Eremaeozetes darwinensis, Colloff, Matthew J., 2012

Colloff, Matthew J., 2012, New eremaeozetid mites (Acari: Oribatida: Eremaeozetoidea) from the south-western Pacific region and the taxonomic status of the Eremaeozetidae and Idiozetidae, Zootaxa 3435, pp. 1-39 : 8-10

Eremaeozetes darwinensis sp. nov.

( Fig. 4 )

Dimensions. Holotype female length 360 μm, breadth 195 μm. Paratype female length 353 μm, breadth 198 μm. Ratio of prodorsum to total length: 0.31 (holotype).

Female. Cerotegument: thin, light; only partially covering prodorsum; sparse ventrally.

Prodorsum: Lamellae broad, narrowing anteriorly, fused posteriomedially, striated posteriolaterally, otherwise smooth, separated along anterior third by narrow oval median slit. Lamellar cuspides curved medioventrally, separated apically. Posteriolateral lamellar margins diagonal, parallel with bothridia ( Fig. 4 a). Rostral seta (ro) thin, minute (4 μm long), emerging from squat tubercle ( Fig. 4 b). Lamellar seta (le) 5 μm long, spiniform, emerging from apex of lamella. Bothridial seta 75 μm long; reflexed; head narrow, club-shaped, barbed. Bothridium prominent, elongate, cup-shaped, with parallel internal ridges; rim undulating.

Notogaster: Length 247 μm; ratio of length to breadth 1.2; notogaster broad, sub-rectangular; broadest humerally in region of pteromorphs. Dorsosejugal suture acute medially, median projection entire, extending as far as bothridia ( Fig. 4 a). Dorsosejugal lobe well-developed, extending anteriorly as far as bothridium, sub-triangular, medial margin concave. Lenticulus entirely on median projection of dorsosejugal suture, 26 μm long, 23 μm broad, ovoid, with discrete, simple margin. With paired undulating longitudinal ridges, expanding laterally at level of setae lp, then converging medially. Lateral ridges between ih, im and h 2. Cuticle in humeral region mildly ridged, foveolate, otherwise smooth. Eleven pairs of setae or their alveoli; da represented by alveolar vestiges, the rest smooth, short (5–8 μm) spiniform, on well-developed cylindrical tubercles. Lyrifissure ih acute, 15 μm long, positioned lateral of gla. Caudal region of notogaster rounded, slightly crenellated, with tubercles of h and p series projecting beyond margin.

Subcapitulum: Mentum long, U-shaped, 1.45 × longer than broad; anterior margin slightly reflexed; region immediately posterior of margin concave, smooth ( Figs. 4 b, c). Central region of mentum convex, with oval plaques. Seta h 16 μm long, m 6 μm.

Coxisternum: Epimeral setae minute, sub-equal (3–5 μm long) except longer 3a (8 μm), spiniform, formula 2- 1-2-2 ( Fig. 4 b). Pre-genital sclerite faint, rectangular, bearing seta 3a. Genital and anal plates separated by distance of two thirds length of genital plate. Genital plates sub-hexagonal, smooth; each plate 52 μm long, 29 μm broad, with six setae; g 1 positioned lateral of g 2-6; g 2 longer than others. Aggenital seta spiniform, 4 μm long, positioned posteriolateral of genital plate.

Anogenital Region: Anal plates sub-rectangular, smooth ( Fig. 4 b); each anal plate 66 μm long, 30 μm broad. Anal setae bacilliform, 9 μm long. Adanal setae bacilliform; ad 1-2 positioned on ridge immediately posterior of anal plates; distance between ad 1 and ad 2 almost three times mutual distance between ad 1; ad 3 positioned laterally. Ventral plate striate posteriorlaterally, otherwise smooth.

Lateral aspect: Rostrum curved ventrally ( Fig. 4 c). Rostral seta minute, spiniform, on squat tubercle at apex of rostrum. Tutorium narrow, fused apically with rostrum – without free apices. Lamellar cuspides pointing ventrally, not reflexed; lamellae curved, free of prodorsum for almost entire length. Lamellar setae minute, spiniform, just posterior of apex of lamellar cusp. Lamellae smooth; pedotectum I slightly striate, curved, lacking tooth. Interbothridial region strongly convex, prominent. Lenticulus bulbous, projecting, dorsal surface flat. Dorsosejugal lobe extending as far as bothridium; pteromorph triangular, pointed, curved, ridged, extending as far as ventral surface, 71 μm long, 45 μm broad basally. Centrodorsal region of notogaster slightly convex from posterior of lenticulus to position level with seta h 2; posterior notogaster between h 2 and p 1 concave.

Legs: Heterotridactylous.

Material examined. Holotype female, two paratype females, two paratype males, leaf litter, native shrub vegetation, McMinns Lagoon, near Darwin, Northern Territory, 12°33'S, 131°04'E, ca. 35 m., coll. I.A. Reid, 21.i.1995. Holotype and paratype deposited in the Australian National Insect Collection, CSIRO Ecosystem Sciences, Canberra.

Etymology. This species is named for the city of Darwin, Northern Territory, the type locality of this species.

Remarks. Eremaeozetes darwinensis differs from other species in the genus by the following combination of characters: 1) the acute dorsosejugal suture with a transverse apex; 2) the notogaster with two broadly-spaced undulating ridges with lateral extensions in the region of setae lp, converging posteriorly; 3) with eleven pairs of notogastral setae or their vestiges: setae da represented by the presence of their alveoli; 4) the posteriolateral striae on the ventral plate; 5) the faint, rectangular pre-genital sclerite; 6) the smooth notogastral cuticle; only slightly foveolate in the humeral region; 7) the heterotridactylous pretarsus.

Eremaeozetes darwinensis is a member of the Reticulatus species group. The configuration of notogastral ridges is most similar to E. rogersi Schatz, McAloon & Hagan, 2006 from Georgia, USA. Like E. schatzi , E. darwinensis is heterotridactylous.

Figures

FIGURE 4. Eremaeozetes darwinensis sp. nov., holotype female, cerotegument removed; a) dorsal; b) ventral; c) lateral aspect.