Pterostichus (Feroperis) silvestris Sun & Shi

Sun, Xiaojie, Shi, Hongliang, Sang, Weiguo & Axmacher, Jan Christoph, 2018, Two new species of Feroperis Lafer (Carabidae, Pterostichus) from China, with a key to all known Chinese species in this subgenus, ZooKeys 799, pp. 95-114 : 95

Pterostichus (Feroperis) silvestris Sun & Shi sp. n. Figs 1-3, 4-6

Type locality.

CHINA: Heilongjiang Province, Hailin County, Taipinggou Forest Farm (44°24.6168'N, 128°24.5570'E), altitude 985 m.

Type materials.

Holotype (IZAS): male, body length 12.9 mm, board mounted, genitalia dissected and glued on plastic film pinned under specimen, "China, Heilongjiang / Taipinggou Forest Farm / Zhangguangcai Mountain"; "Pitfall trap, 985 m, 2016.VI.08 / 44°24.6168'N, 128°24.5570'E / Diekman, MZUC"; "HOLOTYPE ♂ / Pterostichus (Feroperis) / silvestris sp. n. / des. SUN & SHI 2018" [red label]. Paratypes (a total of 1643 specimens [906 males and 737 females], all in IZAS): 247 males and 132 females, the same data as holotype, but labeled as paratype. 126 males and 227 females, "China, Heilongjiang / Taipinggou Forest Farm / Zhangguangcai Mountain"; "Pitfall trap, 985 m, 2016.VI.21 / 44°24.6168'N, 128°24.5570'E / Sun Xiaojie, MZUC"; "PARATYPE / Pterostichus (Feroperis) / silvestris sp. n. / des. SUN & SHI 2018" [red label]. 284 males and 160 females, "China, Heilongjiang / Taipinggou Forest Farm / Zhangguangcai Mountain"; "Pitfall trap, 985 m, 2016.VII.05 / 44° 24.6168'N, 128°24.5570'E / Sun Xiaojie, MZUC"; "PARATYPE / Pterostichus (Feroperis) / silvestris sp. n. / des. SUN & SHI 2018" [red label]. 192 males and 156 females, "China, Heilongjiang / Taipinggou Forest Farm / Zhangguangcai Mountain"; "Pitfall trap, 985 m, 2016.VIII.03 / 44°24.6168'N, 128°24.5570'E / Sun Xiaojie, MZUC"; "PARATYPE / Pterostichus (Feroperis) / silvestris sp. n. / des. SUN & SHI 2018" [red label]. 57 males and 62 females, "China, Heilongjiang / Taipinggou Forest Farm / Zhangguangcai Mountain"; "Pitfall trap, 985 m, 2016.VIII.31 / 44°24.6168'N, 128°24.5570'E / Sun Xiaojie, MZUC"; "PARATYPE / Pterostichus (Feroperis) / silvestris sp. n. / des. SUN & SHI 2018" [red label].

Diagnosis.

This new species can be distinguished from all other species of the subgenus by the combination of following characters: (1) lateral margins of pronotum evenly convex at about anterior two thirds, then gradually contracted and almost straight before posterior angles; (2) pronotum posterior angles weakly protruding, forming indistinct denticles, lateral border not widened at posterior angles, its width subequal to the lateral border of pronotum; (3) apical lamella of the aedeagus as long as 1.5 times its basal width; apex capitate in dorsal view, widened at both left and right margins, but only slightly thickened in lateral view; apical lamella distinctly oblique to the right in dorsal view, with ventral margin slightly twisted dorsally in lateral view (Fig. 2A).

