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New brooding echinoid from the Italian Pleistocene            3

                                                        southern Italy and correlate with deep-sea sapropels          probably lived and developed during a cooling trend; cer-
                                                        (Lickorish & Butler 1996; Pomar & Tropeano 2001;              tainly, assemblages from north-western France
                                                        Roveri & Taviani 2003; Massari & Chiocci 2006). How-          (Neraudeau et al. 2003) developed when this area was no
                                                        ever, the Gelasian was, generally, a period of relatively     longer subject to tropical-subtropical conditions (Mone-
                                                        warm conditions in the Mediterranean (Monegatti & Raffi        gatti & Raffi 2007 with references). Above the latitude of
                                                        2001), with a climate similar to or possibly slightly         50 N, in the southern North Sea Basin, colder conditions
                                                        warmer (at least during interglacials) than that in the       likely occurred during the deposition of the Coralline
                                                        present-day Mediterranean, and may represent a key time       Crag and the Red Crag. However, the climatic setting of
                                                        for understanding what may be expected before the onset       the Coralline Crag, as well as of the southern part of the
                                                        of the warm conditions projected for the end of the 21th      North Sea Basin during the earlyÀmiddle Pliocene, is
                                                        century. A remarkable unevenness has typified the Early        controversial since both subtropical and cold-water mol-
                                                        Pleistocene Mediterranean climate since the end of the        lusc species, such as the boreal bivalve Arctica islandica
                                                        Gelasian, at about 1.8 Ma. From this time on, warm condi-     (Linnaeus, 1767), are found within this stratigraphical
                                                        tions with low seasonality (Garilli 2011) have alternated     range (Monegatti & Raffi 2007; Johnson et al. 2009; Wil-
                                                        with colder periods with higher seasonality (Raffi 1986).      liams et al. 2009 with references; Long & Zalasiewicz
                                                        Climatic differences between interglacial (warmer) and        2011). Possibly, the area underwent a more or less marked
                                                        glacial (colder) settings have become more marked since       alternation of colder and warmer periods, similar to that in
                                                        the onset of the harsher Ice Ages at about 0.8 Ma.            the Calabrian of the Mediterranean area.

Downloaded by [vittorio garilli] at 22:43 08 June 2016  An overview on the distribution of                            Geological setting
                                                                                                                      The investigated deposits are all in northern and southern
                                                        The family Temnopleuridae includes 16 genera, whose           Italy, in a general geological setting that reflects the geo-
                                                        oldest records date back to the Eocene of southern Asia       dynamic evolution of the central Mediterranean area,
                                                        and Australia. Since then the family has spread into a        namely the result of complex interactions between exten-
                                                        wide area mainly consisting of Australia, the Indian          sional and collisional tectonic processes controlled by the
                                                        Ocean and the Indo-West Pacific area, with several gen-        compressive motions of the African and Eurasian plates
                                                        era, most of which are still living within a latitudinal      and their microplates, such as the Adriatic and Apulian
                                                        range of about 41 S to 41 N (Fig. 1). Up to now, there      microplates (Dewey et al. 1989; Scrocca et al. 2003).
                                                        have been no fossil or living records of the family docu-     These processes generated the Alpine, the northern Apen-
                                                        mented in the Mediterranean area. Although no Temno-          nine and the southern Apennine-Maghrebian chains, and
                                                        pleuridae are present today in the north-eastern Atlantic, a  the Tyrrhenian back-arc basin, which are the main tec-
                                                        few genera of this family were well represented in that       tonic elements in central Mediterranean (Fig. 2A).
                                                        area during the late Neogene and the Early Pleistocene.
                                                        The genus Temnechinus Forbes, 1852 was first described            The study sites in northern Italy (Fig. 2AÀC) are in the
                                                        from the ZancleanÀ(?)early Piacenzian (Head 1998;             Adriatic-Apulian foreland structural domain, close to the
                                                        Monegatti & Raffi 2007 with references) Coralline Crag         main thrust of the Northern Apennines (Fig. 2A), a thrust
                                                        and the very late PiacenzianÀmiddle Gelasian (Williams        belt developed mainly in Neogene times during the east-
                                                        et al. 2009) Red Crag formations (Agassiz in Agassiz &        ward roll-back of the subducting Adriatic plate (Scrocca
                                                        Desor 1846; Forbes 1852) of England. Subsequently it          et al. 2003). They belong to the late PlioceneÀEarly Pleis-
                                                        was also cited from north-western France (Roman 1983;         tocene succession of the western Emilia Romagna, which
                                                        Neraudeau et al. 2003) and The Netherlands (Jagt &           formed in the north-western part of the palaeo-Adriatic
                                                        Idema 2002). Interestingly, a rich and diverse marsupiate     Basin under the control of a fan-delta system (Pervesler
                                                        temnopleurid fauna has been described from the late Mio-      et al. 2011). The late Pliocene deposits have been
                                                        cene (Messinian) and Pliocene of north-western France         regarded as a regressive succession transitioning from
                                                        (Roman 1983; Neraudeau et al. 2003; Dudicourt et al.         outer to inner shelf; the overlying Pleistocene deposits
                                                        2005), where the genera Temnechinus, Coptechinus Cot-         formed in shelf, nearshore, and transitional environment
                                                        teau, 1883 and Tremaster Dudicourt et al., 2005, with five     in a shallowing-upward trend (Dominici 2001, 2004; Per-
                                                        species, have been reported. This fauna is strongly differ-   vesler et al. 2011). Three of the deposits studied in north
                                                        entiated from the coeval Mediterranean echinoid assemb-       Italy formed in the Castell’Arquato Basin, a satellite basin
                                                        lages, which had a markedly thermophilic character            of the Adriatic foredeep, where late Neogene sediments
                                                        (Neraudeau et al. 2003). The late Cenozoic temnopleurid-     overlie the Mesozoic Ligurian complex (Roveri & Taviani
                                                        rich assemblage from north-western Europe therefore           2003). Several calcarenite bodies crop out in this basin,
                                                                                                                      particularly the system tracts of the sequences bounded by
                                                                                                                      the 3.1, 2.7 and 2.1 Ma (late PiacenzianÀlate Gelasian)
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