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Giornale di Geologia,  ser.  3",  vol.  60,  1998,  pp.  235-252,  Bolognn

        Chitons (Mollusca, Polyplacophora) collected
        during cruise CS96 in tfie  Strait of Sicily                     1

        Bruno D<li'Anft'IO- Via  Mugcl/e.rr  66D,  1-59100 Prato.
        Claudio Lombardi- Via  Matreotri 9.  1-40062 Molinella  (Bologna).
        Marco  Taviani -lstitu/o di Geologia Marina,  C.N.R.,  Via  Gabelli 101,  1- 40/29 Bologna.

        Summary           As many as 17 species of chitons (Mollusca, Polyplacophora) have been collected during
                        cruise CS96 in the Strait of Sicily. Most materia! is represented by loose pia t es found within
                        coarse-grained skelelal sedimenls which  typically drape slarved areas of banks and shoals
                        down  lo  ca.  110  m  of depth.  While  most  materia!  perlains  lo  Recenl  assemblages,  two
                        subfossil plales of Hanleya nagelfar are considered as probably belonging to glacial Pleistoce-
                        ne  deep-sea coral  assemblages.  The high  number of chilons collecled  clearly  reflecls  lhe
                        existence of many differenl  hard-bottom habilats in  the study-area.
                        Key words:  Polyplacophora, Mollusca, Quatcrnary. Strait of Sicily

          Chitons are primitive shelled benthic mol-  (Tab.  l)  and  the  present  contribution  re-
        luscs belonging to the class Polyplacophora,   ports upon their taxonomic, ecologie and pa-
        known  since  the  Early Paleozoic and  today   Ieobiogeographic aspects.
        represented by more than 800 species. Mem-
        bers of this class are exclusively marine and
        distributed  from  supratidal  to  abyssal
        depths, typically associated to hard substrata   Taxonomy
        (e.g.,  Squires  and  Goedert,  1995).  Modero
        chitons  secrete  a  Sr-rich  aragonitic  shell   We have identified 17 taxa at species leve!
        (Milliman,  1974)  consisting  of eight  plates   (Tab. 2).  With only one exception (Hanleya
        kept together by a chitinous girdle that gets   nagelfar,  probably a  glacial  Pleistocene  fos-
        easily loose post-mortem  because of the dis-  si!), ali  taxa  belong to species typical of the
        integration  of binding  non-mineralized  tis-  Recent Mediterranean fauna.
        sues.  Thus,  loose  chiton  plates  may  contri-
        bute in forming biogenic skeletal sediments,
        although  they  are  quantitatively scarce  and   Class POL YPLACOPHORA Gray 1821
        only occasionally  recorded  in  the  literature   Order NEOLORICATA Bergenhayn 1955
        as  a  minor constituent  (Paleozoic:  Lang et   Suborder LEPIDOPLEURINA Thiele 1910
        al.,  1982;  Recent:  Wilson,  1979,  among  ot-  Superfamily LEPIDOPLEUROIDEA Del-
        hers).  Possible  exceptions  are  skeletal  as-  l'Angelo and Palazzi  1991
        semblages  enriched  in  chiton-plates  known   Family LEPIDOPLEURIDAE Pilsbry 1892
        from  early  Pliocene  and  early  Pleistocene   Genus Lepidopleurus Rissa  1826
        shallow-water  deposits  of Tuscany  (Laghi,     Subgenus Lepidopleurus s.s.
        1984; Dell'Angelo and Forli, 1995).
          Living individuals and loose plates of chi-  Lepidopleurus  (Lepidopleurus)  cajetanus
        tons have been found in many CS96 stations   (Pou, 1791)  Pl.  l, Fig.  8

        1  Scienlific results of Cruise CS96 in  lhe Slrail of Sicily.

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