Eremaeozetes schatzi, 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 : 4-8

Eremaeozetes schatzi sp. nov.

( Figs. 1–3 )

Dimensions. Holotype female length 614 μm, breadth 358 μm. Ratio of prodorsum to total length: 0.31 (holotype).

Female. Cerotegument: heavy, vesicular, densely covering prodorsum and notogaster; less dense ventrally. Cerotegument covering lamellae consisting of row of large, paired, elongate, parallel cells laterally and medially, oblong in dorsal view, with small circular openings ( Fig. 1 a). Dorsosejugal lobes with cerotegument in the form of irregular linear ridges. Lenticulus with lateral margin of large cells. Notogaster with series of large, oblong cells laterally, interspersed with large polygonate vesicles and conical projections with coronate apices; with small, circular vesicles medially.

Prodorsum: Lamellae broad, narrowing anteriorly, fused posteriomedially, longitudinally striated with minute tubercles medially, separated along anterior third by narrow oval median slit. Lamellar cuspides curved medioventrally, overlapping apically. Posteriolateral lamellar margins diagonal, parallel with bothridia ( Fig. 1 a, 2d). Rostral seta (ro) minute (5 μm long), spiniform, emerging from squat tubercle ( Fig. 2 a, d). Lamellar seta (le) 13 μm long, spiniform, emerging from apex of lamella ( Figs. 1 b, 2a, d). Narrow transbothridial ridge present, appearing convex in lateral view. Bothridial seta 91 μm long; head narrow, club-shaped, with barbed cerotegument; head rough, bacilliform with cerotegument removed ( Fig. 2 d). Bothridium prominent, elongate, cup-shaped, with parallel internal ridges ( Fig. 2 d); rim undulating.

Notogaster: Length 440 μm; ratio of length to breadth 1.26; notogaster broad, sub-hexagonal; broadest in region of pteromorphs. Dorsosejugal suture acute medially; median projection extending to transbothridial ridge, divided longitudinally, with paired foveolae ( Fig. 1 b). Dorsosejugal lobe well-developed, sub-triangular, broad and slightly waisted basally, extending anteriorly as far as bothridium. Lenticulus immediately posterior of median projection of dorsosejugal suture, 44 μm long, 31 μm broad, oval, bulbous, with discrete margin. Notogastral cuticle densely tuberculate. Paired oval depressions immediately posterior of lenticulus; elongate median ridge broadening caudally with paired parallel longitudinal ridges on either side, the medial one extending from level of setae la to setae lp, the lateral one extending as far as h 3; cuticle between ridges shallow elongate depressions; transverse ridge between median line and seta lp. Ten pairs of smooth, short (8–14 μm) spiniform setae on prominent conical tubercles; setae of h series about half as long as tubercles. Lyrifissure ih longitudinal, 21 μm long, positioned lateral of setae lm; opening of opisthonotal gland (gla) positioned medial of ip. Caudal region of notogaster rounded, with tubercles of h and p series projecting beyond margin.

Subcapitulum: Mentum elongate, U-shaped, 1.5 × longer than broad; anterior margin reflexed posteriorly ( Fig. 2 c); region immediately posterior of margin concave, striate. Central region of mentum with faint elongated plaques, convex, elevated, with sclerotised peripheral ridge. Seta h 26 μm long, m 15 μm; a 16 μm. Palp setal formula 0-2-1-3-9(1); eupathidium acm on short conical tubercle ( Fig. 2 e).

Coxisternum: Epimeral setae short, sub-equal (6–9 μm long), spiniform, formula 3-1-2-2 ( Fig. 2 a). Pre-genital sclerite short, broad, trapezoid, with undulating anterior margin, bearing seta 3a ( Fig. 2 b). Genital and anal plates separated by distance of half length of genital plate. Genital plates sub-hexagonal, with faint reticulations; each plate 98 μm long, 54 μm broad, with six setae; g 1 positioned lateral of g 2-6; g 2 longer than others. Aggenital seta spiniform, 8 μm long, positioned posterior of genital plate. Ventral plate tuberculate posteriorly, reticulate and with plaques in epimeral region.

Anogenital Region: Anal plates sub-rectangular, with faint reticulations ( Fig. 2 a); each anal plate 129 μm long, 61 μm broad. Anal setae spiniform, 14 μm long. Adanal setae spiniform, shorter than anal setae; ad 1-2 positioned on ridge immediately posterior of anal plates; distance between ad 1 and ad 2 almost twice mutual distance between ad 1; ad 3 positioned laterally.

