Gyrinus gibbus Aubé

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 : 61-62

Gyrinus gibbus Aubé , Gyrinus ovatus Klug and related taxa

History of classification. Dൾඃൾൺඇ (1833: 59, 1836: 66) listed in his catalogues under the generic name Gyrinus a hitherto unknown Neotropical species as ‘Ovatus. Klug. id. [= Brasilia]’. At first, this name appears to be a nomen nudum since Dejean gave no description at all. Aඎൻඣ (1838b: 708 and 709) gave the description of two species: Gyrinus ovatus and Gyrinus gibbus (both currently in the subgenus Neogyrinus Hatch, 1926 ). For the former he referred to Dൾඃൾൺඇ (1836: 66 [cited by Aubé as ‘1837: 66’]) whilst he wrote ‘Gඒඋංඇඎඌ Gංൻൻඎඌ Mihi.’ and so claiming authorship for the latter species. On January 2nd, 1839 (only about three months after the publication of Aubé’s oeuvre) an anonymous contemporary ofAubé gave a talk at the session of the Société Entomologique de France which is a critical review of Aubé’s ‘Species général’ (the talk was published in the Annales de la Société – see Aඇඈඇඒආඈඎඌ 1839). This person must have had much experience in Hydradephaga and undoubtedly access to the collection of Dejean. We even suspect that it was Dejean himself who gave this talk at the Society. On p. 88 of this review it is stated: ‘P. 708. Gyrinus ovatus . Il aurait fallu dire que le nom d’ Ovatus avait été donné par Klug.’ [= It would have been necessary to say that the name Ovatus had been [already] given by Klug.] and ‘P. 709. Gyrinus gibbus . Il aurait fallu dire que M. Dejean avait confondu cette espèce avec l’ Ovatus.’ [= It would have been necessary to say that M[onsieur] Dejean mixed up [or confused] this species with ovatus .]. To our knowledge, subsequently the contribution of this anonymous author was never paid attention to, the two names ovatus and gibbus were accepted as valid and their authorship generally attributed to Aubé (see below for two exceptions).

SIJൺඋඉ (1878: 117) introduced the species Gyrinus apicalis Sharp, 1878 and remarked at the end of his description: ‘The species is allied to Gyrinus gibbus Aubé. ’ The synonymy of G. apicalis with G. gibbus was given by RඣǤංආൻൺඋඍ (1883b: 186, 187) with the following words: ‘La description du Dr Sharp a été faite sur des exemplaires entièrement roux pâle, en dessous, variété de beaucoup la plus répandue.’ [= The description by Dr Sharp was based on specimens with entire light reddish ventral surface.]

OർIJඌ (1953: 188) described a new species from Venezuela and gave it the name Gyrinus racenisi Ochs, 1953 . He mentioned that his new species is closely related to G. ovatus Aubé , but also gave some differentiating characters. Gඎඌඍൺൿඌඈඇ & SIJඈඋඍ (2017: 493) showed in a detailed and convincing manner that the differences given by Ochs represent nothing more than ‘intraspecific variation in elytral features’ and thus G. racenisi must be treated a junior subjective synonym of G. ovatus Aubé.

About two years ago, we had noticed that already KඅඎǤ (1829: 3) described a new Gyrinus species under the specific name ovatus . Study of the syntypes of Klug’s G. ovatus – stored in the MNBG – revealed to our great surprise that these belong by no means to the same taxon as that described by Aubé as G. ovatus , but instead are conspecific with Aubé’s G. gibbus . This synonymy is also supported by the text of a label which was mounted by Ochs on one of the syntypes of G. ovatus Klug (see Fig. 4a ). With this revelation, the remarks in Aඇඈඇඒආඈඎඌ (1839: 88) also became much more plausible.

