Microstructures of Antarctic cidaroid spines: diversity of shapes and ectosymbiont attachments.

• Published in: Marine Biology
• Main Authors: David, Bruno, Stock, Stuart R., De Carlo, Francesco, Hétérier, Vincent, De Ridder, Chantal
• Other Authors: Biogéosciences UMR 6282 Dijon (BGS), Centre National de la Recherche Scientifique (CNRS)-Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement, Department of Molecular Pharmacology and Biological Chemistry, Northwestern University, Advanced Photon Source ANL (APS), Argonne National Laboratory Lemont (ANL)-University of Chicago-US Department of Energy, Laboratoire de Biologie marine, Université libre de Bruxelles (ULB), Funding from the BIANZO I and II projects supported by the Belgian Science Policy (PADDII projects), and from a PhD grant from the Belgian Science Policy (Belspo)., ANR-07-BLAN-0213,ANTFLOCKS,ANTARCTIC SHELF AS A SPECIES FLOCKS GENERATOR(2007)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2009
• Subjects: [SDE.BE]Environmental Sciences/Biodiversity and Ecology; [SDV.BA.ZI]Life Sciences [q-bio]/Animal biology/Invertebrate Zoology; [SDV.EE.IEO]Life Sciences [q-bio]/Ecology; environment/Symbiosis; Antarctic; Drake Passage; Weddell; Weddell Sea; Antarc*
• Online Access: https://hal.archives-ouvertes.fr/hal-00401660; https://doi.org/10.1007/s00227-009-1192-3

14 pages International audience The echinoderm endoskeleton, located in the connective layer of the tegument, is organized into a threedimensional mesh, the stereom. Among echinoids, the cidaroids depart from this pattern, and the shaft of the spine lacks an epidermis. Thus, the spines lack antifouling protection, allowing ectosymbionts such as bryozoans and foraminiferans to attach. This raises a question about the adaptive role of the cortical layer of the stereom. This study examined the micro- and mesostructure of the spines of 11 cidaroid species collected in the Weddell Sea and Drake Passage, and the nature of their ectosymbiont attachments. Scanning electron microscopy was used to characterize the cortex surface and X-ray micro computed tomography (µCT) to describe the symbiont attachments. Spine microstructure features provide a useful taxonomic character for distinguishing among three species in the genus Ctenocidaris, and challenge a previous parasitic interpretation of cortical Wlaments on the spines of Rhynchocidaris triplopora. Ectosymbiont attachments were classiWed as Anchoring, Molding, Cementing, or Corroding. The study suggests that some microstructure features may be protective, keeping the ectosymbionts away from the cortex and loosely attached at intervals along the shaft of the spine, while other micro-structures facilitate attachment over considerable areas of the shaft.