Onysius Broun, 1886

Lawrence, John F., Leschen, Richard A. B. & Zaitsev, Artem, 2020, Onysius Broun: The First New Zealand Genus Of Promecheilidae (Coleoptera: Tenebrionoidea), The Coleopterists Bulletin 74 (1), pp. 27-35 : 28-32

Onysius Broun, 1886

( Fig. 1B )

Onysius Broun 1886: 843 . Type species: Onysius anomalus Broun 1886: 843–844 , by monotypy.

Malacodrya Sharp 1886: 412 . Type species: Malacodrya pictipes Sharp 1886 . Synonymized by Broun (1915: 323).

Diagnosis. Onysius differs from both Chalcodrya ( Fig. 1C ) and Philpottia ( Fig. 1D ) in having the antennae much longer than head and prothorax combined, the elytra tuberculate and much broader than the base of the prothorax, abdominal ventrites 3 and 4 not connate, tegmen subdivided into a basale and apicale, female genital tract with a small bursa and large spermatheca and spermathecal gland, lacinia without an uncus, and metendosternite with a short, broad, median process. Many of these character states also occur in various members of the Promecheilidae , and it is somewhat surprising that the genus was not moved to that family previously. It should be noted, however, that both Watt (1974a) and Lawrence (1994) were mistaken about the connation of four abdominal ventrites in Onysius ; only three are connate, as in other promecheilids. Promecheilidae are a much larger and more widespread group than Chalcodryidae , with nine genera and 20 species distributed from Tasmania to Patagonia and southern Chile, with Onysius as a distinctive New Zealand outlier. The genus may be distinguished from other promecheilids by the characters given in the key below.

Redescription of Onysius anomalus Broun, 1886 . Length 6–8 mm. Body about 2.5 times as long as wide; pronotum slightly shorter than wide with base much narrower than combined elytral bases; elytra almost twice as long as combined width, widest at posterior third and conjointly rounded at apex. Color variable in museum specimens; head light to dark brown; pronotum light brown to cream with variable longitudinal dark markings, usually a dark stripe with darker edges; elytra primarily green in living specimens with variable dark-brown markings, usually with paired chevron-like markings flanking suture at about middle; antennomeres 1–8 yellow or light brown with dark areas at the apices and antennomeres 9–11 dark brown; legs primarily yellow or light brown with darker femora and dark markings on tibiae and tarsomeres; undersurfaces dark brown. Dorsal surfaces subglabrous, with very short, fine setae; ventral surfaces with short fine pubescence. Head prognathous, slightly longer than wide; sides without distinct temples; posterior edge dorsally very slightly biemarginate. Eyes 0.34 times as long as head width, moderately protuberant, anteriorly emarginate, coarsely faceted, without interfacetal setae; distance across eyes 3.00 times distance between them dorsally and 1.73 times this distance ventrally. Frontoclypeal suture absent; frontal ridges extending into eye emarginations and concealing antennal insertions from above. Clypeus 0.33 times as long as wide with sides converging and apex truncate. Labrum 0.50 times as long as wide with sides diverging and apex broadly rounded. Antennae long and slender, extending about to middle of elytra; ratio of segment lengths 1.18: 1.00: 1.82: 1.64: 1.64: 1.64: 1.64: 1.64: 1.91: 1.73: 2.00; antennomere length/width ratios: 1.30, 1.83, 3.33, 3.27, 3.60, 3.60, 3.60, 3.60, 3.00, 2.71, 3.14; antennomeres 1–8 relatively sparsely clothed with long, fine setae, 9–11 densely clothed with very short fine setae. Mandibles 1.8 times as long as wide; outer edge setose, straight to apical third, then

