Malaconothrus laensis, 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 : 419-421

Malaconothrus laensis sp. nov.

( Fig. 12 )

Dimensions. Holotype female length 397 Μm, breadth 183 Μm; paratype female lengths 416, 410, 420 Μm, breadths 192, 189, 195 Μm. Ratio of prodorsum to total length: 0.4.

Female. Prodorsum. Rostrum broad, sub-rectangular, with transverse inter-rostral ridge above acute naso ( Fig. 12 a). Rostral seta (ro) thin, smooth, setiform, 30 Μm long positioned at apex of carina and margin of welldeveloped inter-rostral ridge. Lamellar seta (le) smooth, recurved, 58 Μm long, emerging from alveolus medial of carina. Interlamellar seta (in) smooth, setiform, 83 Μm long, 3 × longer than smooth, setiform seta ex. Prodorsum finely porose; cerotegument of small, regular pits. with well-developed, curved, transverse ridge running posteriorly between in.

Notogaster. Anterior notogastral margin slightly convex; humeral region rounded ( Fig. 12 a). With 15 pairs of long, thick, smooth, setiform setae. Setae mostly sub-equal in length (27–36 Μm); c 1, d 1, e 1-2 and h 2 longer (49–67 Μm). Distance from c 1 to c 2 2 × c 2 to c 3. Notogaster rectangular, margins more-or-less parallel, broadest at level of c 3. With broad median longitudinal ridges with well-developed posterior M-shaped ridge on which are positioned setae h 1 and h 2. Posterior ridge reaching caudal margin between setae p 1, joined with M-shaped ridge medially.

With curved transverse ridge from h 3 to caudal margin of ventral notogastral plate. Seta p 3 anterolateral of, and adjacent to, seta p 2. Ratio of length to breadth 1.5. Caudal margin slightly indented at level of h 2, otherwise Ushaped. Cerotegument covered with small, regular pits.

Coxisternum. Epimeral setal formula 3-1-3-3 ( Fig. 12 b). Setae 1b, 3b, 3c and 4c 28–39 Μm long, much longer than other epimeral setae. Seta 3b in mediolateral position, 4b in posterolateral position. Epimeral plates all separated medially. Epimeral plates I with well-developed spur anterolaterally. Epimeral plates II acute posterolaterally. Epimeres III and IV of equal width, without paired lateral spines. Apodeme IV strongly concave.

Anogenital Region. Genital plates with five pairs of smooth, setiform setae; g 1-3 18–24 Μm long; g 4 52 Μm long, much longer than others, located 2 × distance from g 4 as distance between other setae ( Fig. 12 b). Each genital plate 85 Μm long, 36 Μm broad, sub-rectangular; posterior margin transverse. One pair of anal setae 6 Μm long. Each adanal plate 93 Μm long, 28 Μm broad, with three pairs of smooth, thick, setiform adanal setae, 28–37 Μm long, longer than width of adanal plate. Anterior margin of adanal plate acute, without thickened transverse ridge, overlapped by posterior margin of genital plate.

Legs. Pre-tarsi monodactylous.

Material examined. Holotype, ANIC 400, litter, rainforest, near Lae (6°42'S 146°56'E), Papua New Guinea, coll. R.W. Taylor, 16.vi.1972. One paratype, ANIC 387, rainforest litter, near Kokoda (8°52'S 147°44'E), Papua New Guinea, ca. 500 m., coll. R.W. Taylor, 1.vi.1972. Two paratypes, ANIC 391, rainforest litter, near Lae, Papua New Guinea, ca. 50 m, coll. R.W. Taylor, 11.vi.1972. Holotype and paratypes deposited in the Australian National Insect Collection, CSIRO Ecosystem Sciences, Canberra.

Etymology. This species is named for its type locality near Lae on the Huon Gulf, Papua New Guinea.

Remarks. Malaconothrus laensis sp. nov. differs from other members of the genus by the following combination of characters: 1) inter-rostral ridge; 2) long thick adanal setae; 3) seta p 3 anterolateral of, and adjacent to, seta p 2; 4) with median longitudinal ridges, M-shaped ridge and curved posterior ridge between setae p 1; 5) centrodorsal setae longer than others; 6) with five pairs of genital setae; g 5 2 × longer than others.

Malaconothrus laensis sp. nov. is a member of the Plumosus species group (cf. below). It is morphologically most similar to M. rohri P. Balogh, 1997 from Brazil, but has the epimeral setal formula 3-3-3-3 rather than 3-1-2- 3 and much shorter setae p 2 and p 3.’

Figures

FIGURE 12. Malaconothrus laensis sp. nov., holotype female; a) dorsal; b) ventral.