Malaconothrus talaitae, Colloff, Matthew J. & Cameron, Stephen L., 2013

Colloff, Matthew J. & Cameron, Stephen L., 2013, A phylogenetic analysis and taxonomic revision of the oribatid mite family Malaconothridae (Acari: Oribatida), with new species of Tyrphonothrus and Malaconothrus from Australia, Zootaxa 3681 (4), pp. 301-346 : 333-335

Malaconothrus talaitae sp. nov.

( Figs. 21 , 22 )

Dimensions. Holotype female length 525 μm, breadth 253 μm. Paratype females: mean length (n = 11) 503 μm (range 473–523 μm), mean breadth 232 μm (range 205–265 μm). Ratio of prodorsum to total length: 0.36 (holotype).

Female. Prodorsum. Rostrum broad, rounded, with minute tubercles ( Fig. 21 a). Rostral seta (ro) smooth, curved, setiform, 23 μm long, shorter than mutual distance, on tubercle at apex of carina; with inter-rostral ridge ( Fig. 6 a). Lamellar seta (le) smooth, setiform, 46 μm long, longer than mutual distance, extending beyond apex of rostrum, emerging from medially-directed extension of carina. Interlamellar seta (in) smooth, setiform, 74 μm long, shorter than distance between them. Exobothridial seta ex 1 smooth, 46 μm long. Pedotectum I welldeveloped, blunt. Prodorsum finely reticulate, with poorly-developed concave longitudinal ridges.

Notogaster. Dorsosejugal furrow slightly convex, cerotegument reticulate laterally, becoming fainter medially ( Fig. 21 a). Humeral region rounded. Lyrifissure ia 16 μm long. With 15 pairs of smooth, setiform setae, plus f 1 represented by their alveoli; c 1, d 1 and e 1 much longer than others. Seta c 1 71 μm long, longer than distance to d 1; c 2 55 μm, as long as distance to cp, much closer to c 3 than to c 1; c 3 34 μm, shorter than distance to cp; cp 57 μm, shorter than distance to d 2; d 1 84 μm, longer than distance between them; d 2 65 μm, shorter than distance to e 2; e 1 78 μm, longer than distance between them; e 2 46 μm, shorter than distance to f 2; f 2 59 μm long, shorter than distance to h 2; h 1 51 μm, shorter than distance to p 1; h 2 61 μm, shorter than distance to p 1; h 3 42 μm, markedly shorter than h 2; p 1 44 μm, shorter than distance between them; p 1 positioned dorsally; p 3 62 μm long ( Fig. 6 b), longer than distance to p 2 (59 μm long). Posterior notogaster with faint concave ridges between h 2 and median caudal margin. Lateral longitudinal ridges present, faint. Longitudinal ridges absent lateral of anal and genital plates. Notogastral margins convex, broadest between f 2 and e 2. Ratio of length to breadth 1.33. Caudal margin transverse. Lyrifissurae ip obtuse.

Coxisternum. Epimeral setal formula 3-1-3-2; ( Fig. 21 b). Epimeral setae smooth, setiform; 3b, 3c and 4c 27– 38 μm long, much longer than others (4–18 μm); 1c in posteriolateral position, 3b in mediolateral position, 4b absent. Epimeral plates I and III fused anteriorly, II separated, IV fused posteriorly. Posteriolateral margins of epimeral plates II pointed, sharp. Apodeme IV, as far as posteriolateral acetabulum, concave. Sejugal articulation narrower than epimeral plates II.

Anogenital Region. Four pairs of smooth, setiform genital setae ( Fig. 21 b), g 1-2 subequal in length (20–23 μm), g 3-4 28–30 μm long; g 4 directed anteriorly, distance between insertions of g 3 and g 4 2 × that between g 2 and g 3. Setae shorter than width of genital plate. Each genital plate 96 μm long, 51 μm broad, sub-oval with transverse posterior margin. Without reticulate or striated cerotegument between adanal plate and ventral margin of notogaster. One pair of long (29 μm) flagelliform anal setae, much longer than width of anal plate. Each adanal plate 109 μm long, 27 μm broad; three pairs of long (67–78 μm) smooth, setiform adanal setae, longer than width of adanal plate; ad 1 not on median carina. Anterior margin of adanal plate acute, overlapped by posterior margin of genital plate, without thickened transverse ridge.

