Austronothrus kinabalu sp. nov.

(Figs. 1, 3 a)

Dimensions. Holotype female length 1138 µm, breadth 529 µm. Paratype female length 1082 µm, breadth 553 µm. Ratio of length of prodorsum to total body length: 0.38 (holotype).

Female. Prodorsum: rostrum rounded; rostral setae 49 µm, projecting anterolaterally, reflexed ventrally, on short tubercles ca. 46 µm apart. Lamellar seta recurved, smooth, 138 µm long, with flakes of cerotegument (Fig. 1 a). Lamellar apophysis 38 µm long, 35 µm broad at base, distance between apophyses 2.6 × length. Interlamellar seta 190 µm long, slender, curved, flagelliform, smooth, extending anteriorly as far as base of lamellar apophysis, on short tubercle twice as long as broad. Faint, parallel interlamellar ridges present. Diameter of bothridium 41 µm; anteriolateral auriculate ridge a blunt, tri-lobed projection (Fig. 4 a); hexagonal reticulations of operculum sparingly ornamented with well-developed ridges. Prodorsal microsculpture smooth, porose.

Notogaster: mean ratio of length to breadth 1.32. Notogaster smooth; faint parallel centrodorsal ridges extending from anterior of seta d 1 to posterior of seta e 1 (Fig. 1 a). Lateral suprapleural scissure 37 µm at broadest point, extending posteriorly just beyond base of seta f 2. Dorsosejugal suture a relatively broad (26 µm), straight, transverse hyaline strip bearing apophyses of setae c 1-3. Setae c 1-3 smooth, flagelliform apically, relatively short, sub-equal in length (63–80 µm); on short tubercles. Distance between tubercles of c 3 and c 2, c 2 and c 1 sub-equal (63–69 µm) and between c 1 144 µm. Seta cp very short (17 µm); setae d 1 and d 2 setiform, sub-equal (44–48 µm long), shorter than distance between them; e 1 much longer (81 µm); base of e 1 4 × further from base of d 2 than distance between d 1 and d 2. Seta e 2 35 µm long, f 2 63 µm; f 1 and h 1 long, flagelliform, sub-equal in length (155–178 µm), their bases close together. Caudal margin rounded; apophyses of h 2 projecting posteriodorsally; h 2 stout curved, 173 µm long; h 3 219 µm long on well-developed apophyses (40 µm long), caudal margin between them straight, transverse. Notogastral shield smooth, porose.

Subcapitulum: posterior part of mentum and lateral margin of gena punctate with faint foveae (Fig. 1 b); seta h 12 µm, m 8 µm, a 14 µm.

Venter: Epimeral plates smooth, porose (Fig. 1 b). Epimeral setae variable in length (10–27 µm); formula 4-2-3- 2. Genital plate 213 µm long 138 µm broad; with 10 pairs of genital setae, broad basally, tapering to fine point apically. Aggenital setae sub-equal in length to genital setae. Anal and adanal setae sub-equal in length (25–36 µm). Anal plate 63 µm broad anteriorly, 288 µm long. Seta p 1 144 µm long, flagelliform apically, smooth, on welldeveloped apophyses; setae p 2 and p 3 shorter (128 µm, 70 µm), thin, setiform. Caudal margin between apophyses of setae p 1 rounded.

Legs: Tarsi homotridactylous; lateral and median claws smooth along dorsal edge.

Material examined. Holotype female, paratype female, base of St. John’s Peak, Mount Kinabalu National Park, Sabah, Borneo, Malaysia, 06°02'S, 116°33'E, 3950 m., coll. A. Smetana, 20.vi.1987. Types deposited in Canadian National Collection of Insects, Arachnids and Nematodes, Agriculture and Agri-food Canada, Ottawa.

Etymology. This species is named for its type locality, Mount Kinabalu National Park.

Remarks. Austronothrus kinabalu can be distinguished from other members of the genus by the following combination of characters: 1) ten pairs of genital setae; 2) centrodorsal ridges faint, short; not diverging posteriorly and lacking transverse ridges; 3) dorsosejugal suture straight; 4) setae d 1 and d 2 very short, less than distance between them; 5) very short setae cp; 6) long, flagelliform setae f 1 and h 1; 7) short lamellar apophyses, barely longer than broad; 8) setae of c series sub-equal in length.

Austronothrus kinabalu is most similar to A. rostralis sp. nov. (cf. below) in that they share relatively short lateral notogastral setae (though those of A. kinabalu are considerably shorter than those of A. rostralis) and simple ridges on the prodorsum extending anteriorly of setae in.