Ctenognathus davidsoni Larochelle and Larivière, 2021

Larochelle & Larivière, Marie-Claude, 2021, Synopsis of the tribe Platynini in New Zealand (Coleoptera: Carabidae), Insecta Mundi 2021 (864), pp. 1-96 : 57

Ctenognathus davidsoni Larochelle and Larivière , new species

Fig. 77 , 120 , 128

Ctenognathus davidsoni Larochelle and Larivière , new species. Holotype: male (NZAC) labeled “[ NEW ZEALAND FD] Homer Saddle 3000’ Milford 1.IX.66 J.I. Townsend (hand-written) / HOLOTYPE [male symbol] Ctenognathus davidsoni Larochelle & Larivière, 2021 (red label; typed).” Paratypes: one female (NZAC) and one male (AMNZ) from the same locality as the holotype, bearing blue paratype labels.

Description. Body length 11.2–12.9 mm. Head, pronotum, and elytra rufotestaceous (forebody darker except along lateral margins); abdomen rufotestaceous; antennal segments 1–3 rufotestaceous, 4–11 dark piceous; palpi and legs rufotestaceous. Microsculpture isodiametric on head, moderately transverse on pronotum, and isodiametric on elytra. Iridescence absent. Head, pronotum, and elytra very shiny. Forebody moderately wide in comparison to elytra. Head. Moderately wide. Mandibles moderately long and curved anteriorly. Labrum strongly transverse, moderately emarginate anteriorly. Eyes moderately convex; two setiferous punctures on inner side of each eye. Tempora not inflated. Neck constriction absent dorsolaterally. Mentum: medial tooth slightly emarginate apically; two setae. Submentum with six setae. Palpi with terminal segment obtuse apically. Thorax. Pronotum moderately convex, impunctate, obsoletely wrinkled across base, wide, subcordate, widest before middle; apex slightly emarginate; anterolateral angles slightly developed, narrowly rounded; anterior bead complete; sides moderately rounded, not sinuate posteriorly; lateral beads complete; lateral depressions wide; two setiferous punctures (anterior and posterior) on each side; posterolateral angles acutely rectangular; laterobasal foveae very deep and wide, almost meeting toward pronotal midline, prolonged forward; posterior bead incomplete, obsolete medially; base emarginate. 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. Moderately convex, sloping down toward apex, subovate, widest behind middle. Shoulders moderately rounded. Sides slightly rounded. Scutellar setiferous pore visible. Scutellar striole moderately long, impunctate. Striae shallow, impunctate. Intervals subdepressed; interval 3 with three very deep, large (foveate) setiferous punctures. Umbilicate series with 17–20 setiferous punctures. Subapical sinuations feeble. Apices obtusely rounded. Abdomen. Sterna IV–VI: both sexes with two long apical ambulatory setae. Sternum VII (last visible sternum): male with four long apical ambulatory setae; female with eight long apical ambulatory setae. Aedeagus. Lateral view ( Fig. 120 ): moderately arcuate; base strongly convex dorsally, with basal lobe moderately wide; middle moderately convex dorsally and ventrally, with dorsal membranous area moderately wide, rather strongly biconvex; apex moderately convex dorsally, slightly concave ventrally, with extreme tip subtriangular, moderately wide and long. Dorsal view: very wide, asymmetrical (ostium of membranous area deflected to the left); basal bulb moderately distant from membranous area.

Material examined. 272 specimens ( AMNZ, CMNZ, JNNZ, LUNZ, MONZ, NZAC).

Geographic distribution ( Fig. 128 ). South Island: BR, FD, OL, SL, WD.

Ecology. Lowland, montane, subalpine. Epigean, arboreal. Wet forests (beech). Shaded ground; wet soil. Nocturnal; hides during the day under logs and stones; active at night on mossy tree trunks and logs. Gregarious.

Biology. Seasonality: September, December–April, August. Tenerals: August. Predacious (based on mouthpart morphology). Occasionally infested with fungi (Laboulbeniales).

Dispersal power. Subapterous (incapable of flight). Moderate runner. Regular climber (on trees).

Collecting techniques. Pitfall trapping; turning logs and stones; examining mossy tree trunks and logs at night.

Remarks. This species is named after Robert L. Davidson (Carnegie Museum, Pittsburgh, Pennsylvania), longtime friend and colleague, for his special help and encouragement in our carabid research and for his special taxonomic expertise and dedication as a manuscript reviewer. Ctenognathus davidsoni is morphologically close to C. oreobius and C. hoarei . In addition to morphological characters of the male genitalia, C. davidsoni has the following distinguishing features: antennal segments 1–3 rufotestaceous, 4–11 dark piceous; femora rufotestaceous; sides of pronotum not sinuate, lateral depressions wide throughout, laterobasal foveae very wide, almost meeting toward pronotal midline; elytra with sides slightly rounded, interval 3 with three very deep, large (foveate) setiferous punctures. Ctenognathus davidsoni is found mostly in western areas of the South Island (BR to SL). Ctenognathus oreobius occurs mostly in southeastern areas of the South Island (MK to SL), while C. hoarei is endemic to the Banks Peninsula (MC).

Figures

Figures 77–79. Dorsal habitus. 77) Ctenognathus davidsoni new species. 78) C. oreobius. 79) C. hoarei new species. 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 124–129. Species distribution maps. 124) Ctenognathus adamsi. 125) C. arnaudensis. 126) C. cardiophorus. 127) C. colensonis. 128) C. davidsoni new species. 129) C. earlyi new species.