Pterostichus (Circinatus) yuxiaodongi, 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 : 25

Taxon classification Animalia Coleoptera Carabidae

Pterostichus (Circinatus) yuxiaodongi sp. n. Figures 23, 46, 108

Type locality.

Sichuan: Wolong, Wuyipeng (ca. N31.01°, E103.18°), altitude 2535 m.

Type material.

Holotype (IZAS): male, body length = 15.5 mm, pin mounted, genitalia dissected and glued on plastic film pinned under specimen, "CHINA, Sichuan, Wenchuan / county, Wolong nat. reserve, / Wuyipeng; 2535 m, mixed / forest; 2004.VI.29-VII.14 / YU Xiaodong lgt., HWM3-2"; "IOZ(E) 1891268"; "HOLOTYPE ♂/ Pterostichus (Circinatus) / yuxiaodongi new species / des. SHI H.L. 2015" [red label].

Diagnosis.

Pronotum with single mid-lateral seta; posterior seta distant from hind angle, hind angle completely rounded; basal foveal grooves completely fused, forming simple and deep basal fovea; elytron with faint transverse microsculpture; basal ridge strongly oblique; shoulder angle obtuse, humeral tooth short and obtuse; males with terminal sternum not modified; median lobe of aedeagal apex strongly bent to right side, apical lamella a little shorter than its basal width.

This new species is very similar to Pterostichus dentifer and Pterostichus subtilissimus . They are all relatively large sized within the subgenus, and have the aedeagal apex strongly bent to the right side. Pterostichus yuxiaodongi sp. n. differs from the latter two species by: (1) body form relatively stout, pronotum less narrowed to base (body form a little slenderer, pronotum strongly narrowed to base in the other two species); (2) pronotal basal foveal inner and outer grooves completely fused, forming simple deep fovea (basal fovea bifid anteriorly, inner and outer grooves not fused at anterior part in the other two species); (3) elytral humeral tooth less distinct than the other two species; (4) apical lamella much longer than the other two species.

Description.

Body form somewhat elongate, body length 15.5 mm; dorsal side blackish, moderately shining, elytron without iridescent shine; mouthparts, antenna, tarsus, apex of tibia dark brown; ventral side blackish. Elytral microsculpture shallow, transverse. Head. Frons without punctures; antenna reaching elytron basal sixth; gena a little shorter than length of eye, briefly tumid behind eye. Pronotum a little narrowed to base, lateral margin fairly curved in middle, almost straight before hind angle, widest at approx anterior third; posterior margin a little narrower than anterior margin; PW/PL = 1.17. One mid-lateral seta present, at greatest width. Posterior seta distant from hind angle, distance between seta and hind angle a little shorter than distance between hind angle and inner basal foveal groove; hind angle completely rounded, weakly extended backward; posterior margin slightly emarginate in middle. Basal foveal inner and outer grooves completely fused together, region between them deeply depressed, so that full basal foveal region forms a simple and deep depression; outer margin of depression approx four fifths as long as inner margin; region between pronotal lateral margin and basal fovea approx flat; basal foveal area without punctures, slightly rugose in depression. Elytron oviform, with basal ridge strongly oblique lateral-posteriorly; elytral shoulder strongly narrowed, shoulder angle between basal ridge and lateral margin forming indistinct obtuse angle, humeral tooth small and obtuse, but distinct, pointing to lateral-posterior side; intervals moderately convex; striae somewhat deep, without punctures; scutellar stria moderately long, apex conjunct to first stria; third interval with two setigerous pores adjacent to second stria; umbilical pore series on ninth interval sparse in middle, composed of 17-18 pores (6, 3, 8-9). Ventral side. Proepisternum impunctate; mesepisternum and metepisternum very sparsely punctate near anterior margin. Terminal and penultimate sterna of males not modified. Legs. Fifth tarsomeres glabrous beneath; males with apical half of mesotibia not widened, inner margin simple; first two metatarsomeres with distinct carina on outer surface, such carina absent on third metatarsomere. Male genitalia. Median lobe of male genitalia bent approx 90 degrees, apex not turned ventrally (Fig. 46A); in lateral view, ventral margin straight in middle, and then straight before apex; dorsal margin slightly curved; apical orifice large, located on dorsal side, not turned to left, not opened on ventral side; apical lamella laminate, not turn dorsally or ventrally. In dorsal view, median lobe strongly bent to right side and gradually narrowed after middle of apical orifice; apical orifice not constricted in middle; apical lamella approx quadrate, its length approx 0.8 times its basal width, pointing right-apically; apex truncate; left margin of apical lamella straight; right margin shorter and sinuate, forming an indistinct obtuse angle near apex (Fig. 46B). Right paramere straight, shorter than other species in subgenus; apical half distinctly enlarged, nearly rounded, very faintly bent to its right side; apex completely rounded; length approx 2.4 times greatest width (Fig. 46C). Endophallus (Figs 46D, E, G) without any chitinized piece; bent to dorsal-apical side of aedeagus, all parts of endophallus located on dorsal side of aedeagus; gonopore (gp, gonopore lobe folded in Fig. 46) located at level a little beyond apical lamella, pointing to aedeagal base; dense and heavy spines present on dorsal surface of endophallus close to gp. Three major lobes recognized: basal lobe (bl) large and rounded, located at level of apical lamella, on right side of endophallus; middle lobe (ml) approx same size as bl, apex finely scaled, located adjacent to dorsal face of median lobe; pre-apical lobe (pa) small, tubiform, between ml and gp, without decoration. Female genitalia unknown.

Distribution.

This species is known only from the holotype collected in Wolong, Sichuan Province (Map 2). The altitude is 2535 m.

Etymology.

The new species is dedicated to our friend, Dr Yu Xiaodong (IZAS), who conducted a series of fruitful expeditions in West Sichuan, and collected a large number of interesting Pterostichus specimens, including this new species.

Affinities.

Pterostichus yuxiaodongi sp. n. is closest to Pterostichus dentifer and Pterostichus subtilissimus . These three species are considered to form a species group within the subgenus (For morphology definition see the discussion under infra-subgeneric taxonomy).

Habitat.

The new species was collected by pitfall trap in mixed forest. Along with a very large number of Pterostichus specimens of other species, only one specimen of Pterostichus yuxiaodongi sp. n. was collected in the same batch. So this new species is presumed to be very rare at its type locality, Wolong.