Ponticola

Ponticola View in CoL

Ponticola are small- or medium-sized fishes and comprise approximately 18 species. They were previously considered species within the genus Neogobius , but subsequent molecular and morphological studies have demonstrated that this group represents a distinct genus. Ponticola are common in most rivers flowing to the Black and Caspian Seas, and several species occur mostly in allopatry. In addition to those species included in the species chapters, we recognise only five additional species in West Asia ( P. eurycephalus , P. ratan , P. iljini , P. platyrostris , P. cephalargoides ) that are found in brackish waters only and are not known to enter freshwater habitats. Some authors consider Ponticola odessicus and P. goebelii valid species, yet we have not identified any scientific evidence to support this classification. These species appeared elevated from synonyms to species in checklists without supporting documentation. Ponticola eurycephalus is a coastal species that regularly enters freshwaters in the European part of the Black Sea basin. However, this species is not distributed in West Asia. It is included in the key only to allow its identification. Ponticola ratan is known from the Black Sea and Caspian (where it is occasionally recorded in the Asian parts of these seas). It may be an accidental species, but from its European range, it has only one freshwater population in an inland reservoir in Ukraine. Ponticola eurycephalus and

P. ratan are excluded from the coverage of this book, as well as P. iljini , P. platyrostris , and P. cephalargoides . The selection between freshwater and marine species in Ponticola is somewhat artificial, given the need for a clear border between fresh- and brackish water habitats, particularly in larger river estuaries and coastal limans. Furthermore, the diagnostic characters of the different Ponticola species need to be better documented, and the distribution of several species needs to be better understood. Further reading. Neilson & Stepien 2009 (phylogeny); Vasil’eva & Vasil’ev 2003a (identification key); Vasil’eva et al. 2015 (Caspian species).

Ponticola alasanicus ; Alazani, Georgia; ~ 70 mm SL. © A. Epitashvili.