Australonura limnophila

(Figs 2 – 10)

Redescription. Length: from 0.78 – 1.73 mm (all specimens, N = 18). Females larger than males; specimens from the type locality are larger, while non-type specimens exhibit a wider range of size: females (types): 1.13 – 1.73 mm (N = 8); males (types): 1.18 – 1.47 (N = 2); females (non-types): 0.78 – 1.47 (N = 4); males (non-types): 0.88 – 1.45 mm (N = 4). Habitus similar to Paleonura sp. (Fig. 2). Colour white in ethanol. Secondary granulation regular, constituted of rounded granules, equal to or less than a mac socket in diameter (Figs 6 and 8). No reticulations. Dorsal chaetal groups on weakly differentiated tubercles; tubercles absent or faint on Th. I; tubercles Di and De of Th. II – Abd. III and Di of Abd. IV feebly indicated; DL and L of Th. II – Abd. IV and head tubercles moderately differentiated; tubercles De of Abd. IV and tubercles of Abd. V and VI stronger, with distinct elementary tubercles (Figs 6 and 8). Elementary tubercles faint to well differentiated, marked by stronger secondary granules, without or with low integument boss, not grouped on papilla. Two kinds of ordinary chaetae on tergites: (i) thick mac, straight, slightly tapering, with blunt tips, smooth or, for some of them (mostly laterally and on Abd. VI), very sparsely serrated when carefully examined, the dorsal ones slightly sheathed and feebly tapering, the lateral ones not distinctly sheathed and more distinctly tapering; (ii) smooth mes of similar morphology, often bent and more tapering distally. Tergite S-chaetae thin and long, thinner and subequal or slightly shorter than closest large mac (Figs 2 and 8). Antennae (Fig. 3). All antennal chaetae smooth. Ant. I with seven chaetae, Ant. II with eleven chaetae, the dorsal ones thicker and longer than ventral ones. Ant. III sensorial organ with two thick, bent ms slightly buried in a cuticular fold; guard S thinner than S 1 - S 8 of Ant. IV, with Sgv straight and 30 % longer than Sgd; and one ventral ms. Ant. IV with S 1 - 8, 12 long “ mou ” chaetae, one short ordinary chaeta (i), one small subapical organ; apical bulb indistinct flat, entire, fused to Ant. IV tip. Ocelli 2 + 2 without pigment, located on the edges of tubercle Oc (Fig. 6). 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 minute x-papilla, and three lateral chaetae (c, d, e) (Fig. 4). Labrum elongate, large and rounded apically, with planaria-head-like ventral sclerifications (Fig. 5); labral formula 0 / 2,4. Dorsal head chaetotaxy and tubercles (Table 1 A, Fig. 2, 6 and 7). Eleven tubercles in total: CL, Af, 2 Oc, (Di + Di), 2 De, 2 DL, 2 (L + So). Ten chaetae on tubercle Af, chaeta O absent. Three chaetae present in ocular tubercle including Ocp. Dorso-internal tubercles of the head fused on axis, with four elementary tubercles often inconspicuous anterior to the line Di 1 – Di 1 and none posteriorly. On lateral area of head, mac L 1 displaced towards tubercle DL (Fig. 7). Postcephalic chaetotaxy and tubercles (Table 1 B, Fig. 2 and Fig. 8). Chaetae Di 1, 2, 3 almost on a line parallel to the axis on Th. II – III. Chaetae Di 2 anterior to Di 1 on Abd. I – IV. Chaetal group Di of Abd. IV shifted anteriorly to De. On the tubercle Di of Abd. V, the anterior mes are possibly homologous to Di 3 rather than Di 2, being more distant than Di 1 mac. Legs (Table 1 B and Fig. 9). Ventral mac of the femur moderately differentiated, slightly longer than ventral side of femur. Tita without tenent hairs, without chaeta M and with chaetae B 4 and B 5 moderately elongate. Pretarsal mic relatively long. Unguis without tooth. Microchaetae of furcal rest either present (Fig. 10) or undetectable. Male genital plate with 4 + 4 genital and 7 – 12 circumgenital chaetae; female genital plate with 1 + 1 genital and 11 – 14 circumgenital chaetae. Vi: 5 chaetae; Ve: 8 – 9 chaetae

Discussion. Australonura limnophila was described from specimens of various locations in Southern Argentina, all located at the southern limit of the Valdivian temperate forest ecoregion (Fig. 1). In the original description of the species, the clypeal tubercle is fused with the antenno-frontal; these tubercles are in fact separate on the type specimens we have examined, in agreement with Cassagnau & Oliveira (1990) who already corrected this mistake. Tubercles Di of the head are fused to each other on axis (Fig. 2). It is this character, together with separation of Di and De and the presence of a well-differentiated antenno-frontal tubercle on head, that led us to assign Neanura limnophila to the genus Australonura. However, the uneven dorso-internal cephalic tubercle is very faint, without clearly recognizable elementary tubercles. From the specimens listed in the original description of Cassagnau & Rapoport (1962), some were isolated subsequently in a new species, A. friasica (Cassagnau & Oliveira 1990). A closer examination leads us to consider the specimens of Lago Lacar area as another new species, which is briefly characterized below.

Type material examined. Holotype (male) and two female paratypes on slide from Cassagnau collection: Argentina: Chubut Province: near Lago Futulaufquen, 15 / 03 / 59, Delamare-Deboutteville leg (ARG-Pat 063); deposited in MNHN. Eight paratypes (1 male, 7 females) on slides from Cassagnau collection: ibid: near Lago Menéndez, 16 / 03 / 59, Delamare-Deboutteville leg (ARG-Pat 104); deposited in MNHN (one male, six females) and UNAM (1 female). Other material examined. Specimens of three other populations were listed by Cassagnau & Rapoport (1962). One population (ARG-Pat 025 from Lago Frías) was subsequently separated as a new species, A. friasica, described in Cassagnau & Oliveira 1990. The other two populations are listed as other material, not as types, in Cassagnau & Oliveira (1990). One of them (ARG-Pat 047 from Isla Victoria) corresponds to A. limnophila. The other one (ARG-Pat 111 of Lago Lacar) differs from both A. limnophila and A. friasica, and is probably a new species. Another population from Lago Frías (station ARG-Pat 045) was represented by four specimens on slide in the Cassagnau collection, but not cited in his publications; they can be assigned to A. limnophila. It remains finally two samples in the Cassagnau collection that correspond to A. limnophila; in addition, two recent samples of D’Haese are also A. limnophila; all four samples were taken about 180 km North of the type locality (Fig. 1). Four specimens (two males, two females) on slides. Argentina: Neuquen Province: Villa la Angostura: near Lago Nahuel Huapi: Isla Victoria, dead wood, 03 / 03 / 59, Delamare-Deboutteville leg (ARG-Pat 047). Deposited in MNHN (1 male, two females) and UNAM (1 male). One male on slide. Argentina: Neuquen Province: Parque Nacional Nahuel Huapi: los Arrayanes, Northern part of Quetrihué peninsula, under barks of rotten logs, aspirator sampling, 29 / 10 / 05, D'Haese leg (A 142). Deposited in MNHN. Four specimens (two males, one female and one juvenile) on slides. Argentina: Rio Negro Province: near Lago Frías, 07 / 03 / 59, Delamare-Deboutteville leg (ARG-Pat 045). Deposited in MNHN. One female on slide. Argentina: Rio Negro Province: Parque Nacional Nahuel Huapi: Puerto Blest, 12 / 11 / 05, D'Haese leg (A 190). Deposited in MNHN.