Shark bite marks, including striae, sulci and abrasions, in a well-preserved fossil dolphin skeleton referred to Astadelphis gastaldii (Cetacea, Delphinidae) from Pliocene sediments of Piedmont (northern Italy), are described in detail. The exceptional combination of a fossil dolphin having a significant part of the skeleton preserved and a large number of bite marks on the bones represents one of the few detailed documentations of shark attack in the past. Most bite marks have been referred to a shark about 4 m long with unserrated teeth, belonging to Cosmopolitodus hastalis, on the basis of their shape and their general disposition on the dolphin skeleton. According to our hypothesis, the shark attacked the dolphin with an initial mortal bite to the abdomen from the rear and right, in a similar way as observed for the living white shark when attacking pinnipeds. A second, less strong, bite was given on the dorsal area when the dolphin, mortally injured, probably rolled to the left. The shark probably released the prey, dead or dying, and other sharks or fishes probably scavenged the torn body of the dolphin.
Zygophyseter varolai , a new genus and species of Physeteroidea (Cetacea, Odontoceti), is based on an almost complete skeleton from the Late Miocene (Tortonian) in southern Italy. The extreme elongation of the zygomatic process of the squamosal and the circular supracranial basin (probably for housing the spermaceti organ) delimited by a peculiar anterior projection of the supraorbital process of the right maxilla are the most distinctive features of this bizarre sperm whale. Large body size, large teeth present in both lower and upper jaw, and anteroposteriorly elongated temporal fossa and zygomatic process of the squamosal indicate that this cetacean (for which we suggest the English common name killer sperm whale) was an active predator adapted to feeding on large prey, similarly to the extant killer whale ( Orcinus orca ). A phylogenetic analysis reveals that Zygophyseter belongs to a Middle-Late Miocene clade of basal physeteroids, together with Naganocetus (new genus for the type of ' Scaldicetus ' shigensis ). Moreover, the phylogenetic analysis shows evidence of a wide physeteroid radiation during the Miocene and that the extant Physeter and Kogia belong to two distinct families that form a clade representing the crown-group Physeteroidea.
During the late Messinian,
c
. 5.5 Ma ago, after evaporitic sedimentation and before the Pliocene flooding, the Mediterranean recorded a major environmental change testified by deposition of non-marine sediments of the so-called ‘Lago-mare’ facies. Such deposits are widespread in the Mediterranean basin, usually characterized by molluscs and ostracodes of brackish affinity. Here we present marine fish remains from ‘Lago-mare’ deposits of central Italy. The fossils, represented by both articulated skeletons and otoliths, were collected from nine stratigraphic horizons of the upper portion of the ‘Lago-mare’ sequence of Cava Serredi, Tuscany. Marine euryhaline fishes strongly dominate the assemblages but fully marine stenohaline fishes belonging to the families Myctophidae and Bythitidae are also present. The fossil fish remains are associated with classic ‘Lago-mare’ ostracodes and molluscs. These fossil fishes clearly demonstrate that normal marine conditions were present at least during the upper interval of the ‘Lago-mare’ event, implying that the marine refilling of the Mediterranean was intra-Messinian rather early Pliocene. We argue in favour of the necessity of a new palaeoenvironmental interpretation for the post-evaporitic Messinian of the Mediterranean.
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