Circinatus Sciaky, 1996

Fedorenko, D. N., 2019, New species of Pterostichus subgenus Circinatus (Coleoptera: Carabidae: Pterostichini) from Vietnam, Russian Entomological Journal 28 (4), pp. 358-369 : 358-363

Circinatus Sciaky, 1996

Type species: Pterostichus pohnerti Jedlička, 1934 .

DIAGNOSIS. A subgenus of Pterostichus with the following characters: Body apterous, medium-sized for the genus, more or less shiny black, underside distinctly iridescent, often elytra and sometimes also pronotum slightly less so. Head medium-sized, bisetose above eye; terminal palpomeres subfusiform; frontal foveae rather shallow, short and impunctate; mandibles rather narrow and slightly incurved at apices. Pronotum mostly suborbiculate to ovate, with sides and basal angles rounded, and only inner, impunctate, basal fovea in form of a longitudinal, moderately deep to shallow,

How to cite this article: Fedorenko D.N. 2019. New species of Pterostichus subgenus Circinatus ( Coleoptera : impressed line; disc convex inside rather fine lateral bead. Elytra oblong-oval, with base narrow, humeri widely to completely rounded, humeral angle obtuse, and basal ridge entire; fully striate; intervals subequally wide, with 1–2 discal setae (d2 or d2+d3) in stria 2, parascutellar seta present. Body setation otherwise as for many other Pterostichus : metacoxa bisetose laterally (inner seta missing), metatrochanter with seta, metafemur bisetose; tarsomere 5 mostly glabrous ventrally. Legs slender; meso- and metatarsomeres with outer carinae mostly conspicuous. Prosternal process not beaded, with a fairly thick posterior inclination. Abdominal sternite VII either smooth in sexes or slightly modified in male. Aedeagus with right paramere small.

REDESCRIPTION. Unnecessary, but for species from Vietnam.

Body ( Figs 1–7 ) medium-sized, shiny black. Tibiae, tarsi and antennae red to reddish-brown, antennae becoming slightly paler apicad. Dorsal microsculpture very superficial, isodiametric on head; transverse on pronotum and elytra, consisting of small, moderately wide meshes to dense lines on the former, and of dense transverse lines or very narrow meshes on the latter.

Head fairly small, without neck constriction; eyes medium-sized and moderately convex, genae rather short. Frontal foveae impunctate, shallow and short, parallel just behind clypeus, thence diverging toward and not quite reaching anterior supra-ocular setae. Antennae moderately long, long- er in male, reaching or slightly surpassing elytral base by apical 2.5 segments; antennomeres 4–11 pubescent, scape with dorsal seta, pedicel with ventral seta, antennomere 3 with no setae other than verticellate ones.

Mandibles moderately long, narrow and nearly straight, scrobe medially with a short longitudinal sulcus (missing in P. caobang sp.n.). Mentum bisetose at base of a more or less bifid median tooth. Submentum subcostate, quadrisetose, with outer setae much shorter than inner ones. Terminal labial palpomere subfusiform, penultimate labial palpomere bisetose.

Pronotum suborbiculate to cordiform, with basal angles mostly very obtuse and rather widely rounded; base distinctly narrower than apex in general; sides neither explanate nor reflexed, with fine lateral bead extended slightly inside base; apical bead entire to widely obliterate at middle. Disc moderately convex, medial line fine, obliterate basally; basal and apical transverse impressions indistinct or the former barely traceable. Out of two basal sulci, mostly inner sulcus only present, running as a fairly long, moderately deep, and impunctate line; sometimes outer sulcus traceable or basal foveae sparsely punctate. Lateral setae 1–2, with posterolateral seta inserted in basal angle or much in front, or missing.

Elytra elliptic to subovate, with no humeri, sides round- ed, and preapical sinuation subtle. Base long (i. e., wide between basal margin and basal ridge) and narrow or very so; a distinct or missing lateral bead (fine ridge) running inside a small to missing humeral tooth; basal ridge straight to convex apicad, humeral angle obtuse. Internal preapical plica welldeveloped. Striae deep impunctate or indistinctly crenulate,

6

1st merged in 8th at sutural angle, 2nd and 7th adjoining 8th just before, 3rd and 4th, as well as 5th and 6th, merged pairwise preapically into a short striole that disappears abruptly. Intervals more or less convex. Reflexed lateral margin narrow; neither additional interval nor carina present outside stria 9. Parascutellar striole entire and deep or missing. Parascutellar seta present, interval 3 with two setae (d2+d3) adjoining stria 2 or with d2 only. Stria 7 with two preapical

8

10

12

14

setae. Interval 9 with 15–19 umbilical setae (USS) arranged into anterior group (mostly including six setae in basal fourth), and posterior group (mostly nine setae in apical half), with 1– 2 intermediate setae.

