Topalia corinnensis, 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 : 296-297

Topalia corinnensis sp. nov.

( Fig. 4 )

Dimensions. Holotype length 416 μm, breadth 252 μm. Paratype length 397 μm, breadth 237 μm. Ratio of prodor- sum to total length: 0.35 (holotype).

Adult. Integument: prodorsum with sparsely-distributed tubercles in interlamellar region. Notogaster with small granules; angular foveolae lacking. Cerotegument sparing or absent in centrodorsal region. Underlying cuticle smooth.

Prodorsum: rostrum incised, with two lateral teeth but no median tooth. Lamellae meeting along anterior midline and with pattern of fine, transverse striae. Interlamellar region slightly convex, smooth; setae in on squat tubercles on posteromedian margins of lamellae. Bothridial seta with elongated, ovoid, club-shaped apices bearing blunt spines.

Notogaster: ratio of length to breadth: 1.13. Anterior margin of notogaster wavy, indented medially. Humeral projections (h) rounded, well-developed, bearing seta c 2, incurved posteriorly at level of lyrifissurae ia. Margins of centrodorsal ridge well-developed, converging anterior of setae dm, then diverging; posterior part of ridge rounded, extending posteriorly to point level with setae h 3.

Ventral aspect: epimeral plates I trapezoid, twice as long as broad; epimera III and IV separate, rectangular. Enantiophysis V present; epimeral setation 2-1-2-2. Pedotectum II not extending laterally beyond circumgastric scissure. Perigenital carina more-or-less straight, ca. 38 µm long, extending posteriorly to point level with seta ag. Genital plates 44 µm long, same length as anal plates and almost three times distance between them. Cuticle ante- rior to genital plate granulate. Pedotectum I long, thin, sparingly granulate, extending anteriorly to point almost half way along length of lamellae in dorsal view. Lateral margins of pedotecta II extending to apices of bothridia setae. Gnathosoma the same as in Topalia caliginosa .

Material Examined and Locality Data. Holotype and paratype: ANIC 3757 , sifted litter and mossy logs, rainforest with Eucalyptus sp., State Forest , 2.2 km NE Corinna, Tasmania, 41°38’43”S 145°05’50”E., 45 m., coll. T. Weir & C. Lemann, 14.iii.2008 .

Etymology. This species is named for its type locality; Corinna, Tasmania.

Diagnosis. Topalia corinnensis sp. nov. can be distinguished from other species in the genus by the following combination of characters: (1) rostrum incised medially; (2) anteromedial edges of lamellae meeting; (3) setae in on squat tubercles; (4) anterior margin of notogaster wavy, indented medially; (5) epimera III and IV completely separated; (5) with enantiophysis V between epimera II and III.

Remarks. Topalia corinnensis sp. nov. is morphologically most similar to T. royi sp. nov., with which it shares the wavy anterior notogastral margin with a median indentation and the lamellae with fine striae. Topalia corinnensis sp. nov. differs from T. royi sp. nov. in the separated epimera II and IV, the granular, non-polygonal cerotegument and the presence of enantiophysis V, a character state it shares with T. africana and T. problematica .

Figures

FIGURE 4. Topalia corinnensis sp. nov. (a) dorsal aspect; (b) ventral aspect; (c) cerotegument. Scale bar = 100 µm.