Bembidion (? Nipponobembidion) ruruy, Makarov, Kirill V. & Sundukov, Yuri N., 2014

Makarov, Kirill V. & Sundukov, Yuri N., 2014, Bembidion (? Nipponobembidion) ruruy sp. n., a new brachypterous ground beetle (Coleoptera, Carabidae) from Kunashir Island, Kuriles, Russia, ZooKeys 463, pp. 75-93 : 77-82

Taxon classification Animalia Coleoptera Carabidae

Bembidion (? Nipponobembidion) ruruy sp. n. Figs 1, 2, 3, 4, 5

Holotype

♂ with labels: "Northern Kunashir, 2.5 km NW of Cape Nelyudimyi, N44°29.433', E146°11.783', 4.VIII.2013, leg. K. Makarov & Y. Sundukov" and "HOLOTYPE Bembidion (Nipponobembidion) ruruy Makarov & Sundukov 2014 [printed on red paper]".

The specimen is deposited in ZISP, the genitalia mounted on a slide in Faure-Berlese medium are pinned beneath.

Paratypes.

4 ♂, 3 ♀ from northern Kunashir, 2.5 km NW of Cape Nelyudimyi, N44°29.433', E146°11.783', 4.VIII.2013, leg. K. Makarov & Y. Sundukov; [1 ♀ - ZISP, 1 ♂, 1 ♀ - MPSU, 3 ♂, 1 ♀ - CSRL]; 1 ♂ from northern Kunashir, mouth of Dokuchaev River, N44° 30.317', E146°10.800', 30.VII.2013, leg. Y. Sundukov [CSLR].

Type locality.

RUSSIA: Kuril Archipelago: Kunashir Island, at the foot of Ruruy Volcano.

Etymology.

The species epithet is a Latinized noun in apposition to reflect the name of the volcano at the foot of which the new species was found.

Description.

Body faintly convex. Length 4.1-5.1 mm, width 1.4-2.1 mm.

Head and pronotum black, elytra black- or dark brown, entire upperside with a faint bronze or bluish lustre. Head appendages: antennae black-brown with lighter bases of antennomeres 2-4; palpi black with yellowish apical palpomeres; mandibles entirely brown or with lighter apices; labrum dark brown. Underside black or dark brown. Legs black or black-brown with lighter pro- and mesotrochantera, as well apical parts of metatarsi; all tibiae and tarsi brown (Fig. 1).

Upperside devoid of punctation, only basal pits of pronotum with a few small punctures at bottom. Dorsal microsculpture of head, including clypeus and labrum, with rough isodiametric meshes especially rough inside frontal furrows. Disc of pronotum finely microsculptured, with transverse meshes growing isodiametric and rougher like on head towards margins (Fig. 2A, B). Elytra with a very delicate, transverse microsculpture; the latter near basal elytral margin isodiametric and rougher. Head appendages and extremities with a distinct microsculpture of broad meshes. Microsculpture of pleurites and sternites isodiametric, strongly obliterated at edges of abdominal sternites.

Standard dimensions (mm): HW 0.78-0.95 (M 0.87); HL 0.58-0.74 (M 0.62); PA 0.75-0.94 (M 0.84); PW 1.03-1.30 (M 1.16); PB 0.80-0.95 (M 0.89); PL(t) 0.88-0.99 (M 0.92); PL(m) 0.83-0.95 (M 0.87); EW 1.60-2.05 (M 1.86); EL 2.38-3.05 (M 2.64); Ls 3.84-4.90 (M 4.18); L 4.10-5.10 (M 4.6).

Head not flattened, together with eyes 1.29-1.42 times as broad as long. Eyes moderately convex. Antennae long, in ♂ as long as elytra, in ♀ 0.90-0.95 their length. Mandibles small, with pointed apices. Labrum trapeziform, with six setae along fore margin. Clypeus trapeziform, with two long setae in fore angles. Tooth of mentum large, edged, broadly rounded at apex; mentum with two setae at base. Submentum with two pairs of large setae, external ones being shorter. Gula in basal 1/3 with a deep, thin, longitudinal sulcus (Fig. 2C, D). Temples short, about 1/3 as long as eye diameter. Two supra-ocular setae: one near the middle of eye, the other behind its caudal margin. Frontal furrows non-diverging, parallel, broad, groove-like, expressed from caudal eye margin nearly up to setae on clypeus. Space between frontal furrow and lateral edge of frons convex, not keel-shaped.

Pronotum (Fig. 2A, B) moderately convex, faintly cordiform, transverse (PW/PL(t) = 1.24-1.33 (M 1.29), PW/PL(m) = 1.28-1.37 (M 1.31), broader than head (PW/HW = 1.31-1.37 (M 1.34), broadest at 3/5 off base. Front margin slightly concave, its fine edging broadly interrupted in the middle. Fore angles faintly produced forward, their apices narrowly rounded. Base faintly convex, at basal pits slightly concave and vaguely edged, a little broader than fore margin (PB/PA = 1.01-1.10, M 1.06). Hind angles not produced, obtuse, slightly skewed forward, rounded at apices. Lateral sides in anterior half moderately convex and regularly rounded, in posterior half rectilinearly narrowed towards hind angles. Lateral margins narrowly edged. Two lateral setae on each side: one in front of maximal breadth, the other at caudal angle. Transverse impressions faint. Basal fovea rather large, roundly triangular, flattened and moderately rugose inside, delimited outside by a faint keel.