Underside entirely smooth or mesepisternum anterolaterally, metepisternum, and abdominal sternites II and III moderately to sparsely punctate. Prosternum with a shallow to distinct medial groove running on basal two thirds; intercoxal process not beaded, with apical declivity medially constricted and costate to flat. Mesoventrite behind peduncle nearly flat, with a very fine to indistinct median carina and a small precoxal ridge on each side. Metepisternum short, about as long as wide. Abdomen finely beaded on sides.

Legs fairly slender and lightly armed with spiniform setae. Protibiae barely dilated apicad, with two posterolateral apical spinules and one posterior apical spinule. Metatrochanter rounded apically, nearly half as long as metafemur. Meso- and metatarsomeres 1–3 with a sharp outer (anterior) longitudinal carina and a distinct sulcus just above, or only meso- and metatarsomere 1 with this carina blunt and the sulcus vestigial to missing. Leg setation: profemur posteriorly with three setae, basal, ventromedial, and preapical. Mesofemur with two subequally spaced anteroventral setae and two anterodorsal setae in apical two fifths; mesotibia bisetose laterally, distal seta inserted close to anterior ridge. Metacoxa bisetose (inner seta missing), metatrochanteral seta vestigial or missing; metafemur with two anteroventral (posterior) setae in general, distal seta vestigial to missing; metatibia glabrous laterally. Tarsomeres 1–4 each with one pair of latero-apical setae, tarsomeres 1–2 each with one pair of dorso-apical setae; tarsomere 5 glabrous ventrally.

Aedeagus median lobe ( Figs 8–15 , 31–36 ) strongly curved distal to basal bulb; right paramere short, subclavate to subtriangular ( Figs 21–30 ). Everted and inflated internal sac bent either ventrad or dorsad.

Female genitalia and reproductive tract. Gonosubcoxite with a few setae along oblique apical margin. Gonocoxite shorter, falcate with a double nematiform seta near apex and three ensiform setae, two ventral (outer) and one dorsal (inner). Spermatheca geniculate, seminal canal short to long, barely sclerotized at base; receptaculum long subcylindric, barely dilated apicad and annulated just apically, or short and clavate, with apex much broader than base.

16 17

Secondary sexual differences. In male, abdominal sternite VII not or barely modified, with two setae inserted at a considerable distance from apical margin and often also with apical bead vestigial to obliterate opposite preapical elytral plica or except basally (vs. with four setae close to entire apical bead in female); protarsomeres 1–3 dilated and biserially squamose on ventral side; meso- and metatibia barely wider, with 4–5 smooth tubercles traceable along posteromesal ridge.

DISTRIBUTION. The subgenus has been known [ Shi, Liang, 2015] to be widespread in more southern Chinese provinces Sichuan, Yunnan, Chongqing, Guangxi, Hubei, and Guizhou. Discovery of several new species in Vietnam extends the subgenus range southward to at least Vietnamese provinces Lao Cai and Cao Bang .

HABITS AND HABITATS. The members of the genus are closely associated with dead, often not quite fallen, trees in rainforests. Adults of most species were hand collected under rotten tree trunks and their fragments on the ground or under bark at 1600–2100 m altitudes, with some specimens being taken by pitfall trapping.

In a particular locality, at least two of 2–3 sympatric species were found to live syntopically: P. caobang sp.n. and P. phiaoc sp.n. in Mt. Phia Oac, P. laocaiensis sp.n. and P. phangxipang sp.n. in Mt. Phang Xi Pang, P. batxatensis sp.n. and P. hoanglien sp.n. in the Bat Xat National Park.

