Acrolocha caucasica Tóth, 1976

Shavrin, Alexey V. & Khachikov, Eduard A., 2019, On some species of the genus Acrolocha Thomson, 1858 of the Western Palaearctic Region (Coleoptera: Staphylinidae: Omaliinae: Omaliini), Zootaxa 4576 (2), pp. 347-356 : 349-352

Acrolocha caucasica Tóth, 1976

( Figs. 2 , 9 ¯19)

Acrolocha caucasica Tóth, 1976a: 85

Type material examined. Holotype of Acrolocha caucasica Tóth, 1976 ♂ [The specimen glued on the paper card; abdomen is separated from the forebody and glued by its ventral side under the forebody, apical abdominal segment glued under abdomen; abdominal tergite VIII and sternite VIII are missing; a plastic card with a new preparation of aedeagus in Canadian balsam was pinned under the old plastic card]: ‘Kaukasus | Leder’ <small rectangular label, handwritten>, ‘ Acrolocha [handwritten] | sulculus Steph. [handwritten] | Coll. Reitter’ <rectangular label, printed>, ‘ ♂ ’ <small rectangualr label, printed>, ‘ Holotypus [printed in red] | Acrolocha [handwritten in black] | caucasica Tóth [handwritten in black]’ <rectangular label with red frame, printed>, ‘ Acrolocha | caucasica Toth, 1976 | Shavrin A.V. det. 2018’ <rectangular label, printed> (HNHM).

Allotype of Acrolocha caucasica Tóth, 1976 ♀: same data as the holotype except labels ‘ ♀ ’ <small rectangular label, printed>, ‘ Allotypus [printed in red] | Acrolocha [handwritten in black] | caucasica Tóth [handwritten in black]’ <rectangular label with red frame, printed> (HNHM). Paratypes of Acrolocha caucasica Tóth, 1976 3 ♂♂ [All specimens are glued on paper cards: 1) abdomen of one male is separated from the forebody and glued under it; apical part of the abdomen is glued at the right side of the abdomen; a plastic long and thin card with a preparation of the aedeagus is pinned under the card with beetle; 2) abdomen of 2 nd male separated from the body and glued under the forebody; left antennomeres 3̄11, right foreleg, left middle leg and hind legs are missing; a plastic long and thin card with a preparation of the aedeagus is pinned under the card with beetle; 3) third male is dismembered into three parts and glued on the same card one after another: forebody, meso- and metathoracic sclerites and abdomen; left antennomeres 3̄11 and right antennomeres 9̄11 are missing; a plastic card with a new preparation of aedeagus in Canadian balsam was pinned under the old plastic card]: same data as the holotype except label ‘ Paratypus [printed in red] | Acrolocha [handwritten in black] | caucasica Tóth [handwritten in black]’ <rectangular label with red frame, printed> (HNHM); 4 females [one female is dismembered into two parts and glued on the same card one after another: forebody and meso- and metathoracic sclerites, right antennomeres 3¯11, left metatibia and metatatarsus, and abdomen are missing; one female without left antennomeres 3̄11]: same data as the allotype except label ‘ Paratypus [printed in red] | Acrolocha [handwritten in black] | caucasica Tóth [handwritten in black]’ <rectangular label with red frame, printed> (HNHM).

Additional material. RUSSIA: KARACHAY- CHERKESSIA: 3 ♂♂, 6 ♀: Upper reaches of Dukka River, Dukka Path. 17.07.1996. E.A. Khachikov (CK); 3 ♀♀: environs of Nizhnyaya Teberda , bank of Azchel River near glacial lake. 2600-2700 m a.s.l. 0 1.08.2007. A.S. Prosvirov ( CS) ; ABKHAZIA: 1 ♂, 3 ♀♀: SE slope of Abac Mt. 2070 m a.s.l. 0 7.08.2010. A.S. Prosvirov ( CS) .

