Nothochaetes, Lawrence, John F., Slipinski, Adam, Jäger, Olaf & Pütz, Andreas, 2013

Lawrence, John F., Slipinski, Adam, Jäger, Olaf & Pütz, Andreas, 2013, The Australian Byrrhinae (Coleoptera: Byrrhidae) with descriptions of new genera and species, Zootaxa 3745 (3), pp. 301-329 : 309-311

Nothochaetes gen. n. (Figs 4, 5, 11C–D, F, 12F)

Type species: Pedilophorus fasciculatus Lea 1920 .

Diagnosis. Species of Nothochaetes are easily separated from other Australian byrrhines by the presence of a transverse oblique or strongly curved carina on the pronotal hypomeron (Figs 4C, 11C–D, F) and the dorsal vestiture including longer and shorter stout bristles, the latter often curved and forming fascicles in the type species (Fig. 4). They may also be distinguished by the combination of concealed metanepisterna ( Fig. 5 D), inflated posterior pronotal angles and elytral humeri (Figs 4C, E), 3-segmented antennal club ( Fig. 5 C) and absence of a scutellar shield. N. fasciculatus resembles a small Microchaetes , but lacks the features of that genus given in the key below.

Description. Length 1.8–3 mm. Short and broad; lateral outline more or less continuous. Colour dark reddishbrown to black; undersurfaces, legs and antennae somewhat lighter. Dorsal surfaces clothed with three types of setae: very short, erect, fine hairs; moderately long, suberect, thickened, yellow bristles, which are distinctly curled and may form fascicles in N. fascicularis , and longer, scattered, erect, thickened, reddish-brown bristles; body often covered with exudate and debris. Ventral surfaces clothed with very short, decumbent yellow hairs.

Head slightly shorter than width behind eyes, strongly declined and deeply inserted into prothorax, but with eyes at least partly visible; occipital region with short median endocarina; transverse occipital ridge moderately well developed. Eyes relatively small, not protuberant, located anteriorly. Frontoclypeal suture absent; frontoclypeal region relatively flat; antennal insertions concealed from above; subantennal grooves distinct or weak, extending to edges of eyes. Labrum relatively large and well sclerotized, with distinct transverse groove at base; apex broadly rounded or truncate. Antennae almost as long as head width, 11-segmented, with 3-segmented club; scape about 1.60–2.20 times as long as wide; pedicel about half as long and slightly elongate to twice as long as wide; antennomere 3 1.2–1.9 times as long as 2 and 3.4–4.7 times as long as wide; antennomere 4 or 4 and 5 slightly elongate and following antennomeres gradually shorter and more transverse; club loose with antennomeres 9 and 10 strongly transverse and 11 1.25–1.45 times as long as wide. Mandible broad, subtriangular and obliquely tridentate; dorsal surface with distinct ridge fitting against sides of labrum; mesal surface of mandibular base without mola but with basal brush of hairs. Maxilla with short, densely setose galea and lacinia; apical maxillary palpomeres more or less fusiform; apical labial palpomeres similar to or shorter and broader than those of maxilla. Subgenal ridges absent. Gular sutures well separated; gula transverse; corporotentorium broad, straight; cervical sclerites well-developed.

Pronotum about 0.37–0.50 times as long as wide, widest at or near base; anterior edge truncate or broadly rounded with very slight emargination at middle; sides strongly rounded and somewhat explanate in N. fasciculatus , sinuate in N. howensis ; anterior angles small and subacute; lateral carinae complete, weakly defined or sharply defined and very narrow, at least slightly visible from above, edges with several unevenly spaced tubercles in N. fasciculatus ; posterior angles right to subacute; posterior edge evenly rounded or very weakly biemarginate, unmargined, with distinct posterior accessory ridge beneath; disc moderately, evenly convex at middle but with flattened sides in N. fasciculatus , evenly convex at middle but with broad, shallow impression near each posterior angle in N. howensis . Prosternum in front of coxae relatively short, about 0.5 times as long as mid length of coxal cavity, slightly convex, with paired lateral antennal grooves and a concave head rest above. Prosternal process complete, parallel-sided and truncate at apex. Procoxa more or less cylindrical, with welldeveloped exposed trochantin and short coxal plate produced to form tooth-like process; procoxal cavities strongly transverse, broadly open externally and internally. Notosternal sutures complete and anteriorly open. Hypomeron with an oblique or strongly curved carina separating a smaller anterior fossa separated from larger posterior crural impression.

