Malaconothrus liklik, 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 : 421-422

Malaconothrus liklik sp. nov.

(Fig. 13)

Dimensions. Holotype female length 378 Μm, breadth 187 Μm. Paratypes (n = 4) mean length 388 Μm (range 378– 397 Μm); mean breadth 184 Μm (range 182–189 Μm). Ratio of prodorsum to total length (holotype): 0.3.

Female. Prodorsum. Rostrum broad, sub-rectangular, with transverse inter-rostral ridge above acute naso. Rostral seta (ro) smooth, thin, setiform, 26 Μm long, shorter than mutual distance, on apex of carina at junction with inter-rostral ridge on apex of simple, curved carina (Fig. 13a). Lamellar seta (le) smooth, setiform, 20 Μm long, shorter than mutual distance, not extending as far as base of seta ro; positioned medial of prodorsal carina. Interlamellar seta (in) smooth, thin, setiform, 28 Μm long, length 0.3 × mutual distance; 2 × length of smooth, thin, setiform exobothridial seta ex. Prodorsum smooth, porose. Cerotegument densely granular.

Notogaster. Anterior notogastral margin slightly convex; humeral region rounded (Fig. 13a). Cerotegument of large-broadly-spaced foveolae. Lyrifissure ia very large: 21 Μm long, 4 Μm broad. With 15 pairs of thin, smooth notogastral setae plus f 1, represented by their alveoli; c 1, d 1 and e 1 much longer (45–68 Μm) than others (20–33 Μm). Seta c 2 positioned closer to c 3 than to c 1. Notogaster elongated, shield-shaped; margins parallel, broadest between cp and e 2. Short, acute, diagonal ridges between h 2 and h 1. Longitudinal ridges absent. Setae p 3 markedly anterior of p 2. Ratio of length to breadth 1.4. Caudal margin U-shaped. Lyrifissurae ip curved, acute.

Coxisternum. Epimeral setal formula 3-1-3-3 (Fig. 13b). Epimeral setae smooth, setiform; seta 1b 45 Μm long, very much longer than others; 3b, 3c, 4a and 4c 22–30 Μm long; others 5–14 Μm long; 1c in posterolateral position, 4b lateral, 3b mediolateral. Epimeral plates all separated medially. Posterolateral margins of plates II acute. Posterior margin of epimere II and anterior margin of epimere III with rows of small tubercles. Apodeme IV concave.

Anogenital Region. Genital plates with five pairs of very short, thin, smooth, setiform setae directed posteriorly (Fig. 13b); g 1-4 short, sub-equal (6–9 Μm), g 5 18 Μm long, positioned midway down plate; distance between g 5 and g 4 2 × that between g 4 and g 3. Genital plates oval; each plate 79 Μm long, 41 Μm broad; posterior margin transverse. One pair of minute setiform anal setae, 4 Μm long. Each adanal plate 98 Μm long, 28 Μm broad, Adanal setae ad 2-3 thick, short (6 Μm), spiniform, barbed; ad 1 setiform, smooth, long (24 Μm). Anterior margin of adanal plate acute, overlapped by posterior margin of genital plate, without thickened transverse ridge.

Legs. Pre-tarsi monodactylous.

Material examined Holotype: ANIC 407, litter, rainforest, Hayfield Mission, near Maprik, Papua New Guinea, 3°41'55"S 143°2'58"E, ca. 50 m., coll. R.W. Taylor, 27.vi.1972. One paratype, ANIC 391, rainforest litter, near Lae, Papua New Guinea, ca. 50 m., coll. R.W. Taylor, 11.vi.1972. Two paratypes, ANIC 395, rainforest litter, “Timber Track’, 16 km north-west of Lae, Papua New Guinea, 6°36'S 146°52'E, 220 m., coll. R.W. Taylor, 12.vi.1972. One paratype, ANIC 408, same data as ANIC 407. Holotype and paratypes deposited in the Australian National Insect Collection, CSIRO Ecosystem Sciences, Canberra.

Etymology. The specific name liklik is Tok Pisin for ‘small’.

Remarks. Malaconothrus liklik sp. nov. differs from other members of the genus by the following combination of characters: 1) the presence of a well-developed inter-rostral ridge; 2) setae in 2 × length of ex; 3) the foveolate notogastral cerotegument; 4) the shield-shaped notogaster; 5) the short, acute, diagonal notogastral ridges between h 1 and h 2; 6) the extraordinarily long setae 3b; 7) the small tubercles along the posterior edge of epimere II and anterior edge of epimere III; 8) the five pairs of very short genital setae with g 5 halfway along the plate; 9) the singular, heteromorphic adanal setae, with ad 2-3, short, barbed, spiniform and ad 1 long and setiform.

Malaconothrus liklik belongs to a group of species that are monodactylous, have five or six pairs of genital setae, the centrodorsal setae longer than the others, a shield-shaped notogaster with parallel sides, an inter-rostral ridge and foveolate prodorsal and notogastral cerotegument. The group includes M. chajulensis Palacios-Vargas & Iglesias, 1997 ( Mexico) ; M. dipankari Saha & Sanyal, 1996 ( India) ; M. dorsofoveolatus Hammer, 1979 (Java) ; M. hexasetosus Hammer, 1971 ( Fiji, Java); M. marginatus Yamamoto, 1998 ( China) ; M. pilosellus Balogh & Mahunka, 1969 ( Brazil) and M. pseudolamellatus Willmann, 1932 (Java) . Of these species, only M. dorsofoveolatus and M. hexasetosus share the short, acute, diagonal notogastral ridges. The latter species has six pairs of genital setae and Malaconothrus liklik is morphologically most similar to M. dorsofoveolatus from Java from which it differs by its heteromorphic adanal setae, longer setae ex, 3b and centrodorsal setae and shorter setae h 2.

FIGURE 13. Malaconothrus liklik sp. nov., holotype female; a) dorsal; b) ventral; c) seta d 2.