Search

We describe a new chaetognath species, Spadella valsalinae sp. nov., discovered and collected in the Northern Adriatic Sea (Pula, Croatia). S. valsalinae sp. nov. is a benthic species living at 10-12 m depth attached to the surface of roughly sorted sediment. The cosmopolitan, seagrass-inhabiting species Spadella cephaloptera Busch, 1851 was also recorded in the sampling area. Characters from comparative morphology and molecular phylogeny based on SSU rRNA (18S) sequences support a sister group relationship of S. valsalinae sp. nov. with Spadella lainezi and Spadella ledoyeri. Thus, S. valsalinae sp. nov. represents the first member in the ' Spadella ledoyeri' complex that is not a troglophilic species. By comparison with the various known European Spadella species, we defined a specific set of morphological characters, such as the number, shape and mutual proportions of the teeth, the lateral fins, the corona ciliata, the seminal vesicles, as well as the presence of ventral adhesive papillae, which is unique for S. valsalinae sp. nov . The biogeography of Spadella members in the Mediterranean Sea and the Eastern Atlantic as well as their phylogenetic relationships are discussed, with the focus on processes of neo-endemism in an epeiric area like, for instance, the Northern Adriatic Sea. [ABSTRACT FROM AUTHOR]