Tyrphonothrus kanaka, Colloff, Matthew J., 2013

Colloff, Matthew J., 2013, Species-groups and biogeography of the oribatid mite family Malaconothridae (Oribatida: Malaconothroidea), with new species from the south-western Pacific region, Zootaxa 3722 (4), pp. 401-438 : 404-406

Tyrphonothrus kanaka sp. nov.

( Fig. 2 )

Dimensions. Holotype female length 561 Μm, breadth 313 Μm. Ratio of prodorsum to total length: 0.3.

Female. Prodorsum. Rostrum acute, smooth, porose ( Fig. 2 a). Rostral seta (ro) densely barbed, curved, 36 Μm long, shorter than mutual distance, emerging from flat tubercle on slight transverse indentation. Lamellar seta (le) barbed, setiform, 78 Μm long, longer than mutual distance, enclosed by well-developed, strongly incurved, Sshaped lateral carina. Interlamellar seta (in) smooth, thin, extremely long (190 Μm), 4 × longer than seta ex. Prodorsum finely porose.

Notogaster. Anterior notogastral margins lightly convex. Humeral region obtusely angled ( Fig. 2 a). With 15 pairs of thin, setiform setae. Setae e 2, h 1, h 2 and p 2 much longer (98–122 Μm long) than others (52–83 Μm long). Setae of the p series barbed; p 3 markedly anterior of p 2; p 3 52 Μm long, as long as distance to p 2; p 2 98 Μm long. Median longitudinal ridges absent but with vestiges of posterior acute transverse ridge in the form of series of foveolae between ip and h 1, extending anteromedially posterior to e 1. Margins narrowing anteriorly, broadest in caudal region. Ratio of length to breadth 1.3. Caudal margin broadly pointed, indented at level of seta h 3. Notogaster densely porose interspersed with foveae posteriorly.

Coxisternum. Epimeral setal formula 3-1-3-3. Setae smooth, setiform, thin ( Fig. 2 b). Setae 1b and 2a longer (26–31 Μm) than others (10–18 Μm); 3b in posterolateral position; 4a in median position. Epimeral plates I rounded anterolaterally. Epimeral plates all separated medially. Apodeme IV, as far as posterolateral acetabulum, straight, transverse. Epimeral plate IV with blunt projection laterally.

Anogenital Region. With five pairs of barbed genital setae, g 1-4 subequal in length (15–23 Μm), closely spaced; g 5 34 Μm long, spaced slightly further from g 4 than distance between other setae ( Fig. 2 b). Genital plates subrectangular; each plate 117 Μm long, 52 Μm broad, with anteromedian carina. Posterior margin of genital plate transverse, overlapping adanal plate. Anterior margin of adanal plate transverse, with sclerotised transverse region. Each adanal plate 130 Μm long, 39 Μm broad; three pairs of smooth, setiform setae, 28–34 Μm long. One pair of anal setae 13 Μm long.

Legs. Pre-tarsi heterotridactylous.

Material examined. Adult female holotype, ANIC 581, rainforest litter, Mt. Koghis, New Caledonia, 22°11'S, 166°31'E, 450 m., coll. P. Ward, 18.ii.1977. Holotype deposited in the Australian National Insect Collection, CSIRO Ecosystem Sciences, Canberra.

Etymology. This species is named for the Kanak people, the indigenous inhabitants of New Caledonia.

Remarks. Tyrphonothrus kanaka sp. nov. differs from other members of the genus by the following combination of characters: 1) the barbed rostral and lamellar setae; 2) the notogaster is foveolate posteriorly and porose anteriorly; 3) the relatively long, overlapping notogastral setae; 4) the very long setae e 2, h 1, h 2 and p 2; 5) the barbed setae h 3 and the p series; 6) setae p 3 are half the length of p 2; 7) the longest epimeral setae are 2a; 8) the five pairs of short, barbed genital setae.

Tyrphonothrus kanaka sp. nov. is morphologically closest to a group of species that have five pairs of genital setae and some of the body setae barbed. Many have well-developed centrodorsal and M-shaped notogastral ridges including T. australis (Hammer, 1958) , T. binodulus (Yamamoto & Coetzee, 2004) , T. fijiensis (Yamamoto, Aoki, Wang & Hu, 1993), T. gringai Colloff & Cameron, 2013 , T. mongolicus (Bayartogtokh, 2010) , T. maritimus sp. nov. and T. taylori sp. nov. Others lack well-developed ridges, including the present species and T. crassisetosus Willmann, 1932 . Tyrphonothrus kanaka sp. nov. is most similar to this latter species in this regard, as well as in the broadly pointed caudal region and very long setae le and in, but differs in that only notogastral setae of the p series are barbed and setae in are smooth. Tyrphonothrus crassisetosus also has smooth setae ro, shorter setae in the c and d series and a foveolate prodorsum.

Figures

FIGURE 2. Tyrphonothrus kanaka sp. nov., holotype female; a) dorsal; b) ventral.