Retrozetes koghisensis, 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 : 19-22

Retrozetes koghisensis sp. nov.

( Figs. 11–13 )

Dimensions. Holotype female length 356 μm, breadth 217 μm. Paratype females lengths 375, 381 μm, breadths 205, 198 μm; paratype male length 330 μm, breadth 162 μm. Ratio of prodorsum to total length: 0.41 (holotype).

Female. Cerotegument: reticulate pattern of cells densely covering prodorsum, notogaster and ventral surface; oval centrodorsal region bare ( Fig. 11 a).

Prodorsum: Lamellae broad, lateral margins parallel, extending laterally well beyond margins of bothridia; fused posteriomedially, smooth, separated along anterior third by broad, rectangular fissure ( Fig. 11 a). Lamellar cuspides strongly curved ventrally; with pointed lateral projections; apices pointed, opposed, converging medially, ( Fig. 11 b). Posteriolateral lamellar margin undulating, diagonal, with short projection anterior of bothridium ( Fig. 11 a). Rostral seta (ro) spiniform, minute (4 μm long). Lamellar seta (le) spiniform, 12 μm long, pointing medially, emerging from alveolus on medial margin of lamellar cusp. Interlamellar setae thin, minute (5 μm long), close together on thin transbothridial ridge. Bothridial seta 78 μm long; head narrow, club-shaped, slightly barbed apically; barbs covered in cerotegument. Bothridium cup-shaped, opening narrow, enclosed; rim not undulating.

Notogaster: Length 186 μm; ratio of length to breadth 0.8; notogaster broad, oval, broadest at level of seta la; pteromorphs projecting. Dorsosejugal suture transverse ( Fig. 11 a). Dorsosejugal lobe a short, broad projection bearing apophysis of seta c 2. Lenticulus immediately posterior of dorsosejugal suture, 39 μm long, 42 μm broad, oculate, with lateral ‘points’; margin ridged. Notogastral cuticle smooth, sparingly foveolate laterally. Ten pairs of smooth, short (5–13 μm), thin, curved setae on broad, well-developed tubercles. Setae lm positioned medially, close together. Lyrifissure ih on lateral margin of notogaster, not visible in dorsal view ( Fig. 11 a,c); saccule (sa) anteriomedial of im. Caudal region of notogaster strongly crenellated, with tubercles of h series projecting beyond margin; p series positioned ventrally.

Subcapitulum: Mentum U-shaped, convex, smooth, as long as broad; anterior margin not reflexed ( Fig. 11 b). Seta h 5 μm long, on short longitudinal ridge; seta m directly anterior of h, 5 μm long. Palp setal formula 0-2-1-3- 9(1). Seta d on genu 10 μm long with bulbous apical cerotegument. Eupathidium acm on short conical tubercle ( Fig. 12 a).

Coxisternum: Epimeral setae of variable length (4–12 μm long), setiform, formula 2-1-2-1 ( Fig. 11 b). Genital and anal plates separated by distance of half length of genital plate. Genital plates sub-hexagonal, smooth; each plate 44 μm long, 22 μm broad, with six spiniform setae sub-equal in length, aligned longitudinally. Ovipositor only lightly striate, 88 μm long ( Fig. 12 c); three pairs of proximal eugenital setae: ĸ series thin, ca. 3 μm long; ten pairs of distal eugenital setae: τ series (four pairs) and ψ series (one pair) setiform with curved apices 15–21 μm long. Aggenital seta spiniform, 5 μm long, positioned posteriolateral of genital plate. Ventral plate smooth.

Anogenital Region: Anal plates sub-hexagonal ( Fig. 11 b); each anal plate 51 μm long, 29 μm broad, smooth, with faint median carina. Anal setae 12 μm long, with thick cerotegument, embedded in shallow pits ( Fig. 12 b). Adanal setae setiform, thin, shorter than anal setae; ad 1 positioned on squat tubercle on ridge immediately posterior of anal plates; ad 2-3 positioned laterally, close together; distance between ad 1 and ad 2 3 × mutual distance between ad 1.

Lateral aspect: Rostrum straight, projecting vertically ( Fig. 11 c). Rostral seta minute, spiniform, on squat tubercle on apex of rostrum. Tutorium broad, projecting dorsally and anteriorly; apex with shallow cusp. Lamellar cuspides curved anterioventrally, strongly reflexed posteriorly then dorsally, pointed apically; projecting well above prodorsum and separated for almost their entire length. Lamellar setae positioned at anteriormost point of lamella, some distance posterior of lamellar cusp. Pedotectum I smooth, curved, lacking tooth. Interbothridial region flat. Lenticulus cylindrical, projecting well above dorsal surface, notogaster strongly concave posteriorly. Dorsosejugal lobe extending as far as bothridium. Pteromorph broad, sparingly foveolate, extending as far as ventral surface, 73 μm long, 47 μm broad basally; anterior margin convex, acutely angled apically; posterior margin concave. Centrodorsal region of notogaster slightly convex from posterior of lm to position level with seta h 3, then concave; lateral margin of notogaster between h series and circumgastric scissure wedge-shaped, broadest posteriorly; caudal margin concave; setae lp and h series on bulbous tubercles.

Legs: Pretarsi monodactylous. Solenidion σ flagelliform, very long: 2.5 × length of genu ( Fig. 13 ). Solenidion φ2 on apical, well-developed apophysis; φ1 positioned ventrally. Formulae: Leg I: 0-4-2(1)-4(2)-15(2); Leg II 0-4- 1(1)-3(1)-14(2).

Material examined. Holotype and four paratypes, ANIC 580, leaf litter, rainforest, Mount Koghis, New Caledonia, 22°11'S 166°31'E, 750 m., coll. P. Ward, 18.ii.1977. Holotype and paratypes deposited in the Australian National Insect Collection, CSIRO Ecosystem Sciences, Canberra.

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

Remarks. Retrozetes koghisensis differs from other species in the genus by the following combination of characters: 1) the pointed lateral projections of the lamellar cuspides and the pointed opposing apices; 2) the broad, rectangular lamellar fissure; 3) the hook-shaped lamellar cuspides in lateral view; 4) the oculate lenticulus; 5) the broad tutorium in lateral view, with a shallow apical cusp; 6) the relatively broad pteromorph in lateral view, acutely angled apically and with foveolae anteriorly; 7) the anal setae embedded in shallow pits.

Retrozetes koghisensis is morphologically most similar to R. mirabilis sp. nov. though the latter lacks the double-pointed lamellar cuspides, crenellated notogastral margin and rectangular lamellar fissure of the former.

Figures

FIGURE 11. Retrozetes koghisensis sp. nov., holotype female, cerotegument removed; a) dorsal; b) ventral; c) lateral aspect.

FIGURE 12. Retrozetes koghisensis sp. nov., a) left palp, antiaxial view; b) anal plates with cerotegument removed showing anal setae; c) ovipositor.

FIGURE 13. Retrozetes koghisensis sp. nov., legs, left, antiaxial view, cerotegument removed; a) Leg I; b) Leg II.