Oopterus nanus, Larochelle & Larivière & Larochelle & Larivière, 2017

Larochelle, Larivière, Marie-Claude, Larochelle & Larivière, 2017, Synopsis of the tribe Zolini in New Zealand (Coleoptera: Carabidae), Insecta Mundi 2017 (594), pp. 1-110 : 49-50

Oopterus nanus new species

Fig. 50 , 96 , 136

Holotype: male ( NZAC) labeled: “[ NEW ZEALAND CO] Old Man Ra CO 1615m 26 Feb 74 J.S. Dugdale (hand-written) / ex Celmisia haastii (hand-written) / HOLOTYPE [male symbol] Oopterus nanus Larochelle & Larivière, 2017 (red label; typed).” Paratypes: two females (LUNZ, NZAC) from the same locality as the holotype, bearing blue paratype labels.

Description. Body length 3.9–5.2 mm. Head, pronotum, elytra, and abdomen mostly black; abdomen reddish piceous laterally and apically; antennae, palpi, and legs reddish. Microsculpture strong and isodiametric on head, obsolete and moderately transverse on pronotum, feeble and isodiametric on elytra. Iridescence absent. Very shiny, without metallic luster. Head. Labrum strongly transverse, slightly emarginate anteriorly. Antennae submoniliform, short: segment 1 (scape) moderately long, about 2x longer than its maximum width. Frontal furrows wide, deep, convergent. Eyes moderately convex; two setiferous punctures on inner side of each eye. Tempora moderately inflated (about half as long as eyes). Mentum: medial tooth entire, acute apically, moderately shorter than lateral lobes. Paraglossae membranous, prominent, slightly longer than ligula. Thorax. Pronotum moderately convex, impunctate, wrinkled discally, strongly transverse, widest before middle; apex subtruncate; anterolateral angles poorly developed, rounded; anterior bead incomplete, obsolete medially; sides strongly rounded, not sinuate posteriorly; lateral grooves absent; two setiferous punctures on each side; posterolateral angles subrectangular; posterolateral carinae absent; laterobasal foveae well defined, impunctate, shallow, very wide, rectangular, not prolonged forward, double; posterior bead absent; base emarginate, much narrower than pronotal apex, slightly narrower than elytral base. Legs. Short. Elytra. Subdepressed, oblong, widest about middle. Basal margin incomplete, reaching about stria 4. Shoulders obtuse. Sides subparallel. Scutellar striole obsolete. Striae complete, shallow, finely punctate; stria 3 with four unusually large setiferous punctures. Recurrent stria long, sharp, directed apically toward stria 5, 6 or 7. Subapical seta present. Intervals depressed. Sutural apices obtuse. Abdomen. Last visible sternum (sternum VII): male with two apical ambulatory setae; female with four apical ambulatory setae. Aedeagus. Lateral view ( Fig. 96 ): strongly arcuate, narrowed in apical half; base moderately biconvex dorsally; middle strongly convex dorsally, slightly convex ventrally, with dorsal membranous area very wide and moderately long; apex slender, strongly concave dorsally, slightly concave ventrally, with extreme tip wide, unusually long. Dorsal view: narrow, asymmetrical (ostium of membranous area deflected to right); apex straight; basal orifice narrow, closed anteriorly, moderately distant from membranous area. Parameres with four to six apical setae.

Material examined. 196 specimens ( AMNZ, JNNZ, LUNZ, NZAC).

Geographic distribution ( Fig. 136 ). South Island: CO, OL.

Ecology. Alpine. Epigean. Fellfields; tussock grasslands. Open ground. Nocturnal; hides during the day under stones and in mat plant litter. Gregarious.

Biology. Seasonality: November–April. Tenerals: January–February. Predacious (based on mouthpart morphology).

Dispersal power. Subapterous (incapable of flight). Slow runner.

Collecting techniques. Lifting stones; sifting plant litter.

Remarks. The species name is based on the Latin noun nanus , denoting a dwarf, referring to the small size of the beetle. Oopterus nanus is morphologically close to O. anglemensis . In addition to diagnostic characters of the male genitalia, O. nanus has the following distinguishing features: body length 3.9–5.2 mm; pronotum not cordate, laterobasal foveae well defined, rectangular; elytra subdepressed, oblong, sides subparallel. The two species are allopatric: O. nanus occurs in southern areas of the South Island (CO, OL), while O. anglemensis is restricted to Stewart Island.

Figures

Figures 47–50. Dorsal habitus. 47) Oopterus ocularius. 48) O. marrineri. 49) O. anglemensis new species. 50) O. nanus new species. Scale line = 1 mm.

Figures 90–97. Aedeagi, lateral. 90) Oopterus trechoides new species. 91) O. sculpturatus. 92) O. taieriensis new species. 93) O. ocularius. 94) O. marrineri. 95) O. anglemensis new species. 96) O. nanus new species. 97) O. garnerae new species.

Figures 136–141. Species distribution maps. 136) Oopterus nanus new species. 137) O. nunni new species. 138) O. ocularius. 139) O. palmai new species. 140) O. patulus. 141) O. punctatus new species.