gradually curved to bidentate apex; incisor edge with simple sharp-edged lobe separated from mola by distinct notch; molae more or less asymmetrical, concave with 2 apical teeth and no fine ridges or asperities; prostheca a well-developed setose membranous lobe; a similar membranous lobe at base of mola. Maxilla with lacinia slender and parallel-sided, with obliquely truncate apex; galea 2-segmented with basigalea short and broad and distigalea about 3 times as wide as lacinia and broadly rounded at apex; apical maxillary palpomere 1.8 times as long as wide, widest at apex, which is truncate. Mentum 0.5 times as long as wide, with straight sides and truncate apex. Ligula slightly expanded apically, apex subtruncate with median incision; labial palps separated by about 3 times the basal width of one; apical palpomere 1.7 times as long as wide with obliquely truncate apex. Submentum not separated from gula; gulamentum about 1.57 times as long as wide; gular sutures diverging posteriorly. Corpotentorium relatively narrow and bisinuate. Cervical sclerites absent. Pronotum about 0.8 times as long as wide, widest at anterior angles, which are produced laterally but not anteriorly; base distinctly narrower than combined elytral bases; anterior edge weakly sinuate; sides slightly concave at middle; posterior angles obtuse; posterior edge slightly convex on either side of small median emargination; lateral carinae complete and visible from above; all edges with fine marginal bead; disc somewhat irregular, with weak anterolateral and posteromesal impressions. Prosternum in front of coxae about 0.50 times as long as mid length of procoxal cavity, flattened, oblique and anteriorly concave. Prosternal process complete, at middle 0.15 times as wide as mid length of coxal cavity, dorsally curved behind coxae and strongly produced laterally to form narrowly rounded lobes distinctly overlapping postcoxal (hypomeral) lobes in ventral view; apex slightly concave. Notosternal sutures complete. Procoxae conical and somewhat projecting below prosternum, with lateral extensions and trochantins more or less concealed. Procoxal cavities slightly transverse, broadly closed externally, with small slot-like extensions at bases of notosternal sutures. Scutellar shield 0.26 times as wide at base as pronotum, 0.75 times as long as wide and angulate at apex. Elytra about 1.70 times as long as combined width and 4.0 times as long as pronotum; sides subparallel anteriorly, slightly widened at apical third, with apices rounded and slightly separated; disc with distinct humeri, irregularly tuberculate with the three largest tubercles behind middle; lateral edges of elytra laterally expanded posteriorly, forming on each side a flattened ridge with an undulate edge consisting of a series of curved, flat processes just above epipleura, the largest at posterior end and the smallest near base; punctation fine and sparse, consisting of oval, ringed pits bearing minute setae, with longer, erect setae scattered among them; epipleura very narrow and more or less complete. Mesoventrite about 0.68 times as long as wide, including intercoxal process, which is widened and elevated posteriorly with apex broadly emarginate between two knob-like processes; anterior edge truncate, without procoxal rests, separated by complete sutures from mesanepisterna, which are well separated at midline. Mesocoxal cavities separated by 0.25 times shortest diameter of one cavity, partly closed laterally by mesepimeron; mesocoxae with exposed trochantins. Metaventrite 0.65 times as long as wide, widest posteriorly, moderately convex, with distinct discrimen 0.77 times as long as ventrite excluding intercoxal process, the apex of which bears a pair of anterolateral pockets; posterior portion of coxite with submarginal internal ridge extending from the discrimen