Atalotegaeus deficiens, 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 : 33-35

Atalotegaeus deficiens sp. nov.

( Fig. 14 )

Dimensions. Holotype female length 495 μm, breadth 343 μm. Paratype female length 503 μm, breadth 356 μm. Ratio of prodorsum to total length: 0.39 (holotype).

Description of adult. Prodorsum: rostrum acute with small inverted V-shaped area of lighter cuticle; rostral setae (ro) short, curved, smooth, visible in dorsal aspect. Lamellae broad, extending well beyond lateral margin of prodorsum, separated medially, without translamella, lateral margins strongly convex ( Fig. 14a ). Lamellar seta (le) well-developed, with spinose ornamentation, curved, emerging sub-apically on median edge of lamella; lamellar cusp with single apical tooth, extending just beyond rostrum. Interlamellar setae (in) long, smooth, curved, on short inverted V-shaped ridge. Bothridia prominent, projecting laterally to inner margins of humeral processes, openings angled anterolaterally, posterior margin with anterior condyle of enantiophysis H in form of V-shaped projection. Bothridial setae long, curved, setiform, smooth.

Notogaster: ratio of length to breadth: 0.87; notogaster rounded, convex. Humeral processes thin, fine, waisted at base, extending anterior of apices of setae in, with two blunt lateral protuberances, apex pointed, lateral margin slightly concave ( Fig. 14a ). With seven pairs of notogastral setae: la, lp, h 2, h 3 and p series present, setae of l and h series with spinose ornamentation on one side, strongly curved, in sub-marginal position, p series very short, smooth, visible in dorsal view.

Ventral aspect: subcapitulum acute apically; subcapitular setae short, smooth, sub-equal in length ( Fig. 14b ). Chelicerae chelate-dentate and of normal proportions. Tutorium prominent, broad, with blunted apex. Epimeral plates I discrete, broadly separated in midline, sub-triangular, plates II only partially divided in midline, plates III with no median division, plates IV lacking posterior margin; epimeral setation 3-1-3-2; setae sub-equal in length. Pedotectum I (pd I) not prominent, sub-rectangular laterally in ventral view; pd II triangular, sharply pointed; discidium broad, pointed, with blunt apex. Ventral plate ovoid, broader than long. Genital and anal plates separated by distance of half length of genital plate; genital plates 65 µm long, with six 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, 87 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. 53-1046, ANIC 580 , litter, rainforest, Mount Koghis [Mont Koghi], New Caledonia, 23°11'S, 166°31'E, 749 m. [summit], coll. P.S. Ward, 18.ii.1977.

Etymology. The specific name, deficiens , refers to the absence of notogastral seta lm.

Diagnosis. Atalotegaeus deficiens can be distinguished from other species in the genus by the following combination of characters: (1) the small inverted V-shaped area of lighter cuticle on the rostrum; (2) the lamellar setae with spinose ornamentation; (3) the inverted V-shaped ridge on the prodorsum from which setae in emerge; (4) the long, smooth, curved setae in; (5) the two blunt protuberances at the base of the humeral process; (6) the absence of setae lm, thus seven pairs of notogastral setae; (7) setae of l and h series with spinose ornamentation on one side; (8) the prominent broad tutorium with a blunted apex.

Remarks. This species is morphologically most similar to A. crobylus (cf. above) in that both have similar morphology of the lamellar cusp and chelate-dentate chelicerae of normal proportions, but A. deficiens differs in having lamellar setae with spiniform ornamentation, the presence of the inverted V-shaped ridge on the prodorsum and the absence of setae lm.

Figures

FIGURE 14. Atalotegaeus deficiens sp. nov., adult (a) dorsal aspect; (b) ventral aspect. Scale bar = 200 μm.