Kinorhyncha from Italy, a revision of the current checklist and an account of the recent investigations

Except for the noticeable investigations carried out in 1928 by Karl Zelinka in the Gulf of Naples and Gulf of Trieste, research on the Italian kinorhynch fauna has been rather erratic in space and time. According to the current checklist of the Italian marine biota, 48 species of Kinorhyncha were reported up to 2008 along the Italian coastlines. However, 31 of them are considered nomina dubia and hence of doubtful utility. Here we point out those taxa and provide new information based on recent publications and on novel investigations carried out in selected areas of the Adriatic Sea (3 localities), Ligurian Sea (4), Tyrrhenian Sea (8), and Ionian Sea (1). New data derives from qualitative as well as from quantitative samples. The analysis of the new samples yielded 6 families, 9 genera, and 29 species, of which only 16 were previously recorded from peninsular waters. In summary, we recorded one new genus and two new species for Italy, together with 13 additional species that appear new to science. Particularly interesting is the finding of two new species belonging to rare genus Condyloderes, as it represents the first record of this taxon in the Mediterranean Sea. The most speciose genus is Echinoderes, followed by Pycnophyes with 10 and 8 species, respectively. The former genus includes the taxon showing the highest abundance, E. capitatus, with recorded densities up to 184 ind./10 cm2, while the latter includes the most common species P. communis, found in 7 out of the 16 new investigated localities. New faunistic information prompted the revision of the checklist, which in the new version includes 36 species in 9 genera and 6 families. Old and new data were utilized for a preliminary discussion on the geographic distribution of the recorded fauna, from which it appeared that five species only can be considered ubiquitous in the four Italian sea basins, whereas the other taxa appear to be restricted to one or two seas. However, many sectors of the Italian coastline remain unexplored. Besides those areas (e.g., mid Tyrrhenian and Ionian coasts), future research should be focused on peculiar habitats, such as submarine caves, lagoons, and coarse biogenic sediments, as many species and species records come from these neglected biotopes, often representing biodiversity hotspots.