The new species is special in the subgenus for its male genitalia with apical lamella capitate, both margins widened near apex in dorsal view, and not strongly thickened in lateral view. These aedeagal characters can distinguish it from most species of Feroperis except for the five species P. chechcirensis Lafer, 1979, P. vladivostokensis Lafer, 1979, P. rasilis Park & Kwon, 1996, P. seungmoi Park & Kwon, 1996, and P. pawlowskii Lafer, 2011. Among them, P. chechcirensis can be readily distinguished by its pronotal posterior angles being obtuse, without any trace of denticle; P. vladivostokensis and P. rasilis are different in their pronotal posterior angles being strongly pointed, forming very large denticles. From the remaining two species, P. seungmoi can be easily identified by its characters that widest of pronotal lateral channels at about 1/3 length to the posterior margin, so P. silvestris is considered to be closer to P. pawlowskii (North Korea: Nampotesan, 41°44'N, 128°24'E), based on their more similar external characteristics and close areas of distributions.

Considering P. pawlowskii , the new species is distinguishable from it by the presence of micro-punctures on vertex and by the pronotal disc with very fine punctures rather than reticular traces. Furthermore, these two species can be also distinguished by: (1) the pronotum widest at about basal 2/3 in P. pawlowskii , vs widest at about 3/5 in P. silvestris ; (2) in P. silvestris , the pronotum less constricted to the base; (3) in P. pawlowskii , the apical lamella of aedeagus shorter, its length reaching as long as 1.2 times the basal width, apex almost straight or very weakly bent to the left in dorsal view; while in P. silvestris , the apical lamella of the aedeagus is distinctly longer, its length about 1.5 times the basal width, apex distinctly bent to the right in dorsal view.

Description.

