Pterostichus (Circinatus) tumulus, 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 : 19-22

Taxon classification Animalia Coleoptera Carabidae

Pterostichus (Circinatus) tumulus sp. n. Figures 20, 32, 55, 83, 105, 125

Type locality.

Guizhou: Fanjingshan Mt. (ca. N27.90°, E108.70°), altitude 1780 m.

Type material.

Holotype (IZAS): male, body length 13.7 mm, pin mounted, genitalia dissected and glued on plastic film pinned under specimen, "CHINA, Guizhou / Fanjing Shan, / 1780 m, 2001.8.1"; "Liang H.B. leg. / Institute of Zoology / Chinese Acad. Sci."; "HOLOTYPE ♂/ Pterostichus (Circinatus) / tumulus new species / des. SHI H.L. 2015" [red label]. Paratype, a total of 1 female: 1 female (IZAS): "CHINA, Guizhou, Jiangkou, / Fanjing Mt. S. Slope, 4500-/ 5300 steps, 1778-1973 m / N27.90180, E108.70372 -/ N27.90784, E108.70052 "; "2012.VIII.25 night, on tree / trunk, broadleaf forest, SHI / Hongliang, HUANG Xinlei, / LIU Yizhou leg. IOZ, CAS / 梵净山4500–5300步”.

Diagnosis.

Pronotum with single mid-lateral seta; posterior seta distant from hind angle; pronotum strongly narrowed to base, hind angle forming obtuse angle, lateral margin slightly sinuate before hind angle; elytral microsculpture distinct, approx isodiametric; males with one elongate large tubercle on terminal sternum; fifth tarsomeres glabrous beneath.

The sp. n. differs from other species of Circinatus in having the pronotal hind angle not completely rounded, forming an obtuse angle, except for four species ( Pterostichus baenningeri , Pterostichus maitreya sp. n., Pterostichus ailaoicus sp. n. and Pterostichus wangjiani sp. n.), which also have the hind angle more or less obtuse. But Pterostichus tumulus sp. n. can be easily distinguished from latter four species by: (1) pronotal posterior seta distant from hind angle (very close to hind angle in latter four species); (2) elytral microsculpture distinct, almost isodiametric (very faint and linear in latter four species except for Pterostichus wangjiani sp. n.); (3) males with one large tubercle on terminal sternum (different characters in latter four species).

In Fanjingshan Mt., Pterostichus tumulus sp. n. is sympatric with and almost the same size as Pterostichus maitreya sp. n., but they can be easily separated by characters listed above.

Description.

Body form a little elongate, body length = 13.7-13.8 mm; dorsal side blackish, moderately shining, elytron without iridescent shine; mouthparts, antenna, tarsus, apex of tibia dark brown; ventral side blackish. Elytral microsculpture distinct, isodiametric or slightly transverse. Head. Frons without punctures; antenna reaching elytron basal eighth; gena shorter than length of eye, briefly tumid behind eye. Pronotum strongly narrowed to base, lateral margin curved in middle, slightly sinuate before hind angle, widest at approx anterior third; posterior margin much narrower than anterior margin; PW/PL = 1.17-1.18. One mid-lateral seta present, located at greatest width; posterior seta distant from hind angle, distance between seta and hind angle approx equal to distance between hind angle and inner basal foveal groove; hind angle distinct, forming obtuse angle; lateral margin slightly elevated near hind angle. Basal fovea moderately deep but not well defined; inner groove subparallel to median line, almost straight near posterior margin; outer groove faint but present, shallowly engraved near hind angle, approx one third length of inner one; outer area of inner groove deeply depressed; basal foveal area without punctures. Elytron oviform, with basal ridge almost straight; elytral shoulder a little widened, shoulder angle between basal ridge and lateral margin forming indistinct obtuse angle, humeral tooth small but present; intervals feebly convex; striae moderately deep, without punctures; scutellar stria long, apex free; third interval with two setigerous pores adjacent to second stria; umbilical pore series on ninth interval sparse in middle, composed of 16-17 pores (6, 1, 9-10). Ventral side. Proepisternum almost impunctate, very sparsely punctate near posterior margin; mesepisternum and metepisternum densely and finely punctate. Male terminal sternum with an elongate tubercle on middle, tubercle apex rounded and impunctate; tubercle gradually turned into a short ridge at approx apical two fifths of sternum; ridge not reaching apex of sternum, region after it with fine longitudinal wrinkles (Fig. 125). Legs. Fifth tarsomeres glabrous beneath; males with apical half of mesotibia slightly widened, inner margin crenulate; first metatarsomere with distinct carina on outer surface, such carina on basal half of second metatarsomere superficial. Male genitalia. Median lobe of male genitalia bent approx 90 degrees, apex abruptly bent ventrally (Fig. 32A); ventral margin straight in middle, then sinuate; dorsal margin gradually curved; apical orifice large, slightly turned to left side, opened on ventral side; in lateral view, apical lamella laminate with base slightly thickened, distinctly sinuate and turned dorsally, its length approx one sixth length of apical orifice; in dorsal view, apical lamella on right side of aedeagal apex, pointing apically, slightly oriented to left side; apical lamella short, roundish, widened to apex, apex rounded, its base grooved on dorsal surface; length of apical lamella approx 1.2 times its basal width (Fig. 32B). Right paramere straight and narrow, nearly digitiform, apical half only slightly enlarged and then gradually narrowed to apex, apex narrowly rounded; length approx 3.7 times greatest width (Fig. 32C). Endophallus not studied. Female genitalia. Spermatheca (Fig. 55) with seminal canal approx two times as long as receptaculum; receptaculum clavate, gradually expanded to apex; seminal canal inserted at base of common oviduct, base of seminal canal strongly sclerotized. Stylomere II with two ensiform setae near middle of outer margin, and a smaller one near middle of inner margin; two short nematiform setae located in a furrow near apex. Female sternum VIII (Fig. 83B) short and wide, approx evenly chitinized, without denser pigmentation; posterior margin with sparse fine setae, notched in middle; anterior margin deeply notched in middle; middle transparent region wide and V-shaped, adjacent to anterior notch in middle. Female tergum VIII (Fig. 83A) with major portion well chitinized, with irregular fine spots, a narrow region along posterior margin less chitinized; anterior margin weakly notched in middle, posterior margin slightly arcuate.

Distribution.

This species is known only from Fanjingshan Mt. in Guizhou Province (Map 1). The altitude range is approx 1778-1973 m.

Etymology.

The scientific name comes from a Latin noun “tumulus”, which means small hill, referring the male of new species with a tubercle on terminal sternum.

Affinities.

In Pterostichus tumulus sp. n., the aedeagus is very similar to Pterostichus baenningeri , and the new species is assumed to be close to this and related species (listed in Table 1). These species all have the small apical lamella located on the right side of the median lobe apex and grooved on the dorsal surface. However, Pterostichus tumulus sp. n. differs from the other species because of the position of posterior pronotal seta, elytral microsculpture, male terminal sternum character, and shape of the receptaculum. These characters suggest an intermediate position for Pterostichus tumulus between Pterostichus baenningeri and some species from northern Yunnan, such as Pterostichus dimorphus sp. n.

Habitat.

Pterostichus tumulus sp. n. was collected together with Pterostichus maitreya sp. n. from mid-high altitude mixed forest in Fanjingshan Mountain, but seems rarer.