laterally but ending before sides of ventrite. Metanepisternum about 4 times as long as wide, widest anteriorly, narrowed posteriorly. Metacoxae separated by distance about 0.4 times as great as longest width (longitudinal diameter) of a coxa; coxae strongly transverse, only slightly narrower laterally than mesally, without coxal plates, with long, transverse internal apodeme. Metendosternite with long stalk, long lateral arms, and a short, broad anterior process; laminae absent and anterior tendons located on the distal third of each arm. Hind wing about 3 times as long as wide, with long apical field, almost half as long as entire wing, with two vaguely indicated radial extensions; radial cell relatively small, about twice as long as wide with inner posterobasal angle slightly obtuse; crossvein r3 absent; cross-vein r4 moderately long; basal portion of RP short and R-M loop narrow; medial spur extending posteriorly but ending well before wing margin; medial field with four free veins (MP3+4, CuA2, CuP+AA3 and AA4) and a large, vaguely indicated, undivided medial fleck; wedge cell elongate, narrow and apically acute; anal lobe well developed, without embayment. Legs moderately long and slender; trochanterofemoral joint strongly oblique, with base of femur almost in contact with coxa; hind legs slightly longer than fore legs or mid legs; femora weakly inflated; tibiae not or barely widened apically, lined with fine setae, spurs paired, short and subequal. Tarsi 5-5- 4 in both sexes; tarsomeres not lobed but with dense covering of fine setae beneath; pretarsal claws long, diverging, with slight enlargement at base; empodium bisetose. Abdomen, excluding invaginated segments, 1.16 times as long as wide, with five ventrites, the first three of which are connate; metacoxal cavities well developed; ventrite 1, excluding acute intercoxal process, about 0.58 times as long as ventrite 2; ventrites 2–5 each slightly shorter than the one preceding it; apex of ventrite 5 broadly rounded. Sternite VIII in male about 1.24 times as long as wide, without median strut. Basal tergites lightly sclerotized; tergite VII 1.05 times as long as wide. Pregenital ring (segments IX and X) in male anteriorly narrowed to form spiculum gastrale. Aedeagus of tenebrionoid type, symmetrical, with tegmen 6.2 times as long as wide, barely wider at middle, base narrowly rounded; basale 3.8 times as long as wide, at least partly separated from apicale, which is 2.67 times as long as wide and 0.63 times as long as basale, with sides slightly converging to apex, which is deeply cleft forming two acute lobes with a few fine apical setae. Penis subequal in length to tegmen, 7.4 times as long as wide, narrowed and narrowly rounded at both ends. Tergite VIII (pygidium) about 0.7 times as long as wide at base, with apex lightly sclerotized and broadly rounded and base membranous with paired wing-folding patches. Sternite VIII in female with spiculum ventrale slightly shorter than ovipositor and forked at base. Ovipositor about 4.23 times as long as wide, lightly sclerotized except for proctigeral, paraproctal and coxital bacula; paraprocts 1.48 times as long as gonocoxites, each of which is subdivided into three lobes, whose length ratio is 10: 8: 24; proximal lobe with oblique basal baculum, distal lobe not abruptly narrowed, lightly sclerotized; each gonostylus about 0.17 times as long as gonocoxite, 3 times as long as wide, parallel-sided and well sclerotized; ventral sclerite almost as long as gonocoxite, slightly wider at middle and narrowly acute at each end. Internal female tract with relatively small bursa, at the anterior end of which is a slender spermathecal gland about as long as and attached basally to an elongate spermatheca with several transverse partitions on the basal half and a very slender tube at the apex.

