Scirtes zwicki, Watts & Cooper & Saint, 2017

Watts, Chris H. S., Cooper, Steven J. B. & Saint, Kathleen M., 2017, Review of Australian Scirtes Illiger, Ora Clark and Exochomoscirtes Pic (Coleoptera: Scirtidae) including descriptions of new species, new groups and a multi-gene molecular phylogeny of Australian and non-Australian species, Zootaxa 4347 (3), pp. 511-532 : 523-524

Scirtes zwicki sp. nov.

( Figs 23, 24 )

Type material. Holotype ♂, “NT Holmes Jungle/CHS Watts 10/1/14 / at light.”, NTM. Paratypes 12 ♂, 1 ♀ as for holotype, SAMA.

Description (number of dissected males examined, 13).

Habitus. Length 2.5–2.9 mm, elongate oval.

Head. Area between eyes black, frons light testaceous, division between areas of colour distinct. Antenna light testaceous, becoming darker towards apex. Eyes moderately large, width between eyes dorsally about 3.0× dorsal width of eye. Setae moderately long, pale. Frons with sides moderately diverging, front edge weakly concave, edges quite strongly beaded. Antennomere 1 of antenna barrel-shaped; antennomere 2 about half as long, narrower, barrel-shaped: antennomere 3 about as long as antennomere 2, about half as wide, widening towards apex; antennomere 4 about twice length of antennomere 3; antennomeres 5–10 subequal, narrow, cylindrical, a little shorter than antennomere 4; antennomere 11 elongate/oval, a little longer and flatter than antennomere 10, 1.6× length of and flatter than antennomere 10.

Pronotum. Central half dark testaceous-black, margins abruptly light testaceous. Short, 2.3× as wide as long. Punctures moderately sized, about 1.5 puncture widths apart, each puncture with a moderately long pale seta. Hind angles weakly obtuse, front edge sinuate, margins weakly beaded.

Scutellar shield. Light testaceous. Equilateral triangle, lateral sides weakly convex.

Elytron. Light testaceous, area adjacent to scutellum sometimes darker. Sides weakly flanged in basal third. Moderately and evenly punctate, most punctures about 1.5 puncture widths apart, each puncture with a short pale seta. Epipleuron relatively wide in front quarter, becoming narrower over rest of elytron, front portion flat.

Ventral surface. Light testaceous, prosternum often diffusely darker. Prosternal process very narrow. Receiving notch on mesoventrite well-marked, narrowly diamond-shaped, reaching past front of mesocoxae.

Mesoventral process long, narrow, reaching to metaventrite. Anterior extension of metaventrite in midline small, triangular, not bounded behind by ridge; rear midline extension of metaventrite short, about twice as wide as long. Metacoxal plate square, anterior-lateral corner extending about half way along metaventrite; hind edge weakly angled towards midline; sides beaded, posterolateral angles rounded. Metatrochanter small, elongate, about 1.7× as long as wide. Metafemur greatly swollen, widest about middle, weakly notched on rear margin near apex. Dorsal metatibial spine relatively short, about twice length of ventral spine and about half length of segment 1 of metatarsus; segment 1 of metatarsus a little longer than other segments combined. Ventrites with small, shallow punctures each with a short seta, reticulation moderate, fine.

Male. Little external difference between the sexes. Basal piece of penis indistinct, trigonium very long and thin, apical half bifid, lobes weakly paddle-shaped; without parameroids. Tegmen a little more than half as long as penis, lobes thin, elongate, well separated. Apices broad with two well-developed sharply pointed lobes ( Fig. 23e ). Sternite 9: well developed, elongate, apical portion bullet-shaped with strongly sclerotized apical cap, apodemes about twice as long as apical portion, anterior ends fused ( Fig. 23c ). Tergite 9: membranous, without setae, apodemes moderately long ( Fig. 23a ). Tergite 8: relatively narrow, moderately sclerotized, apical portion with ruffled margin, without setae, apodemes weakly sclerotized, a little longer than apical portion, weakly diverging ( Fig. 23b ).

Female. Coxites broad, elongate/triangular with numerous pores, styli small, narrowly oval, positioned slightly inside of apex. Bursal sclerite well developed, anterior end rounded behind which is a flared structure with two variable rows of short spines ( Fig. 10 ). Prehensor either fused with basal sclerite or absent.

Etymology. Named after Peter Zwick, a long time student of Australian Scirtidae who has helped CHSW significantly in his studies of the family.

Notes. A small species easily recognised by the black areas on the head and pronotum strongly contrasting with the testaceous elytra, greatly swollen metafemora and the large, relatively close-set eyes. Collected from or near riverine rainforest in coastal Northern Territory. It will run to S. emmaae in the key in Watts (2004), but can be separated by its smaller size and extremely elongate bifid penis ( Fig. 23 ).

Larva. Not known.

Figures

FIGURES 23 – 28. 23) Male terminalia of Scirtes zwicki: a) tergite 8, b) tergite 9, c) sternite 9, d) trigonium, e) tegmen. 24) Habitus photograph of Scirtes zwicki; 25) ditto, ♀ S. albamaculatus. 26) Clypeolabrum of last instar larva of S. lynnae; 27) ditto, S. serratus; 28) ditto, S. triangularis.

FIGURES 6 – 10. Prehensor and bursal sclerite of: 6) Scirtes albamaculatus; 7) S. exoletus; 8) S. nigerpalpus; 9) S. orientalis; 10) S. zwicki.