Elytra oblong-oval, rather large, broad (EL/EW = 1.39-1.69 (M 1.42), EL/PL(t) = 2.70-3.11 (M 2.91), EW/PW = 1.55-1.67 (M 1.59), slightly convex, broadest at 2/3 of elytral length. Shoulder not protruding, broadly rounded. Basal margin reaching apex of 4th (4 specimens) or 5th (5 specimens) stria, near shoulder arcuated and gradually turning into lateral margin. Lateral margin flattened and narrow. External apical angle broadly rounded. Striae complete, moderately deep, non-punctate, interspaces faintly convex; stria 7 either well-developed or superficial and faint in anterior half, but evident throughout; stria 8 fused to 9th about midway of series umbilicata (Fig. 3A, B). Subscutellar stria rather short, placed inside interspace 1. Subscutellar pore placed at junction of striae 1 and 2. Interval 3 with two well-expressed discal pores lying at stria 3: frontal at ca 2/5, caudal at ca 2/7, off base. Apical stria deep, cariniform, uninterrupted, fused to 5th stria, carrying two setigerous pores: one at apex, the other opposite stria 4. Series umbilicata consisting of eight setae: four in humeral group, and two each in the middle and at apex (Figure 3A, B).

Hindwings (Fig. 3E) shortened, 0.65-0.54 times as long as elytra. Among longitudinal veins only larger ones retained, basal parts of R, CuA, CuP, AA3 and AP1+2 being well-expressed while MP poorly visible. Transverse veins represented by r1 and r2, both only incompletely delimiting an rc cell (designations after Fedorenko 2009).

Legs moderately long, slender; metatarsus subequal in length to metatibia. All tibiae and meso- and metatarsomeres 1 with distinct longitudinal furrows. Meso- and metatarsomeres 3 and 4 with short dorsal keels. Claws thin, about 0.6 times as long as last tarsomere. Meso- and metafemora with 4 setae near caudal margin. Ventro-apical setae of penultimate tarsomere long, reaching beyond 2/3 of claw length.

Underside non-punctate (Fig. 1C, D). Metasternal process narrowly bordered only on sides (Fig. 3C, D). Metepisterna shortened: external margin 1.5 times as long as breadth along fore margin (1 ♂ and 1 ♀ measured). Metacoxae with three setae. Metatrochantera with one seta midway. Abdominal sternites simple, with neither pubescence nor additional setae; apical sternite at apex with two setae in ♂, four setae in ♀ (Fig. 3F, G).

Aedeagus rather slender, its ventral margin faintly curved, apex moderately broad, rounded. Central sclerite complex (CSC) of endophallus with a large brush sclerite and a rather short, S-shaped flagellum with an adjacent flagellar sheath. Right lobe of CSC poorly sclerotized, distinctly microsculptured, reaching down to basal notch of aedeagus. Left lobe small, sclerotized, devoid of a marked sculpture. Ventral sclerite patch small, lying beneath bush sclerite. Ostial microtrichial patch well-developed. Left part of endophallus with two additional structures: a short row of spinicles located level to brush sclerite and a rather long laterodistal sclerite formed by fused cuticular scales (Fig. 4A, B). Left paramere broad (Fig. 4D), with four (one long in the middle and three short) setae at apex; right paramere (Fig. 4C) narrow, with three (one long in the middle and two short) apical setae and one short subapical seta on ventral side.

Female genital apparatus as in Fig. 5. Apical segment of gonocoxite with 1-2 long, subapical, external setae and 2-3 ensiform setae in basal half of external margin (Fig. 5D). Copulatory bursa oval, without additional sclerites, about 1.5 times as long as broad. Duct of spermatheca long, fluted, terminating inside copulatory bursa ventrolaterally. Spermatheca (Fig. 5E) well-sclerotized, elongated and clearly curved, 1.5-2.0 times as broad as duct. Glandular duct long, entering inside distal part of spermatheca.

Distribution.

Kunashir Island, southern Kuriles, Russia; known only from the island’s northern part at the foot of Ruruy Volcano.

Habitats.

Much of the type series was taken inside a water-logged gravel-clay mixture and in crevices of a wet rocky cliff at the bank of a mountain stream running through a narrow mudslide-formed canyon (Fig. 6). The same places yielded abundant Bembidion (Plataphodes) tetraporum Bates, 1883, Bembidion (Ocydromus) dolorosum (Motschulsky, 1850) and Nebria (Nakanebria) shibanaii Uéno, 1955.

Comparative notes.

The shape of the head and pronotum, the elytral chaetotaxy pattern, and the complex of characters related to flight loss (shortened elytra, obliterated elytral shoulder, short metepisterna) allow for Bembidion ruruy sp. n. to be assigned to the hitherto monobasic Japanese subgenus Nipponobembidion Habu & Baba, 1968. However, the new taxon differs significantly from Bembidion ainu Habu & Baba, 1968, the type species of that subgenus, by its habitus, endophallus armament, and perhaps also its paramere chaetotaxy, the left paramere in the sole male Bembidion ainu known to date carrying only one apical seta. The following key can be proposed.