Leiognathus fasciatus (Lacepede, 1803)

Chakrabarty, Prosanta & Sparks, John S., 2008, Diagnoses for Leiognathus Lacepède 1802, Equula Cuvier 1815, Equulites Fowler 1904, Eubleekeria Fowler 1904, and a New Ponyfish Genus (Teleostei: Leiognathidae), American Museum Novitates 3623 (1), pp. 1-12 : 5

Leiognathus fasciatus complex Clade I: Sparks et al., 2005.

TYPE SPECIES: Equula longispinis Valenciennes , in Cuvier and Valenciennes, 1835 .

OTHER INCLUDED SPECIES: Equula fasciata ( Lacepède, 1803) .

DIAGNOSIS: Members of Equula can be distinguished from all other leiognathids by the presence of a series of round yellow blotches arrayed horizontally along the flank.

REMARKS: Members of Equula can be further distinguished from all other ponyfishes, except Leiognathus , by the presence of a nonsexually dimorphic light organ.

Sparks et al. (2005) recovered a clade they referred to as the ‘‘ Leiognathus fasciatus complex’’ (Clade I in that study) as the sister group to the remaining members of Leiognathidae . The ‘‘ Leiognathus fasciatus complex’’ of Sparks et al. (2005) included two nominal species, Leiognathus fasciatus and L. longispinis . The oldest available name for this group is Equula Cuvier, 1815 , which is henceforth removed from synonymy with Leiognathus and assigned to this clade. Tortonese (1973) considered Equula Cuvier, 1815 , to be a junior synonym of Leiognathus Lacepède, 1802 , but this synonymy was not based on an explicit comparative analysis. Because of the influence of the work of Cuvier and Valenciennes (1835), many species of leiognathids were initially described as members of Equula , and for much of the early part of the last century most leiognathid species were considered to be members of this genus.

The two species of Equula can be easily distinguished from each other by the presence of a markedly elongate ($ 60–100% of BD) second anal-fin spine in E. longispinis (vs.,50% of BD in E. fasciata ), a feature lacking in all other leiognathids ( Jones, 1985; Sparks, 2006a).

A homonym, Equula longispina De Vis, 1884 exists for Equula longispinis Valenciennes , in Cuvier and Valenciennes, 1835, which is objectively invalid and was provided the replacement name of Leiognathus hastatus Ogilby, 1912 ( Eschmeyer, 2007) . Leiognathus hastatus Ogilby, 1912 (5 Equula longispina De Vis, 1884 ) is considered to be a synonym of Photoplagios leuciscus ( Günther, 1860; see Hoese and Bray, 2006, and Eschmeyer, 2007). Leiognathus smithursti ( Ramsay and Ogilby, 1886) was recently deemed a junior synonym of Equula longispinis ( Sparks, 2006a) .