Scutellar shield absent. Elytra about 0.82–0.97 times as long as wide and 1.85–2.5 times as long as pronotum; sides strongly rounded, in lateral view sharply narrowed at about middle, forming with first abdominal ventrite crural impression for hind leg; with distinct angulate humeri; disc strongly, more or less evenly convex; elytral apex without ventral interlocking tongue; epipleuron short, not extending beyond mesocoxae, broad and concave, continuous mesally with anterior pronotal housing and forming with hypomeron crural impression for fore leg and mid leg.

Mesoventrite strongly transverse, separated by complete sutures from mesanepisterna, which are very widely separated; anterior edge on different plane than metaventrite, with a pair of large, strongly declined to vertical procoxal rests continued onto mesanepisterna and with moderately deep mesoventral cavity; discrimen very short or not apparent. Mesoventral process short, broad and apically emarginate forming a pair of apicolateral condyles. Mesocoxae subglobular to slightly transverse, with short coxal plates and with exposed trochantins. Mesocoxal cavities separated by about 1.75–2.0 times shortest diameter of coxal cavity, partly closed laterally by mesepimera and with mesanepisterna, which are more or less fused together.

Metaventrite short, its shortest length slightly greater than shortest diameter of mesocoxal cavity; laterally curved postcoxal lines present, but weakly developed in N. fasciculatus ; discrimen about half the length of ventrite in N. howensis , shorter in N. fasciculatus ; anterior metaventral process with pair of anterolateral cavities for receiving mesoventral condyles; metanepisternum and metepimeron concealed by elytra ( Fig. 5 D). Metacoxae about a third as long as wide at base, not projecting, separated by about 0.15 times basal width, extending laterally to meet elytra, with well-developed coxal plates, widest mesally and narrowing laterally. Metendosternite with very short, broad stalk, long lateral arms, and no laminae or anterior process. Hind wings absent.

Legs relatively short, slender; femora slightly wider at or near middle, without or with weak tibial impression; tibiae subequal in length to femora, parallel-sided or barely wider at or near middle, tibiae slightly wider at apical third; outer edge with fringe of long, spine-like setae ( Figs 5 B, E); apex with paired spurs. Tarsi 5-5-5, tarsomere 4 reduced, tarsomere 3 bearing a long, hyaline, setose ventral process longer than body of tarsomere; pretarsal claws simple.

Abdomen about 0.75 times as long as wide at base with five ventrites, the first three of which are connate; first ventrite with pair of broad impressions to receive hind legs; intercoxal process short and broad, narrowly truncate at apex; ventrite 5 as long as 2–4 combined, broadly rounded at apex, with shallow (female) or deep (male) apical impression in howensis . Abdominal tergites lightly sclerotized or membranous. Functional spiracles on abdominal segments I–VIII. Anterior edge of sternite VIII in male with short, broad, angulate or rounded anterior projection. Sternite IX in male elongate, subtruncate at base (anteriorly) and broadly rounded or subacute at apex (posteriorly); tergite IX transverse and undivided, broadly emarginate at apex; tergite X (proctiger) free or partly fused to tergite IX, broadly rounded or truncate at apex. Aedeagus with phallobase symmetrical and about as long as wide in N. fasciculatus , almost twice as long as wide in howensis , subtriangular or parallel-sided and broadly rounded at base; parameres not diverging, broader at base, narrowed apically and subacute at apex; penis slender, parallel-sided or subapically expanded, with apex narrowly rounded ( N. fasciculatus ) or enlarged and arrowhead-like ( N. howensis ); basal struts short. Female proctiger ( Fig. 5 A) slightly elongate and broadly rounded at apex free or partly fused to tergite IX. Anterior edge of sternite VIII in female biemarginate or with short angulate or truncate anterior process (spiculum ventrale), posterior edge broadly rounded; tergite VIII transverse and undivided; tergite IX consisting of paired laterotergites (paraprocts) connected at midline by a slender, lightly sclerotised strip. Female proctiger 1.33– 1.55 times as long as wide. Ovipositor 1.65–1.75 times as long as wide; paraprocts about 1.07 times as long as gonocoxites, each of which has a laterally compressed distal lobe, with an apical, slender gonostylus 0.36–0.44 times as long.

Etymology. Nothos (Greek, adjective), false, and chaite (Greek, f), long hair. Name implies similarity to the unrelated byrrhid genus Microchaetes .

Included species: N. fasciculatus (Lea 1920: 286) comb. n. and N. howensis sp. n

Distribution: Tasmania, Victoria and Lord Howe Island.

Figures

FIGURE 5. Nothochaetes: A – C, N. howensis sp. n.: A, female abdominal apex, ventral. showing ovipositor. with elongate proctiger in background; B, mid leg; C, antenna. D – E, N. fasciculatus (Lea): D, pterothorax, ventral, with left mesocoxa removed; E, fore leg.