In the Mediterranean Sea, the symbiosis between the gorgonian Paramuricea clavata (Risso, 1826) and the polychaete Haplosyllis chamaeleon Laubier, 1960 (Annelida, Syllidae, Syllinae) has only been documented from the western basin. Our findings extend its geographic distribution to the north-central basin and represent the first record of H. chamaeleon in Italy and Croatia. Periodic observations from the Ligurian Sea allowed establishing that the symbiont occurs on P. clavata almost throughout the year, showing a reproductive period longer than previously reported. Morphometric comparisons of three Mediterranean populations, from Portofino Promontory (Ligurian Sea), Cape of Creus (Catalan Sea) and Chafarinas Archipelago (Alboran Sea) proved that there were no significant differences in body measurements, whilst the observed differences in dorsal cirri length pattern could be consider intra-specific. Our behavioural observations confirm that the species had (i) a kleptoparasitic behaviour, (ii) did not cause injuries to the host and (iii) did not induce the host to generate any malformation.

Mesophotic “mentions”
0 x (total of 3718 words)

Classification
* Presents original data
* Focused on 'mesophotic' depth range
* Focused on 'temperate mesophotic ecosystem'

Fields
Behavior
Ecology
Reproduction
Biodiversity

Focusgroups
Octocorallia (Soft Corals)
Other invertebrates

Locations
Italy - Ligurian-Tyrrhenian
Croatia

Platforms
SCUBA (open-circuit or unspecified)