Lateral aspect: Rostrum curved ventrally, slightly reflexed posteriorly at apex ( Fig. 1 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 0.9 of entire length. Lamellar setae minute, spiniform, on apex of lamellar cusp. Lamellae and pedotecta striate; pedotectum I smoothly curved, lacking tooth. Interbothridial region strongly convex, prominent. Lenticulus bulbous, prominent, projecting above dorsum. Dorsosejugal lobe extending anterior of bothridium; pteromorph triangular, pointed, curved, extending as far as ventral surface, 177 μm long, 89 μm broad basally. Centrodorsal region of notogaster slightly convex from posterior of lenticulus to position level with setae h 3 and p 3; posterior notogaster between h 2 and p 1 concave.

Legs: Heterotridactylous.

Protonymph. Length 384 μm, breadth 214 μm. Prodorsum: Rostral seta (ro) straight, smooth, 10 μm long, emerging from conical apophysis as long as seta ( Fig. 3 a). Lamellar seta (le) 7 μm long, straight, smooth, on carina extending from posterior of ro to bothridium. Interlamellar seta (in) smooth, straight, 5 μm long. Carinae with curved transverse ridge anterior of in. Bothridial seta (bs) elongate, flagelliform, 136 μm long. Prodorsum smooth.

Gastronotic Region: Length 253 μm; ratio of length to breadth 1.26; sub-rectangular ( Fig. 3 a). Cuticle with sparse, broadly-spaced plicate ridges. With 15 pairs of short (22–27 μm), setiform setae; p series positioned ventrally; l series positioned along lateral margin.

Coxisternum: Epimeral plates separated along sternal line by unsclerotised cuticle with sinuous, interdigitating ridges ( Fig. 3 b). Epimeral setal formula 1-0-1-0. Epimeral setae smooth, setiform, 6–11 μm long. Epimeral plates smooth.

Anogenital Region: Each genital plate 38 μm long, 10 μm broad, with one smooth, setiform seta, 8 μm long ( Fig. 3 b). Genital plates surrounded by longitudinal striate cuticle. Each anal plate 73 μm long, 10 μm broad, smooth. Setae of p series 7–11 μm long, thin, smooth.

Material examined. Holotype female, three paratype females one paratype male, two paratype protonymphs, 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 paratypes deposited in the Australian National Insect Collection, CSIRO Ecosystem Sciences, Canberra.

Etymology. This species is named in honour of my friend and colleague Dr Heinrich Schatz, in recognition to his research contribution to the systematics, ecology and biogeography of oribatid mites.

Remarks. The association of the protonymph with the adult is based on their presence in the same sample; the thin, elongate shape of the bothridial seta and the setation of the legs (not shown). The protonymph has the full complement of dorsal setae (da, dm and dp), absent in the adult.

Eremaeozetes schatzi differs from other species in the genus by the following combination of characters: 1) the acute dorsosejugal suture with paired median foveolae; 2) the notogaster with five ridges dividing four longitudinal oval depressions; 3) the notogastral setae on prominent conical tubercles; those of the h and p series projecting beyond the causal margin; 4) the sub-triangular dorsosejugal lobe, waisted basally; 5) the densely tuberculate notogaster and posterior ventral surface; 6) the bothridial seta with a long, narrow head with barbed cerotegument;7) the lamellae overlapping apically with an elongated oval fissure; 8) the trapezoid pre-genital sclerite with an undulating anterior margin; 9) the heterotridactylous pretarsus.

Eremaeozetes schatzi is a member of the Reticulatus species group ( Schatz, 2003; cf. Discussion below). It has a pre-genital sclerite, longitudinal notogastral ridges separating median fields with lateral lobed extensions and a posteriomedian longitudinal ridge. The configuration of notogastral ridges, the mentum and the well-developed tubercles of the notogastral setae is most similar to E. auracana Monetti, Oppedisano & Fernandez, 1994 from Argentina. Unlike other members of the Reticulatus species group, E. schatzi is heterotridactylous.

Figures

FIGURE 1. Eremaeozetes schatzi sp. nov., holotype female; a) dorsal, with cerotegument; b) dorsal, with cerotegument removed; c) lateral aspect with cerotegument removed.

FIGURE 2. Eremaeozetes schatzi sp. nov., holotype female, cerotegument removed; a) ventral; b) pre-genital sclerite; c) subcapitulum; d) prodorsum (squash preparation); e) palp tarsus.

FIGURE 3. Eremaeozetes schatzi sp. nov., protonymph, cerotegument removed; a) dorsal; b) ventral.