Diapositive 1 - de l'Université libre de Bruxelles

Chapitre IRESULTSThe massive skeleton of the hypercalcified calcisponge Petrobiona massiliana appears asa solid mass of calcite with crests and depressions (Figure 13.A). These crests areorganized along multi-directional axes (Figures 13.B, 13.C) and support the thin livingtissues, which cover the upper part of the skeleton and contain an abundance of spicules.Figure 13: Petrobiona massiliana (SEM): A. Longitudinal section perpendicular to surface, alongmajor growth axis (Scale bar = 1 mm) Cr: skeletal crests, D: depression of the skeleton, LT: livingtissues, S: spicules, Sk: massive skeleton, Ca: canalicules. B. Edge of massive skeleton showingmulti-directional growth of crests (Scale bar = 100 µm). C. Detail of crest edge of cleaned skeleton,showing cone-shaped protuberances (C) and multi-directional growth of a single crest around maingrowth direction (Scale bar = 100 µm). D. Detail of fractured skeleton showing entrapped spicules(ES), and imprints of some other (SI) (Scale bar = 10 µm). E. Diapason triactine entrapped duringskeletal growth (Scale bar = 10 µm). F. Skeletal pit shaped excavations (arrows), probablyoccasioned by a Cliona sp. (Scale bar = 100 µm).40