Gyrinus australis Fabricius, 1775

Fery, Hans & Hájek, Jiří, 2021, Nomenclatural and taxonomic notes on some species of Gyrinidae (Coleoptera), Acta Entomologica Musei Nationalis Pragae 61 (1), pp. 55-71 : 56

Gyrinus australis Fabricius [ Dineutus ] and Gyrinus australis Brullé [ Macrogyrus ]

History of classification. Bඋඎඅඅඣ (1835: 231) in his Histoire naturelle des insectes expressly treated the genus Gyrinus Geoffroy, 1762 as being composed of six subgenera ( Gyrinus s. str.; Enhydrus Laporte, 1835 [not 1834]; Orectochilus Dejean, 1833 ; Porrorhynchus Laporte, 1835, Dineutes [= Dineutus Macleay, 1825 ] and Gyretes Brullé, 1835 ). However, in the species diagnoses following this statement, the author omitted the generic name and gave all species names only as binomina with the subgeneric name, e.g. ʻEnhydrus australis . Br. ʼ on p. 237. This somewhat contradicting approach was, however, either overlooked or neglected by subsequent authors, who considered these subgeneric names as generic names, and thus assumed different original combinations for the newly described species: Enhydrus australis instead of Gyrinus (Enhydrus) australis Brullé, 1835 , and Gyretes aeneus instead of Gyrinus (Gyretes) aeneus Brullé, 1835 (see Aඎൻඣ 1838b: 653, 751).

However, we believe that the fact that Brullé used binomina in the species descriptions has no impact on the actual combination of the taxa; it is noteworthy, that Bඋඎඅඅඣ (1837: 52) still considered his Gyretes as a subgenus of Gyrinus . See a similar case in Dytiscidae (Zංආආൾඋආൺඇඇ 1921) and its solution (Hගඃൾκ 2012, Nංඅඌඌඈඇ & Hගඃൾκ 2020).

Homonymy. Gyrinus australis Brullé, 1835: 237 (currently in Macrogyrus Régimbart, 1883 a [not 1882]) is a junior primary homonym of G. australis Fabricius, 1775: 235 (currently in Dineutus ), and thus Brullé’s name is permanently invalid. At present both taxa are treated as different valid species. The fact that Bඋඎඅඅඣ (1835) published his species in the subgenus Enhydrus is irrelevant (see Article 57.4 of the ICZN).

Macrogyrus canaliculatus Régimbart, 1883 a: 450 is a junior subjective synonym which could substitute Brullé’s homonym. However, since Aඎൻඣ (1838b: 785) treated Fabricius’ species already in the genus Dineutus , and RඣǤංආ- ൻൺඋඍ (1892: 670, 741) treated Brullé’s species in the genus Macrogyrus – thus both long before the year 1900 – the specific name must not be replaced. According to Article 23.9.5 of the ICZN, this case must be ‘… referred to the Commission for a ruling under its plenary power’ and we propose conservation of the junior homonym.

Gyrinus australis Brullé [ Macrogyrus ] and Andogyrus