Scapheremaeus zephyrus, Colloff, Matthew J., 2010

Colloff, Matthew J., 2010, The hyperdiverse oribatid mite genus Scapheremaeus (Acari: Oribatida: Cymbaeremaeidae) in Australia, with descriptions of new species and consideration of biogeographical affinities, Zootaxa 2475, pp. 1-38 : 30-32

Scapheremaeus zephyrus sp. nov.

( Fig. 15 )

Dimensions. Holotype female: length 384, breadth 202; paratype female: length 391, breadth 211. Ratio of length of prodorsum to total length (holotype): 0.28.

Prodorsum. Rostrum broad, U-shaped, with transverse striae ( Fig. 15 a). Rostral seta (ro) smooth, short (9) straight, spiniform. Lateral carinae present as a pair of well-developed lateral ridges. Lamellar seta short (6), bacilliform, on short tubercles at apices of straight costulae. Intercostular area with slight, faint interlamellar ridge and mid-transcostular ridge; with large, polygonate plaques posterior of mid-intercostular ridge. Faint interbothridial ridge present. Interlamellar seta absent. Sensillus with large, club-shaped, darklypigmented head, sparingly ornamented with flat tubercles, ca. 24 long, 15 broad, emerging on short stalk from bothridium (diameter 11) positioned adjacent to dorsosejugal suture.

Notogaster. Length 272. Circumdorsal scissure entire, oval ( Fig. 15 a), with well-developed diagonal humeral extensions. Lenticulus wedge-shaped, sub-rectangular, (27 long, 18 broad) with discrete margins and a ridge of cuticle immediately posterior of it. Without a shallow depression or tubercle either side of lenticulus. No humeral process evident in dorsal view, but lateral margin of notogaster concave immediately posterior of humeral region. Dorsal circumnotogastral plate sparingly plicate. Centrodorsal plate 211 long, 130 broad, oval, broadest at level of setae lp. Centrodorsal ridge and posteriolateral concavities absent. Centrodorsal microsculpture consisting of large, sparsely-distributed, shallow alveoli. With nine pairs of short bacilliform notogastral setae, similar in size and shape, positioned on well-developed cylindrical or conical tubercles; two pairs of setae on centrodorsal plate, five pairs on dorsal circumnotogastral plate; two pairs of short, spiniform setae in p series positioned on ventral circumnotogastral plate. Opening of gla about mid-way between setae lm and lp. With three pairs of lyrifissures visible dorsally and one laterally. Posterior margin of dorsal circumnotogastral plate rounded, crenellated; circumnotogastral plate narrower in caudal region than laterally.

Ventral region. Epimeral setae setiform, thin, subequal in length, formula 3-1-2-2 ( Fig. 15 b). Microsculpture of ventral plate with transverse and longitudinal striae and alveoli in epimeral region. Subhexagonal genital plates as broad as long, striate, with six pairs of longitudinally-aligned genital setae positioned close to, but not on, medial edges. Genital setae sub-equal in length; same size and shape as epimeral setae. Anal setae setiform, 10, positioned on posterior half of anal plates, almost their length from median edge. With two pairs of subequal, spiniform adanal setae; ad 2 positioned at least their length from margin of anal plates; mutual distance between ad 1 half that between ad 1 and ad 2. Circumgastric scissure with two shallow V-shaped invaginations medial of setae p 1. Ventral circumnotogastral plate not plicate but with short, V-shaped, overlapping, scale-like ridges.

Lateral aspect. Mid-line of rostrum curved, acute ( Fig. 15 c). Hysterosoma markedly dorsoventrally flattened. Exobothridial seta absent. Humeral process consisting of broad, shallow, triangular region, bearing lyrifissure ia ventrally. Centrodorsal region flat, ridge absent.

Legs. Heterotridactylous.

Material Examined. Holotype female and paratype female, ex. litter, coastal heathland, Little Target, Beecroft Peninsula (35°03´S, 150°48´E), New South Wales, coll. D.J. Smith and P. Greenslade, 9.vi.1995. Non-type material: larva and protonymph (same sample as types).

Etymology. Scapheremaeus zephyrus sp. nov. is named from the Latin, zephyr, meaning ‘light [sea] breeze’, or ‘west wind’, an allusion to its lightly-sclerotised, lightly-ornamented cuticle and its coastal type locality.

Remarks. Scapheremaeus zephyrus sp. nov. differs from other members of the genus by the following combination of characters: 1) the flat centrodorsal region, when viewed laterally; 2) the sparse, alveolate centrodorsal microsculpture; 3) the circumnotogastral plate much narrower caudally than laterally; 4) the scale-like ornamentation of the ventral circumnotogastral plates; 5) nine pairs of notogastral setae (missing setae p 3) and two pairs of adanal setae (missing setae ad 3)

Scapheremaeus zephyrus sp. nov. is a member of the Carinatus species-group. It shares with S. alisonae sp. nov. and S. nivalis sp. nov. the character states of this group, as well as the reduction in notogastral setation (nine pairs) and adanal setation (two pairs); small, broad, triangular humeral processes, notched circumgastric scissure and the genital setae in alignment.

Figures

FIGURE 15. Scapheremaeus zephyrus sp. nov. a) dorsal; b) ventral; c) lateral.