Malaconothrus knuellei, 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 : 330-332

Malaconothrus knuellei sp. nov.

( Figs. 19 , 20 )

Dimensions. Holotype female length 419 μm, breadth 211 μm. Paratype female length 435 μm, breadth 214 μm. Ratio of prodorsum to total length: 0.34 (holotype).

Female. Prodorsum. Rostrum broad, rounded. Rostral seta (ro) smooth, thin, setiform, 41 μm long, shorter than mutual distance, on apex of simple, curved lateral carina ( Fig. 19 a). Lamellar seta (le) smooth, setiform, 46 μm long, longer than mutual distance, extending beyond base of seta ro. Interlamellar seta (in) smooth, thin, setiform, 86 μm long, as long as mutual distance, 3 × length of smooth, setiform exobothridial seta ex. Prodorsum smooth, porose. Cerotegument with small alveoli.

Notogaster. Dorsosejugal furrow slightly convex; humeral region angular with narrow wedge-shaped ridge ( Fig. 19 a). Cerotegument alveolate. Lyrifissure ia very large: 22 μm long, 8 μm broad. With 15 pairs of thin, smooth notogastral setae; e 2, h 1 and h 2 longer (68–85 μm) than others (29–53 μm). Seta c 2 positioned much closer to c 3 than to c 1. Posterior notogaster with faint, M-shaped ridge, not joined medially; ridge absent anterior of p 1. Longitudinal ridges absent. Notogaster elongated, barrel-shaped; margins convex, broadest at level of e 2. Ratio of length to breadth 1.38. Caudal margin U-shaped, slightly indented. Lyrifissurae ip curved, acute.

Coxisternum. Epimeral setal formula 3-1-3-2 ( Fig. 19 b). Epimeral setae smooth, setiform; 1b, 3b, 3c, 4a and 4b 24-40 μm; longer than others (6-10 μm); 1c in posteriolateral position, 4b lateral, 3b median. Epimeral plates I fused medially; II-IV separated. Posteriolateral margins of plates II rounded. Apodeme IV concave.

Anogenital Region. With five pairs of long, thin, smooth, flagelliform genital setae directed posteriorly ( Fig. 19 b); g 1 shortest (37 μm), g 2-3 52 μm long g 4-5 70 μm long. Most setae longer than width of genital plate. Genital plates sub-hexagonal; each plate 90 μm long, 38 μm broad; posterior margin transverse. One pair of setiform anal setae, 11 μm long, as long as width of anal plate. Each adanal plate 101 μm long, 22 μm broad; three pairs of long thin, smooth, flagelliform adanal setae, ad 1 (74 μm) longer than others. Anterior margin of adanal plate acute, overlapped by posterior margin of genital plate, without thickened transverse ridge.

Legs. Pre-tarsi I and II heterotridactylous; lateral claws smaller than median claw; claws on legs III and IV same size ( Fig. 20 ). Legs short and broad: Leg I 157 μm long. Ratio of length to breadth of Tarsi: I 2.1; II 2.3; III 3.14; IV 3.18. Setal formula: Leg I 1-4 -2(1)-4(1)-11(3); Leg II 1-5 -2(1)-2(1)-10(1); Leg III 2-2 -1-2(1)-10; Leg IV 1-2 -1-2-10. All setae smooth except barbed setae d and v ” on Femur IV. Tarsi with proral setae (p) similar shape and size as unguinal setae (u), short, broad, pointed ( Fig. 20 ); solenidia ω1-3 clustered; famulus (ε) minute, conical (6 μm); fastigial setae (ft) homeomorphic: long, pointed. Seta d on Tibia I and II very long (53–62 μm). Tarsus II with setae ft as for Tarsus I; Tarsus III with ft ” shorter and thinner than ft ’ ( Fig. 20 b, c). Trochanter III with long setae v (34–48 μm). Tarsus IV with seta s markedly longer and thicker than primiventral setae (pv) and positioned anterior of them ( Fig. 20 d).

Material examined. Holotype female, soaking wet liverworts, Leura Cascades Walk, near Leura, Blue Mountains, New South Wales, 33°43'17"S 150°19'21"E, 880 m, coll. M.J. Colloff, 17.i.2011. Paratype female, ANIC 430, rainforest, Eacham National Park, Queensland. 17°17'24"S 145°37'38"E, 760 m., coll. R.W. Taylor, 1– 7.iv.1973. Holotype and paratype deposited in the Australian National Insect Collection, CSIRO Ecosystem Sciences, Canberra.

Etymology. This species is named in honour and in memory of Professor Willi Knülle (Institut für Angewandte Zoologie, Freie Universität Berlin) in recognition of his contribution to acarology, especially to the systematics of the Malaconothroidea.

Remarks. Malaconothrus knuellei sp. nov. differs from other members of the genus by the following combination of characters: 1) setae ro and le are subequal in length; 2) setae c 1 and c 3 are at least twice the length of c 2; 3) the massive lyrifissurae ia; 4) setae e 2, h 1 and h 2 are longer than the other notogastral setae; 5) the faint Mshaped posterior notogastral ridges, separated medially; 6) the epimeral setal formula is 3-1-3-2; 7) the epimeral seta 4a is much longer than the others; 8) the five pairs of very long, flagelliform genital setae; 9) the extremely long, flagelliform seta ad 1.

Malaconothrus knuellei sp. nov. is morphologically most similar to M. jowettae as detailed under the remarks section for that species above.

Figures

FIGURE 19. Malaconothrus knuellei sp. nov., holotype female; a) dorsal; b) ventral.

FIGURE 20. Malaconothrus knuellei sp. nov., left legs, antiaxial view; a) Leg I; b) Leg II; c) Leg III; d) Leg IV.