Ctenognathus helmsi ( Sharp, 1881 )

Larochelle & Larivière, Marie-Claude, 2021, Synopsis of the tribe Platynini in New Zealand (Coleoptera: Carabidae), Insecta Mundi 2021 (864), pp. 1-96 : 50-51

Ctenognathus helmsi ( Sharp, 1881)

Fig. 71 , 114 , 133

Anchomenus helmsi Sharp, 1881: 47 . Lectotype (here designated): female (BMNH) labeled “ Anchomenus helmsi [WD]

Greymouth N. Zd. (hand-written) / Greymouth New Zealand. Helms. (white label with red horizontal line; typed)

Sharp Coll. 1905–313. / LECTOTYPE [female symbol] Anchomenus helmsi Sharp, 1881 designated by Larochelle &

Larivière, 2021 (red label; typed).” Agonum (Platynus) helmsi: Csiki 1931: 853 . Anchomenus helmsi: Hudson 1934: 174 . Agonum helmsi: Johns 1977: 316 . Anchomenus helmsi: Townsend 1997: 15 . Ctenognathus helmsi: Larochelle and Larivière 2007: 81 , 111.

Description. Body length 9.5–11.6 mm. Head, pronotum, and elytra mostly piceous black; lateral margins of pronotum and elytra reddish; abdomen piceous black, yellowish lateroapically; antennae and palpi rufotestaceous; femora dark yellow; tibiae and tarsi reddish. Microsculpture isodiametric on head, moderately transverse on pronotum, and isodiametric on elytra. Iridescence absent. Very shiny. Forebody narrow in comparison to elytra. Head. Moderately wide. Mandibles moderately long and curved anteriorly. Labrum strongly transverse, slightly emarginate anteriorly. Eyes strongly convex; two setiferous punctures on inner side of each eye. Tempora not inflated. Neck constriction shallow dorsolaterally. Mentum: medial tooth subtruncate or slightly emarginate apically; two setae. Submentum with four setae. Palpi with terminal segment obtuse apically. Thorax. Pronotum moderately convex, impunctate, obsoletely wrinkled throughout, narrow, strongly cordate, widest about middle; apex strongly emarginate; anterolateral angles well developed, rounded; anterior bead complete; sides strongly rounded, strongly sinuate posteriorly; lateral beads complete; lateral depressions wide; two setiferous punctures (anterior and posterior) on each side; posterolateral angles acute, slightly projected laterally; laterobasal foveae very deep, moderately wide, prolonged forward; posterior bead complete; base subtruncate. Apex of prosternum glabrous or pubescent (glabrous in all other species). Legs. Very long. Metafemora with two posteroventral setae. Meso- and metatarsomeres 1–4 well developed, tricarinate dorsally, deeply bisulcate laterally. Metatarsomeres 4 moderately bilobed, symmetrical apically. Metatarsomeres 5 setose ventrally (with very short setae). Elytra. Moderately convex, sloping down toward apex, subovate, widest about middle. Shoulders strongly rounded. Sides strongly rounded. Scutellar setiferous pore visible. Scutellar striole moderately long, impunctate. Striae deep, impunctate. Intervals subdepressed; interval 3 with three moderately deep, small setiferous punctures. Umbilicate series with 16–18 setiferous punctures. Subapical sinuations strong. Apices obtusely rounded. Abdomen. Sterna IV–VI: both sexes with two long apical ambulatory setae. Sternum VII (last visible sternum): male with two long apical ambulatory setae; female with four long apical ambulatory setae. Aedeagus. Lateral view ( Fig. 114 ): moderately arcuate; base strongly convex dorsally, with basal lobe narrow; middle moderately convex dorsally, strongly concave ventrally, with dorsal membranous area strongly widened in apical half and very long; apex slender, slightly convex dorsally, slightly concave ventrally, with extreme tip subtriangular and moderately long. Dorsal view: moderately wide, asymmetrical (ostium of membranous area deflected to the left); basal bulb moderately distant from membranous area.

Material examined. 322 specimens ( AMNZ, BMNH, CMNH, LUNZ, MONZ, NZAC).

Geographic distribution ( Fig. 133 ). South Island: BR, NN, SD, WD.

Ecology. Lowland, montane. Epigean. Wet forests (beech, broadleaf, podocarp). Associated with streams and mud flats. Shaded ground; wet soil. Nocturnal; hides during the day under logs and stones. Gregarious.

Biology. Seasonality: September–March, May. Tenerals: November, February–May. Predacious (based on mouthpart morphology). Occasionally infested with fungi (Laboulbeniales).

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

Collecting techniques. Turning logs and stones; pitfall trapping.

References. Larochelle and Larivière 2001: 130 (as “ Anchomenus ” helmsi ; catalogue; biology, dispersal power, ecology, geographic distribution, references), 2007: 81, 111 (as Ctenognathus helmsi ; list), 2016: 37 (list).

Remarks. Sharp described Anchomenus helmsi from two specimens, one of which (a female) was located (BMNH) and is here designated as lectotype. This type designation is made to preserve stability of nomenclature in the future.

Figures

Figures 69–72. Dorsal habitus. 69) Ctenognathus kaikoura new species. 70) C. sandageri. 71) C. helmsi. 72) C. xanthomelus. Scale line = 1 mm.

Figures 108–114. Aedeagus, lateral. 108) Ctenognathus takahe new species. 109) C. arnaudensis. 110) C. marieclaudiae new species. 111) C. edwardsii. 112) C. kaikoura new species. 113) C. sandageri. 114) C. helmsi.

Figures 130–135. Species distribution maps. 130) Ctenognathus edwardsii. 131) C. elevatus. 132) C. garnerae new species. 133) C. helmsi. 134) C. hoarei new species. 135) C. intermedius.