Malaconothrus murmurensis, 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 : 423-424

Malaconothrus murmurensis sp. nov.

( Fig. 14 )

Dimensions. Holotype female length 495 Μm, breadth 245 Μm. Ratio of prodorsum to total length: 0.4 (holotype).

Female. Prodorsum. Rostral seta (ro) 24 Μm long, not reaching apex of rostrum, smooth, emerging from incurved apex of slightly curved carina forming partial, transverse inter-rostral ridge posterior of acute rostrum ( Fig. 14 a). Lamellar seta (le) smooth, setiform, 20 Μm long, shorter than mutual distance, emerging from alveoli just medial of carina. Interlamellar seta (in) smooth, setiform, 48 Μm long, just over 2 × length of exobothridial seta (ex). Prodorsum finely porose.

Notogaster. Anterior notogastral margin straight; humeral region rounded ( Fig. 14 a). With 15 pairs of setiform, smooth, relatively short setae, plus f 1 represented by their alveoli. Setae sub-equal in length (20–34 Μm), not overlapping; centrodorsal setae d 1 and e 1, plus h 2 and e 2, slightly longer. Alveoli of centrodorsal setae completely aligned longitudinally. With partial M-shaped ridge posteriorly, not fused medially; acute, diagonal elements bearing setae h 2, h 1 and alveolus of f 1. Notogaster shield-shaped; margins more-or-less parallel, broadest at level of cp. Caudal margin very slightly indented at level of h 2, otherwise U-shaped. Seta p 3 positioned markedly anterior of p 2. Ratio of length to breadth 1.4. Lyrifissurae ip transverse. Notogaster densely porose.

Coxisternum. Epimeral setal formula 3-1-3-2 ( Fig. 14 b). Setae on epimeres I and II very short, setiform, smooth. Setae 3b, 3c, 4a and 4c longer (16–24 Μm long) than others (5–11 Μm); setiform smooth; 1c in posterolateral position; 3 b mediolateral; 4b lateral. Epimeral plates I and III each fused anteriorly, II fused posteriorly, IV separated; epimeral plates I with well-developed spur anterolaterally; posterolateral margins of epimeral plates II with pair of blunt spines. Apodeme IV, as far as posterolateral acetabulum, strongly concave.

Anogenital Region. Genital plates with four pairs of smooth, curved, setiform setae subequal in length (15–22 Μm), g 1-3 closely spaced; g 4 on posterior margin of plate, directed anteriorly, at least twice distance from g 3 as from g 3 to g 2 ( Fig. 14 b). Each genital plate 96 Μm long, 46 Μm broad, sub-hexagonal. One pair of anal setae 6 Μm long. Each adanal plate 98 Μm long, 33 Μm broad; three pairs of smooth adanal setae; ad 3 very short (5 Μm), ad 1-2 setiform and much longer (17–22 Μm). Anterior margin of adanal plate acute; overlapped by posterior margin of genital plate.

Legs: Pre-tarsi heterotridactylous.

Material Examined. ANIC 417, rainforest litter, Mur Mur Ridge [Mur Mur Pass] near Tambul, Papua New Guinea, 5°53'S, 144°4'E, 2450 m., coll. R.W. Taylor & G. Baker, 17.vii.1972. Holotype deposited in the Australian National Insect Collection, CSIRO Ecosystem Sciences, Canberra.

Etymology. This species is named for its type locality, the Mur Mur Pass.

Remarks. Malaconothrus murmurensis sp. nov. differs from other members of the genus by the following combination of characters: 1) the heteromorphic adanal setae with ad 3 short and ad 1-2 long and setiform; 2) notogastral setae sub-equal in length; 3) seta in just over 2 × length of ex; 4) partial, transverse inter-rostral ridge; 5) narrow longitudinal notogastral ridges positioned laterally; 6) posterior M-shaped notogastral ridge not fused medially; 7) centrodorsal setae completely aligned longitudinally; 8) genital seta g 4 near posterior margin of plate, directed anteriorly.

Malaconothrus murmurensis sp. nov. is a member of a group of species morphologically most similar to species in the Opisthoseta group in terms of the disposition of the genital setae, tridactyly, a partial inter-rostral ridge and notogastral setae sub-equal in length, but it lacks the reticulate cerotegument of other members of the group.

Figures

FIGURE 14. Malaconothrus murmurensis sp. nov., holotype female; a) dorsal; b) ventral.