Paraplagusia blochii, Bleeker, 1851

Kottelat, Maurice, 2013, Nomenclature And Identity Of The Tongue Soles Paraplagusia Bilineata, “ Cynoglossus Bilineatus ” And Paraplagusia Blochii (Teleostei: Pleuronectiformes), Raffles Bulletin of Zoology 61 (2), pp. 763-766 : 765

PARAPLAGUSIA BLOCHII

The fish referred to as Paraplagusia blochii is usually considered to be a species described by Bleeker (1851a: 21; repeated in 1851b: 411). In fact, Bleeker did not describe a new species, but, instead, had only proposed a new replacement name for the Pleur. bilineatus of Bloch (1787). Bleeker’s redescription of the species (as Plagusia blochii ) ends with an explicit reference to Bloch (1787: pl. 188). Likewise, in the introduction (1851a: 5, 1851b: 402), Bleeker explained that there was confusion among authors about the characters of Plag. bilineata , that most authors referred under this name to a species with two lateral lines on the blind side, and that the real Plag. bilineata has only one. He described the species with two lateral lines on the blind side as Plag. quadrilineata and he replaced the name of Bloch’s Plag. bilineata by Plag. blochii , in order to avoid confusion with Plag. bilineata as had been confused by earlier authors.

Bleeker’s (1851a: 5) text reads as follow: “Regarding Plagusia bilineata Cuv. there is still confusion among authors in the report of its characters. Apart from Pleuronectes bilineatus Bl. and Jerree potoo E. of Russell, in which species the lateral line is double on the left side but single on the right side, authors understand as Plagusia bilineata also a species with a double lateral line on the right side, and this species, very different from Plagusia bilineata , is probably the one already named Plagusia quadrilineata by Kuhl and Van Hasselt and which is described below. For this reason I propose to abandon the name Plagusia bilineata , while for the species that I consider the same as Pleuronectes bilineatus Bl., I have chosen the name of that ichthyologist”.

Plagusia quadrilineata is a Cynoglossus , as discussed above. Bleeker’s reference to Cuvier is a footnote in Cuvier (1829: 344): “ Pl [agusia] bilineatus, Bl. 188, ou Jerré potoo, E., Russel, 74 [ Russell, 1803]”. In the Atlas ichthyologique, Bleeker (1870: 27) listed Plag. blochii in the synonymy of Paraplagusia bilineata .

Since Plag. blochii is a new replacement name, it takes the same type as Pleur. bilineatus and is an objective junior synonym. Therefore, the ‘lectotype’ of Plag. blochii (RMNH 17879) designated by Menon (1980: 16) has no type status.

Authors usually treated Par. blochii as the valid name of a species distinct from Par. bilineata (e.g., Menon, 1980; Chapleau & Renaud, 1993; Munroe, 2001). As Plag. blochii is a replacement name for Par. bilineata , it cannot be used for this second species, which is without a name. I name it here Paraplagusia bleekeri , new species; a description of the species can be found in Menon (1980: 16, as Par. blochi ), and a diagnosis in the keys of Munroe (2001) and Chapleau & Renaud (1993). The 185 mm SL specimen that Menon (1980: 16) invalidly designated as ‘lectotype’ of Plag. blochii is designated as holotype of Par. bleekeri . This specimens is among those used by Bleeker for his description of P. blochii . The type locality is one of the eight localities in Java listed by Bleeker where he collected or observed the species: Batavia, Cheribon, Tegal, Tjilatjap, Samarang, Rembang, Surabaja, Pasuruan.

It is possible that several species are confused under the name Par. blochii of authors.