Scatella austrina Mathis & Wirth 1981

Scatella (Neoscatella) austrina

DIAGNOSIS.—Specimens of this species are similar to those of S. norrisi but may be distinguished from them and other congeners by the following combination of character states: mesofrons more sparsely pollinose than parafrons or fronto-orbits, particularly laterad of ocellar triangle, appearing subshiny to shiny; lateroclinate fronto-orbital bristles subequal in length; dorsum of interfoveal carina narrowly developed; distance between antennal bases about equal to length of second or third antennal segment; coloration of face in both sexes similar, mostly unicolorous, light yellowish to yellowish brown; marginal facial setae distinctly larger than those along median surface, with two to three pair of large, slightly dorsally curved setae aligned between interfoveal carina and posteroventral corner of face; orientation of eye at slight oblique angle to oral margin; scutum and scutellum bicolored, mostly brown to dark brown, but with considerable gray to slightly greenish or bluish gray coloration, lacking a distinct median stripe; setae of front coxa and femur similar in both sexes; tarsi blackish brown, concolorous with tibiae and femora; brownish coloration of male wing darker than female wing; first costal section of male wing thickened, becoming slightly narrower apically; larger white area in cell R3 subquadrate to slightly attenuated medially in female wing, in male wing weakly developed, narrower and attenuated medially, appearing more or less as 2 spots; apical white area in cell R5 narrowly rectangular in both sexes, oriented at distinctly oblique angle to bordering veins on posterior and anterior margins.

DESCRIPTION.—Small to moderately small shore flies, length 1.87 to 2.46 mm; mostly brown, but with considerable gray to faintly bluish gray coloration; pollinose to sparsely pollinose, some areas subshiny to shiny.

Head: Head width-to-height ratio averaging 1 : 0.68; frons mostly sparsely pollinose, area immediately laterad of ocellar triangle sparsely pollinose to nearly bare, subshiny to shiny; mesofrons separated from parafrons by membranous appearing, dark gray wedges extending posteriorly from anterior margin; ocellar triangle distinctly pollinose, brown; mesofrons brown anteriorly, becoming shiny, metallic mostly black posteriorly, some specimens with faintly greenish, thin strip anteromedially; lateroclinate fronto-orbital bristles subequal in length. Antenna with first and second segments blackish, third segment appearing grayish black due to pubescent vestiture; third segment subequal in length or slightly longer than combined length of first and second segments; arista with small hairlike setae above, these generally inconspicuous, appearing mostly bare; distance between antennal bases short, less than length of third segment. Face with distinct interfoveal carina, appearing distinctly setose, especially marginal setae, with 3–4 larger setae aligned between interfoveal carina and posteroventral angle of face; face mostly grayish brown, slightly darker dorsally. Eye nearly round, eye width-to-height ratio averaging 1:1; gena moderately high, eye-to-cheek ratio averaging 1 : 0.31; gena more whitish gray than face, but becoming darker posteriorly. Clypeus mostly concealed.

Thorax: Mostly sparsely pollinose, brown, but with several grayish to faintly bluish or greenish gray areas, especially humeral callus, a spot just anterior of transverse suture, and a short stripe anterior and just laterad of larger acrostichal setae; mesopleuron and anterior portion of pteropleuron mostly brown, otherwise pleural areas becoming gradually brownish gray to gray ventrally and posteriorly. Legs concolorous, mostly dark; femora grayish brown with some blackish tinges; tibiae entirely brownish black; tarsi mostly blackish. Wings (Figures 32–33) sexually dimorphic; male wing differing as follows: costa thickened, especially the first costal section; infuscation darker brown; whitish area of cell R3 as 2 spots either narrowly connected or completely separated; otherwise similar to female wing a described in diagnosis.

Abdomen: Dorsum of female specimens mostly gray, but with some linear brown areas medially and laterally; males with terga 1–4 mostly gray, but with anterior margins brown, brownish area becoming wider laterally, fifth tergum mostly brown. Male terminalia (Figures 37–38) as follows: as in generic description, but conspicuously setose, especially toward ventral apices (fused surstyli).

TYPE MATERIAL.—Holotype male is labeled: “Potato Point, 9.5 km E. of Bodalla, NSW 20 July, 1973 Z. Liepa/HOLOTYPE Scatella (Neoscatella) austrina Mathis and Wirth [handwritten, red].” Allotype female and 26 paratypes (16, 10), have the same label data as the holotype. Other paratypes as follows: NEW SOUTH WALES: COILA LAKE, Tuross Hds., 19 Jul 1973, Z. Liepa (11, 22;. ANIC, USNM); LAKE CURALO, Eden (nr. sandbar), 3 Aug 1973, Z. Liepa (23, 15; ANIC, USNM); LAKE MUMMUGA, Dalmeny, 20 Jul 1973, Z. Liepa (1; ANIC); MORUYA RIVER, 19 Jul 1973, Z. Liepa (1, 1; ANIC); WALLAGA LAKE, Bermagui, 21 Jul 1973; Z. Liepa (1, 4; ANIC). VICTORIA: LAKE TYERS (inlet, nr. sandbar), 5 Aug 1973, Z. Liepa (11, 1; ANIC, USNM). The holotype and most of the paratopotypes are in the Australian National Insect Collection, Canberra. The holotype specimen is double mounted (minute nadel in polyporus block) and is in excellent condition.

GEOGRAPHIC DISTRIBUTION (Figure 36).—Southern coast of New South Wales.

ETYMOLOGY.—The species epithet austrina is of Latin derivation and means southern, referring to the southern hemisphere distribution of this species.