Ctenognathus xanthomelus ( Broun, 1908 )

Larochelle & Larivière, Marie-Claude, 2021, Synopsis of the tribe Platynini in New Zealand (Coleoptera: Carabidae), Insecta Mundi 2021 (864), pp. 1-96 : 51-52

Ctenognathus xanthomelus ( Broun, 1908)

Fig. 72 , 115 , 148

Anchomenus xanthomelus Broun, 1908: 346 . Holotype: male (BMNH) labeled “Type (circular red-bordered label; typed)

/ 2665. [male symbol] (hand-written) / New Zeal. Broun. Coll. Brit. Mus. 1922–482. (white label with red horizontal

line; typed) / [RI/WN] Manawatu Gorge. (hand-written) / Anchomenus xanthomelus (hand-written).” Anchomenus xanthomelas [sic]: Hudson 1923: 356. Agonum (Anchomenus) xanthomelus: Csiki 1931: 865 . Anchomenus xanthomelas [sic]: Hudson 1934: 174. Ctenognathus xanthomelus: Larochelle and Larivière 2007: 81 , 111.

Description. Body length 10.0– 11.4 mm. Head, pronotum, and elytra mostly piceous black; lateral margins of pronotum and elytra reddish; abdomen piceous black, yellow lateroapically; antennae and palpi rufotestaceous; femora pale yellow; tibiae and tarsi reddish. Microsculpture isodiametric on head, very transverse (with microlines) on pronotum, and moderately transverse on elytra. Iridescence present on pronotum. Very shiny. Forebody narrow in comparison to elytra. Head. Moderately wide. Mandibles moderately long and curved anteriorly. Labrum strongly transverse, slightly emarginate anteriorly. Eyes moderately convex; two setiferous punctures on inner side of each eye. Tempora not inflated. Neck constriction shallow dorsolaterally. Mentum: medial tooth slightly emarginate apically; two setae. Submentum with six setae. Palpi with terminal segment truncate apically. Thorax. Pronotum moderately convex, impunctate, deeply wrinkled across base, narrow, strongly cordate, widest about middle; apex slightly emarginate; anterolateral angles poorly developed, rounded; anterior bead complete; sides strongly rounded, strongly sinuate posteriorly; lateral beads absent; lateral depressions wide; two setiferous punctures (anterior and posterior) on each side; posterolateral angles rectangular; laterobasal foveae very deep, moderately wide, prolonged forward; posterior bead complete; base subtruncate. Legs. Moderately 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 glabrous ventrally. Elytra. Very convex, sloping down toward apex, ovate, widest about middle. Shoulders strongly rounded. Sides strongly rounded. Scutellar setiferous pore visible. Scutellar striole moderately long, impunctate. Striae deep, finely punctate. Intervals slightly convex; interval 3 with three moderately deep, small setiferous punctures. Umbilicate series with 16–18 setiferous punctures. Subapical sinuations feeble. Apices obtuse. 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. 115 ): moderately arcuate, strongly widened in apical half; base moderately convex dorsally, with basal lobe narrow; middle moderately concave dorsally, strongly concave ventrally, with dorsal membranous area moderately wide and moderately long; apex subtriangular, strongly convex dorsally, slightly concave ventrally, with extreme tip narrow 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. 127 specimens ( AMNZ, BMNH, LUNZ, MONZ, NZAC).

Geographic distribution ( Fig. 148 ). North Island: BP, RI, TK, TO, WN, WO.

Ecology. Lowland, montane. Epigean. Wet forests (broadleaf, podocarp). Associated with streams, slopes, and mud flats. Shaded ground; wet soil. Nocturnal; hides during the day under logs and fallen branches, also in heaps of dead leaves and mud. Gregarious.

Biology. Seasonality: October–January, March–April, June. Tenerals: November–December, February, June. Predacious (based on mouthpart morphology). Occasionally infested with mites.

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

Collecting techniques. Pitfall trapping; turning logs and fallen branches; examining heaps of dead leaves and mud; pan trapping (yellow pan traps).

References. Larochelle and Larivière 2001: 132 (as “ Anchomenus ” xanthomelas ; catalogue; biology, dispersal power, ecology, geographic distribution, references), 2007: 81, 111 (as Ctenognathus xanthomelus ; list), 2016: 38 (list).

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 115–122. Aedeagus, lateral. 115) Ctenognathus xanthomelus. 116) C. intermedius. 117) C. colensonis. 118) C. otagoensis. 119) C. earlyi new species.120) C. davidsoni new species.121) C. oreobius. 122) C. hoarei new species.

Figures 148–153. Species distribution maps. 148) Ctenognathus xanthomelus. 149) Kiwiplatynus bidens. 150) K. taranaki new species. 151) Kupeplatynus crenatus. 152) K. lucifugus. 153) K. sulcitarsis.