Clupeidae

The diversity of shads (Alosa) from the Black and Caspian Seas is poorly understood and early authors follow Berg (1949) listing 15 species and forms from the Caspian Sea only. The number of species has not been reviewed comprehensively in recent years and we treat the species accepted by Kottelat and Freyhof (2007) as valid awaiting a sound taxonomic review especially of the Caspian marine species. Alosa curensis is sometimes mentioned as a valid species from Azerbaijan. This very poorly known shad was only found once by Suvorov (1907) and Berg (1949) mentioned that it is only known from the types collected from Kizilagach Bay (Qizilagac Bay) in Azerbaijan. Alosa curensis has teeth on the jaws, 31–43 gill rakers, and the gill rakers length exceed the length of the gill filaments. With this combination of characters, A. curensis keys out as A. sphaerocephala with the identification key given by Berg (1949) and we cannot exclude that it might be a synonym of this marine species. Since no records of A. curensis exist from freshwaters, we therefore excluded it from the current checklist.

Clupeonella cultriventris is widespread along coasts of the Black and Caspian Seas, entering lower reaches of rivers. Own (unpublished) molecular and morphological studies fail to distinguish the Caspian population (C. caspia) from the Black Sea population (C. cultriventris). Hoestlandt (1991) followed by Kottelat and Freyhof (2007) separate these two tyulkas largely based on the length of paired fins, a character we found to be very much overlapping in own materials examined. Therefore, we treat C. caspia as a synonym of C. cultriventris.

Clupeonella tscharchalensis is described from Lake Chelkar (47°50′N 59°36′E) in Kazakhstan. It is considered to be a freshwater species inhabiting rivers of the northern Caspian Sea basin (Hoestlandt, 1991) and to be invasive in the Don River. Tyulkas analysed from the Don are identified as C. cultriventris by own (unpublished) molecular and morphological data. Until tyulkas from Lake Chelkar are further studied, we treat C. tscharchalensis as a valid species having less gill-rakers than C. cultriventris.