The case ofBougainvillia triestinaHartlaub 1911 (Hydrozoa, Cnidaria): a 100-year-long struggle for recognition

Abstract

Bougainvillia triestina was described by Hartlaub in 1911 from specimens collected in the Gulf of Trieste (North Adriatic, Italy). Two years later, after re-examination of the same specimens, Neppi & Stiasny (1913) concluded that these were in fact juvenile medusae of Bougainvillia autumnalis (now synonymized with Bougainvillia muscus). Based on unique morphological traits and genetic analyses (16S rRNA, 18S rRNA, COI) of specimens of different stages recently collected in the shallow and enclosed coastal area of Ploce Harbour and Mali Ston Bay (South Adriatic, Croatia), we can confirm, 100 years after its first description, B. triestina as a valid, distinct species, clearly distinguishable from B. muscus (Allman 1863). Based on its occurrence in the Adriatic Sea, B. triestina seems to prefer productive coastal areas with a wide range of temperatures and salinities. Therefore, we expect that this species inhabits other coastal areas of the Mediterranean Sea as well as those of other seas and oceans. Given this, it is probable that in previous investigations some records of B. triestina were incorrectly attributed to B. muscus.