Trichotichnus hamulipenis Kataev & Hongbin & Wrase 2022, sp. n.
Creators: name: Kataev, Boris M.
name: Hongbin, Liang
name: Wrase, David W.
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Carabidae
Trichotichnus
Trichotichnus hamulipenis

description: Trichotichnus (s. str.) hamulipenis sp. n.
(Figs. 20, 94–105)
Description (10 males and 5 females measured). Body length 8.8–10.2 mm. Habitus as in Figs. 94 & 95.
Body dark brown to black, shiny on dorsum, very slightly iridescent on elytra; labrum and mandibles along lower outer margin, occasionally also base of mandibles and narrow lateral margins of pronotum reddish brown. Palpi, antennae, tibiae and tarsi brownish yellow or light brown; femora blackish brown.
Head moderately sized (HWmax/PWmax 0.70–0.76, HWmin/PWmax 0.55– 0.58). Eyes large and convex, almost hemispherical (HWmax/HWmin 1.25–1.33), in lateral view almost round. Genae narrow, about as wide as antennomere 2 apically. Tempora short, glabrous. Fronto-clypeal suture superficial or slightly impressed, very widely rounded. Frontal foveae wide and shallow. Fronto-ocular furrows reaching supraorbital furrows, distinct along entire length, deepened at clypeus. Supraorbital furrows narrow, touching upper margin of eye. Supraorbital setigerous pores small, situated slightly before level of posterior margin of eye and removed from supraorbital furrows by distance approximately equal to width of antennomere 2 apically; in many specimens one or two very small unsetigerous punctures present medially of each supraorbital seta. Labrum very shallowly concave anteriorly. Clypeus slightly convex, very shallowly emarginate along anterior margin, with a pair of setigerous pores each located at anterior angle. Mentum separated from submentum, with moderately wide median tooth; epilobes markedly widened apically; submentum with one pair of long setae. Ligular sclerite widened apically, truncate at apex, with one pair of ventroapical setae. Paraglossae very narrow, shorter than ligular sclerite and separated from it by wide notches. Labial penultimate palpomere about as long as ultimate palpomere. Left mandible sharply bent in the apical quarter, blunted at tip. Dorsal microsculpture very fine, consisting of obliterated, more or less isodiametric meshes. Antennae slender and long, surpassing pronotal basal edge in female by three, in male almost by four apical antennomeres, with antennomeres 4–8 about 3.5 times as long as wide. Basal antennomere very slightly longer than antennomere 3.
Pronotum transverse (PWmax/PL 1.34–1.48), widest slightly before the middle (PWmax/PWmin 1.24–1.35), more strongly narrowed apically than basally, with one lateral seta somewhat removed from lateral edge to internal margin of lateral depression and inserted slightly before widest point of pronotum. Sides rounded along entire length or with very short sinuation just before basal angles; lateral bead narrow, slightly widened basally. Apical margin very shallowly emarginate, very narrowly bordered along entire length, but occasionally border obliterated at the middle. Apical angles widely rounded, almost not protruding ahead. Basal margin more or less straight, bordered along entire length, slightly longer than apical margin and markedly shorter than base of elytra between humeral angles. Basal angles very obtuse, with small obtuse denticle at tip protruding laterally. Pronotal disc convex medially. Lateral depression beginning from apical angles, moderately narrow in apical third, rather strongly widened in the basal two third and fused with wide and deep laterobasal depressions; basal foveae located within laterobasal depressions, shallow, occasionally indistinct; basal area convex medially. Median line distinct, superficial or slightly impressed. Anterior transverse depression shallow or deepened. Surface either densely punctate almost throughout, with coarsest punctures in laterobasal depressions and with finest punctures in central part of disc, or punctation restricted only to rather wide area along margins. Microsculpture highly obliterated, indistinct transverse meshes recognizable mostly along base.
