Cercyon (Clinocercyon) retius, Ryndevich & Prokin, 2017

Ryndevich, Sergey K. & Prokin, Alexander A., 2017, Two new species of Cercyon (Clinocercyon) from Russian Far East (Coleoptera: Hydrophilidae), Zootaxa 4300 (1), pp. 125-134 : 126-129

Cercyon (Clinocercyon) retius sp. nov.

( Figs. 1–13 )

Type locality: Russia, Far East , Kunashir Island, mouth of the Medny stream.

Type material: Holotype: male, o. Kunashir , ust'e ruch. Medny [Kunashir island, mouth of the Medny stream, 43°16'41''N 145°56'29''E, 3.VII.2008, leg. Makarov [in Russian], ( ZISP) . Paratypes (27): 1 female, Rossiya , o. Kunashir , ust’e ruch. Medny [ Russia, Kunashir Island, mouth of Medny stream], 3.07.2008, ekskrementy [excrements], leg. Makarov [in Russian] ( ZISP) ; 1 female, o. Kunashir , okr. Mendeleevo [Kunashir Island, near Mendeleevo], 30.VI.1985, leg. Nikitskiy [in Russian] ( ZMMU) ; 1 female, YuZ Kunashir , kord. Alekhinskiy [South-West Kunashir Island, kordon Alekhinskiy], 1.VIII.2011, leg. S.A. Kurbatov [in Russian] (CSK) ; 1 male, 1 female, Kunashir , kordon Filatovskiy , dol. r. Filatova [ Kunashir Island , valley of river Filatova near kordon Filatovskiy] alt. ~ 24 m, 44°11'38''N 146°01'11''E, 7–10.X.2009, leg. A. Prosvirov [in Russian], ( MPU, CSR) ; 3 males, 3 females, Kunashir , sopki k Yu. ot ozera Peschanoe [ Kunashir Island , sugarloafs South of lake Peschanoe], 43°53’15’’N 145°37'33''E, 43°54'55''N 145°35'01''E, 8.VII.2008, leg. Makarov [in Russian] ( MPU, NMPC, CSR) ; 1 spec., о. [island] Кunashir , sopki Yu. Z. ot ozera Peschanoe [sugarloafs South-West of lake Peschanoe ], 43°55'13'' 145°34'32''E 2.VIII.2011 leg. К. Маkarov, А.Zaitsev [in Russian ], (САР); 1 spec., Кunashir , nizhnee tech. ruch. [lower reaches of stream] Dalniy 44°28'52''N 146°05'42''E 9.VIII.2013, leg. К. Маkarov, Yu. Sundukov, [in Russian ], (САР); 1 spec., о. [island] Кunashir , Yu bereg m. [South coast of cape] Vodopadnyy 43°54'39''N 145°39'31''E, presn. boloto [freshwater swamp], 22.VIII.2011, leg. К. Маkarov, [in Russian], ( ZISP) ; 1 spec., о. [island] Кunashir , sopki Yu. Z. ot ozera Peschanoe [sugarloafs South-West of lake Peschanoe], 43°55'13'' 145°34'32''E, 21.VIII.2011, А.Zaitsev [in Russian], ( ZISP) ; 1 spec., о. [island] Кunashir , okr. [near] Tret’yakovo, dol. ruch. [valley of stream] Valentyny, 43°59'05''N 145°39'29''E 10.VIII.2011 leg. К. Маkarov, [in Russian], ( ZISP) ; 1 female, Rossiya [ Russia], Kunashir, mys [cape] Ivanovskiy, 18– 21.09.2014, leg. Yu. Sundukov [in Russian], ( CSR) ; 1 female, Rossiya , o. Kunashir , nizhnee techenie r. Saratovka [ Russia, Kunashir Island, lower reaches of river Saratovka], 14– 15.07.2014, leg. Yu. Sundukov, L. Sundukova [in Russian], ( CSR) ; 2 males, 4 females, same data but 12– 18.07.2014, [in Russian], ( MPU, CSR) ; 1 female, Rossiya , o. Kunashir [ Russia, Kunashir Island], okr. [near] cordon Saratovskiy, 2–4.07.2014, leg. Yu. Sundukov, L. Sundukova [in Russian], ( NMPC) ; 1 male, 1 female. Yu. Primor’e , Lazovskiy zapovednik, okr. kordona Korpad' [ South Primorye , Lazovsky State Nature Reserve, near Korpad' kordon], 45°15'21''N 134°08'07''E, 15.VII.2005, v pomete barsuka [in excrement of the common badger], leg. K. Makarov [in Russian] ( MPU, CSR) .

