Topalia katyae, 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 : 299

Topalia katyae sp. nov.

( Fig. 6 )

Dimensions. Holotype length 344 μm, breadth 221 μm. Paratype length 350 μm, breadth 205 μm. Ratio of prodor- sum to total length: 0.36 (holotype).

Adult. Integument: prodorsum and lamellae with minute granular tubercles in interlamellar region ( Fig. 6c ); notogaster with sparse tubercles. Cuticle reticulate ( Fig. 6a ).

Prodorsum: rostrum incised, with two lateral teeth and shorter median tooth. Lamellae separated along midline, with narrow anterior translamella positioned ventrally, not striate. Interlamellar region flat; setae in on squat tubercles on posteromedian margins of lamellae. With pair of blunt condyles (c) medial to bothridia. Bothridial seta with short, spherical club-shaped apices bearing blunt spines.

Notogaster: ratio of length to breadth: 1.02. Anterior margin of notogaster smooth, convex, entire; faint ridge connecting bases of setae c 2. Humeral projections (h) bilobed, with prominent anterior lobe posterolateral of bothridia and separated from posterior lobe by pronounced indentation. Margins of centrodorsal ridge well-developed, wavy, connecting with faint transverse ridge at level with setae lp. Cuticle of centrodorsal ridge punctate.

Ventral aspect: epimeral plates I trapezoid, only slightly longer than broad. With two pairs of pronounced, sclerotised epimeral foveolae (ef); anterior pair between epimera I and II; posterior pair between epimera II and III. Epimera III and IV separate, rectangular. Epimeral setation 2-1-3-3. Pedotectum I long, broad, with incurved apices, extending anteriorly to point almost half way along length of lamellae. Pedotectum II not extending laterally beyond circumgastric scissure. Perigenital carina broad, short, slightly curved, ca. 28 µm long, extending posteriorly to point anterior of seta g 3. Genital plates 47 µm long, slightly longer than anal plates and over four times distance between them. Ventral plate and sclerotised ring around genital plates sparingly granulate.

Material Examined and Locality Data. Holotype and paratype: ANIC 3507 , 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. M. Christian & M. Sexton, 8.iii.1985 .

Etymology. This species is named in memory of Dr Ekaterina “Katya” Sidorchuk in recognition of her considerable contribution to the systematics and taxonomy of the Oribatida .

Diagnosis. Topalia katyae sp. nov. can be distinguished from other species in the genus by the following combination of characters: (1) the presence of a pair of interlamellar condyles; (2) the transverse notogastral ridge; (3) the narrow, wavy centrodorsal ridge, not expanded posteriorly; (3) the lamellae divided medially; (4) the presence of two pairs of epimeral foveolae; (5) the epimeral setal formula 2-1-3-3; (6) the reticulate notogastral cuticle.

Remarks. Topalia katyae sp. nov. has two unusual characters; the ⊥-shaped pattern of notogastral ridges, not found in other Topalia spp., and the pair of condyles on the interlamellar region, and is thus not particularly similar in morphology to other Topalia spp. However, T. katyae sp. nov. shares interlamellar condyles with T. africana Mahunka, 1985 from South Africa and T. clavata Hammer, 1966 from New Zealand and divided lamellae with T. caliginosa sp. nov., T. royi sp. nov. and T. velata Hammer, 1966 from New Zealand.

Figures

FIGURE 6. Topalia katyae sp. nov. (a) dorsal aspect; (b) ventral aspect; (c) cerotegument. Scale bar = 100 µm.