Pterostichus (Circinatus) adelphus, Shi, Hongliang & Liang, Hongbin, 2015

Shi, Hongliang & Liang, Hongbin, 2015, The genus Pterostichus in China II: the subgenus Circinatus Sciaky, a species revision and phylogeny (Carabidae, Pterostichini), ZooKeys 536, pp. 1-92 : 8

Taxon classification Animalia Coleoptera Carabidae

Pterostichus (Circinatus) adelphus sp. n. Figures 4, 34, 53, 71, 90, 135

Type locality.

Sichuan: Meigu County, Dafengding national reserve, Hongxi station (N28.65850° E103.06123°), altitude 2541 m.

Type material.

Holotype (IZAS): male, body length = 11.1 mm, pin mounted, genitalia dissected and glued on plastic film pinned under specimen, "CHINA, Sichuan Prov., Meigu / county, Dafengding nat. res., / Hongxi station, mixed forest; / N28.65850 E103.06123 "; "2541 m, 2012.VI.13 day, under dead / log; SHI Hongliang & YANG / Ganyan lgt. Inst. Zool., CAS / 美姑县大风顶洪溪保护站”; "HOLOTYPE ♂/ Pterostichus (Circinatus) / adelphus new species / des. SHI H.L. 2015" [red label]. Paratypes, a total of 3 males, 1 female: 3 males, 1 female (IZAS): "CHINA, Sichuan Prov., Yizi pass btw. Meigu county and Ebian county, mixed forest; N28.67477 E103.05248, 2923 m; 2012.VI.15; by pit fall trap; SHI Hongliang & LIU Ye leg.".

Diagnosis.

Pronotum with three or four mid-lateral setae; hind angle completely rounded; basal fovea almost impunctate; pronotum wide and round; elytral microsculpture linear; males with terminal sternum not modified; apical lamella located on middle of aedeagal apex, length approx same as basal width. This new species has the widest apical lamella among the species of the agilis -group.

This new species is sympatric with and very similar to Pterostichus cavazzutianus s. str. Besides the significant differences in male genitalia (apical lamella shape and endophallus, Figs 34, 35), the two species also differ in: (1) Pterostichus adelphus sp. n. with wider and rounder pronotum, body slightly stouter than Pterostichus cavazzutianus s. str.; (2) basal fovea almost impunctate in Pterostichus adelphus sp. n. but distinctly punctate in Pterostichus cavazzutianus s. str.; (3) elytral lateral expansion much wider in Pterostichus adelphus sp. n.; (4) male terminal sternum not modified in Pterostichus adelphus sp. n., but shallowly depressed in Pterostichus cavazzutianus s. str.

Description.

Body form relatively stout, body length 9.9-11.1 mm; dorsal side black, shining; elytron with faint iridescent shine; mouthparts, antenna and tarsus yellowish brown; ventral side almost black. Both sexes with similar elytral microsculpture, very faint and linear. Head. Frons without punctures; antenna reaching elytron basal fifth; gena approx same length as eye, briefly tumid behind eye. Pronotum round, widest before middle, PW/PL = 1.21-1.32; usually four (sometimes three) mid-lateral setae present, first one close to anterior angle, last one near middle of lateral margin, a little distant from other three; posterior seta far distant from hind angle, distance between seta and hind angle approx same as distance between hind angle and inner basal foveal groove; hind angle completely rounded; basal fovea shallow, faintly defined; inner groove subparallel to median line, slightly curved outwards; outer groove completely vanished, outer area of inner groove flat; basal foveal area usually impunctate, sometimes with very sparse punctures on inner area of inner groove. Elytron oviform, basal ridge slightly oblique; elytral shoulder slightly narrowed, basal ridge and lateral margin forming obtuse angle, humeral tooth indistinct; intervals feebly convex; striae moderately deep, without punctures; scutellar stria short but complete; third interval with two setigerous pores adjacent to second stria; umbilical pore series on ninth interval sparse in middle, composed of 15-16 pores (6, 1, 8-9). Ventral side. Proepisternum impunctate or slightly punctate near posterior margin; mesepisternum densely punctate; metepisternum impunctate; terminal or penultimate sternum of males not modified. Legs. Fifth tarsomeres glabrous beneath; males with apical half of mesotibia slightly widened, inner margin slightly crenulate; first metatarsomere with distinct carina on outer surface, such carina on second and third metatarsomeres superficial. Male genitalia. Median lobe of aedeagus bent approx 90 degrees, apex slightly bent ventrally (Fig. 34A); ventral margin straight in middle, dorsal margin gradually curved; apical orifice large, slightly turned to left side, not opened on ventral side; apical lamella short, approx one fourth length of apical orifice, laminate, not thickened; in dorsal view, apical lamella located at middle of aedeagal apex, approx triangular with rounded apex, wide and short, length approx equal to basal width (Fig. 34B). Right paramere straight and slender, length approx 3.5 times greatest width, apex rounded (Fig. 34C). Endophallus (Fig. 34D, E, F) short, bent to ventral side, across apical lamella, and then turned to aedeagal base; gonopore (gp) located at approx same level as apical lamella. Six distinct lobes recognized: ventral-basal lobe I (vb-I) very small, close to base of apical lamella, membranous with its upper surface scaled; ventral-basal lobe II (vb-II) large and strongly chitinized, arcuate, strongly pointed, its upper surface with a membranous structure connected with vb-III; ventral-basal lobe III (vb-III) small, rounded with apex pointed, located on left side of vb-II, evenly decorated with very fine scales; ventral-apical lobe (va) short and wide, almost covered by vb-II, heavily pigmented, decorated with coarse scales, located on right side of vb-II; pre-apical lobe (pa) narrow and long, tubiform, without decoration, located on right lateral side; right lobe (rl) large, much thicker and a little longer than pa in ventral view, apex truncate, evenly decorated with fine scales. Female genitalia. Spermatheca (Fig. 53) with seminal canal approx three times as long as receptaculum; receptaculum capitate, club approx half length of receptaculum; spermathecal gland slightly expanded; seminal canal inserted at base of common oviduct, base of seminal canal sclerotized. Stylomere II with two ensiform setae at outer margin and one at middle of inner margin, two very short nematiform setae located in furrow near the apex. Female sternum VIII (Fig. 71B) with dense and fine spines on posterior margin; posterior margin rounded, shallowly notched in middle; posterior region chitinized, anterior region semi-chitinized, middle transparent region V-shaped, not adjacent to posterior notch in middle. Female tergum VIII (Fig. 71A) with anterior third well chitinized, posterior two thirds semi-chitinized and pigmented with dense spots.

Distribution.

This species was known only from the border between Meigu and Ebian counties (Sichuan, Liangshan Yi Autonomous Prefecture). The two collecting localities are approx 2 km apart. (Map 2)

Etymology.

The name adelphus derives from the Greek epithet “adelph” which means brother, referring to the similarity of this new species to a sympatric species Pterostichus cavazzutianus .

Affinities.

This new species seems to be close to Pterostichus cavazzutianus in their similarities in the elytral microsculpture and short apical lamella of aedeagus.

Habitat.

This species was collected in mixed forest with dominant large pines, and rich in dead logs. Most specimens were collected by pitfall trap, and also one was found under or in dead logs. In Yizi pass, Pterostichus adelphus sp. n. was found together with other three Circinatus species ( Pterostichus bullatus , Pterostichus cavazzutianus s. str., Pterostichus zhygealu sp. n.), but seems rarer than other species. This locality has the richest diversity of the subgenus Circinatus .

Variation.

Two paratypes have three setigerous pores on one or both elytra.