engleski

Where do aliens come from? : The case of Thalia orientalis

A planktonic tunicate determinated as Thalia orientalis Tokioka, 1937 was recorded for the first time in the Adriatic in 2007, when prevalent circulation pattern in the North Ionian Gyre was changing from cyclonal to anticyclonal, thus starting to bring more of western Mediterranean waters into the Adriatic Sea. Since T. orientalis is present in Red Sea as well as in Atlantic, it was hard to determine where from exactly did it arrive. In order to determine the origin of the Adriatic specimens we sequenced 757 nucleotide long fragment of 18S rRNA gene from the Adriatic and Pacific specimens of the T. orientalis. Uncorrected p-distance between sequences was 1.98%, which suggests that the specimens are of separate entities. The Adriatic and Pacific specimens differ also morphologically in the shape of atrial palps and medioventral projections. As Thalia orientalis was described based on specimens from the Pacific, Adriatic specimens should be considered as a new, still undescribed species. Our results emphasize importance of DNA methods in determining the origin of alien species as well as the mechanisms of their dispersal.

18S ; Thaliacea, alien species ; cryptic species ; Adriatic Sea

nije evidentirano