Distribution. The sole species of the genus, Onysius anomalus , has been collected infrequently but is quite widespread in New Zealand (see map in Watt 1974a). It has not been collected north of Auckland, many central areas of the North Island, and in the South Island it has not been recorded from Fiordland or from drier regions in the east. It is absent from offshore islands, apart from Stewart Island.

Biology. Onysius anomalus occurs in forests with moderate to high rainfall and up to 1,370 m ( Watt 1974a). Collections are mainly from beating vegetation, and the color indicates it may be associated with mossy habitats, much like some true chalcodryids with green and black mottling of the dorsal surfaces. Their diet remains unknown, and one dissected female had the setose lumen of the crop containing undifferentiated material with no identifiable fungal spores or hyphae and possibly some plant matter.

Material examined. North Island: AK: 1 (male, dissected), Waitakere Ra , Cutty Grass Tk , 4 Dec 1973, G. Kuschel, Nestegis montana , 36°56.109’S, 174°31.498’E ( NZAC) ; 1, Waitakere Ra, Piha , 12 Apr 2000, Malaise trap, Wasp Survey ( AMNZ) ; TO: 1, Pureora, Waipapa Res , 570m, 15 Mar 1984, J. Hutcheson, Malaise trap, Podocarpus , 38°28.454’S, 175°34.234’E ( NZAC) ; WN: 1, Wainuiomata , March 1921, A.C. O’ Connor, 41°15.263’S, 174°57.798’E ; 1, Kaitoke, 9 Apr 11, A.C. O’ Connor, 41°5.167’S, 175°9.483’E ( NZAC) ; South Island: NN: 1, Canaan , 17–26 Jan 49, 40°56.596’S, 172°53.435’E ( NZAC) ; 1, Canaan , 17–26 1.49, 40°56.596’S, 172°53.435’E ( NZAC) ; 1, Kawatiri , 20.1.35, E.S. Gourlay, 41°41.519’S, 172°36.783’E ( NZAC) ; 1, Dun Mt ( Third House ), 11.11.26, A. Philpott, 41°19.512’S, 173°19.476’E ( NZAC) ; 1, Dun Mt , 760m, 6 Feb 73, J. McBurney, 41°20.045’S, 173°20.225’E ( NZAC) ; 1, Mt Owen , 5000’, 23–26.2.60, J.I. Townsend, W.P. Thomas, 41°33.129’S, 172°32.491’E ( NZAC) ; 1, Mt Moa , 20.10.1915, 40°56.401’S, 172°56.376’E ( NZAC) ; 1, Glen Hope , 12-9-1915, 41°38.867’S, 172°38.975’E ( NZAC) ; 1 (female, dissected), Cobb River , 3000’, 9.4.39, L.J. Dumbleton, 41°5.093’S, 172°33.352’E ( NZAC) ; SD: 1, Picton, Helms , 41°17.969’S, 173°59.627’E ( NZAC) ; 1, Picton , 30–31 Mar 1935, ES Gourlay ( AMNZ) ; NC: 1, NC, South Branch Hurunui River , 23.ii–5.iii.1999, S. Pawson, on sticky trap ( LUNZ) ; MC: 1 (female, dissected), Mt Peel , 4000’, 22.1.43, E.S. Gourlay, 43°50.803’S, 171°9.395’E ( NZAC) ; BR: 1, Fletchers Ck, 18 Apr 1972, J.C. Watt, Beech Forest Utilisation Project, 41°59.036’S, 171°50.797’E ; 1, L. Rotoiti, 5 Jan 1978, A.K. Walker, Coleman lantern, 41°48.014’S, 172°49.994’E ( NZAC) ; 1 (male, dissected) Lake Rotoiti , 2000’, 29.10.64, G. Kuschel, 41°48.014’S, 172°49.994’E ( NZAC) ; 1, Porarari R. 30m, G.R. Champness, Malaise trap, 18.xii.1984 – 9.i.1985 ( LUNZ) ; OL: 1, Kidds Bush , 13 Jan 2006, R. Leschen, T. Buckley, R. Hoare, beating, 44°26’S, 169°15’E ( NZAC) ; SL: 1, Owaka , 15.1.59, E.S. Gourlay, 46°27.130’S, 169°39.320’E ( NZAC) ; 1, Catlins Coast, Tautuku Bay Nature Walk, 27 Jan 2007, R. Leschen, T. Buckley, K. Marske, beating, 46°34.620’S, 169°26.627’E ( NZAC) ; WD: Franz Josef Glacier , 2 Jan 1984, L. Masner ( ANIC) ; Stewart Island ( SI): 1, Mt Anglem , 3000’, 29 Jan 1962, G. Kuschel, 46°44.350’S, 167°54.992’E ( NZAC) ; 1, same, but 6.3.35, E.S. Gourlay ( NZAC) ; 1, Christmas Village , 26.1.62, J.I. Townsend, 46°44.710’S, 167°58.670’E ( NZAC) ; 1 (male dissected), South Cape Island ( NE), Feb 69, B.A. Kuschel, beating, 47°14.532’S, 167°25.109’E ( NZAC) .

Figures

Fig. 1. Dorsal habitus of Promecheilidae and Chalcodryidae. A) Sirrhas variegatus (© CSIRO; scale bar = 1 mm), B) Onysius anomalus, C) Chalcodrya hilaris Watt, D) Philpottia mollis Broun.