Tasmanura Womersley 1937

Tasmanura Womersley, 1937

Fig. 1, 1–3; Fig. 2, 1 –16, Fig. 3, 1–2; Fig. 4, 1–2; Fig. 5, 1–2. (Figures from some specimens collected from other localities are used to illustrate generic characters where they are obscured on the type specimen). Tables 1–2

TYPE SPECIES. Tasmanura evansi Womersley, 1937 (Figs 3–5).

TYPE LOCALITY. AUSTRALIA, Female (HT), National Park (now Mt Field), Tasmania, 3000 feet asl (900m), local coordinates – 42.683848S, 146.591548E December 1936, leg. J.W. Evans.

Other material of the genus examined all from Tasmania. Slide material: 1 male, Mt Michael, - 41.243100S 147.016550E, 740m asl, in leaf litter, 29.xi.1989, leg. R. Coy; 1 male, Franklin River Bridge, 51 km W of Bronte, - 42.364080S 145.697360E, 737m asl, in moss, 3.iii. l985, leg. PG; Projection Bluff, -41.962470S, 147.121850E, 1100m asl, leg. R. Coy; 1 male Lake Highway, Quamby Bluff area, 99 km N Bothwell, - 41.67344S, 146.73621E, 750m asl, eucalypt forest, moss and ground litter, 15.ix.1975, C10, leg. J. Ireson.

Ethanol material. One specimen from each of the following localities: Gordon River, Melaleuca forest, ground litter, 1.iii.1977, 23, leg. J. Maddern; Gordon River, wet sclerophyll, ground litter, 16.ii.1974, 63F1, leg. J. Maddern; Gordon River, rainforest, in moss, 18.ii.1976, 63C2, leg. J. Maddern; Quamby Bluff, moss, Nothofagus rainforest, 13.ix.1977, lg. J. Ireson; Mt Field, Nothofagus gunnii rainforest, 23.iii.1984, leg. P.G.; Franklin River, 5 km W Bronte Park, 4. III.1985, leg. PG.

Specimens photographed but not collected were from: Cradle Mountain, Tarkine Wilderness, Mountain Lodge, all Tasmania (A. Murray, pers. comm.), (Fig. 1. 1–3).

Redescription of genus (based on re-examination of the holotype and other specimens listed above). Womersley's original description (in italics):

Colour: background pale, dorsally blue, with darker pigmented patches of enlarged secondary tubercles (see Fig. 1.1–3, Fig. 2.8), paler legs; sternites white. The dark pigmented patches of cuticle with enlarged tubercles vary in distribution between species.

Size: 1.6mm (HT slightly contracted); up to 2 mm other specimens.

Habitus (Fig. 1.1–3, Fig. 2. 1): broad, dorsoventrally flattened species with laterally expanded paratergites, slightly broader than half body length measured at widest point; digitations and bosses absent; abd V extended posteriolaterally over abd V1; abd VI just visible dorsally, not bilobed; abd V not bilobed but slight indentation centre of posterior margin, anus completely ventral. Intersegmental segments present between th I and II, th II and III and between all abdominal segments to abd II and III but without chaetae. Body often with amorphous white or yellow deposits at reflex bleeding sites at boundary of paratergites and tergites. Antennae about the same length as that of head.

Ratio length to breadth measured at abd III = 1.5:1.

Vestiture: antennae somewhat plurichaetose but otherwise chaetae sparse on body and legs of holotype but other species plurichaetose; body chaetae short, all shorter than segments are long, and smooth, pointed, arranged in groups; th I with 1 + 1 Di, 2 + 2 De, 5 + 5 Dl; no chaeta on intersegments; cuticle dorsally densely covered with prominent, evenly arranged conical, black pigmented tertiary tubercles. S-chaetae long, fine, ratio length to adjacent ordinary chaeta on th II = 4.5:1. Cuticular structures consist of round structures, columnar in form.

Height of cuticular tubercles:distal abdominal VI chaetae = 1:2 (HT)

Antennae: cylindrical to triangular, about half diameter of head in length; antennal III organ with slightly elongated papillae (S chaetae) in a slight groove; flanked by two ordinary? chaeta, Sgv thickened; (Womersley, 1937 fig.) with two much longer thick chaetae in this position); ant IV with trilobed apical bulb, S-chaetae at least eight, long curved only slightly thickened; ventral file on antenna IV of about 30 short, slightly broadened, blunt chaetae interspersed with numerous short, smooth and acuminate mesochaetae (Fig. 2.5,7).

Head and thorax: buccal cone fairly elongated, wedge shaped, blunt; mandible (Fig. 2.4) elongate with 10 teeth, three basal subequal stronger teeth and 7 apical smaller teeth, maxilla (Fig. 2.3) with two long, thin, lamellae each with about 20 teeth and a third lamella with minute denticles and point at tip; ocelli patch round, pigmented (Fig. 2.2), labrum with 5/4/2/2 from posterior to anterior, 4 most anterior long and fine; eight round equal sized ocelli on each side inserted in a hemispherical cuticular protuberance, postantennal organ with only 4 tubercles observed on holotype but up to 16 elongate tubercles arranged in a single ring (Fig. 2.2) on other species, (4 tubercles were recorded by Womersley) about equal to the anterior ocellus in width on holotype, labium with A,B,C,D present, chaeta A slightly displaced laterally, F much longer than E; small papillated chaeta L present distally on labium (Fig. 2.6); head ventrally with 3+3 chaetae along mid line (Fig. 2.9); clavate tenent hairs absent; empodial appendage absent; claw with small inner tooth, at 0.25 of inner claw length from base (Fig. 2.10). Leg chaetotaxy of holotype in Table 1, more chaetae on other species (trochanter and femur: Fig. 2.11). M chaeta present slightly displaced apically, short, fine; two pre-tarsal chaetae present. No pseudopore seen between head and th I in adult.

Ratio tibiotarsus: internal length of claw: distance of internal claw tooth from base of claw = 6:3:1. (HT)

Abdomen: ventral tube (Fig. 2.12) with 4/5 chaetae on holotype, more on other species; rami tenaculum with 2+2 teeth (Fig. 2.13,14), no chaetae on stem; furca reduced to a small bilobed remnant with 5+5 microchaetae (Womersley states that there are only 3 chaetae on the dental remnant but illustrates 3 on one side and 5 on the other, but 5+5 on HT) (Fig. 2.14), mucrones absent; ventral anal lobes with about 14 chaetae plus 2 hr on each lobe; abd VI with six short, distal fine chaetae (HT) (Fig. 2.15).

Female with 12 chaetae, male from Mt Michel with ten chaetae anterior to genital opening.

Comments. The genus differs from all other Australian Pseudachorutinae in the extreme dorso-ventrally flattened body, the expanded paratergites; the reduction of furca to two small setose bulbs, the presence of 8+8 ocelli, the maxilla with two finely toothed lamellae and a third with coarser teeth, instead of smooth lamellae, a PAO with probably variable number of lobes from 4 to12 considering all species, and extremely coarse, pigmented, granulated cuticle. On this basis the genus is here confirmed to be of generic status. A more detailed redescription of the type species, Tasmanura evansi, awaits recollection of more specimens from the type locality.

Table 2 lists all genera known that are dorso ventrally flattened with extremely laterally expanded paratergites for comparison with Tasmanura and lists their significant characters. It is noticeable that nearly all genera are from southern regions.