Psychristus (Psychristus) dentatus, Jaeger & H, 2009

Jaeger, B. & H, Ban, 2009, Two new species of Psychristus subgenus Psychristus ANDREWES 1930 from Southeast Asia, India and Pakistan, with additions to the Psychristus discretus group (Col., Carabidae), Linzer biologische Beiträge 41 (2), pp. 1635-1657 : 1637-1639

publication ID	https://doi.org/ 10.5281/zenodo.5279282
persistent identifier	https://treatment.plazi.org/id/039F194A-C343-EC2B-FF06-1A91FBEDFCC7
treatment provided by	Carolina
scientific name	Psychristus (Psychristus) dentatus
status	sp. nov.

Treatment

Psychristus (Psychristus) dentatus View in CoL nov.sp. ( Figs 1-3 View Figs 1-3 , 22 View Figs , 26 View Figs 26-27 , 28 View Figs 28-32 )

Psychristus spec. 1 : Jaeger 1997: 81.

T y p e m a t e r i a l:H o l o t y p e ♀ (NHMB) labelled " NW THAILAND, 9.-16.5. / Mae Hong Son, 1991 / Ban Huai Po, 1600-2000 m / J. Horák leg." and " HOLOTYPE ♀ / Psychristus View in CoL (s.str.) / dentatus spec. nov. / des. B. Jaeger 2009". P a r a t y p e: 1♀ (cITO) labelled "NE India, Meghalaya state / West Garo hills, NOKREK Nat. Park / 9.-17.V.1996, alt. 1100 ± 150 m / GPS N25°29.6’, E90°19.5’ (WGS 84) / E. Jendek & O. Šouša leg.", " Psychristus View in CoL / spec. nov. ??? / near shibatai / det. B. Jaeger 1996" and " PARATYPE ♀, Psychristus View in CoL (s.str.) / dentatus spec. nov. / des. B. Jaeger 2009".

D e s c r i p t i o n: General appearance as figured ( Fig. 1 View Figs 1-3 ). Body length 4.1 mm; width 1.6 mm.

Ground colour of dorsal surface dark reddish brown (holotype) to blackish brown (paratype), with elytral interval 1, pronotal base and apex medially and lateral margins of elytra and pronotum somewhat reddish. Labrum reddish, mandibles reddish brown, with outer margins and apex blackish brown, palpi yellowish. Ventral surface except paler mouthparts reddish brown (holotype) or dark reddish brown to blackish brown (paratype). Legs and antennae dark yellowish, femora slightly infuscated.

Head ( Figs 2-3 View Figs 1-3 ) including eyes, comparatively narrow, only 0.73 times as wide as pronotum, with eyes small and moderately prominent (head 1.42-1.43 times as wide as head between eyes). Apical margin of labrum distinctly emarginated. Mentum with epilobes ( Fig. 28 View Figs 28-32 ) moderately to distinctly projecting forward and distinctly acuminate at apices. Ligula narrowly rounded at apex, usual pair of setae inserted somewhat posterior to apical margin. Mental tooth sharp, more than half as long as epilobes. Mandibles of average size, not distinctly prolonged and curved, apices not truncate. Antennae 1.77- 1.89 times as long as pronotum and 0.66-0.70 times as long as elytra, with antennomere 1 and 2 glabrous, except for usual setae, 3 moderately pubescent and 4-11 distinctly pubescent. Microsculpture restricted to distinct isodiametric meshes on labrum and less distinct meshes at sides behind eyes.

Pronotum ( Figs 2-3 View Figs 1-3 ) somewhat cordate, 1.23-1.25 times as wide as long, 1.38 times as wide as head, widest in first half of second third, lateral seta inserted just anterior to widest point. Surface somewhat convex on disc, distinctly bent downward to anterior angles and somewhat depressed at basal area. Anterior margin almost rectilinear to weakly arcuate, faintly bordered laterally, angles only slightly projecting forward and narrowly rounded at tips. Sides convex in anterior three-quarters and at posterior quarter almost straight and parallel, or slightly constricted in front of pronotal base. Posterior angles sharp and somewhat obtuse, with a small denticle at tip. Base about 1.17-1.19 times as wide as apical margin between anterior angles and 0.84 times as wide as maximum pronotal width, arcuate medially and somewhat oblique to posterior angles. Lateral furrows distinct, confluent with lateral basal impressions at basal quarter. Basal foveae distinctly impressed, not separated by convexities from basal and lateral margin, the latter somewhat reflexed. Base in and between impressions coarsely punctate. Pronotal surface also in lateral furrows and along sides, and at anterior quarter with few scattered punctures. Median line distinctly to moderately impressed, reaching basal margin and disappearing in front of anterior margin, distinctly punctate in basal third and moderately punctate in remaining parts. Anterior transverse impression moderate to distinct. Microsculpture represented only by mesh rudiments in basal foveae, remaining surface smooth.

