Australonura paraguayensis sp. nov.

(Figs 15–24)

Type material. Holotype male: Paraguay, Departamento de Alto Parana, Ciudad del Este, 10/03/1983, leg C. Dlouhy. Original slide label: “3a Paraguay (Alto Parana): Centre forestier (C.F.A.P) échantillon du sol. Puerto Presidente Stroessner, Parcella IV. (pin). 10-III-1983 /03. leg C. Dlouhy ”; deposited in UNAM . Paratypes: Paraguay, Departamento de Alto Parana, 12 km south of Ciudad del Este (ex-Puerto Presidente Stroessner), April 1984, Ecole Forestière, soil sample, C. Dlouhy col., two females (one deposited in UNAM, one in MNHN) and one male (deposited in UNAM) . Ibid, 24 March 1983, Centre forestier (C.F.A.P), soil sample, C. Dlouhy, one female (deposited in UNAM) . Paraguay, Departamento de Canindeyú, 2 November 1979, “près de l’embouchure du Rio Carapa et du Rio Alta Paraná. Tamisage de feuilles mortes et bois pourri dans forêt, Expédition zoologique du Muséum de Genève”, one female and one juvenile (deposited in Museum de Genève) .

Description. Length: 0.76–1.11 mm (N=2). Habitus of stocky Paleonura . Color white in ethanol. Secondary granules conical. Tertiary granules (elementary tubercles) well differentiated dorsally on head and body, often papillate, grouped in conspicuous tubercles, including the dorso-internal ones on tergites. Cephalic tubercles Di fused on the midline. Four kinds of dorsal ordinary chaetae: (i) unilaterally strongly ciliated mac, swollen basally; (ii) ciliated mes morphologically similar to ciliated mac, but shorter and usually thinner; (iii) smooth and acuminate mes; (iv) smooth and acuminate mic (Figs 15, 19, 20, 21, 22 and 23). Tergite S-chaetae much thinner than mac and at least 30% shorter than closest mac (Figs 21 and 23).

Antennae. Ant. I with seven chaetae, of which three dorsal ciliated mac (Fig. 15); Ant. II with eleven chaetae, of which three ciliated mac dorsally. Ant. III sensorial organ with two thickened ms in a cuticular fold; two guard S straight, Sgv as thick as and 20–25% longer than Sgd, and thinner and longer than Ant. IV S1–S8 (Fig. 18); one ventro-external ms more basally. Ant. IV with S1-S8 thick, strongly bent and subequal (Fig. 18).

Ocelli 2 + 2 without pigment, located on the edges of tubercle Oc (Fig. 15). Mandibles thin, bidentate; maxilla heads styliform. Labium long with four basal chaetae (E,F,G,f with F very long), three distal chaetae (A,C,D) with one or possibly two minute x-papillae, and three lateral chaetae (c,d,e) (Fig. 16). Labrum ogival, rounded apically (Fig. 17); labral formula 0/2,4.

Vi: 5 chaetae; Ve: ≥ 6 chaetae Dorsal head chaetotaxy and tubercles (Table 3A and Fig. 15). Eleven tubercles in total: CL, Af, 2 Oc, (Di+Di), 2 De, 2 DL, 2 (L+So). Four chaetae on tubercle Af, chaeta O absent, chaeta D free or on the edge of tubercle CL. Three chaetae on ocular tubercle, Ocp present. Dorso-internal tubercles of the head fused on axis, with four elementary tubercles anterior to the line Di1-Di1 and a few other ones poorly delimited between the mac Di1. DL tubercle with 4 DL chaetae; mac L1 included in the (L+So) tubercle of head.

* Lateral chaetal group of Abd. V located ventrally without individualized tubercle, probably including one chaeta VL.

Postcephalic chaetotaxy and tubercles (Table 3B and Figs 20–23). Chaetae Di1, 2, 3 not on a line on Th. II–III, Di1 being clearly external to the line Di2–Di3; Di3 as a mic, much shorter than Di2 (Fig. 20). Chaetae Di2 posterointernal to Di1 on Abd. I–IV. Chaetal group Di of Abd. IV at the same level as De and DL. Tubercles Di of Abd. V closely adjacent, but not fused across the midline, their anterior mes (Di2) less distant than Di1 mac (Fig 23).

Legs (Table 3B and Fig. 24). Tita without tenent hairs and without chaeta M; B4 and B5 moderately elongate. Pretarsal mic rather long. Unguis without tooth.

Microchaetae not seen on furcal rest. Male genital plate with 4+4 genital and 12 circumgenital chaetae; female genital plate with 1+1 genital and 12 circumgenital chaetae.

Discussion. Australonura paraguayensis sp. nov. was recorded as Paleonura sp. from Paraguay by Palacios- Vargas & Mejía Recamier (2009). It differs from all Australonura described so far by the separation of tubercle Di on Abd. V. Aside this character, it is very similar to A. grossi (Yosii, 1966) from Australia in tubercle arrangement and chaetotaxy. It is easily distinguished from A. limnophila and A. friasica by its dorsal mes and mac densely ciliated and the strong differentiation of its dorsal tubercles, as well as important chaetotaxic characters (Table 4).