Retrozetes novaecaledoniae, 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 : 24-27

Retrozetes novaecaledoniae sp. nov.

( Figs. 15 , 16 )

Dimensions. Holotype female length 306 μm, breadth 183 μm. Ratio of prodorsum to total length: 0.36 (holotype).

Female. Cerotegument: strongly reticulate; densely covering prodorsum, notogaster and ventral surface; covering of pedotecta II triangular, projecting anteriolaterally. Oval centrodorsal region bare posterior of setae lm ( Fig. 15 a).

Prodorsum: Lamellae broad, lateral margins sloping acutely, concave posteriolaterally, extending well beyond margins of bothridia; fused posteriomedially, smooth, separated along anterior third by broad, U-shaped fissure ( Fig. 16 b). Lamellar cuspides strongly curved ventrally, reflexed posteriorly then again anteriorly: S-shaped.

Lamellae with median, Y-shaped sclerotised cuticular strip ( Fig. 15 b). Posteriolateral lamellar margin diagonal, concave. Rostral seta (ro) minute. Lamellar seta (le) spiniform, 23 μm long, emerging from Y-shaped cuticular strip, pointing anteriomedially, apices crossing. Interlamellar setae spiniform, 7 μm long, close together, projecting posteriorly. Bothridial seta 59 μm long; head broad, club-shaped, heavily barbed. Bothridium cup-shaped, opening narrow, enclosed; rim not incised.

Notogaster: Length 193 μm, as long as broad, oval, broadest at level between setae la and lp; pteromorphs projecting. Dorsosejugal suture transverse ( Fig. 15 b). Dorsosejugal lobe a short, conical projection bearing apophysis of seta c 2. Lenticulus immediately posterior of dorsosejugal suture, 24 μm long, 26 μm broad, oval; margin simple. Notogastral cuticle smooth. Ten pairs of smooth, short (5–9 μm), spiniform, curved setae on broad, well-developed tubercles. Setae lm positioned medially, close together. Lyrifissurae ih on lateral margin of notogaster, not visible in dorsal view; saccule (sa) anterior of lp. Caudal region of notogaster scalloped; tubercles of h and p series projecting beyond margin.

Subcapitulum: Mentum U-shaped, convex, smooth, as long as broad; anterior margin not reflexed ( Fig. 16 b). Seta h spiniform, 6 μm long; m and a 4 μm long. Palp setal formula 0-2-1-3-9(1). Seta d on genu setiform; eupathidium acm on short conical tubercle ( Fig. 16 b).

Coxisternum: Epimeral setae setiform, of variable length (5–14 μm long); 1b longer than others; formula 2-1- 2-2 ( Fig. 16 a). Genital and anal plates separated by distance of half length of genital plate. Genital plates subhexagonal, smooth; each plate 47 μm long, 22 μm broad, with six spiniform setae sub-equal in length, aligned longitudinally. Aggenital seta setiform, 5 μm long, positioned posteriolateral of genital plate. Ventral plate smooth beneath foveolate cerotegument.

Anogenital Region: Anal plates sub-hexagonal ( Fig. 16 a); each anal plate 50 μm long, 24 μm broad, smooth, with faint median carina. Anal setae 6 μm with bacilliform cerotegument. Adanal setae spiniform, ad 1 positioned on squat tubercle on broadly curved ridge 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 with narrow apex projecting vertically ( Fig. 16 a). Rostral seta on squat tubercles. Tutorium narrow, lath-like, projecting anteriorly; apex strongly pointed. Lamellar cuspides S-shaped: narrowing and curved anterioventrally, strongly reflexed posteriorly then recurved anteriorly; narrow and pointed apically and projecting well above prodorsum and separated for almost their entire length. Lamellar setae positioned dorsal of apex of tutorium, some distance posterior of anteriormost point of lamella. Pedotectum I smooth, undulating, lacking tooth. Interbothridial region convex. Lenticulus strongly conical, rounded apically, projecting well above dorsal surface, notogaster concave posteriorly. Dorsosejugal lobe not extending to bothridium. Pteromorph sparingly foveolate, lath-like, sub-rectangular, extending to ventral surface, 90 μm long, 30 μm broad basally; anterior margin straight, curved apically; posterior margin slightly concave. Centrodorsal region of notogaster strongly convex from lm to level with lp; 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.

Material examined. Holotype female, ANIC 587, leaf litter, rainforest, Montagne des Sources, New Caledonia, 22°09'S 166°35'E, 560 m., coll. P. Ward, 28.ii.1977. Paratype female, paratype male, 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 New Caledonia.

Remarks. Retrozetes novaecaledoniae differs from other species in the genus by the following combination of characters: 1) the narrow, reflexed, S-shaped lamellar cuspides; 2) the long lamellar setae projecting from well developed apophyses on the medial edge of the lamellar cuspides; 3) the broad, U-shaped lamellar fissure; 4) the Yshaped sclerotised cuticular strip on the lamellae; 5) the spiniform interlamellar setae; 6) the oval notogaster, slightly longer than broad, with a crenellated margin; 7) the narrow tutorium in lateral view, with a sharp projecting apex; 8) the long, narrow pteromorph in lateral view, acutely angled apically and with a concave posterior edge. Retrozetes novaecaledoniae is morphologically most closely related to R. koghisensis (cf. above).

Figures

FIGURE 15. Retrozetes novaecaledoniae sp. nov., holotype female; a) dorsal, with cerotegument; b) dorsal, with cerotegument removed.

FIGURE 16. Retrozetes novaecaledoniae sp. nov., holotype female, cerotegument removed; a) ventral; b) subcapitulum; c) lateral aspect.