Frontiers in Marine Science (Nov 2015)
Phylogeny of the sand goby group (Gobionellidae, Teleostei) based on mitochondrial gene sequences and morphological data <br />
Abstract
The sand gobies are a monophyletic group of small, nearshore marine to freshwater fishes, including 43 species in four genera that inhabit Europe and the Mediterranean Sea. Herein, we evaluate the phylogenetic relationships of the sand goby group based on molecular and morphological data. We sequenced fragments of mitochondrial gene, cytochrome c oxidase I, from 87 specimens from 20 localities collected from Greece and the Venice lagoon. We examine morphometric and meristic variation on 269 sand goby specimens from 17 localities using multivariate analysis. Principal component analysis demonstrated that variables accounting for most of the interspecific differentiation were first dorsal fin length, anal fin length and size of the head among species. Discriminant analysis revealed that about 91% of the examined fish could be correctly classified into the seven species considered. The most important morphometric variables for species differentiation were the shape of the head, the distance between the two dorsal fins and the width of the caudal peduncle. Phylogenetic analysis supported the systematic classification of genus Economidichthys through the clustering of E. pygmaeus and E. trichonis. The split-up of K. caucasica populations from the Ionian Sea including K. milleri with the K. caucasica populations from the Aegean Sea demonstrated a paraphyletic problem. Within these groupings there is limited genetic differentiation between Ionian populations. In terms of taxonomic implications, our data suggest that K. caucasica from the Ionian Sea and K. milleri should be regarded as synonyms. Finally, the genus Pomatoschistus is divided into three clades corresponding to the species P. minutus, P. marmoratus and P canestrinii. The differentiation between the samples of the Aegean and Ionian Sea is likely a result of the hydrogeologic characteristics and climatic conditions that existed during the Pleistocene.
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