Scirtes serratus Watts & Cooper & Saint 2017, sp. nov.

Scirtes serratus sp. nov.

(Figs 18, 27)

Type material. Holotype ♂, “SA 1 Km S Nangwarry 22/9/07 CHS Watts/ Bred from larva/ On slide with larval exuviae”, SAMA.

Description (number examined, 1).

Habitus. Length approximately 3.4 mm, oval.

Head. Testaceous. Antenna light testaceous, basal antennomeres lighter. Eyes rather small, width between eyes dorsally about 3.2× dorsal width of eye. Setae moderately long. Frons with sides moderately diverging, front edge weakly concave, edges weakly beaded. Antennomere 1 of antenna barrel-shaped; antennomere 2 about two-thirds as long and not much narrower, barrel-shaped; antennomere 3 about same size as antennomere 2, slightly narrower, wider towards apex; antennomere 4 about 2× length of antennomere 3; antennomeres 5–10 subequal, narrow, cylindrical, a little shorter than antennomere 4; antennomere 11 elongate/oval, 1.5× length of and flatter than antennomere 10.

Pronotum. Testaceous; broad, 2.2× as wide as long. Punctures moderately large, about a puncture width apart, each puncture with a moderately long golden seta. Hind angles weakly obtuse, front edge sinuate, margins weakly beaded.

Scutellar shield. Testaceous. Equilateral triangle, lateral sides weakly convex.

Elytra. Testaceous. Sides weakly flanged in basal third. Strongly and evenly punctate, somewhat larger than on pronotum, most punctures less than a puncture width apart or less, each puncture with a moderately long pale seta. Epipleuron relatively wide in front quarter becoming narrower over rest of elytron, front portion flat.

Ventral surface. Testaceous. Pronotal process very narrow at apex. Mesoventral notch “U”-shaped. Mesoventral process long, narrow, reaching to metaventrite. Metacoxal plate almost square, anterior-lateral corner extending a short way along metaventrite; hind edge straight; sides beaded, posterolateral angles rounded.

Metatrochanter small, relatively squat, about 1.2× as long as wide. Metafemur greatly swollen, widest a little before middle, weakly notched on rear margin near apex. Dorsal metatibial spine relatively short, about a third length of ventral spine, ventral spine about two-thirds length of segment 1 of metatarsus; segment 1 of metatarsus a little longer than other segments combined. Ventrites with very small, shallow punctures each with a short seta; reticulation moderate, fine, more pronounced towards rear.

Male. Basal piece short, round; trigonium long and thin, 1.6× length of basal piece; tip rounded; ventral edge deeply serrated; two parameroids, right hand one a little shorter than trigonium with weak apical hook, left hand one broad, apex rounded, about a third length of right hand one. Tegmen as long as penis, lobes thin, elongate, well separated (Fig. 18). Abdominal segments not known.

Female. Not known.

Etymology. Name refers to the serrated ventral edge of the trigonium.

Notes. Known from only one specimen reared from a larva collected from a shallow seasonal swamp. The failure to collect more over several springs suggests that the species is rare. It will run to S. orientalis in the key in Watts (2004) but can be separated by the strongly serrated ventral edge of the trigonium.

The larva is known from a single exuvia in poor condition, lacking terminal abdominal segments. It will run to the S. helmsi / S. orientalis couplet in the key to Australian Scirtes larvae in Watts (2014). It is larger than S. orientalis (approximately 8 mm long vs 6 mm) and larger than S. lynnae with which it is sympatric. It cannot be separated from S. helmsi, which also occurs in the vicinity, on the limited material available.