Leptochitonidae Dall, 1889

Family Leptochitonidae Dall, 1889 View in CoL

Genus Lepidopleurus Risso, 1826 View in CoL

Type species. Chiton cajetanus Poli, 1791 , by subsequent designation ( Herrmannsen 1846). Non Lepidopleurus (Carpenter MS) Dall, 1879 View in CoL (= Lepidozona Pilsbry, 1892 View in CoL ).

Distribution. Lepidopleurus is known from the Eocene to the Recent, with only a living species known ( L. cajetanus ), from the Mediterranean Sea and the Atlantic Ocean (from Spain and Portugal south to Morocco and Canary Islands). Lepidopleurus sp. has been cited from the Permian of Malaysia ( Gobbett & Hutchison 1973: pl. 10, fig. 9), but we consider this single record doubtful.

The genus is recorded with confidence in the Eocene of Ukraine ( Bielokrys 2000), Germany and France ( Dell’Angelo et al. 2011), upper Eocene/lower Oligocene of U.S.A. ( Dell’Angelo et al. 2011), Oligocene of Germany ( Janssen 1978), Miocene of Japan ( Itoigawa et al. 1977), France, Italy and Paratethys ( Dell’Angelo et al. 2007a, 2015 a, 2016, 2018a; Studencka & Dulai 2010), Pliocene of Spain ( Almera 1894; Dell’Angelo et al. 2004), France ( Dell’Angelo et al. 2018b) and Italy ( Dell’Angelo et al. 2001a, 2013)], Pleistocene of Italy ( Sacco 1897; Sabelli & Taviani 1979; Chirli 2004), Greece ( Garilli et al. 2005; Koskeridou et al. 2009), and Tunisia ( Castany et al. 1956).

Remarks. The relationships between Lepidopleurus Risso, 1826 and Leptochiton Gray, 1847 , have been long debated (Pilsbry 1892; Ferreira 1979; Dell’Angelo & Palazzi 1989, 1991), and even the molecular phylogenetic study by Sigwart et al. (2011) has not solved all problems. We consider Lepidopleurus (“valves solid, tegmentum heavily sculptured of heavy concentric ridges”) and Leptochiton (“valves thin, tegmentum finely granulose, granules of equal size”) to be distinct genera ( Kaas & Van Belle 1985a). The main morphological characteristics of the Lepidopleurus spp. considered in the present study are reported in Tab. 1.