Redescription. Measurements (n=29, in mm): maximum width of head including eyes: 0.45–0.50; length of head (from base of labrum to neck constriction): 0.26–0.32; length of antennae (holotype): 0.44; length of eyes: 0.12̄0.15; length of pronotum: 0.33–0.41; maximum width of pronotum: 0.57–0.66; sutural length of elytra (length of elytra from apex of scutellum to posterior margin of sutural angle): 0.71–0.78; maximum width of elytra: 0.68–0.83; width of abdominal segment IV: 0.67̄0.84; length of aedeagus: 0.32̄0.36; total length of body (from base of labrum to apex of abdomen): 1.98–2.40 (holotype: 2.00). Habitus as in Fig. 2 .

Head castaneous brown to yellow-brown, usually with darker basal portion; antennomeres 6̄11 (or 7̄11), pronotum and abdomen reddish-brown to brown (sometimes entire body brown to dark-brown); antennnomeres 1̄5 (or 1̄6) and apical abdominal tergites yellow-brown to brown; legs yellow. Punctation of head usually invisible due very strong microsculpture, sometimes sparse and moderately deep in middle, denser and smaller in posterolateral portions; punctation of pronotum relatively regular, dense and small, sometimes with moderately wide impunctate logitudinal area along midline; scutellum without visible punctures; median part of elytra with very small indistinct to distinct punctures arranged in six to seven longitudinal rows between coarse microsculpture; abdomen without visible punctures. Forebody shiny; head with very coarse, wide and coriaceous microsculpture, stronger and larger in middle portion, smaller, more or less diagonal in posterolateral area and betweeen ocelli; neck with irregular moderately wide microsculpture as that in surface between ocelli; pronotum with coarse irregular microsculpture as that in head, sometimes narrower and more transverse along midline and/or denser in lateral portions; scutellum with distinct isodiametric meshes; microsculpture of elytra distinct, but less deeper than that in pronotum, coarser between punctures in middle and sometimes in lateroapical potion, small and shallow in apical portion; abdominal tergites with distinct cellular small microsculpture, sometimes coarser and larger on abdominal tergite VII.

Head 1.5¯1.7 times as broad as long, with shallow occipital line and evenly convex frons and vertex, with slightly convex infraorbital ridges separated from vertex by very narrow and sometimes indistinct grooves in front ocelli, usually reaching level of midlength of eyes. Eyes large, widely convex; postocular parts with very smooth almost indistinct postocular carina, strongly narrowed posteriad. Ocelli moderately large, distance between ocelli about as long as distance between ocellus and posterior margin of eye or slightly longer. Maxillary palpi with apical palpomere about three times as long as penultimate, gradually narrowing from middle toward moderately acute apex. Antennae short, reaching posterior margin of pronotum when turned backwards; apical five antennomeres with strong pubescence; antennomeres with lengths × widths (paratype, male): I: 0.11 × 0.05; II: 0.03 × 0.02; III: 0.02 × 0.02; IV: 0.02 × 0.02; V̄VI: 0.02 × 0.03; VII: 0.03 × 0.04; VIII: 0.03 × 0.05; IX̄X: 0.04 × 0.05; XI: 0.08 × 0.05.

Pronotum markedly convex, transverse, 1.6¯1.7 times as broad as long, 1.2¯1.3 times as wide as head, widest in middle, gradually rounded anteriad and distinctly narrowing toward posterior angles; middle part of anterior margin somewhat straight, slightly concaved or rounded; surface of disc of pronotum moderately evenly convex, without or with indistinct moderately wide longitudinal impressions.

Elytra about as broad as long and about twice longer than pronotum, parallel-sided almost in all length and sometimes indistinctly widened in anterior half; hind margin of elytra straight to rounded, truncate toward suture.

Metatrochanter evenly rounded apically, without projection. Apical metatarsomere about as long as four preceding tarsomeres.

Abdomen slightly narrower, wider or about as wide as elytra, with two small suboval wing-folding patches (tomentose spots) on abdominal tergite IV and distinct narrow palisade fringe on apical margin of abdominal tergite VII.

