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76 Gianmarco Ingrosso et al.

and Cladocora caespitosa (Linnaeus, 1767), live in shallow water and are
obligatorily or facultative zooxanthellate, i.e., they may harbour microalgal
endosymbionts that are known to enhance coral calcification (Schuhmacher,
1984 and references therein).
The bioconstructions of C. caespitosa are the best known (Fig. 3B). This
species, endemic to the Mediterranean Sea, exhibits growth rates that may
1
exceed 5mmyear (Peirano et al., 1999) and calcification rates that average
1.1–1.7kg CaCO 3 m 2 year 1 (Rodolfo-Metalpa et al., 1999), which is com-
parable to values of many tropical reef corals (Peirano et al., 2001). The col-
onies of C. caespitosa, obligatorily zooxanthellate, are common throughout
the Mediterranean on rocks and pebbles about 3–30m depth, often in turbid
water (Bianchi, 2009). When abundant, C. caespitosa may typically occur in
two distinct formations: beds and banks (Morri et al., 2000b). Beds are com-
posed by numerous small (10–30cm in diameter) subspherical colonies in
dense populations. Banks are made up of large colonies, reaching several dec-
imetres in height and covering areas of several square metres. Banks originate
from beds under conditions of undisturbed accretion by means of three mech-
anisms: (i) fusion of adjacent colonies; (ii) “pouring” of the build-up due to
gravity; and (iii) inclusion of satellite colonies (Peiranoetal.,1998). Mixed
distributions of beds and banks can also be found, while a third formation
has been recently described: free-living coral nodules or coralliths (Kersting
et al., 2017a,b).
Banks are the most important bioconstructions of C. caespitosa and may
deserve to be called reefs. They harbour a rich associated biota comprising
several phyla (Antoniadou and Chintiroglou, 2010; Koukouras et al., 1998;
Lumare, 1966), but no species seems exclusive to this habitat (Bianchi,
2009). In the Gulf of Trieste (North Adriatic Sea), Pitacco et al. (2014) esti-
mated 89 infauna taxa associated with C. caespitosa and the most abundant
were molluscs (50%), followed by polychaetes (20%) and crustaceans
(7%). Along the Italian coast (Fig. 3D), banks have been described in the
Gulf of Manfredonia (Colantoni and Gallignani, 1975), the Ionian Sea
(Lumare, 1966), the Ligurian Sea (Morri et al., 1994b) and the Gulf of
Trieste (Pitacco et al., 2014; Zunino et al., 2018).

2.2.5 Vermetid Reefs
Vermetids are sessile and gregarious prosobranch gastropods of the family
Vermetidae, widely distributed in the warm southern waters of the Medi-
terranean Sea (Keen, 1961), where their reefs or platforms are built up by
a complex of four cryptic species, all previously named Dendropoma petraeum
(Monterosato, 1884) (Fig. 4A). Templado et al. (2016) split the old taxon