Abstract A new species belonging to the the genus Novafabricia Fitzhugh is described. The main diagnostic features are the distribution pattern of thoracic pseudospatulate setae, limited to setigers 3–7, and the presence of two dorsal lobes on the anterior margin of the anterior peristornial ring. The presence of N. bilobata in the Mediterranean suggests a world-wide distribution for the genus.
Sabellaria species are among the most important frame-builders in temperate, shallow marine areas. These polychaetes are suspension feeders able to build bioconstructions using sand and shell fragments cemented with a sticky mucous. Such feature makes these invertebrates “unusual bioconstructors”, as they do not produce calcium carbonate. Sabellaridae reefs are widespread in the Mediterranean and along the Atlantic coast of Europe, but their sedimentological aspects are still poorly known. Over short time intervals, these bioconstructions can rapidly alternate between phases of growth, stasis and destruction during different seasons. In this paper, we compare reefs of two Sabellaria species (S. alveolata—Ostia, Roma and Tyrrhenian Sea; S. spinulosa—Torre Mileto, Foggia and Adriatic Sea) found at two different sites along the Italian coast. We describe the morphology of worm tubes at the macro- and microscale. Similarities and differences are discussed based on eco-biological features and physical environmental conditions. This work shows a measurement and observation scheme for this type of bioconstructions that has been verified at both the macro- and microscale and which was shown to be useful for defining evolutionary trends of sabellarian bioconstructions. The monitoring parameters were identified and verified over a long period.
Abstract The redescriptions of the sabellid polychaete genus Pseudofabricia and of the type species P. aberrans Cantone, 1972 are reported. The species was previously described from incomplete material. The features of the tentacular crown, lacking in the original description, are reported here. Pseudofabricia seems to be closely related to Fabricia Blainville by the presence of well‐developed dorsal lips and to Novafabricia Fitzhugh in the shape of the anterior peristomial ring ventrally developed as a tongue‐like process. The genus is endemic to the Mediterranean Sea and P. aberrans is most common in shallow Posidonia oceanica beds.
Perkinsiana antarctica (Kinberg, 1867) and P. littoralis (Hartman, 1967) are redescribed from holo‐ and topotypes. Two new species, P. milae and P. borsibrunoi , are described from the Ross Sea (Antarctica) and compared with other species of the genus. Records of P. antarctica are numerous, but re‐examination indicates that many of these represent misidentifications: the species may have a distribution limited to subantarctic areas.
Sabellida are widespread, diverse and abundant in marine benthic habitats. Their distribution patterns on hard-bottom substrates are poorly studied so far. Little is known about the factors influencing their distribution, including the protection regimes that are known to affect assemblage diversity. We analyzed hard-bottom Sabellida at 1.5 and 5 m depths at the Torre Guaceto Marine Protected Area (MPA) (SE Italy) to describe diversity and distribution patterns, and to identify potential factors influencing their distribution. The Sabellida diversity varied significantly among stations and was higher at 5 m depth. No relation with the protection regime was found. Among environmental variables, only sedimentation appeared related, suggesting that local trophic features might have influenced the observed pattern. Among habitat formers, only the macroalga Halimeda tuna significantly explained part of the observed variation, probably due to its role as a basibiont for some Sabellida taxa. Other predictor variables of Sabellida distribution were the abundances of some invertebrate taxa, especially Syllidae and some filter feeders such as Sabellariida and Cirripedia, probably due to shared ecological requirements, rather than a direct effect on Sabellida distribution. The relation with the Syllidae remains obscure so far, albeit some kind of interaction (including predator/prey interactions) between these two taxa cannot be excluded. Sabellida should be taken into account when analyzing patterns of biodiversity of hard-bottom environments.
