Bembidion (Euperyphus) dimidiatum Menetries , 1832

Neri, Paolo & Toledano, Luca, 2021, Geographic and taxonomic notes, addenda and corrigenda on the subtribe Bembidiina Stephens, 1827 of the 2017 ' Catalogue of Palaearctic Coleoptera' (Coleoptera, Carabidae, Bembidiina), ZooKeys 1044, pp. 563-587 : 563

Bembidion (Euperyphus) dimidiatum Menetries, 1832 comb. nov.

Bembidion (incertae sedis) Bembidion dimidiatum Mènètriès, 1832

Notes.

Mènètriès (1832) describes Bembidion (Peryphus) dimidiatum from the banks of “Potkoumà” near “Pétigorsk” on "quelques individus". After the description, B. dimidiatum was retained as strictly related to B. oblongum Dejean, 1831 or B. ripicola Dufour, 1820 (currently all species belonging to the subgenus Bembidion Euperyphus Jeannel, 1941). Netolitzky (1914a) synonymized B. dimidiatum with B. tricolor (Fabricius, 1801) (= B. varicolor (Fabricius, 1803); the synonymy derives from the fact that the author examined Caucasian specimens identified as B. dimidiatum actually belonging to B. (Bembidionetolitzkya) varicolor and was perhaps unaware that this last species also occurs in the Caucasus and shares the same particular pattern of color of the European Bembidion varicolor . But later (1935) the author himself retained B. dimidiatum as closely related to Bembidion oblongum , and in any case not similar to B. conforme Dejean, 1831 or B. tricolor (both belonging to subgenus Bembidion Bembidionetolitzkya Strand, 1929). Netolitzky (1943a: 112/84, note 83) reported that B. dimidiatum belongs to the "Gruppe des B. ripicola - Bembidion oblongum " and retained it as close to B. testaceum parallelipenne Chaudoir, 1850; moreover, Netolitzky (1943b: 17/113, note 18) mentioned that, if they were synonyms, B. dimidiatum should have priority over B. parallelipenne ; he did not formally state in any way this synonymy. Later, Kryzhanovskij et al. (1995) and Lorenz (1998) listed B. dimidiatum as a synonym of B. parallelipenne but expressed doubts. Marggi et al. (2003: 271) completely changed direction, moving Bembidion dimidiatum to "incertae sedis", explaining the decision as follows: " Bembidion (Peryphus) parallelipenne ? syn. Bembidion dimidiatum Ménétriés, 1832, resurrected as Bembidion (incertae sedis) Bembidion dimidiatum Ménétriés, 1832. It is not a member of Actedium , as given in Lorenz, 1998" ( Marggi et al. 2003: 21).

The same settlement is confirmed by Lorenz (2005) and Marggi et al. (2017). Unfortunately, the sentence of Marggi et al. (2003) above and in particular the reference to Actedium probably caused the moving of B. dimidiatum to "incertae sedis", and are unclear; we verified that in Lorenz (1998) neither B. parallelipenne , nor B. dimidiatum are reported as belonging to the subgenus Bembidion Actedium . From the literature we ascertained that B. dimidiatum certainly belongs to the subgenus Bembidion Euperyphus (as currently intended, see above); there still remains uncertainty regarding its precise position, with three ( B. parallelipenne parallelipenne , B. parallelipenne exisonum Lutshnik, 1938, B. parallelipenne pseudoripicola Iablokoff-Khnzorian, 1963) taxa currently assigned to the same group. In our opinion it seems unlikely that all the three Caucasian forms could be valid, and it would be necessary to verify them; in any case we suppose that the subspecies more similar to B. dimidiatum , mainly due to the elytral coloration, could be B. pseudoripicola ; in case of possible synonymies the problem of priority already reported by Netolitzky (1943b: 17/113, note 18) mentioned above should be considered. However B. dimidiatum must be included in the subgenus Bembidion Euperyphus as currently intended.