Scapheremaeus minjambuta, 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 : 16-18

Scapheremaeus minjambuta sp. nov.

( Fig. 8 )

Dimensions. Holotype female: length 414, breadth 282. Ratio of length of prodorsum to total length (holotype): 0.26.

Prodorsum. With pattern of irregular ridges laterally ( Fig. 8 a). Rostrum broad, rounded; rostral seta (ro) smooth, curved, short, ca. 20 long. Lateral carinae absent. Lamellar seta spiniform, 14, on short tubercle. Apical trans-costular ridge present. Costulae diffuse, poorly defined ridges; inter-costular region irregular transverse ridges. Interbothridial ridge and interlamellar seta absent. Sensillus with large, smooth, clubshaped, darkly-pigmented head, ca. 20 long, 15 broad, emerging on short stalk from bothridium (diameter 15) positioned half its own diameter from dorsosejugal suture. Region posterior of interbothridial ridge with irregular ridges.

Notogaster. Length 312. Circumdorsal scissure entire, oval ( Fig. 8 a). Lenticulus wedge-shaped (34 long, 26 broad) with discrete margin. Humeral process well-developed, acute, spine-shaped when viewed dorsally. Dorsal circumnotogastral plate plicate. Centrodorsal plate 250 long, 135 broad, oval, broadest at level of setae lp, with well-developed centrodorsal ridge and posteriolateral concavities. Centrodorsal microsculpture consisting of irregular transverse ridges and foveolae. With ten pairs of notogastral setae those of c, l and h series bacilliform, short (ca. 20-25), smooth, covered in dark, club-shaped cerotegument, positioned on short tubercles; two pairs of setae on centrodorsal plate, five pairs on dorsal circumnotogastral plate; with three pairs of setae in p series, spiniform, with bacilliform cerotegument, positioned on ventral circumnotogastral plate. Opening of gla not visible. With five pairs of lyrifissures visible dorsally; ia positioned on ventral circumnotogastral plate medial of humeral process. Posterior margin of dorsal circumnotogastral plate smooth, rounded.

Ventral region. Epimeral setae setiform, setae 1b longer than others, almost twice the length of 1a, formula 3-1-2-2 ( Fig. 8 b). Microsculpture of ventral plate with irregular ridges and plaques. Rounded genital plates, slightly broader than long, with longitudinal ridges and six pairs of genital setae, sub-equal in length, positioned close to, but not on, medial edges; g 1 positioned lateral of g 2-6. Anal setae spiniform, 16, positioned almost their length from median edge of striate anal plates. With three pairs of spiniform adanal setae, subequal in length; ad 1 positioned close together. Posterior margin of circumgastric scissure indented.

Legs. Heterotridactylous; covered in thick cerotegument consisting of irregular ridges; porose areas on trochantera and femora. Seta l " on tibia I spiniform, straight, thick, barbed. Formula Leg I: 1-4-3(1)-3(2)- 14(2); Leg II: 1-4-3(1)-3(1)-12(1).

Lateral aspect. Mid-line of rostrum vertical ( Fig. 8 c). Hysterosoma dorsoventrally flattened. Exobothridial seta absent. Humeral process a sharp, dagger-shaped process.

Material Examined. Holotype female, soil and moss, burnt area, Eucalyptus forest, Mount Buffalo National Park, 36°42´39″S, 146°50´06″, 621 m., coll. J. Błoszyk & S. Konwerski, 16.vii.2007 (MTB-032).

Etymology. Scapheremaeus minjambuta sp. nov. is named after the Minjambuta Aboriginal People, for whom Mount Buffalo was part of their traditional country, and where they gathered during summer for ceremonies and to feed on the migrating swarms of Bogong Moth, Agrotis infusa (Boisduval) , that congregate there.

Remarks. Scapheremaeus minjambuta sp. nov. differs from other members of the genus by the following combination of characters: 1) well-developed trans-lamellar ridge, but costulae poorly-defined, consisting of diffuse ridges; 2) large, acute humeral processes visible dorsally; 3) wedge-shaped lenticulus; 4) smooth sensillus; 5) circumgastric scissure with a U-shaped extension behind the anal plate; 6) centrodorsal region of transverse ridges and irregular foveolae and 7) setae g 2 displaced laterally from alignment of the other genital setae.

Scapheremaeus minjambuta sp. nov. is a member of the Petrosus species-group. It is morphologically most similar to S. bulbosensillatus sp. nov. (cf. remarks above).

Figures

FIGURE 8. Scapheremaeus minjambuta sp. nov. a) dorsal; b) ventral; c) lateral.