Atalotegaeus crobylus, 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 : 32-33

Atalotegaeus crobylus sp. nov.

( Fig. 13 )

Dimensions. Holotype female length 545 μm, breadth 378 μm. Paratype female length 540 μm, breadth 328 μm. Ratio of prodorsum to total length: 0.45 (holotype).

Description of adult. Prodorsum: rostrum acute; rostral setae (ro) short, curved, smooth, visible in dorsal aspect. Lamellae broad, extending beyond lateral margin of prodorsum, separated medially, lateral margins convex, with an incomplete translamella ( Fig. 13a ). Lamellar seta (le) smooth, recurved, very short, emerging in sub-apical position on median edge of lamella; lamellar cusp with single tooth, extending just beyond rostrum. Interlamellar setae (in) long, smooth, strongly curved in almost circular configuration, emerging on posteromedian prodorsum. Bothridia relatively short, projecting as far as inner margins of humeral processes, openings angled anterolaterally, anterior margin with rounded, convex ledge. Bothridial setae long, curved, bacilliform, smooth, slightly expanded apically.

Notogaster: ratio of length to breadth: 0.79; notogaster rounded, convex. Humeral processes extending to point level with middle of lamella, thin, fine, waisted at base, with V-shaped projection pointing posterolaterally, then expanded and with fine, pointed apex, lateral margin slightly concave ( Fig. 13a ). With eight pairs of notogastral setae, l, h 2 and h 3 and p series present, setae la and lm smooth, strongly curved in almost circular configuration, in centrodorsal position, setae h 2 and h 3 straight, smooth, in sub-marginal position, short (65 μm); p series very short (15 μm).

Ventral aspect: subcapitulum acute apically; subcapitular setae short, smooth, setae a half length of m and h ( Fig. 13b ). Chelicerae chelate-dentate, of normal proportions. Tutorium short, blunt. Epimeral plates discrete, broadly separated in midline, sub-rectangular to sub-triangular, plates IV shorter than others; epimeral setation 3-1- 3-2; setae 3b and 3c longer than others. Pedotectum I (pd I) small, narrow; pd II small, with blunt point; discidium acutely pointed. Ventral plate ovoid, broader than long. Genital and anal plates close together at distance of less than half length of genital plate; genital plates 66 µm long, with five pairs of setae sub-equal in length, g 4 displaced laterally; lyrifissure iad in para-anal position, close to margin of anal plate. Anal plates lozenge-shaped, 98 µm long; setae of the ad series short, similar length to setae of the p series. Pre-anal organ (po) T-shaped.

Type designation, material examined and locality data. Holotype female ANIC accession no. 53-1047, paratype female, ANIC accession no. 53-1048, ANIC 297 , moss and litter, Nothofagus cunninghami rainforest, Cumberland Creek Valley, near Picnic Area [Cumberland Memorial Scenic Reserve], Yarra Ranges National Park , Victoria, 37°34’S 145°52’E, 920 m., coll. R. W. Taylor and R. J. Bartell, 4.xi.1970.

Etymology. The prefix of the specific name, crobyl-, is derived from the Greek κρώβυλος (krobylos) meaning a curl, referring to the shape of the interlamellar setae.

Diagnosis. Atalotegaeus crobylus can be distinguished from the other species in the genus by the following combination of characters: (1) the extremely short, thin rostral setae; (2) the mentum much broader than long; (3) the presence of an incomplete translamella; (4) the long, recurved and overlapping setae in; (5) the relatively short, broad bothridia with a markedly convex, rounded anterior border; (6) the apices of the humeral processes are flexed outwards and their lateral margins concave apically; (7) notogastral setae la and lm are strongly recurved; (8) the minute setae of the p series, sub-equal in length to the anal setae; (9) the small, blunt pedotectum II.

Remarks. This species is morphologically most similar to A. mensarosi (cf. below), but differs in the outwardcurving humeral processes and strongly recurved setae la and lm and in lacking the reticulate microsculpture on the lamellae, the prominent pedotecta I and the extremely long, flagelliform setae in. Similarities between A. crobylus and A. deficiens sp. nov. are detailed below.

Figures

FIGURE 13.Atalotegaeus crobylus sp. nov., adult (a) dorsal aspect showing notogastral setae in the centrodorsal position (cd), sub-marginal (sm) and marginal (m) positions; (b) ventral aspect. Scale bar = 200 μm.