Phylogenetics and biogeography of the Balkan ‘sand gobies’ (Teleostei: Gobiidae): vulnerable species in need of taxonomic revision

Abstract

Within the Atlantic-Mediterranean region, the 'sand gobies' are abundant and widespread, and play an important role in marine, brackish, and freshwater ecosystems. They include the smallest European freshwater fish, Economidichthys trichonis, which is threatened by habitat loss and pollution, as are several other sand gobies. Key to good conservation management is an accurate account of the number of evolutionary significant units. Nevertheless, many taxonomic and evolutionary questions remain unresolved within the clade, and molecular studies are lacking, especially in the Balkans. Using partial 12S and 16S mitochondrial ribosomal DNA sequences of 96 specimens of at least eight nominal species (both freshwater and marine populations), we assess species relationships and compare molecular and morphological data. The results obtained do not support the monophyly of Economidichthys, suggesting the perianal organ to be a shared adaptation to hole-brooding rather than a synapomorphy, and urge for a taxonomic revision of Knipowitschia. The recently described Knipowitschia montenegrina seems to belong to a separate South-East Adriatic lineage. Knipowitschia milleri, an alleged endemic of the Acheron River, and Knipowitschia cf. panizzae, are shown to be very closely related to other western Greek Knipowitschia populations, and appear conspecific. A distinct Macedonian-Thessalian lineage is formed by Knipowitschia thessala, whereas Knipowitschia caucasica appears as an eastern lineage, with populations in Thrace and the Aegean. The present study combines the phylogeny of a goby radiation with insights on the historical biogeography of the eastern Mediterranean, and identifies evolutionary units meriting conservation attention.

Recent contributions to the distribution of the freshwater ichthyofauna in Greece

“…Other serious taxonomic issues include the tiny sand gobies of Western Greece. For example, recent genetic work has provided new evidence that Knipowitschia populations from various water bodies of the western coast of Greece may be conspecific with Knipowitschia milleri, previously thought to occur only in the lower part of the Acheron River (Vanhove et al, 2011b). Bearing in mind that few Ionian Knipowitschia populations are adequately studied morphologically, and that much phenotypic variation is observed in the Knipowitschia generally (Kovačić, 2005(Kovačić, , 2008, it is uncertain whether the morphological features of the Acheron K. milleri represent distinctive identification attributes.…”

Immigrant reproductive dysfunction facilitates ecological speciation

“…1) has only existed for ß4500 years (Westman and Sohlenius 1999), there are several species that exhibit characteristics of local adaptation in this area (Johannesson and André 2006;Johannesson et al 2011), including the sand goby (Pomatoschistus minutus) (Pallas) (Larmuseau et al 2010(Larmuseau et al , 2009a(Larmuseau et al , 2009b. Several closely related species have, however, entered and speciated in freshwater in the Balkan region (Vanhove et al 2012). S1) is widely distributed and inhabits the shores of the Mediterranean Sea, the North East Atlantic, and the Baltic Sea including the very low salinity waters in the Gulf of Bothnia, but it has not been found in freshwaters (Kullander et al 2012).…”

Acoustic and visual courtship traits in two sympatric marine Gobiidae species – Pomatoschistus microps and Pomatoschistus minutus

“…P. microps and P. minutus belong to two different clades of the 'sand goby group' radiation. The divergence time of the two clades is estimated to be 2-5 Mya (Huyse et al 2004;Vanhove et al 2012) and behaviors including sound may have diverged during this time, and hence show a phylogenetic signal (Malavasi et al 2012). The two other sympatric 'sand goby group' species in shallow bays of Sweden (Kullander et al 2012), Gobiusculus flavescens (Fabricius, 1779) and P. pictus, as well as the deep water species Pomatoschistus norvegicus (Collett, 1902), appear to belong to the same clade as P. minutus.…”

“…The two other sympatric 'sand goby group' species in shallow bays of Sweden (Kullander et al 2012), Gobiusculus flavescens (Fabricius, 1779) and P. pictus, as well as the deep water species Pomatoschistus norvegicus (Collett, 1902), appear to belong to the same clade as P. minutus. P. marmoratus, the sister species to P. microps (Huyse et al 2004;Vanhove et al 2012), is not found in Sweden (Kullander et al 2012). G. flavescens, which is semipelagic and not benthic, is at present not in the genus Pomatoschistus, rendering it paraphyletic and in need of revision (Vanhove et al 2012).…”

“…P. marmoratus, the sister species to P. microps (Huyse et al 2004;Vanhove et al 2012), is not found in Sweden (Kullander et al 2012). G. flavescens, which is semipelagic and not benthic, is at present not in the genus Pomatoschistus, rendering it paraphyletic and in need of revision (Vanhove et al 2012).…”