Differential diagnosis. Body broadly oval. Dorsal side without microsculpture. General colour of body from brownish-yellow to brownish. Head black with brownish spot in middle of base. Centre of pronotum darkened (brown or blackish) ( Figs. 1, 2 ). Maxillary palpomeres yellow or brownish-yellow, palpomere 4 almost symmetrical, almost equal to palpomere 3 in length ( Figs. 1, 4 ). Preepisternal plate very elongate, ca. 6.0–7.8 × as long as wide, metaventrite without femoral lines ( Fig. 4 ). Hind femora with distinct microsculpture (as horizontal cells) ( Fig. 5 ), front and middle femora with rudimentary microsculpture. Median projection of sternite 9 very narrow with big membranous part, apex with 2 very short setae, paramere strongly broadened at apex, inner edge subapically with very short setae. Median lobe with parallel sides, strongly narrowing apically, apex slightly rounded and curved ( Figs. 6–13 ).

Description. Form and Colour. Body broadly oval ( Figs. 1, 2, 4 ), length 2.2–2.7 mm, width 1.4–1.9 mm (holotype length 2.4, width 1.7). General colour of body brownish-yellow. Head black with brownish spot in middle of base. Centre of pronotum darkened (brown or blackish) from 0.3 to 0.6 of pronotum width. Antennae yellowish except for brownish-yellow club. Epipleura brownish-yellow. Ventral surface yellowish brown, carina of prosternum, metaventrite, metaventral pentagon, preepisternal plate and abdominal ventrites darker, brown. Legs yellowish-brown, tarsi paler ( Fig. 4 ). Head. Dorsal side without microsculpture, with dense moderately coarse punctures. Anterior margin of clypeus narrowly rimmed. Eyes small, somewhat protruding, interocular distance ca. 5.9–6.3× as wide as one eye in dorsal view ( Fig. 1 ). Mentum glabrous, ca. 1.7–1.8× as wide as long, densely and coarsely punctate, slightly depressed anteromedially Antennae with 9 antennomeres, scapus ca. 1.2× as long as antennomeres 2–5 combined, club compact. Maxillary palpomere 2 strongly swollen, palpomere 4 almost symmetrical, almost equal to palpomere 3 in length ( Fig. 1, 4 ). Thorax. Pronotum ca. 2.8× as wide as long. Pronotal punctation similar to that on head. Lateral margins of pronotum narrowly rimmed, the rim overlapping anterior and posterior corners, anterior and posterior margin without rim. Prosternum with strong longitudinal carina medially; antennal groove distinct, fairly large, rounded laterally ( Fig. 4 ). Preepisternal plate very elongate, ca. 6.0–7.8× as long as wide, widest in anterior part near middle or in middle ( Fig. 4 ). Metaventrite with raised glabrous, clear sparse punctate median pentagonal area; femoral lines absent. Elytra with 10 punctate striae, striae 1–6 very slightly impressed, striae 1–6, 7 and 10 reaching base, striae 8 and 9 not reaching base. Elytral intervals flat. Ground punctures on intervals very fine ( Figs. 1–3 ). Humeral bulge not distinct. Elytra and pronotum without hairs. Epipleura of elytra wedge-shaped, bent downwards ( Fig. 4 ). Femora with sparse and shallow punctures ventrally and distinct tibial groove. Hind femora with distinct microsculpture (as horizontal cells) ( Fig. 5 ), front and middle femora with rudimentary microsculpture. Tarsi with densely arranged white setae ventrally, first metatarsomere about as long as metatarsomeres 2–3 combined. Abdomen. Abdomen with five exposed ventrites, first ventrite distinctly longer than the other ventrites, ca. 1.6× as long as second, with distinct median longitudinal carina, fifth ventrite arcuate, not emarginate apically ( Fig. 4 ). Male genitalia ( Figs. 6–13 ). Median projection of sternite 9 very narrow with large membranous part, apex with 2 very short setae, median portion shorter than lateral struts ( Figs. 9, 13 ). Phallobase slightly longer than parameres, asymmetrical basally. Parameres strongly broadened at apex, inner edge subapically with very short setae ( Figs. 6–10 ). Apex of parameres membranous ( Fig. 11 ). Median lobe with parallel sides, strongly narrowing apically, with short ароdemes ( Figs. 7, 12 ), apex slightly rounded and curved; gonopore small, situated subapically. ( Fig. 8 )

Variation. Some specimens have a slightly dark spot near lateral margins of elytra ( Figs. 2–3 ).

Etymology. The name reflects the reticulate surface sculpture of femora, derived from Latin: rete – network (masculine).

Biology. Apparently C. retius sp. nov. is a coprobiontic species, because it was found in the excrement of the common badger (Meles meles (Linnaeus, 1758)) and other excrements (without specifying the species of animal on the label).

Distribution. Russian Far East (Kunashir Island and continental Far East of Russia: Lazovsky State Nature Reserve).

Figures

FIGURES 1 – 5. Habitus and metafemora of Cercyon retius sp. nov. 1, 2: dorsal view; 3: lateral view; 4: ventral view; 5: metafemora.

FIGURES 6 – 13. Male genitalia of Cercyon retius sp. nov. 6,10: phalobase and parameres; 11: apex of paramere; 7,12: median lobe; 8. apex of median lobe; 9,13: sternite 9. Scale bar = 0.5 mm.