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.

在地中海中，仅从西部盆地记录到了高古生物Paramuricea clavata（里索，1826年）与多毛Ha Haplosyllis chamaeleon Laubier，1960年（安妮莉达，西里达，西里奈）之间的共生。我们的发现将其地理分布扩展到中北部盆地，并代表了意大利和克罗地亚的H. chamaeleon记录。利古里亚海的定期观测可以确定共生菌存在于克拉维塔角藻上几乎整个一年中，生殖期都比以前报告的要长。来自波托菲诺海角（利古里亚海），克鲁斯角（加泰罗尼亚海）和恰法里纳斯群岛（阿尔伯兰海）的三个地中海种群的形态计量学比较证明，人体测量值没有显着差异，而观察到的背侧卷毛长度模式差异可以考虑内部特定。我们的行为观察结果证实，该物种具有（i）隐匿性寄生行为，（ii）不会对寄主造成伤害，并且（iii）不会诱使寄主产生任何畸形。