Retrozetes
Creators: name: Colloff, Matthew J.
Publisher: name: Zenodo
Year: 2012
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Sarcoptiformes
Eremaeozetidae
Retrozetes

description: Retrozetes gen nov.
Diagnosis. Cerotegument thick, reticulate-alveolate. Lamellae extremely long, elevated above prodorsum; separated and recurved apically, extending well beyond rostrum and prominent projecting tutorium; with narrow slit or broad separation anteriorly. Lamellar setae on medial margins of lamellar cusps, sub-apical. Lamellar cuspides folded ventrally in the transverse plane. Interlamellar setae present. Bothridial seta with long stalk, broadening and barbed apically. Bothridium small, cup-shaped. Dorsosejugal suture transverse; bounded laterally by conical apophyses of setae c 2 positioned on strongly reduced dorsosejugal lobes. Lenticulus strongly protuberant on conical projection, positioned close to dorsosejugal suture. Notogaster in dorsal view broader than long; in lateral view wedge-shaped with posterior margin elevated; centrodorsal region convex, elevated. Notogaster with ten pairs of setae, lm in centrodorsal position; at least one pair of sacculi. Mentum elongated, anterior margin not reflexed. Epimeral setal formulae 2-1-2-2 or 2-1-2-1. Pre-genital sclerite absent. Genital and anal plates separated by distance of about half length of genital setae. Aggenital setae present. Six pairs of genital setae, all in alignment, g 1 not displaced laterally of others. Anal setae two pairs, with or without thick, bacilliform cerotegument. Setae ad 2- 3 positioned close together near lateral margin of ventral plate; ad 1 in post-anal position. Legs monodactylous. Solenidion σ on genu I greatly elongated, flagelliform.
Type species. Retrozetes koghisensis sp. nov.
Remarks. Retrozetes shares character states with Idiozetes including the presence of sacculi; the very long lamellar cuspides; the conical, protuberant lenticulus; a strongly projecting tutorial apex, the enclosed bothridia with small openings and a rim without an incision and the long, typically thin, blade-like pteromorphs. Retrozetes also shares character states with Rogerzetes, particularly the sub-apical lamellar setae; the lamellar cuspides folded ventrally in the transverse plane; the transverse dorsosejugal suture and with setae lm close together in the centrodorsal position.
Eremaeozetes hanswursti Mahunka 1999 from Singapore is a Retrozetes based on the following character states and is hereby recombined: 1) in lateral view the notogaster is wedge-shaped and deepest posteriorly and the circumgastric scissure is clearly visible; 2) the centrodosal region with an oval area; 3) the humeral region and cerotegument of humeral regions strongly triangular (cf. Fig. 12 of Mahunka, 1999 and Fig. 15 herein); 3) the marginal arrangement of the notogastral setae except the centrodorsal lm and the presence of a saccule medial to seta lp; 4) the genital setae are aligned longitudinally: g 1 is not displaced laterally as in Eremaeozetes; 5) the configuration of the lamellae with a central, expanded notch and medially-opposed lamellar setae in dorsal view and reflexed (though covered in cerotegument) in lateral view; 6) the large anal setae each at the far ends of the plate, curved and covered in thick cerotegument; 7) its small size, 152-158 μm long, fits closer with the length of Retrozetes spp. (mean 308 μm, range 252–356 μm) than Eremaeozetes spp. (mean 426 μm range 288–614 μm).
description: Published as part of 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, pp. 1-39 in Zootaxa 3435 on page 19, DOI: 10.5281/zenodo.282079