Palaeoenvironmental, paleontologic and stratigraphic significance of vertebrate remains in pleistocene limnic and alluvial deposits from southeastern Sicily

Abstract

In southeastern Sicily on the Hyblean Plateau limnic deposits overlie early Pleistocene marine sediments and are covered by early Middle Pleistocene marine sands. In the limnic deposits fossil remains of large mammals have been collected and these represent the oldest found in a well-established Pleistocene stratigraphic succession in Sicily. The faunal association includes: Elephas falconeri Busk, the smallest Sicilian elephant, an elephant less reduced in size than E. falconeri, a canid ( Vulpes sp.?), rodents [ Leithia melitensis (Adams)], Chiroptera, Insectivora, fishes, birds, amphibians ( Bufo sp., Discoglossus sp.), and reptiles ( Lacerta sp., Testudo sp., Emys orbicularis Linnaeus). Alluvial fan deposits overlying the limnic deposits contain Elephas mnaidriensis Adams, Hippopotamus pentlandi Meyer, Cervus siciliae Pohlig and Bovidae. These new findings provide the stratigraphic evidence to definitively discredit previous chronological schemes for the Pleistocene dwarf elephants, which assumed a progressive decrease of the size with time, a hypothesis recently questioned by isoleucine epimerization age determination, which, however were object of discussion. These findings also represent a new step toward a better knowledge of the taphonomic conditions of the Pleistocene mammal-bearing deposits in Mediterranean islands, traditionally linked to karstic environment. Distribution of mammal faunas in the Hyblean Plateau proves fundamental in recognizing and dating Pleistocene mammal faunas in Sicily; the new findings fully confirm the assumption that Sicily experienced two elephant immigrations in Pleistocene times.