Scapheremaeus ewani, Colloff, Matthew J., 2009

Colloff, Matthew J., 2009, Comparative morphology and species-groups of the oribatid mite genus Scapheremaeus (Acari: Oribatida: Cymbaeremaeidae), with new species from South Australia, Zootaxa 2213, pp. 1-46 : 24-26

Scapheremaeus ewani sp. nov.

( Fig. 12 )

Dimensions: Length: holotype: 390; paratype: 394. Breadth: holotype: 220; paratype: 212.

Integument. Cerotegument consisting of dark, coarse nodules. All surfaces of the body with ornate microsculpture

Prodorsum. Tuberculate laterally, with rugose pattern of poorly defined ridges medially between costulae. Rostrum pointed, rostral setae (ro) smooth, curved, ca. 17 long; lamellar setae (le; ca. 8 long) bacilliform, on squat, poorly-defined tubercles. Costulae with translamellate structure in posterior half; converging anteriorly; ending posteriorly as far as bothridia. Interlamellar setae and their alveoli absent. Sensillus club-shaped, darkly-pigmented, head ca. 18 broad, tuberculate; apex not extending beyond prodorsal margin.

Notogaster. Length 354. Circumdorsal scissure entire, with diagonal extensions into humeral region. Lenticulus present (ca. 31 long, 18 broad). Centrodorsal region 275 long, 157 broad with microsculpture consisting of transversely-directed ridges interspersed with tubercles. Microsculpture of region lateral of circumdorsal scissure consisting of parallel irregular ridges and troughs. Ten pairs of spiniform notogastral setae covered in dark cerotegument, giving them a club-shaped appearance; only seven pairs visible in dorsal view; lm and lp positioned on centrodorsal region. Caudal region convex. Lyrifissurae ih, ips and ip arranged radially on posterior half of laterodorsal region.

Lateral aspect. Prodorsal microsculpture composed of round, oval and elongate tubercles arranged in linear patterns. Costulae projecting markedly above surface of prodorsum; tubercle of lamellar seta free of prodorsal surface. Carina an angular ridge ventral of lamella; cusp or free projection absent. Pedotectum I auriculate, covering acetabulum I; pedoctectum II midway between acetabula II and III, apex directly ventral of short humeral spine.

Ventral region. Epimeral setal formula, numbers of aggenital, and anal setae typical of genus; 3 pairs of spiniform, darkened adanal setae; 6 pairs of genital setae; g 2 in line with g 1 along medial edge of genital plate. Caudal region trilobed. Ventral microsculpture consisting of series of ridges and tubercles. similar to that of centrodorsal region. Lyrifissure iad in para-anal position.

Gnathosoma . Typical of family. Tectum of mentum slight, not extending anteriorly as far as bases of setae a.

Legs. Claws heterotridactylous.

Material examined: Holotype and paratype: gutter of flight intercept trap, Casuarina woodland, 79 km NNW Renmark, 33°31’S 140°24’E; coll. K. Pullen, 29 March –3 May, 1995. Types in ANIC.

Etymology. This species is named after my eldest son, Ewan MacLeod Colloff.

Remarks. Scapheremaeus ewani sp. nov. can be distinguished from other members of the genus by the following combination of characters: 1) long curved rostral setae and bacilliform lamellar setae, 2) the incurved shape of the costulae with both a medial and posterior transcostular ridge; 3) a complete circumdorsal scissure with humeral extensions; 4) striae lateral of the costulae; 5) short, sub-triangular humeral processes; 6) 10 pairs of setiform notogastral setae with black, club-shaped cerotegument, those of the p series on ventral circumnotogastral plate; 7) a prominent centrodorsal ridge; 8) the centrodorsal microsculpture consisting of well-developed lateral ridges.

This species is most similar morphologically to S. lambieae (see remarks section for this species above), but differs in the morphology of the costulae and the centrodorsal microsculpture.

Figures

FIGURE 12. Scapheremaeus ewani sp. nov. (E) a) dorsal aspect; b) ventral aspect; c) lateral aspect.