Lateral Aspect. Prodorsum smoothly curved from seta in to apex of rostrum ( Fig. 21 c). Seta le projecting as far as base of seta ro. Seta ex 1 projecting posteriolaterally; seta ex 2 represented by alveolar vestige. Pedotectum I welldeveloped, blunt, triangular process. Interbothridial region concave. Notaspis flat: ratio of height to length 0.47. Pleuraspis with well-developed humeral process.

Legs. Pre-tarsi heterotridactylous; lateral claws sparingly barbed on dorsal edge ( Fig. 22 ). Legs short and broad: Leg I 185 μm long; tarsi sub-conical. Ratio of length to breadth of tarsi: I 2.18; II 2.07; III 2.52; IV 3.65. Setal formula: Leg I 1-5 -4(1)-4(1)-11(3); Leg II 1-6 -4(1)-3(1)-10(1); Leg III 2-3 -2-2(1)-10; Leg IV 0- 2 -2-2-10. All setae on all segments smooth. Tarsus I with proral setae (p) short, broad basally, flagelliform apically ( Fig. 22 a): short, blunt and broad on other tarsi; unguinal setae (u) short, blunt and broad: peg-like; solenidia (ω1-3) clustered; famulus (ε) short, conical (12 μm); fastigial setae (ft) heteromorphic: ft ” short, blunt and broad and ft ’ longer, broad basally, tapering and pointed apically. Tarsus II with setae ft as for Tarsus I ( Fig. 22 b). Tarsus II with both setae ft long, broad basally, pointed apically ( Fig. 22 c). Tarsus IV with ft ” long (53 μm), curved, pointed; seta s same shape but slightly longer than primiventral setae (pv) ( Fig. 22 d).

Material examined. Holotype female and 26 paratype females, moss ( Dicranoloma billiardieri ), Nothofagus cunninghami forest, The Beeches, Lady Talbot Drive near Warburton, Yarra Ranges National Park, Victoria, 37°29'14"S, 145°49'59"E, 800 m., coll. G. Perdomo, May 2009. Holotype and paratypes deposited in the Australian National Insect Collection, CSIRO Ecosystem Sciences, Canberra.

Etymology. This species is named in honour of Amelia de Perdomo, grandmother of its collector Giselle Perdomo, and known affectionately as ‘Talaita’.

Remarks. Trimalaconothrus talaitae sp. nov. differs from other members of the genus by the following combination of characters: 1) the rostral setae are short and reflexed; 2) the interlamellar setae are only slightly longer than the exobothridial setae; 3) the presence of the inter-rostral ridge; 4) the reticulate notogastral cerotegument; 5) the median setae c 1, d 1 and e 1 are longer than the other notogastral setae and overlapping; 6) the concave ridges between h 2 and the caudal margin; 7) the four pairs of relatively long genital setae, with g 4 separated from the others and pointing anteriorly; 8) epimeral setae 1b and 3b are longer than the others; 9) the very long adanal setae: ad 2 are longer than the others.

Malaconothrus talaitae sp. nov. is morphologically most similar to M. darwini , as detailed in the remarks section for that species above.

Figures

FIGURE 6. Tyrphonothrus gringai sp. nov., holotype female, left legs, antiaxial view; a) Leg I; b) Leg II; c) Leg III; d) Leg IV.

FIGURE 21. Malaconothrus talaitae sp. nov., holotype female; a) dorsal; b) ventral; c) lateral.

FIGURE 22. Malaconothrus talaitae sp. nov., left legs, antiaxial view; a) Leg I; b) Leg II; c) Leg III; d) Leg IV.