COMMENTS. The species from Vietnam match Circinatus groundplan well, except for some features as follows: the body being rather slender in general, the pronotum more slender, and only one discal elytral seta present. Some leg setae, i.e., metatrochanteral seta and distal metafemoral seta, as well as lateral tarsal sulcus in couple with lateral tarsal carina, tend to be reduced. As a result, the setae are usually vestigial or missing, and the tarsal carinae are imperceptible in some species. Besides, all the species from Vietnam share a distinctive internal sac (endophallus groundplan) as follows: when everted and inflated the sac is spiral and directed either apicad

18 19 20

or dorsad. But P. phiaoc sp.n. has the internal sac bent ventrad. This character, combined with two discal elytral setae and a quadrisetose pronotum, brings P. phiaoc sp.n. closer to the baenningeri species group, whereas the consubgeners from Vietnam belong to a separate species group/lineage.

Four species are here recorded either in central ( P. laocaiensis sp.n. and P. phangxipang sp.n.) or northwestern part ( P. batxatensis sp.n. and P. hoanglien sp.n.) of the Hoang Lien mountain ridge, and the sympatric species have been found to live syntopically. Of them, P. laocaiensis sp.n. is closer to P. batxatensis sp.n. while P. phangxipang sp.n. to P. hoanglien sp.n., which relationships are supported by two characters, the body being slightly larger (vs. smaller) and the posterolateral pronotal seta missing (vs. present) in the former two and the latter two species, respectively. Unfortunately, there are no available data on distribution patterns of the species discussed to understand whether they interact along the Hoang Lien mountain ridge or not.

Figures

Figs 1–3. Dorsal habitus: 1 — Pterostichus phiaoc sp.n., female paratype; 2 — P. caobang sp.n., holotype; 3 — P. expolitus sp.n., holotype. Рис. 1–3. Габитус дорЗально: 1 — Pterostichus phiaoc sp.n., паратип самка; 2 — P. caobang sp.n., голотип; 3 — P. expolitus sp.n., голотип.

Figs 4–7. Dorsal habitus: 4 — Pterostichus phangxipang sp.n., female paratype; 5 — P. hoanglien sp.n., female paratype; 6 — Pterostichus batxatensis sp.n., holotype; 7 — P. laocaiensis sp.n., male paratype. Рис. 4–7. Габитус дорЗально: 4 — Pterostichus phangxipang sp.n., паратип самка; 5 — P. hoanglien sp.n., паратип самка; 6 — Pterostichus batxatensis sp.n., голотип; 7 — P. laocaiensis sp.n., паратип самец.

Figs 8–15. Median lobe of aedeagus: 8–9 — Pterostichus phangxipang sp.n.; 10–11 — P. hoanglien sp.n.; 12–13 — P. batxatensis sp.n.; 14–15 — P. laocaiensis sp.n.; 8, 10, 12, 14 — left view; 9, 11, 13, 15 — right view. Scale bars: 1 mm. Рис. 8–15. СреднЯЯ долЯ Эдеагуса: 8–9 — Pterostichus phangxipang sp.n.; 10–11 — P. hoanglien sp.n.; 12–13 — P. batxatensis sp.n.; 14–15 — P. laocaiensis sp.n.; 8, 10, 12, 14 — слева; 9, 11, 13, 15 — справа. Масштаб: 1 мм.

Figs 31–36. Everted and inflated internal sac of aedeagus: 31–33 — Pterostichus phiaoc sp.n.; 34–36 — P. batxatensis sp.n.; 31, 34 — left view; 32, 35 — dorsal view; 33, 36 — right view. Scale bar: 1 mm. Рис. 31–36. Вывернутый и надутый внутренний мешок Эдеагуса: 31–33 — Pterostichus phiaoc sp.n.; 34–36 — P. batxatensis sp.n.; 31, 34 — слева; 32, 35 — дорЗально; 33, 36 — справа. Масштаб: 1 мм.

Figs 21–30. Right paramere: 21–22 — Pterostichus phangxipang sp.n.; 23–24 — P. batxatensis sp.n.; 25 — P. phiaoc sp.n.; 26–27 — P. laocaiensis sp.n.; 28–30 — P. hoanglien sp.n.; 21, 23, 25, 26, 28–29 — left view; 22, 24, 27, 30 — ventral view. Scale bar: 1 mm. Рис. 21–30. ПраваЯ парамера: 21–22 — Pterostichus phangxipang sp.n.; 23–24 — P. batxatensis sp.n.; 25 — P. phiaoc sp.n.; 26– 27 — P. laocaiensis sp.n.; 28–30 — P. hoanglien sp.n.; 21, 23, 25, 26, 28–29 — слева; 22, 24, 27, 30 — вентрально. Масштаб: 1 мм.