Posidonia oceanica meadows are among the most valuable coastal ecosystems in the Mediterranean Sea, providing key ecological functions and socio-economic benefits. Despite conservation efforts, these meadows declined markedly throughout the late 20th century due to cumulative human pressures, although their condition has stabilised more recently under protection, and natural recolonization has even begun in some areas. In this...

In recent decades, our understanding of deep-sea ecosystems has significantly improved, yet the taxonomic identity of associated species often remains understudied and this is particularly true for octocorals. This study describes the octocoral fauna inhabiting cold-water coral habitats on seamounts, canyons, and the continental slope of the Ligurian Sea (NW Mediterranean Sea), ranging from 400 to 822 m. Eighteen specimens wer...

Savalia savaglia is one of the few zoantharians capable to grow with a parasitic habitus, infesting damaged gorgonians, such as Eunicella spp., Paramuricea sp., Leptogorgia spp., and antipatharians. It causes tissue necrosis in its hosts and progressively overgrows their skeleton with its own coenenchyme. While previous studies have mainly focused on its distribution, biology, ecology, and conservation, little information is a...

Synagoga mira Norman, 1888 is a poorly known ascothoracidan that has never been reported since its original description in 1888, which was based on a few specimens recovered from colonies of the black coral Parantipathes larix (Esper, 1788) collected in the Gulf of Naples (Mediterranean Sea). A series of Remotely Operated Vehicle (ROV) campaigns conducted between 2006 and 2022 along the Italian coast (western Mediterranean Sea...

The study of cryptic sponges can be challenging, as they are difficult to detect in the environment without the use of destructive methods. The permanence of mineral skeletal components of Porifera in sediments is therefore a tool that can provide support for a more comprehensive study of sponge fauna. In this context, sediments collected from four karst lakes in Ha Long Bay (Vietnam), plus two surrounding sea areas, were proc...

An analysis of 483 remotely operated vehicle (ROV) dives carried out along the Italian coast on hard substrata at mesophotic depths (40–200 m) allowed an overview of the rich sponge diversity (53 taxa) of the deep continental platform to be obtained for the first time. About 40% of the potential actual species diversity was recognisable using ROV, suggesting that this group is among the richest yet underestimated using this te...

A 21-day continuous monitoring of a highly tridimensional forest of the black coral Antipathella subpinnata (Ellis and Solander 1786) was carried out in the NW Mediterranean Sea at 63 m depth using an autonomous lander to investigate the diel short-term dynamics of the vagile fauna associated to the forest. The survey allowed to assess several aspects of the forest attractiveness and its use, especially by the ichthyofauna, in...

The zoanthid Parazoanthus axinellae (Schmidt, 1862) is a widespread coral species in the Mediterranean coralligenous assemblages where two morphotypes are found: Slender and Stocky, differing in size, color, and preferred substrate. Due to these marked differences, Slender and Stocky morphotypes were hypothesized to be two species. Here, we used 2bRAD to obtain genome‐wide genotyped single nucleotide polymorphisms (SNPs) to in...

Several bathyal cold-water coral provinces, characterized by a lush growth of habitat-forming scleractinians, have been recognized in the Mediterranean Sea. However, the search for this biogenic habitat only marginally targeted the Italian coast of the Ligurian Sea (NW Mediterranean basin) despite historical and a few recent local studies in the region reporting the presence of corals. This study used bathymetry maps, side-sca...

During scientific expeditions in Indonesia and Vietnam, several sponge specimens belonging to the genus Cladocroce were collected. The integration of morphological and molecular analyses, incorporating species delimitation models (ABGD, ASAP, and bPTP) and phylogenetic approaches using three molecular markers (COI, 28S, and 18S–ITS1–5.8S–ITS2–28S), allowed us to discriminate three congeneric species. Two of these species (C. b...

The sub-fossil red coral deposits of Sciacca (Sicily Channel) have attracted scientific attention for nearly 150 years. Their origin and formation have been long questioned and investigated, given the fact that they represent one of the most intriguing geobiological events ever to occur in the Mediterranean basin. Less attention was given to the paleo-community associated with the sub-fossil coral. Radiocarbon age determinatio...

Distribution and occurrence data of the sea fan Leptogorgia sarmentosa (Esper, 1791) in the Mediterranean Sea were updated thanks to new photographic surveys, highlighting the presence of the species off NE Sardinia and, in particular, in the Tavolara-Punta Coda Cavallo Marine Protected Area (TPCCMPA). The estimated average distance among colonies strongly suggests that they are not able to sexually reproduce and that they pro...

The precious coral Corallium rubrum (Linnaeus, 1758) is a charismatic Mediterranean species. A recent large-scale investigation along the Italian coast highlighted its widespread occurrence at mesophotic and upper bathyal depths, especially on coralligenous and bathyal vertical hardgrounds. The lack of morphometric data limited the considerations on the structure and health status of the populations, fundamental to identify th...

The carbonatic scleraxis of Corallium rubrum (L.), commonly known as red coral, is often found infested by excavating sponges. These boring organisms produce galleries inside the compact axis of the coral in a variety of shapes compromising the integrity of the skeleton and reducing its commercial value. Three sponge species, already known to bore into Corallium rubrum, have been identified in colonies collected from Cape Verd...