso-anterior view; 5—anterior part of tutorium, lateral view; 6—subcapitulum, left half, ventral view; 7—palptarsus; 8—anterior part of chelicera; 9—pedotectum II, ventro-lateral view, epimeral seta 3c and basal part of leg II; 10—genital plate, left; 11—anal plate, left. Scale bars (4–6, 4–6, 8–11) 20 µm, scale bar (7) 10 µm.

FIGURES 12–15. Fenestrobates marauni sp. nov., adult: 12—leg I, left, antiaxial view; 13—leg II, left, antiaxial view; 14—leg III, right, antiaxial view; 15—leg IV, right, paraxial view. Scale bar 20 µm.