BackgroundThe Raphitomidae family in the Mediterranean Sea is under revision. Accordingly, new data are of taxonomic and comparative relevance. In this study, new material from the Hellenic Seas is presented.ResultsThe Raphitomidae fauna of Greece was collected and investigated during the period from October 2008 to February 2018. Thirty-five (35) species were identified and their status was compared with existing checklists and other collections. This effort revealed two new Raphitoma species, and one new record for the Mediterranean Sea. Also from the present collection, four species are new records for the East Mediterranean, 10 for the Hellenic fauna and six are reported for second time. The main identification characteristics and baseline ecological information are given and discussed.ConclusionsBy this report, the Hellenic Raphitomidae biodiversity is enriched by 10 new records, out of which, two are new species, one is new record for the Mediterranean Sea, and four for the East basin.

BackgroundThe Hellenic Seas are influenced by on-going environmental changes and the introduction of alien species, which are expected to have an impact on their biodiversity. This study contributes to the knowledge of the Hellenic marine gastropod biodiversity, expanding data over the entire Greek territory, during the period from October 2008 to March 2017.ResultsThis work presents 45 species of gastropods not previously reported from Greece or reported only once, belonging to 19 families. From those species, one (Horologica sp.) is, most probably, an undescribed species, 17 are new for the Eastern Mediterranean Sea and 40 are new for the Hellenic fauna. Main taxonomic characteristics and ecological information such as habitat, distribution and origin, are given and discussed.ConclusionsBy this report, the Hellenic gastropod biodiversity is enriched by 40 new records, out of which, 17 are new for the Eastern Mediterranean Sea, 4 are Lessepsian migrants previously reported for the Mediterranean Sea and 1 is probably a new species.

At least 10 pairs of similar, most probably closely related, species of Raphitoma are often sampled in the same Mediterranean localities. In each pair, one member bears a planktotrophic protoconch and the other a lecithotrophic one. We propose that the phenomenon may be attributed to a simple gene that functions in conjunction with others and environmental factors to exhibit a discontinuous multifactorial inheritance leading to poecilogony. Below a threshold, the animals may produce fewer and larger germ cells, giving rise to fewer and larger eggs and large lecithotrophic embryos with large paucispiral protoconch I, while above that threshold, more and smaller germ cells leading to smaller eggs and to planktotrophic larvae with small protoconch I and large multispiral protoconch II. Preliminary measurements are in support of our hypothesis. Analysis of mitochondrial DNA markers as well as interbreeding experiments could bring an end to the existing confusion.