Male. First four protarsomeres markedly widened. Apical margin of abdominal tergite VIII ( Fig. 9 ) straight. Apical margin of abdominal sternite VIII ( Fig. 10 ) rounded apically. Genital segment as in Fig. 11 . Aedeagus (Fig. 15¯19) usually short, broad and oval, with moderately long median lobe gradually narrowing toward small rounded apex, located between pair of elongate widely curved processes with rounded or truncated apical portions, not reaching apex of median lobe; parameres moderately short and wide, reaching or slightly exceeding apex of median lobe, with slightly narrowed apex bearing two long apical and two moderately short lateroapical setae; apex of aedeagus with pair of lateral moderately wide auriculate processes slightly exceeding apices of parameres; endophallus large and complicated (Figs. 18¯19). Aedeagus laterally as in Fig. 19.

Female. First four protarsomeres not widened. Apical margins of abdominal tergite VIII ( Fig. 12 ) and sternite VIII ( Fig. 13 ) rounded apically. Accessory sclerite wide and elongate, rounded apically; genital segment as in Fig. 14 .

Comparative notes. Based on the shape of moderately convex head, strong microsculpture of the elytra, shapes of metatrochanter and male abdominal sternite VIII lacking projections, as well as on the presence of lateroapical auriculate processes on the apical part of the aedeagus, A. caucasica is similar to Eastern Palaearctic A. zhongdianensis Shavrin & Smetana, 2016 ( China: Yunnan), A. wahuiense Zhong, Zhao & Li, 2009 ( China: Sichuan) and A. miyamorii Watanabe, 1990 ( Japan) , from which it differs by the narrower and darker body with coarser microsculpture of the forebody, more transverse antennomeres 7¯10 and pronotum with less distinct or lacking longitudinal impressions, slightly shorter elytra, and details of the morphology of the aedeagus.

For illustrations of compared species see Shavrin & Smetana (2016), Watanabe (1990) and Zhong et al. (2009).

Remarks. Acrolocha caucasica was described by Tóth (1976a) based on nine specimens without providing exact localities, collected by Hans Leder at the end of 19th century in the Caucasus (see the Material section). Unfortunately, the aedeagi of the three type specimens have apparently become unstuck from very thin, transparent and flexible original plates, which were made by Tóth using presumably Euparal. These aedeagi were found by the curator of the Museum on the bottom of the box with type specimens and were reglued by him on transparent plates, with the result that the origin of them may be confused between holotype and paratypes (Gy. Makranczy, pers. comm.). Three aedeagi from the type series are figured in the present study (Figs. 15¯17), of which the aedeagus in Fig. 17 was figured by Tóth (1976a). The aedeagus of one “ paratype ”, not figured in the present study, is similar in shape to that of aedeagus in Fig. 16. Apparently, all aedeagi were overdeveloped in KOH and after that, most of them were deformed (Figs. 16¯17) and their internal structures partly destroyed, and for this reason the internal sac for them were not figured. The aedeagus provided by Tóth (1976a) is one of the most deformed aedeagi: internal sac located partly outside apex of the aedeagus, shapes of apical curved processes significantly changed and elevated above parameral surface of the aedeagus, apical margins of these processes took the shape of semicircular emarginations (Fig. 17 and Fig. 1 in Tóth 1976a). Indeed, the aedeagus of A. caucasica has wide oval shape as in Figs. 15, 18. The internal sac is shown based on fresh preparation of the aedeagus from Karachay- Cherkessia (Figs. 18-19). An insignificant variability of aedeagi was observed in the shape of its apical part, length of the median lobe and degree of the curvature of auriculate and curved apical processes.

It was cited as “ A. caucasica Gusarov. sp.nova [sic!]” from Karacahay-Cherkessia by Khachikov (1998). The species is known from several localities of Caucasus.

Figures

FIGURES 1–3. Habitus of Acrolocha: 1—A. amabilis (Heer, 1841) (Crimea), 2—A. caucasica Tóth, 1976 (Karachay- Cherkessia), 3—A. pliginskii Bernhauer, 1912 (Rostov Area). Scale bar: 1.0 mm.

FIGURES 9–14. Abdominal segments of Acrolocha caucasica Tóth, 1976: 9—male tergite VIII, 10—male sternite VIII, 11— male genital segment, 12—female tergite VIII, 13—female sternite VIII, 14—female genital segment and accessory sclerite. Scale bar: 0.1 mm.