Atalotegaeus monteithi (Colloff, 2023)

Colloff, Matthew J., 2023, The oribatid mite superfamily Eutegaeoidea (Acari, Oribatida), with descriptions of new taxa from Australia and New Caledonia and a re-assessment of genera and families, Zootaxa 5365 (1), pp. 1-93 : 37-38

Atalotegaeus monteithi (J. & P. Balogh, 1983) comb. nov.

( Fig. 17 )

Neseutegaeus monteithi J. & P. Balogh, 1983b, p. 292.

Dimensions. Holotype female 469 μm, breadth 365 μm.

Redescription of adult. Prodorsum: rostrum acute; rostral setae (ro) short, straight, smooth, visible in dorsal aspect. Lamellae broad, smooth, separated medially, not extending as far as apex of rostrum, lateral margins convex, translamella incomplete ( Fig. 17a ); lamellar seta (le) very short, fine, flagelliform, emerging from shallow excavation on apex of cusp, with sharp tooth medially. Interlamellar setae (in) long, smooth, recurved, on posteromedian margins of lamellae. Bothridia broad, with anterior condyle of enantiophysis H in form of V-shaped flange; bothridium projecting beyond inner margin of humeral processes, openings angled laterally, lip with long cylindrical posterior projection. Bothridial setae very long, curved, bacilliform, smooth.

Notogaster: ratio of length to breadth: 0.83; notogaster rounded, convex. Humeral process narrow, fine, pointed, waisted basally, lateral margin convex, extending to point level with middle of lamella ( Fig. 17a ), with prominent mound at base and laterally and smaller one posteriorly. With eight pairs of notogastral setae: l, h 2 and h 3 and p series; setae of l and h series smooth, recurved, shorter than distance between them, sub-equal in length, setae la and lm in centrodorsal position, others sub-marginal; p series shorter than l and m series.

Ventral aspect: subcapitulum acute apically, mentum as long as broad; subcapitular setae short, smooth, sub-equal in length ( Fig. 17b ). Chelicerae chelate-dentate and of normal proportions. Tutorium short, rounded apically, not visible in ventral aspect. Epimeral plates discrete except IV, broadly separate in midline, sub-rectangular to sub-triangular, plates III shorter than others; large gap between plates II and III, epimeral setation 3-1-3-3; epimeral setae sub-equal in length: 3a-c clustered on medial part of plate. Pedotectum I (pd I) poorly-developed, with short curved point; pd II small, pointed; discidium acute, pointed. Ventral plate broader than long. Genital and anal plates about half length of genital plates apart; genital plates 62 µm long, with six pairs of minute setae, sub-equal in length, g 5 displaced laterally; lyrifissure iad in para-anal position, close to margin of anal plate, less than length of iad. Anal plates lozenge-shaped, 90 µm long; setae of the ad series very short, setiform, thin, on faint curved ridge posterior to anal plates. Pre-anal organ (po) T-shaped.

Material examined and locality data. Holotype, ANIC accession no. 53-650, leaf litter, Nothofagus moorei rainforest, Barrington Tops National Park, via Salisbury , New South Wales, 1,524 m., coll. G.B. Monteith, 10.ii.1965.

Diagnosis. Atalotegaeus monteithi can be distinguished from other species in the genus by the following combination of characters: (1) the gap between epimeral plates II and III; (2) the curved, transverse ridge posterior of the anal plates; (3) the short, flagelliform lamellar setae; (4) the long cylindrical projection on the lip of the bothridium; (5) the relatively short, strongly recurved setae la and lm; (6) the mound-like structures at the base of the humeral process; (7) the partial translamella; (8) the anterior condyle of enantiophysis H.

Remarks. The recombination of Neseutegaeus monteithi to Atalotegaeus is detailed above in the remarks section on Neseutegaeus . The description of N. monteithi by J. and P. Balogh (1983a) differs in certain respects from the redescription of the holotype above. I found the bothridial setae were smooth apically, not ciliate and the bothridium has a large apical projection. Also, the apex of the lamellar cusp has a medial tooth and the two mound-like structures at the base of humeral process are larger than originally illustrated.

Figures

FIGURE 17. Atalotegaeus monteithi (J. & P. Balogh, 1983a) comb. nov., adult (a) dorsal aspect; (b) ventral aspect. Scale bar = 200 μm.