Macropterous. Elytra ( Fig. 1 View Figs 1-3 ) 1.57-1.58 times as long as wide, 2.69-2.71 times as long and 1.37-1.39 times as wide as pronotum. Surface moderately convex. Sides almost parallel or slightly diverging posteriorly, widest at about middle. Humeri distinctly angulate, with a large, sharp and somewhat projecting humeral tooth. Basal bead arcuately turning into humerus and forming a distinct angle with lateral margin. Scutellar pore puncture present, scutellar stria lacking. Elytral striae distinctly impressed and impunctate, intervals relatively flat to moderately convex, interval 2 and 3 at apex moderately convex, narrow and parallel or somewhat constricted. Interval 3 in posterior half with a setiferous pore at stria 2. Subapical sinuation moderate. Series umbelicata 6 (5+1 or 3+2- 1) - 8 (4-2+2 or 1+3-2+2). Microsculpture anterior to basal margin and on scutellum quite distinct, consisting mostly of isodiametric meshes; behind basal margin distinct and almost transverse, becoming obsolete on disc, at outer intervals 8-9 with moderately impressed faintly transverse meshes, becoming very lightly impressed and somewhat isodiametric at intervals 5-7 and almost obsolete at intervals 1-4 (in the holotype the elytral microsculpture is generally less distinct and restricted to basal area and intervals 7-9).

Ventral side without pubescence. Proepisterna with a few single shallow punctures, prosternum laterally, mesosternum and mesepisterna with some coarser punctures, metasternum and abdomen impunctate. Prosternal process with two longer setae. Metepisterna distinctly narrowed posteriad, at inner margin about 1.6 times as long as basal margin. Abdominal sternites 3-5 with the usual pair of setae, sternite 6 at apical margin with two setae at each side in females (character state of male unknown).

Legs: Female pro- and mesotarsi not dilated, without a dentiform process and adhesive hairs ventrally, except pro- and mesotarsomere 4 each with two pairs of elongated, somewhat widened and flattened seta, which probably have adhesive function. Pro- and mesotibiae with average number and size of spines at outer margins (two smaller and one larger spine in protibiae and five to six smaller to medium sized spines in mesotibiae).

Female genitalia: Shape of hemisternite and basal and apical segment of gonocoxa as figured ( Fig. 22 View Figs ). Male genitalia unknown.

C o m p a r i s o n s P. dentatus nov.sp. ( Figs 1-3 View Figs 1-3 ) can be separated easily from all other members ( Figs 4-12 View Figs 4-6 View Figs 7-9 View Figs 10-12 ) of the P. discretus group by the narrow head with small and only moderately protruding eyes (HW/PW <0.74, HW/HWbE <1.44); the deeply emarginated labral margin; the distinctly developed and projecting humeral tooth; the different shape of pronotum and weakly developed microsculpture of elytra, at least at outer intervals and behind base.

Additional characters separating the species from P. brunneus are the darker body colour; the smaller and less curved mandibles; the presence of a setiferous pore in the apical half of elytral interval 3; and the reduced size and number of spines at the outer margins of pro- and mesotibiae. From P. discretus it is distinguished additionally by the shape of the elytra, which are shorter and narrower relative to the pronotum (EL/PL <2.72, EW/PW <1.40), with dorsal surface less convex (seen in profile) and elytral intervals 2 and 3 narrowed and moderately convex at apex (instead of flat and somewhat dilated); and the antennae, which are longer relative to the elytra (AL/EL> 0.65). From P. shibatai it differs additionally by the larger size; the darker body colour; the elytra, which are longer (EL/EW> 1.56), but shorter and narrower relative to the pronotum (EL/PL <2.72, EW/PW <1.40); and the antennae, which are longer relative to the elytra (AL/EL> 0.65).

E t y m o l o g y: The Latin adjective dentatus, meaning toothed, refers to the distinct humeral tooth.

D i s t r i b u t i o n: Currently known from northwest Thailand and northeast India (Meghalaya State) ( Fig. 26 View Figs 26-27 ), where the species has been collected at 1600-2000 m and at 1100 m, respectively. Because P. dentatus is macropterous, it is obvious that it should be distributed more widely in South East Asia; at least it could be expected from Myanmar.