Howickia lepidostylus Marshall

Marshall, S. A., Luk, S. P. L. & Dong, H., 2014, A revision of the New Zealand species of Howickia Richards, Zootaxa 3887 (1), pp. 1-36 : 13-15

Howickia lepidostylus Marshall sp. nov.

( Figs. 29–33 )

Description. Colour: Face and gena microtrichose except for a bare anterodorsal patch on the gena. Legs mostly brown with orange knees; tarsi dirty white to yellowish.

Head: Interfrontal bristles in 3 pairs, upper 2 large and slightly cruciate. Two orbital bristles, upper orbital bristle large, lower small. Ocelli large, ocellar triangle raised and distinct. Eye 2.0–2.7X genal height. Anterior genal bristle large. Arista with relatively long hairs, hairs at least twice as long as width of first aristomere.

Thorax: Scutum with single postpronotal, notopleural, supraalar, postalar and prescutellar dorsocentral bristles; postalar and prescutellar dorsocentral bristles subequal, basal scutellars shorter, half as long as apical scutellar bristles. Acrostichal setulae uniformly small; most specimens with a small anterior (postsutural) dorsocentral bristle slightly larger than surrounding acrostichals. Scutellum microtrichose, 2.0X as wide as long. Wing and halter well developed; wing almost uniformly infuscated, with pale areas along hind margin and along a distinct longitudinal fold running up the at middle of cell dm. Vein R2+3 very short, running almost directly to costa, slightly sinuate; R4+5 distally turned up to costa, costa bypassing apex of R4+5 by several vein widths. Halter stem white, knob rounded and dark anterodorsally, white posteroventrally, uniformly microtrichose.

Abdomen: Syntergite 1+2 separate laterally, entirely fused medially and equal in length to tergites 3 and 4. Male abdomen: Sternite 5 1.5X as long as sternite 4, posteromedial area with small median comb of 8 flat bristles preceded by a pale medial patch flanked by 2 rows of 3–4 stout, short bristles on each side. Synsternite 6+7 strongly modified, sternite 6 with a broad anterior apodeme projecting over sternite 5 and a bifid, toothed posteroventral lobe, sternite 7 with a bifid ventral lobe (like H. oliveri but unlike other congeners). Subanal plate broad but contiguous only in upper half, cerci widely separated below; lower/outer part of cercus projecting ventrally as small point. Surstylus with a short, subquadrate anterior lobe and a much larger, ventrally projecting posterior lobe with dark, broad, flat, scale-like bristle at apex and 3–4 flat, scale like bristles along posterior margin. Distiphallus simple, looped on basal half, expanded distally. Postgonite narrow, almost straight, slightly tapered distally, posterior surface flat. Basiphallus frame-like, projecting posteriorly at right angle to distiphallus base for a distance of about half the width of the distiphallus base.

Female abdomen (see also comments below): Tergite 7 narrowly notched posteriorly; tergite 8 split into 3 parts, small middle part entirely separate from darker and larger lateral parts. Female sternite 8 small, pale and oval anteriorly, very dark and straight along posterior margin. Interior of segment 8 with a large, heavily sclerotized Ushaped internal sclerite, with arms facing posteriorly (homology uncertain, no obvious homologue present in closely related species but this sclerite is probably homologous with the smaller U-shaped anterior part of sternite 8 in wingless species). Hypoproct with an anteromedial bare portion and a transverse microtrichose portion. Large but indistinct, thin, ring-like internal vaginal sclerites (spectacles-shaped sclerites) present.

Type material. Holotype (male, NZAC) and 18 male paratypes ( NZAC, DEBU): New Zealand, Moehau Mt., Coromandel Range, 21–25.Apr.1984, bush on upper Okahutahi Stream, Malaise and water tray, H. Oliver. Other paratypes: Kauaeranga Valley, near Thames, H. A. Oliver (1 male, NZAC); Moehau, Okahutahi Stream, liver bait trap, 21–25.1984, H. Oliver (2 males, NZAC); S.E. National Park near Tongariro River, meat-baited pitfall trap, 4–26.Jan.1971, H.A. Oliver and J. Gillespie (3 females, 1 male, in alcohol, NZAC).

Other material examined: Three females, same locality as holotype. Three females and one headless male, in alcohol: meat-baited pitfall trap near Whangaiterenga Stream, near Thames, 18.Jan.1971 – 18.Apr.1971, H.A. Oliver.

Etymology. Howickia lepidostylus is named for the distinctive scale like bristles on the surstylus.

Comments. Although this species is very distinctive in many characteristics of both male and female terminalia, there seem to be no non-abdominal characters by which to reliably distinguish H. lepidostylus from the much more common H. oliveri . Almost all of the males here designated as types of H. lepidostylus were collected along with much longer series of H. oliveri ; males and females of these species were associated by their proportions in the collections (it was assumed that the rare females corresponded to the rare males).

Figures

FIGURES 29 – 33. Howickia lepidostylus Marshall, sp. n.: 29, epandrium, posterior; 30, epandrium, left lateral; 31, male sternite 5 and synsternite 6 + 7; 32, aedeagus and associated structures; 33, female terminalia, left lateral.