The siboglinid tubeworm, Lamellibrachia sp. (Annelida: Vestimentifera) has recently been described and reported from various sites in the eastern basin and in a single site in the western basin of the Mediterranean Sea. Here we report a further record of Lamellibrachia sp. in the western Mediterranean, where these giant worms were sampled—by the grabbers of a working class ROV—from the shipwreck of the liner ‘Catania’, sunk in 1917 at 490 m depth off the coast of Cetraro (Calabria, southern Tyrrhenian Sea, Italy). Twenty-seven entire tubes were collected ranging from 23 to 60 cm in length and from 0.6 to 13 mm in diameter. Clear annulations were present near the tube openings. Only two of the tubes contained specimens of Lamellibrachia, both lacking most of the posterior portion (including the opisthosoma); the obturaculum was 13 mm long in both specimens; three sheath lamellae and eight branchial lamellae occurred in one specimen, and six and 14 in the other. DNA analysis through COI sequencing suggests a close similarity with specimens collected in the eastern Mediterranean (GenBank EU046616) and belonging to a new species recently described. It needs still to be clarified which type of energy source the obligate symbiotic bacteria of these worms may use for nutrition, since no sulphur emissions can be documented on and around the shipwreck. The ‘Catania’ contained some wooden structures and was transporting cotton balls and oil seeds, so the symbiotic bacteria may rely on degradation of these materials. This record stresses the importance of shipwreck as a possible stepping stone habitat for the large scale dispersion of Vestimentifera.

Despite the importance of early life-history processes in regulating population assemblages of benthic invertebrates at hydrothermal vents, they remain poorly understood, mainly because of the inaccessibility of these habitats. Vestimentiferan tubeworms provide an excellent system to study settlement in these habitats; they inhabit tubes that remain intact for some period even after the occupants die, and thus provide a proxy for rates of settlement and post-settlement mortality. In 2007, we collected rocks supporting populations of Lamellibrachia sp. using a TV-grab, from Mussel Ridge hydrothermal vent field on Monowai Volcanic Complex, at the Tonga–Kermadec arc. Twenty-two discrete patches of similarly sized individuals and of discrete length–frequency distributions were identified and quantified. Mean length of individual tubeworms ranged from <0.5 to 6.38 cm, and abundance per patch ranged from 6.8 to 108 ind cm−2. Post-settlement mortality was ~5%. These results suggest that gregarious settlement of pulses of larvae is likely occurring by Lamellibrachia sp., a process that has not yet been described in deep-sea hydrothermal vent tubeworms. The abundance of adult tubeworms on Monowai was low, and allochthonous larval supply from neighbouring seamounts unlikely. Consequently, gregarious settlement can increase the probability of maintenance and expansion of the existing populations.

Specimens of the vestimentiferan tubeworm Lamellibrachia sp. were collected from the wreck of the SS ‘Persia’ at 2800 m depth south-east of Crete, in association with decomposing paper in the ship's mailroom. Anaerobic breakdown of cellulose by bacterial consortia including sulphate-reducers is proposed as the source of sulphide required by Lamellibrachia's chemoautotrophic symbionts. Timing of wreck colonization is unknown but observed tube dimensions suggest growth rates at least equal to those measured for Lamellibrachia luymesi at Gulf of Mexico hydrocarbon seeps. The organic substrate supporting vestimentiferan growth in the ‘Persia’ is remarkable in consisting of highly refractory, human-modified terrestrial plant material. This record therefore expands the range of energy sources known to support chemosynthetic communities at the deep-sea floor.