Retrozetes fernandezi, 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 : 27-29

Retrozetes fernandezi sp. nov.

( Fig. 17 )

Dimensions. Holotype female length 318 μm, breadth 190 μm. Paratype female length 320 μm, breadth 188 μm. Ratio of prodorsum to total length: 0.42 (holotype).

Female. Cerotegument: amorphous, weakly-developed, covering only parts of prodorsum and notogaster; ventral surface reticulate. Oval centrodorsal region bare posterior of setae lm ( Fig. 17 a).

Prodorsum: Lamellae broad, lateral margins parallel, extending beyond margins of bothridia; fused posteriomedially, smooth, separated along anterior third by drop-shaped fissure, broadening basally ( Fig. 17 a). Lamellar cuspides strongly curved ventrally, reflexed posteriorly. Posteriolateral lamellar margin diagonal, concave. Rostral seta minute (4 μm long). Lamellar seta (le) spiniform, 14 μm long, emerging from alveolus on medial margin of lamellar cusp, pointing anteriomedially, apices crossing. Interlamellar setae spiniform, 7 μm long, close together. Bothridial seta 63 μm long; head broad, club-shaped, heavily barbed; stalk S-shaped: reflexed. Bothridium cup-shaped, opening narrow, enclosed; rim not undulating.

Notogaster: Length 171 μm, ratio of length to breadth 0.9; oval, broadest at level of seta lp; pteromorphs projecting. Dorsosejugal suture transverse ( Fig. 17 a). Setae c 2 broadly-separated. Dorsosejugal lobe short conical projection bearing apophysis of seta c 2. Lenticulus immediately posterior of dorsosejugal suture, 27 μm long, 40 μm broad, oval, narrowing toward apex. Notogastral cuticle smooth. Ten pairs of smooth, short (4–8 μm), spiniform setae on broad tubercles. Setae lm positioned medially, close together. Lyrifissurae ih acute; 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, 1.5 × as long as broad; anterior margin not reflexed ( Fig. 17 b). Seta h spiniform, 9 μm long, on curved transverse ridge; m 7 μm long.

Coxisternum: Epimeral setae setiform, 4–7 μm long; formula 2-1-2-2 ( Fig. 17 b). Genital and anal plates separated by distance of half length of genital plate. Genital plates sub-hexagonal, smooth; each plate 34 μm long, 23 μm broad, with six spiniform setae sub-equal in length, aligned longitudinally. Aggenital seta setiform, 6 μm long, positioned posteriolateral of genital plate. Ventral plate smooth beneath reticulate cerotegument.

Anogenital Region: Anal plates oval ( Fig. 17 b); each anal plate 50 μm long, 27 μm broad, smooth, with faint median carina. Anal setae 6 μm with bacilliform cerotegument. Adanal setae spiniform, ad 1 positioned on large tubercle posterior of anal plates; ad 2-3 positioned laterally, close together; distance between ad 1 and ad 2 4.5 × mutual distance between ad 1.

Lateral aspect: Rostrum with narrow projecting apex ( Fig. 17 c). Rostral seta minute. Tutorium narrow, lathlike, projecting anteriorly; apex strongly pointed. Lamellar cuspides curved anterioventrally, strongly reflexed posteriorly; narrow and pointed apically and projecting well above prodorsum and separated for almost their entire length. Lamellar setae positioned dorsal of apex of tutorium, near anteriormost point of lamella. Pedotectum I smooth, convex, lacking tooth. Interbothridial region flat. Lenticulus strongly conical, rounded apically, projecting slightly anteriorly, well above dorsal surface; notogaster concave posteriorly. Dorsosejugal lobe extending as far as bothridium. Pteromorph sparingly foveolate, curved anteriorly, extending as far as ventral surface, 74 μm long, 41 μm broad basally; anterior margin concave, pointed apically; posterior margin convex. Centrodorsal region of notogaster slightly convex from anterior of lm to position level with h 3; lateral margin of notogaster between h series and circumgastric scissure strongly wedge-shaped, broadest posteriorly; caudal margin flat, vertical; setae lp, h and p series on bulbous tubercles.

Legs: Pretarsi monodactylous.

Material examined. Holotype, ANIC 414, litter, rainforest, near Vanimo, Papua New Guinea, 2°42'S 141°18'E, ca. 50 m, coll. R.W. Taylor, 10.vii.1972. Paratype, ANIC 388, litter, rainforest, near Kokoda, Papua New Guinea, 8°54'S 147°43'E, 500 m., coll. R.W. Taylor, 1.vi.1972. Holotype and paratype deposited in the Australian National Insect Collection, CSIRO Ecosystem Sciences, Canberra.

Etymology. This species is named for Dr Nestor Fernandez in recognition of his contribution to research on taxonomy of oribatid mites, particularly those of the Southern Hemisphere.

Remarks. Retrozetes fernandezi differs from other species in the genus by the following combination of characters: 1) the broad, pointed, reflexed lamellar cuspides; 2) the drop-shaped lamellar fissure; 3) the reflexed bothridial stalk; 4) the sharp projecting apex of the tutoria; 5) the broadly-separated setae c 2; 6) the oval lenticulus, broader than long; 7) the large tubercle of seta ad 1; 8) the strongly wedge-shaped profile of the notogaster in lateral view.

Retrozetes fernandezi is morphologically most similar to R. mirabilis (cf. above).

Figures

FIGURE 17. Retrozetes fernandezi sp. nov., holotype female, cerotegument removed; a) dorsal; b) ventral; c) lateral aspect.