Dyobelba granulata, Bayartogtokh, Badamdorj & Norton, Roy A., 2007

Bayartogtokh, Badamdorj & Norton, Roy A., 2007, The Dyobelba tectopediosa species-group (Acari: Oribatida: Damaeidae) from the Southeastern USA, with a key to world species of Dyobelba and notes on their distribution, Zootaxa 1591, pp. 39-66 : 57-60

Dyobelba granulata sp. nov.

(Figs. 11-12)

Diagnosis. Prodorsum with apophysis P not strongly projected anterodistally; tubercles Aa and Ba well developed; alveolate sculpturing distributed in dorsal and lateral patches. Sensillus very long, thin, smooth, flagellate, with shepherd’s crook bend. Notogastral setae claw-shaped, with conspicuous barbs, setae c1 and c2 directed anteriorly, those of l and h rows directed posteriorly; spinae adnatae relatively small. Tectum of podocephalic fossa projected at lateral end as triangular tooth under trochanter I; ventral enantiophyses V and S well developed; all epimeral setae on conspicuous small tubercles; discidium well developed. Setae d on genua I-III slightly longer and thicker than respective coupled solenidia σ; solenidia ϕ of tibiae II and III shorter than their coupled setae d.

Description. Dimensions. Body length 333–372 (353) Μm; length of notogaster 230–271 (249) Μm; width of notogaster 196–235 (215) Μm.

Integument. Body yellowish brown. Surface of body and legs with thick granular cerotegument. Microtuberculate throughout, conspicuous on rostrum, bothridial region, in areas of alveolate sculpturing as noted below, and on basal leg segments. All setae of prodorsum and notogaster with thin cerotegument, at least basally and medially.

Prodorsum (Figs. 11A, D, 12A). With slight transverse groove at level of seta ro and pair of central swellings behind level of legs I (above sigillae for cheliceral retractor muscles). Prodorsal tubercle Aa well developed, Ap absent; postbothridial tubercle Ba nearly triangular in shape, its tip usually rounded, but sometimes acute. Propodolateral apophysis not strongly projected anterodistally. Alveolate sculpturing in following regions: anterolateral to prodorsal swellings (but not on them); on propodolateral apophyses extending to lateral region of epimeres I, II; in sejugal furrow between tubercles Ba; on all acetabular tecta, least developed on III, IV, that on I continuous with dorsal patches. Tooth (lt) at dorsal end of acetabular tectum I weak or absent. Rostral and lamellar setae mostly smooth, with sparse barbs at base; interlamellar seta relatively short, thin, smooth, directed posteriorly; exobothridial seta thin, smooth, shorter and thinner than in; sensillus long, thin, smooth, flagellate, with distal shepherd’s crook bend. Bothridium typical of family, irregularly funnelshaped, directed posterolaterad.

Notogaster (Figs. 11A, 12A). Oval, slightly longer than wide. Spinae adnatae small, thin, absent from several paratype specimens; directed anteroventrally. Notogastral setae of rows c, l and h curved, claw-shaped, with conspicuous barbs mostly restricted to sides and outer curvature, with narrow hyaline (birefringent) base abruptly broadening due to thin, flat vane stretching across inner curvature of main axis (Figs. 5F, 11D); c1 and c2 curved anteriorly, l and h rows curved posteriorly. Setae of p row thin, smooth, directed laterally.

FIGURE 11. Dyobelba granulata sp. nov. A, dorsal view. B, ventral view. C, prodorsum and anterior part of notogaster. D, isolated notogastral setae c2 and la, dorsal aspect. (Only bases of legs drawn in A-C).

Gnathosoma . Subcapitular mentum slightly wider than long. Mentum with or without weak transverse carinae; with granular microtubercles, some merged to form weak transverse striae. Subcapitular setae h, m and a medium long, thin, smooth. Cheliceral setae cha and chb smooth.

Epimeral region (Figs. 11B, 12A). Lateral end of tectum of podocephalic fossa projected as triangular tooth under trochanter I (seen only on edge in Fig. 11B); medial end of tectum often with small tooth. Ventrosejugal tubercles Va and Vp well developed, large subtriangular, nearly round at tip. Parastigmatic tubercles Sa and Sp subtriangular; Sa much larger than Sp. Discidium nearly triangular, rounded at tip. Epimeral setae medium long, thin, smooth; all situated on distinct small tubercles.

Ano-genital region (Figs. 11B, 12A). Ano-genital setae medium long, smooth. Adanal lyrifissure situated obliquely, at level anterior to anal setae an2. Anal and genital plates with granular microtubercles.

Legs ( Figs. 12 B-E). Structure of legs I–IV mostly typical for genus, sub-moniliform. Trochanter and femur IV subequal in length. Distal tectum of trochanters III and IV not projected, but rounded. Femora I and II simple, without proximal spur or retrotectum. Setae d of genua I–III slightly longer and thicker than respective coupled solenidia σ; solenidia ϕ of tibiae II and III conspicuously shorter than respective coupled setae d.

Material examined. Holotype (female): North Carolina, Yancey Co., Blue Ridge Parkway, 5 miles south from entrance road to Mt. Mitchell State Park, litter at base of red spruce in spruce, yellow birch forest, 14 August 1974, Col. R. A. Norton. Paratypes: 23 (11 males, 12 females) with same data as holotype; one (unsexed) from Buncombe Co., Horse Trough Ridge Overlook, col. R. A. Norton, 15 May 1976, ex. litter in mixed hardwood slope forest (red oak, sugar maple, shingle oak). Paratypes are distributed among the FMNH (5), CNC (5), NUMU (2) and RAN (12) collections; three are slide-mounted, the remainder are in alcohol.

Remarks. Dyobelba granulata sp. nov. is known only from North Carolina (Yancey and Buncombe Co.). It appears to be endemic to the middle and southern Appalachian region in the eastern USA. The known habitat is litter in mixed forests.

Adults are distinguishable from others in the tectopediosa species-group in having the combination of: 1) longitudinally-directed notogastral setae that are claw-like, barbed and unusually wide; 2) a flagellate sensillus with shepherd’s crook bend; 3) central prodorsal swellings that lack alveolation; and 4) the presence of prodorsal tubercle Aa. It is most similar to D. dindali sp. nov., from which it can be distinguished by having thicker notogastral setae and less extensive prodorsal alveolation.

Etymology. The specific name “ granulata ” refers to the thick, rough granular cerotegument of the body.

Figures

FIGURE 12. Dyobelba granulata sp. nov. A, lateral view. B, leg I (left, antiaxial aspect). C, genu and tibia II (left, paraxial aspect). D, genu and tibia III (right, antiaxial aspect). E, leg IV (right, antiaxial aspect).