Alessandro Ceregato

A molecular phylogeny of bivalve mollusks: ancient radiations and divergences as revealed by mitochondrial genes.

Background Bivalves are very ancient and successful conchiferan mollusks (both in terms of species number and geographical distribution). Despite their importance in marine biota, their deep phylogenetic relationships were scarcely investigated from a molecular perspective, whereas much valuable work has been done on taxonomy, as well as phylogeny, of lower taxa. Methodology/Principal Findings Here we present a class-level bivalve phylogeny with a broad sample of 122 ingroup taxa, using four mitochondrial markers (MT-RNR1, MT-RNR2, MT-CO1, MT-CYB). Rigorous techniques have been exploited to set up the dataset, analyze phylogenetic signal, and infer a single final tree. In this study, we show the basal position of Opponobranchia to all Autobranchia, as well as of Palaeoheterodonta to the remaining Autobranchia, which we here propose to call Amarsipobranchia. Anomalodesmata were retrieved as monophyletic and basal to (Heterodonta + Pteriomorphia). Conclusions/Significance Bivalve morphological characters were traced onto the phylogenetic trees obtained from the molecular analysis; our analysis suggests that eulamellibranch gills and heterodont hinge are ancestral characters for all Autobranchia. This conclusion would entail a re-evaluation of bivalve symplesiomorphies.

DROWNED KARST LANDSCAPE OFFSHORE THE APULIAN MARGIN (SOUTHERN ADRIATIC SEA, ITALY)

The south Adriatic shelf offshore of the predominently carbonate Apulian coast is characterized by a peculiar rough topography interpreted as relic karst formed at a time of lower sea level. The study area covers a surface of about 220 km, with depths ranging from 50 to 105 m. The most relevant and diagnostic features are circular depressions a few tens to 150 m in diameter and 0.50 to 20 m deep thought to be dolines at various stages of evolution. The major doline, Oyster Pit, has its top at about 50 m water depth and is 20 m deep. It is partly filled with sediments redeposited by episodic mass failure from the doline’s flank. Bedrock samples from the study area document that Plio-Pleistocene calcarenites, tentatively correlated with the Calcarenite di Gravina Fm, are a prime candidate for the carbonate rocks involved in the karstification, although the presence of other units, such as the Peschici or Maiolica Fms, is not excluded. The area containing this subaerial karst landscape was submerged about 12,500 years ago as a result of the postglacial transgression over the continental shelf.

Chemosynthetic Bivalves of the Family Solemyidae (Bivalvia, Protobranchia) in the Neogene of the Mediterranean Basin

Abstract The Mediterranean area is the locus of a variety of deep-sea chemosynthetic environments that have been exploited by bivalves of the family Solemyidae during Cenozoic to present time. Large solemyids represented by the Solemya doderleini group were widely distributed in Neogene deep-sea reducing habitats, including cold vent hydrocarbon sites. Based upon the diagnostic structure of the ligament, Solemya doderleini (Mayer), 1861 and S. subquadrata (Foresti), 1879 are moved to the genus Acharax Dall, 1908. After the Messinian Salinity Crisis Acharax doderleini re-colonized deep-sea sulphide environments up to the Pliocene at least. At present, Acharax occurs in similar settings in the adjacent eastern Atlantic Ocean. Thus far, large solemyids are not documented from the present deep Mediterranean Sea in spite of a vast number of seep and reducing habitats with chemosynthetic biota, especially concentrated in its Eastern basin. Promisingly, however, a single live juvenile specimen of Solemyidae has been recently found at bathyal depth associated with a pockmark in the Nile Deep Sea Fan.

Building a Natural and Cultural Heritage Repository for the Storage and Dissemination of Knowledge: The Algarium Veneticum and the Archivio di Studi Adriatici Case Study

ABSTRACT The Archivio di Studi Adriatici (ASA) is a repository of the Institute of Marine Sciences (ISMAR-CNR) of Venice. The ASA repository, completely open source and open access, hosts natural collections, heritage books, documents, and maps of the Institute of Marine Sciences. It was developed following the discovery of a historical algal collection at the Biblioteca Storica di Studi Adriatici of Venice. This collection, after having been catalogued, has been digitized with a digital planetary scanner. Digitized specimens and metadata, compiled using Dublin Core and Simple Darwin Core formats, are hosted on a website, based on Fedora Repository and Islandora framework.