Distribution of Architectonicidae (Heterobranchia, Gastropoda) of the Western Mediterranean Pliocene: Ecological and historical considerations

The palaeobiogeography of Pliocene Architectonicidae from the Western Mediterranean and adjacent Atlantic areas is analyzed. Quantitative analyses (calculation of faunal affinity indices and clustering) are presented. The distribution shows a heterogeneous pattern: three species (A. simplex, A. monilifera and A. obtusa) extend over the entire area, the others show a more restricted distribution. The interpretation of the causal factors of this distribution is based on ecological aspects (related to available outcrop data and to the biology of these species) and on historical aspects. Depth and type of sediment are major controls in this distribution. Commensalism with coelenterates could also be a determinating factor.