Body length 12.8-14.9 mm (mean ± SD: 13.8 ± 0.65, n = 20), both sexes with similar body shape. Dorsal surface black and shiny; tarsi and antennae dark brown; head and pronotum without microsculpture; elytra with very fine and isodiametric microsculpture. Head mostly smooth, polished, with very fine and sparse punctures on vertex and occiput; eyes moderately convex; antennae reaching the base of pronotum. Pronotum wider than the head (PW/HW =1.11-1.52, mean ± SD: 1.44 ± 0.09, n = 20); rounded in shape, widest at about 3/5 length to the posterior margin (PW/PLt = 1.11-1.38, mean ± SD: 1.27 ± 0.07, n = 20; PW/PLm = 1.22-1.52, mean ± SD: 1.40 ± 0.07, n = 20); lateral margins evenly convex from apex to about basal 1/3, then gradually contracted and almost straight before the posterior angles (PW/PA = 1.27-1.47, mean ± SD: 1.37 ± 0.05, n = 20; PW/PB = 1.23-1.43, mean ± SD: 1.32 ± 0.05, n = 20); apical width of pronotum nearly same as its basal width (PB/PA = 0.94-1.14, mean ± SD: 1.04 ± 0.05, n = 20). Anterior angles obtuse and rounded, distinctly contracted inward; lateral channels narrow in front of midpoint and gradually expanded towards the base, with flatten and sparse punctures on them. Posterior angles obtuse, weakly protruding and forming weak denticles of angle exceeding to 100° (147.4°-166.8°, mean ± SD: 155.1° ± 5.10°, n = 18, Fig. 7 A–B); pronotal lateral border not widened at posterior angles, width similar or less wide as lateral border of the pronotum anterior to the posterior angles; carinae between lateral margins and pronotal basal foveae strong, parallel to the fine median line. Basal foveae moderately deep, clearly defined throughout except at the basal area, outer basal foveal groove long and deep, reaching the posterior margin of the pronotum, inner basal foveal groove short and weakly incised, not reaching the posterior margin of the pronotum; basal foveae slightly rugose and sparsely punctate; disc moderately convex and smooth, only very finely and sparsely punctate. Elytra oviform (EL/EW = 1.35-1.56, mean ± SD: 1.43 ± 0.05, n = 20; EL/PLt = 2.03-2.31, mean ± SD: 2.21 ± 0.08, n = 20; EW/PW = 1.17-1.29, mean ± SD: 1.22 ± 0.03, n = 20), widest near the middle; elytral base slightly depressed in the middle; striae deeply impressed, with fine and sparse punctures; parascutellar striae long, apex free, short or connected with first stria; parascutellar pore present on the base of first stria. Third interval generally with 3-6 setigerous pores, situated mostly closer to the second stria (location and number of discal pores variable in some individuals: additional pores occasionally present at the first, second, third and fifth intervals, same specimen may has different discal pore placement on left and right elytron); umbilicate series of pores on the ninth interval, each side composed of 16-20 pores, sparser in the middle, denser anteriorly and posteriorly. Hind wings reduce as leathery wing bud. Ventral side: pro- and mesoepisternum sparsely punctate and shallowly rugose; metepisternum with coarse punctures; abdominal sterna glabrous in the middle, with shallow wrinkles laterally; sterna IV and V with sparse coarse punctures and shallow rugosity laterally. Legs long and slender; first meso- and metatarsomeres with distinct carina on the outer surface, these occur also near the base of the second tarsomeres; fifth tarsomeres with 2-4 pairs of setae on ventral surface. Male genitalia: median lobe of aedeagus bent more than 90 degrees at basal 2/5 (Fig. 2C); in lateral view, ventral margin straight in the middle, apical portion not bent to the ventral side; apical orifice slightly turned to the left; apical lamella long and strongly oblique to the right, length about 1.5 times as it basal width; apex strongly widened in dorsal view, widened with similar angles at both left and right margins (Fig. 2A); apex slightly thickened in lateral view. Right paramere very long and strongly bent, gradually narrowed to apex, apical portion thick, apex sharp (Fig. 2B). Endophallus (Fig. 3) extending from the dorsal-left side of aedeagus to ventral side, major parts of endophallus located on the ventral side of the aedeagus, basal portion strongly swollen to the dorsal direction; gonopore (gp) located near the basal-ventral direction of the aedeagus, pointing towards the aedeagal base. Six distinct recognizable lobes: left lateral lobe (ll) compressed, forming a widening triangular shape towards the base of gp when viewed dorsally, surface with fine scales; left ventral lobe (lv) divided into two separate sub-lobes; lv-1 trochoid, apex positioned towards aedeagal base, base adjacent to rb; lv-2 very small, situated at about half the height of lv-1; right ventral lobe (rv) composed of two sub-lobes: rv-1 small and compressed, on the base of left-ventral surface of endophallus, close to the aedeagal apex, surface with fine scales; rv-2 large and oblate, between the base of gp and rv-1, surface with fine scales; dorsal lobe (dl) very large and strongly bulging, apex coniform and pointing to the ventral direction. Female genitalia: spermatheca with the seminal canal as long as about six times the length of the receptaculum; receptaculum tubiform, with round apex; spermathecal gland very long; the seminal canal inserted at the base of the common oviduct, base of the seminal canal sclerotized (Fig. 5). Stylomere 1 (Fig. 4) with thick setae ventro-apically, stylomere 2 with two ensiform setae at the outer margin and with one ensiform seta at the upper middle part of its inner-ventral margin. Tergum VIII (Fig. 5A) with major portion chitinized, two small semi-chitinized patches with dense spots on each side; anterior margin with a wide, U-shaped notch in middle. Sternum VIII (Fig. 5B) with sparse setae on posterior margin; posterior margin curved, deeply notched in the center; posterior region chitinized, anterior region semi-chitinized, with a V-shaped transparent region on the center, adjacent to the central posterior notch.

Distribution.

This species is known only from the type locality, Taipinggou Forest Farm, Zhangguangcai Mountain in Heilongjiang Province of China.

Etymology.

The name " silvestris " derives from the Latin adjective “silvestris”, which means "pertaining to a forest or wood", as well as "living in forest". This species is named for its distinct habitat, with all individuals collected in natural forest types such as mixed secondary forest and mature forest habitats.