Elytra convex, elongate oval (EL/EW 1.43–1.55, EL/PL 2.59–3.310, EW/PWmax 1.24–1.38), widest in the apical third. Humeri angularly rounded, at most with indistinct denticle poorly recognizable in caudal view. Subapical sinuation distinct but shallow. Sutural angle blunted or narrowly rounded at tip. Basal edge evenly arched or oblique; internal humeral angle very obtuse, almost indistinct. Striae impunctate, reaching anteriorly basal edge, impressed shallowly on disc and slightly more deeply apically. Intervals faintly convex or somewhat flat on disc, markedly narrowed and moderately convex apically. Parascutellar (abbreviate) striole long, with a small setigerous pore basally. Interval 3 with a very small discal setigerous pore adjacent to stria 2 behind the middle. Marginal umbilicate series without distinct gap at middle. Microsculpture strongly obliterated, consisting of indistinct transverse lines (recognizable at least apically and on lateral intervals).
Wings wholly or partly reduced.
Prosternum with very fine short setae. Metepisternum short, 1.18–1.25 times as long as wide, markedly narrowed posteriorly.
Legs relatively long. Metacoxae without additional setae. Metafemur ventrally with two setae at posterior margin and without setae at anterior margin. Protibia on dorsal side without longitudinal sulcus, outer margin preapically with one stouter and two very thin spines in male (Fig. 20) and with three comparatively stout, similar sized spines in female. Tarsi dorsally glabrous; pro- and mesotarsomeres 1–4, particularly in male, with dense long ventro-lateral setae (as in Fig. 20); tarsomere 5 with three or four pairs of ventro-lateral setae. Metatarsus slender, about as long as (occasionally slightly shorter or longer than) HWmax, with tarsomeres somewhat weakly widened distally; metatarsomere 1 slightly shorter than metatarsomeres 2 and 3 combined; metatarsomeres 1–4 moderately densely setose ventrally. In male, pro- and mesotarsomeres 1–4 moderately widened and with adhesive scales ventrally; pro- and mesotarsomeres 2 and 3 longer than wide. In both sexes, mesotarsomere 1 elongate, slightly shorter than mesotarsomeres 2 and 3 combined.
Abdominal sternites without additional long setae; apex of last visible abdominal sternite (VII) in male subtruncate and with one pair of marginal setae, in female rounded and with two pairs of marginal setae.
Median lobe of aedeagus (Figs. 98–100, 103–105) stout, in lateral view arcuate; ventral side flattened in apical portion; terminal lamella in dorsal view wide, wider than long, not concave, strongly narrowed posteriorly, with very narrowly rounded apex; in lateral view sharply hooked ventrally. Apical orifice mostly in dorsal position, but slightly shifted to the left. Internal sac with large apical spine and twisted spiny patches.
Female genitalia (Figs. 101 & 105): gonocoxite comparatively narrow in ventral view, about 0.6 times as long as gonosubcoxite, with rather wide base.
Etymology. The specific name is a Latin compound noun, referring to the sharp hook on the apex of the median lobe of the aedeagus.
Comparison. This new species is similar to members of the longitarsis species group sensu Habu, 1961 and 1973 (but excluding T. noctuabundus) in many characters, including elongate body with relatively long legs, one pair of marginal setae on last abdominal sternite of male, densely setose tarsi ventrally (Fig. 20) and elongate male pro- and mesotarsomeres, but differing in having protibia not sulcate and wings reduced. In general habitus and male genitalia, it is most similar to T. vespertinus Habu, 1954 from Japan; the latter species, however, is distinguished by having femora brownish yellow, not infuscate, protibia with a longitudinal sulcus ventrally, and median lobe of aedeagus hooked at apex and with terminal lamella in dorsal view acute at tip; in addition, both species have a different pattern of spiny patches in internal sac.
Distribution. Known from China (Yunnan) and Nepal.
Remarks. The species forms two subspecies.
description: Published as part of Kataev, Boris M., Hongbin, Liang & Wrase, David W., 2022, New data on carabid beetles of Trichotichnus s. str. (Coleoptera: Carabidae) of Yunnan (China) and adjacent areas, with description of six new species and two new subspecies, pp. 301-353 in Zootaxa 5159 (3) on pages 338-340, DOI: 10.11646/zootaxa.5159.3.1, http://zenodo.org/record/6781669