Trigonotoma nitidicollis Chaudoir 1868
Creators: name: Fedorenko, D. N.
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Carabidae
Trigonotoma
Trigonotoma nitidicollis

description: 1. Trigonotoma nitidicollis Chaudoir, 1868
Figs 2, 7, 15, 23, 31, 39–40, 49, 54, 62–64.
Chaudoir, 1868: 160 (‘Cochinchine’); Csiki, 1929: 517; Dubault et al., 2010a: 21; Roux et al., 2016: 96, 160 (part.). — ssp. minuta Dubault et al., 2010a: 23 (Phetchabun, Thailand); Roux et a l., 2016: 162.
MATERIAL. 5♂♂, 3♀♀, (SIEE), Vietnam, Dong Nai Province, Cat Tien National Park, at light HQL 450, 17.V–18. VI.2005 (D. Fedorenko); ♂, 3♀♀ (ZIN), Binh Phuoc Province, IV.2017 (A.Astrashabov); ♂ (SIEE), Gia Lai Province, ~ 40 km NEE of Pleiku, 14°12′11″N 108°18′54″E, Kon Ka Kinh Natn. Park, h = 890 m, 9–22.V.2016 (D. Fedorenko); 2♀♀ (SIEE), Quang Binh Province, Phong Nha – Ke Bang NP, Bo Trach, h = 375 m, 17°22′14″N 106°13′18″E, 12–21.V.2022 (D. Fedorenko); 2♂♂, ♀ (SIEE), same data except at light; ♀ (SIEE), Minh Hoa Distr., Ke Bang, env. Yen Hop, 14–15.IV.1999 (A. Devyatkin); ♀ (ZIN), Laos, 70 km NNW of Ventiane, Nam Lik Eco Vill. on Nam Lik River, 200 m, 18.614469°N, 102.4847°E, 10–30.VI.2017 (A.V. Gorokhov, M. Omel’ko); ♀ (SIEE), Thailand, near Chiang Mai, VIII.2005 (A. Sokolov).
Aedeagus and internal sac examined in five or four males, respectively; genitalia and reproductive tract examined in three females.
DIAGNOSIS. A large-sized macropterous species, with forebody dorsum bright metallic and elytra mostly black. Tarsi without lateral sulci or posterolateral setae. Sides of pronotum straight in front of basal angles; these very obtuse and mostly rather widely rounded. Aedeagus (Figs 39–40, 49, 54) smooth ventrally, apex in right dorsolateral view trapezoidal and nearly straight at right margin; internal sac tubiform, without clusters of long and dense spicules (Figs 62–64). Female bursa copulatrix very long (Fig. 31).
REDESCRIPTION. For recognition only. BL 23.7– 26 mm. Body black, forebody bright metallic, head green, pronotum cupreous green; elytra black, rarely with very slight violaceous or greenish lustre. Labial palps and antennomere 11 more or less reddish brown, exposed labral membrane often reddish yellow. Head and pronotum without meshed microsculpture, elytral microsculpture consisting of uneven isodiametric to subtransverse meshes.
Frontal sulci fine yet deep, reaching the level of anterior supra-ocular seta, each side between and inside anterior and posterior seta with an oblique impressed line. Left mandible obliquely striated at base of dorsal side.
Pronotum (Fig. 2): basal sulci slightly less than a third as long as pronotum, inner as fine impressed lines, these not quite reaching base and slightly converging apicad; outer sulci more shallow, curved outward and merging into lateral groove; a superficial to vague branch emerges from near this sulcus anteriorly to run parallel and close to lateral groove and obliterate 1/3–2/5 from base. Basal fovea (between inner and outer sulcus) moderately deep, flat and more or less rugulose or sparsely transversely rugose at bottom, finely and rather sparsely punctate, mostly closer to outer sulcus, more seldom nearly impunctate or densely punctate; base impunctate between inner sulci. Apical bead barely shorter than lateral fourths.
Elytral striae deep, densely and rather finely punctate on disc, moderately punctate toward apex and lateral margin. Intervals convex on disc, more so toward lateral margin and still more convex toward apices.
Metatarsomere 1 with 2–4 anterolateral and no posterolateral setae.
GEOGRAPHIC DISTRIBUTION. Widespread in Indochina, mostly in the east (Vietnam and Laos). The species range needs clarification due to confusion of the species with T. aurifera.
HABITATS AND HABITS. Most specimens were taken at light, at low altitudes.
COMMENTS. Trigonotoma nitidicollis and T. aurifera were only based on the holotypes, female or male, respectively. Having found no differences between the type and many non-type specimens examined, except for a distinctive internal sac of aedeagus in a male from ‘Paksé’, southern Laos, Dubault et al. [2010a] recognized the two species as conspecific taxa. Five Figures in Roux et al. [2016: 161] show two dorsal habitus of the female holotype (wrongly named ‘ Holotype male’), four different aspects of aedeagus, and the internal sac characteristic of T. nitidicollis sensu Dubault et al., 2010, yet with no reference to the specimens dissected. The fact that twelve males from Myanmar or Thailand and only four males from Vietnam or Laos had been examined before [Dubault et al., 2010a] might suggest that the major part of the material covered T. aurifera, but the male from ‘Paksé’ belonged to T. nitidicollis.
According to the description, T. nitidicollis minuta has hitherto been considered to represent a local population of the species, distinctive in only having the pronotum wider, with basal angles less rounded, and the body a bit smaller, ca. 20 mm in length, or 20–22 mm [Roux et al., 2016]. It is very similar to a male specimen from Thailand at my hand. Yet, the internal sac of aedeagus is very distinctive from those of the other species of Trigonotoma, including T. nitidicollis and T. aurifera, which may suggest species rank of T. n. minuta.
description: Published as part of Fedorenko, D. N., 2024, Notes on Trigonotoma and Pareuryaptus (Coleoptera: Carabidae: Pterostichini) from Vietnam, pp. 43-71 in Russian Entomological Journal 33 (1) on pages 45-47, DOI: 10.15298/rusentj.33.1.05, http://zenodo.org/record/14162968