Dyobelba crossleyi, 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 : 60-63

Dyobelba crossleyi sp. nov.

( Figs. 13 , 14 )

Diagnosis. Prodorsum with propodolateral apophyses P strongly developed, projecting anterolaterally; tubercle Ba well developed; enantiophysis A absent; sensillus long, thin, smooth, flagellate, with shepherd’s crook bend. Notogastral setae slightly thickened in middle, with conspicuous barbs, most with small basal vane on inner curvature; spinae adnatae minute. Tectum of podocephalic fossa projected as strong triangular tooth under trochanter I; ventral enantiophyses V and S well developed; all epimeral setae situated on conspicuous small tubercles; discidium well developed; setae d on genua I–III nearly equal to or slightly longer and thicker than their coupled solenidia σ; solenidia ϕ of tibiae II and III as long as their associated setae d.

Description. Dimensions. Body length 305-366 (332) Μm; length of notogaster 207-244 (227) Μm; width of notogaster 171-207 (191) Μm.

Integument. Body yellowish brown. Surface of body and leg segments with very thick granular cerotegument. Microtuberculate throughout, conspicuous on prodorsum, especially in areas of alveolate sculpturing as noted below, and around leg acetabula. All setae of prodorsum and notogaster with thin cerotegument, covering basal and medial parts.

Prodorsum ( Figs. 13 A, D, 14A). With pair of weak central swellings at level of legs I (above sigillae for cheliceral retractor muscles). Enantiophysis A absent; postbothridial tubercle Ba nearly triangular in shape, its tip usually rounded, but sometimes acute. Propodolateral apophysis P strongly developed, projecting anterolaterad. Alveolate sculpturing in following regions: on and lateral to central swellings of prodorsum (but not between them); on apophysis P, extending ventrally to lateral regions of epimeres I, II; across dorsosejugal furrow with narrow medial extension on slight swelling at level of setae in; on all acetabular tecta, weakly on III, IV. Dorsal end of acetabular tectum I with distinct, posteriorly directed tooth (lt). Rostral and lamellar setae smooth or with sparse, weak barbs. Interlamellar seta relatively short, thin, smooth, directed posteriorly. Exobothridial seta thin, smooth, shorter and thinner than in. Sensillus long, thin, smooth, flagellate, with shepherd’s crook bend distally. Bothridium irregularly funnel-shaped, directed posterolaterad.

Notogaster ( Figs. 13 A, 14A). Oval, slightly longer than wide. Spinae adnatae small to minute, little longer than lyrifissure ia; mutual distance about four times greater than that of notogastral setae c1. Notogastral setae of c, l and h rows slightly thickened medially, conspicuously barbed on outer curvature, with small proximal vane on inner curvature. Setae of p row relatively short, smooth, directed lateroventrad.

Gnathosoma . Subcapitular mentum slightly wider than long. Mentum with pair of transverse carinae posterior to setae h; with inconspicuous microtubercles throughout, some merged as short striae. Hypostomal setae h, m and a medium long, conspicuously barbed. Cheliceral setae cha and chb smooth.

Epimeral region ( Figs. 13 B, 14A). Lateral end of tectum of podocephalic fossa strongly projected as triangular tooth underneath trochanter I (seen only on edge in Fig. 13 B). 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 setae situated on distinctly developed microtubercles.

Ano-genital region ( Figs. 13 B, 14A). Ano-genital setae medium long, smooth. Adanal lyrifissure (iad) situated obliquely, approximately at level of setae an2.

Legs ( Figs. 14 B-E). Structure of legs I–IV mostly typical for genus, sub-moniliform. Distal tectum of trochanters III and IV rounded, not projected. Femora I and II with small, rounded proximal spur. Setae d on genua I–III nearly equal to or slightly longer and thicker than their coupled solenidia σ; solenidia ϕ of tibiae II and III as long as their associated setae d.

Material examined. Holotype (female): Georgia, Thomas Co., US Rt. 19, ca 13 miles north of Florida state line, col. R. A. Norton, 15 August 1974, ex. litter under large live oak. Paratypes: five (three males, two females) with same data as holotype. Paratypes are deposited in the FMNH (1), CNC (1), NUMU (1) and RAN (2) collections. All specimens are in alcohol.

Remarks. Dyobelba crossleyi sp. nov. is known only from the type locality in southern Georgia (Thomas Co.); all material came from leaf litter under live oak, Quercus virginiana .

Adults are distinguishable from others in the tectopediosa species-group in having the combination of: 1) longitudinally-directed notogastral setae that are barbed and only slightly thickened; 2) a flagellate sensillus with shepherd’s crook bend; 3) central prodorsal swellings that are alveolate except medially; and 4) the absence of prodorsal tubercle Aa. It is most similar to D. dindali sp. nov., from which it can be distinguished by lacking tubercle Aa, having less extensive prodorsal alveolation, and having a more prominent propodolateral apophysis.

Etymology. This species is named in honor of Prof. D. A. Crossley (retired), eminent soil ecologist at the University of Georgia. Oribatid mites were often a focus during his exemplary career as researcher and teacher.

Figures

FIGURE 13. Dyobelba crossleyi sp. nov. A, dorsal view. B, ventral view. C, part of epimeral and hypostomal regions. D, prodorsum and anterior part of notogaster.

FIGURE 14. Dyobelba crossleyi sp. nov. A, lateral view (legs removed). B, leg I (right, antiaxial aspect, trochanter removed). C, genu and tibia II (left, antiaxial aspect). D, genu and tibia III (right, antiaxial aspect). E, leg IV (right, antiaxial aspect).