Finally, it was only recently that we became aware of the fact that Aඎൻඣ (1838b: 708) had by no means the intention to describe a new species G. ovatus , but instead attributed the taxon he described to Dൾඃൾൺඇ (1836: 66; see remark above). In turn, Dejean attributed the species ‘Ovatus.’ to ‘ Klug. id. [= Brasilia]’ thus, relating to Klug’s description from the year 1829. It may appear quite astonishing, but we must state that a name ‘ Gyrinus ovatus Aubé’ has never been availably published. Misguided by mixed up specimens in Dejean’s collection and being unaware of Klug’s description Aubé gave nothing else than a description of a species which he believed to be meant in Dejean’s catalogue (1836: 66). Whenever necessary, this name should be given as Gyrinus ovatus Klug sensu Aඎൻඣ (1838b).

Additionally, we want to add the following annotations:

– The name Gyrinus gibbus Aubé is included in SIJൾඋൻඈඋඇ’s ‘Index animalium’ (1926: 2688) as well as the name Gyrinus ovatus Klug (SIJൾඋൻඈඋඇ 1929: 4653). However, the name ‘ Gyrinus ovatus Aubé’ is missing in Sherborn’s index. Thus, most likely Sherborn was already aware that Aubé was not the author of the name Gyrinus ovatus , but instead Klug.

– Klug’s name was used in a very few works. Except those mentioned above, we know only of Sඍඎඋආ (1843: 33) and a modern PhD-thesis for which, however, we have no evidence that it was availably published (Gඬආൾඓ Lඎඍඓ 2014: 39; undoubtedly, the author didn’t know about the synonymy with G. gibbus because he had not studied the syntypes of Klug’s species). Most interestingly, KඅඎǤ (1850: 14) himself used the name G. ovatus with author Aubé, possibly due to respect of the authority of Aubé or because he became aware of WIJංඍൾ (1847: 46) who was the first to cite G. ovatus with author Aubé.

Results. The discovery of the name G. ovatus Klug and the finding that the name ovatus Aubé is only a sensu -name lead to the following results:

(1) The name Gyrinus racenisi Ochs, 1953 is the only available name for the species which thus far was known under the name G. ovatus Aubé and must be applied further on.

(2) The name Gyrinus ovatus Klug, 1829 must be used instead of its junior subjective synonym Gyrinus gibbus Aubé, 1838 syn. nov. Article 23.9 of the ICZN cannot be applied to give gibbus precedence over ovatus Klug because we found only 18 works published during the last 50 years in which Aubé’s name was used as valid name.

Although the literature on G. racenisi (also under the name G. ovatus Aubé ) and G. ovatus Klug (under the name G. gibbus ) is not especially sparse, we are aware of only two publications in which characteristic features are figured. Vංൽൺඅ Sൺඋආංൾඇඍඈ (1959: 239, fig. 21) illustrated the aedeagus of Gyrinus ovatus Klug sensu Aubé ; however, the quality of this figure is rather poor and may fit both that of Klug’s ovatus and G. racenisi as well. However, Gඎඌඍൺൿඌඈඇ & SIJඈඋඍ (2017) provided drawings of the male and female genitalia as well as excellent photos of the habitus of both species, which help to make reliable identifications.

Since the specimens studied by Gඎඌඍൺൿඌඈඇ & SIJඈඋඍ (2017) belong to non-typical material, we believe it important to here give information regarding the type material placed at our disposal. In particular, we provide photos of the habitus as well as that of male and female genitalia.

Considering the huge distribution areas of G. ovatus Klug , it cannot be excluded that its current definition includes more than one species (see the Discussion section under G. gibbus in Gඎඌඍൺൿඌඈඇ & SIJඈඋඍ 2017: 489). This is why we here designate a lectotype not only for this taxon, but also for its junior subjective synonyms G. gibbus and G. apicalis .

Figures

Figs 4–6: Habitus of Gyrinus lectotypes. 4 – Gyrinus ovatus Klug, 1829; 5 – Gyrinus apicalis Sharp, 1878; 6 – Gyrinus gibbus Aubé, 1838. 4a–6a – respective labels.