Idiozetes hagenensis, 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 : 29-30

Idiozetes hagenensis sp. nov.

( Fig. 18 )

Dimensions. Holotype female length 384 μm, breadth 252 μm. Ratio of prodorsum to total length: 0.41. Female. Cerotegument: amorphous, reticulate in parts, strongly-developed, covering entire body.

Prodorsum: Lamellae broad and very long, lateral margins undulating, extending beyond margins of bothridia; fused posteriomedially, smooth, separated along anterior two thirds by hourglass-shaped fissure, broadening apically and basally ( Fig. 18 a). Lamellar cuspides curved ventrally and medially, not reflexed posteriorly. Posteriolateral lamellar margin convex. Rostral seta curved, setiform, 23 μm long, on squat apophysis giving rostrum bifurcate appearance ( Fig. 18 b). Lamellar seta (le) spiniform, 30 μm long, emerging from well-developed apophysis with narrow, truncated apex on medial margin of lamellar cusp, pointing medially, apices crossing. With drop-shaped ridge with central hollow on median prodorsum. Interlamellar seta absent. Bothridial seta 94 μm long; head broad, club-shaped, lightly barbed; stalk elongated. Bothridium cup-shaped, opening broad; rim not undulating.

Notogaster: Length 171 μm, ratio of length to breadth 0.9; oval, heavily waisted anteriorly; broadest at level of seta lp; with medial ridge pteromorphs wing-like, strongly projecting laterally. Dorsosejugal suture complex, incomplete, extending from anteriomedial margin of dorsosejugal lobe to anterior of lenticulus; U-shaped ridge with central hollow extending onto prodorsum ( Fig. 18 a). Dorsosejugal lobe short, conical, lateral projection posterior of bothridium. Lenticulus positioned between bothridia immediately posterior of dorsosejugal suture, 46 μm long, 48 μm broad, oval, surrounded by ridge of cuticle narrowing posteriorly and extending into cruciform ridge extending medially entire length of notogaster. Notogastral cuticle smooth. Twelve pairs of smooth, short (9–15 μm), setiform setae on short tubercles; c 1 thick, spiniform; complete c series present. Setae la positioned close together on lateral extensions of pronounced medial ridge extending to caudal margin. Outline of notogaster in sagittal section (not shown) in form of pointed (Gothic) arch. Four pairs of sacculi present. Caudal region of notogaster rounded, globular.

Subcapitulum: Mentum oval, convex, smooth, 1.3 × as long as broad; anterior margin reflexed ( Fig. 18 b). Seta h and m spiniform, 12–16 μm long, on reflexed anterior margin.

Coxisternum: Epimeral setae setiform, 4–7 μm long, 1b longer than others; formula 2-1-2-2 ( Fig. 18 b). Genital and anal plates almost abutting, surrounded by band of cuticle more heavily sclerotised than that of rest of ventral plate. Genital plates sub-hexagonal, smooth; each plate 70 μm long, 38 μm broad, with six spiniform setae subequal in length, aligned longitudinally. Aggenital seta absent. Ventral plate smooth.

Anogenital Region: Anal plates sub-hexagonal ( Fig. 18 b); each anal plate 72 μm long, 41 μm broad, smooth. Two pairs of thick, spiniform anal setae, 6 μm long, positioned on central part of plates. Adanal setae spiniform, all positioned on squat tubercles positioned more-or-less equidistantly posterior of anal plates.

Lateral aspect: Rostrum slightly reflexed, concave ( Fig. 18 c). Tutorium broad, bifurcate, apices toothed, pointed, projecting markedly beyond rostrum ( Fig. 18 b,c). Lamellar cuspides curved anterioventrally but not reflexed; pointed apically, projecting well above prodorsum, separated for almost entire length. Lamellar setae positioned dorsal of apex of tutorium, near anteriormost point of lamella. Pedotectum I smooth, convex, lacking tooth. Interbothridial region slightly convex. Lenticulus strongly conical, rounded apically, strongly projecting anteriorly, well above dorsal surface; notogaster deeply concave posteriorly. Dorsosejugal lobe extending as far as bothridium. Pteromorph in form of narrow, strongly curved ribbon of cuticle extending laterally from notogaster, waisted basally; extending as far as ventral surface, 161 μm long, 46 μm broad basally; anterior margin concave, pointed apically; posterior margin convex. Notogaster strongly convex, with distinct dorsomedian ridge extending from posterior of lenticulus to setae of p series.

Legs: Pretarsi monodactylous.

Material examined. Holotype, ANIC 419, near Mount Hagen, Papua New Guinea, 5°52'S 144°15'E, ca. 1700 m., coll. R.W. Taylor, July, 1972. Holotype deposited in the Australian National Insect Collection, CSIRO Ecosystem Sciences, Canberra.

Etymology. This species is named for its type locality, Mount Hagen.

Remarks. Idiozetes hagenensis differs from other species in the genus by the following combination of characters: 1) the bifurcate rostrum in ventral view; 2) the narrow apophysis of the lamellar seta with its truncated apex; 3) the hourglass-shaped lamellar fissure; 4) with twelve pairs of notogastral setae, including the full complement of the c series; 5) the cruciform notogastral ridge; 6) the conical, laterally-projecting dorsosejugal lobes; 7) with two pairs of anal setae; 8) the apex of lenticulus extending at least as far as the bothridia in lateral view; 9) the almost circular notogaster.

Idiozetes hagenensis is morphologically most similar to Idiozetes erectus Aoki, 1976 with which it shares the configuration of the lamellae, the drop-shaped ridge on the prodorsum It differs in having lamellar setae, apparently absent from I. erectus (cf. Aoki, 1976, his Fig. 23), the more forwardly-positioned lenticulus, the cruciform notogastral ridge, the full complement of setae in the c series, six pairs of genital setae and two pairs and anal setae.

Figures

FIGURE 18. Idiozetes hagenensis sp. nov., holotype female, cerotegument removed; a) dorsal; b) ventral; c) lateral aspect.