The morphology and mitochondrial DNA barcode of Knipowitschia caucasica (Berg, 1916) (Gobiiformes: Gobiidae) from Karpuzay, Levantine Sea, the easternmost record of Knipowitschia species in the Mediterranean Sea.

Knipowitschia is a sand-goby genus historically comprising 17 species. The congeneric Knipowitschia species show discordance between morphology and genetics in two ways: the morphologically similar species that are clearly distinct by genetics and the morphologically and ecologically distinct populations that are similar by genetics. A sample of Knipowitschia individuals has been collected from Karpuzay Creek on the Levantine Sea coast. It is the easternmost Mediterranean record of any Knipowitschia, and a number of arguments suggest it is native. Among the presently valid Knipowitschia species, the population was identified by both genetics and morphology as K. caucasica. The detailed morphological description and genetics are provided for this population. The morphology of the present sample fits within the highly variable morphology of east Aegean populations presently recognized as K. caucasica, although with the extreme values of the already known morphological and coloration variability.

Morphological and molecular characterization of the Makran Glossogobius cf. giuris (Teleostei: Gobiidae) and the Glossogobius giuris species complex taxonomy.

The Indo-West Pacific Glossogobius giuris(Hamilton, 1822) species complex has four spatially circumscribed independent lineages, partially taxonomically resolved. A sample of gobies from the G. giurisspecies complex was recently collected from the Makran River System, south-eastern Iran, which drains into the northern Oman Sea. The taxonomic status of thispopulation was clarified using a molecular and morphological framework. Molecular and morphological data both revealed that the examined sample from the Makran River System is conspecific with G. giurisB which is widely distributed in the coastal habitats and basins of the Indian Ocean. In addition, consensus from different molecular species delimitations, K2P genetic distance, and tree topologies confirmed the four lineages of the G. giuris species complex as distinct taxonomic entities, hereby highlighting the necessity of an integrative morphological and molecular approach to complete the clarification of taxonomic diversity within this group. Glossogobius giuris species complex taxonomy is discussed and solution recommended.

Ponticola hircaniaensis sp. nov., a new and critically endangered gobiid species (Teleostei: Gobiidae) from the southern Caspian Sea basin.

Ponticola hircaniaensis sp. nov. is described as a new gobiid species from the Kaboudval Stream, southern Caspian Sea basin. The new species is diagnosed among Caspian Sea basin Ponticola species by the following combination of characters: second dorsal-fin branched rays 1416, anal-fin branched rays 1012, scales in lateral series 5259; lower jaw slightly, if at all, prognathous; head and body yellowish brown showing a reticulate brown pattern on a yellow background, first dorsal fin with a marginal bright orangish-yellow band and a dark anterior spot, upper part of pectoral-fin base with a distinct dark brown stripe; length of third spine in first dorsal fin 13.418.3 % of standard length (SL), second dorsal-fin spine length 11.113.8 % SL, caudal peduncle length and depth 16.420.1 % and 11.112.8 % SL, respectively, head depth at nape 70.981.0 % of head length (HL), and at eye 52.566.0 % HL; sagittal otolith dorsal rim with a broad concavity in the middle, dorsal depression absent or indistinct, sulcus length/sulcus height and sulcus height/otolith height ratios 1.471.82 and 0.340.40, respectively. It is also characterised by a K2P nearest neighbour distance of 5% to P. kessleri in the mtDNA COI barcode region. Mitochondrial and nuclear DNA analyses suggested extensive hybridization between P. hircaniaensis sp. nov. and P. gorlap at Kaboudval, providing evidence for the first record of hybridization in the Ponto-Caspian gobiids. Based on narrow geographic range isolated above the Zarrin Gol Dam (< 2 km2), extensive hybridization with P. gorlap, and other threats, the new species should be considered Critically Endangered.

Identification of Mediterranean marine gobies (Actinopterygii: Gobiidae) of the continental shelf from photographs of in situ individuals.

Numerous photographs of live fishes posted by anglers and divers on social media and citizen science databases are important sources of information for ichthyological research. However, validating records that extend the known ecology and bathymetric or geographic distribution of species should rely on a rigorous identification process. The family Gobiidae, with their small size, superficial resemblance among species and high species richness are particularly difficult to identify. Therefore, the identification from photographs of live individuals of Mediterranean marine gobies from the continental shelf was studied. A dichotomous identification key is provided based on photographs of live individuals, allowing positive identification of 41 out of the 66 species reviewed in this publication. Then, for all 66 species we provide a brief description of important characters, which can be used for provisional identification for those species that could not be positively identified using the key. Pending further progress in identification of live individuals, we suggest that records extending the known geographic and ecological species distribution be taken into account only if they could be validated using the dichotomous identification key.