Topalia dunlopi, Colloff, 2019

Colloff, Matthew J., 2019, The oribatid mite genus Topalia in Australia (Oribatida: Nosybeidae) and the taxonomic status of related families and genera, Zootaxa 4647 (1), pp. 290-321 : 298-299

Topalia dunlopi sp. nov.

( Fig. 5 )

Dimensions. Holotype length 347 μm, breadth 211 μm. Paratypes mean length (n = 8) 324 μm (range 299–340 μm); mean breadth 200 μm (range 183–211 μm). Ratio of prodorsum to total length: 0.32 (holotype).

Adult. Integument: prodorsum and notogaster with network of large foveolae separated by angular ridges interspersed with minute granular tubercles. Cerotegument present in centrodorsal region. Underlying cuticle with fine striae ( Fig. 5c ).

Prodorsum: rostrum incised, with two lateral teeth and shorter median tooth. Lamellae meeting along anterior midline, not striate. Interlamellar region flat; setae in on squat tubercles posterior of posteromedian margins of lamellae. Bothridial seta with short, spherical club-shaped apices bearing blunt spines.

Notogaster: ratio of length to breadth: 1.12. Anterior margin of notogaster smooth, convex, entire. Humeral projections (h) rounded, narrow, bearing seta c 2 at level of posterior incurve. Margins of centrodorsal ridge welldeveloped, slightly converging anterior of setae dm, then diverging; posterior part of ridge rounded, extending posteriorly to point posterior of level of setae h 3. Posterior notogastral setae on squat tubercles.

Ventral aspect: epimeral plates I trapezoid, twice as long as broad; epimera III and IV separate, rectangular. Epimeral setation 2-1-2-2. Pedotectum I long, thin, extending anteriorly to point almost half way along length of lamellae. Lateral margins of pedotecta II extending only just further than margins of pedotecta I. Perigenital carina thin, curved, ca. 34 µm long, extending posteriorly to point anterior of seta ag. Genital plates 43 µm long, same length as anal plates and over twice length of distance between them. Sclerotised ring around genital plates with parallel striae. Ventral plate sparingly granulate.

Material Examined and Locality Data. Holotype: ANIC 1025 , leaf litter under Araucaria heterophylla, Red Road Track, Norfolk Island, coll. T.A. Weir, 14.xi.1984. Eight paratypes: ANIC 3506 , trough of flight intercept trap, Maurge Jowett’s [garden] (Red Road), Norfolk Island, 29° 0’37.73”S, 167°56’43.49”E, ca. 250 m., coll. 1.ii.1985.

Etymology. This species is named in honour of my colleague Dr Michael Dunlop ( CSIRO Land and Water) in recognition of his contribution to ecology and conservation in Australia.

Diagnosis. Topalia dunlopi sp. nov. can be distinguished from other species in the genus by the following combination of characters: (1) the medially incised rostrum; (2) the parallel striae on the sclerotised ring around the genital plates; (3) the cerotegument consisting of a network of large foveolae separated by angular ridges; (4) the anteromedial edges of lamellae adjoining; (5) the anterior margin of the notogaster smooth, convex; (6) epimera III and IV separate; (7) the epimeral setation of 2-1-2-2.

Remarks. Topalia dunlopi sp. nov. is morphologically most similar to T. corinnensis sp. nov., with which it shares the medially incised rostrum, the separate epimera III and IV and the medially-adjoining lamellae. Topalia dunlopi sp. nov. differs from T. corinnensis sp. nov. in the shape of the anterior margin of the notogaster, the pattern of cerotegument and the absence of enantiophysis V.

Figures

FIGURE 5. Topalia dunlopi sp. nov. (a) dorsal aspect; (b) ventral aspect; (c) cerotegument (top) and underlying cuticle (bottom). Scale bar = 100 µm.