Mustelercta Arzilla (De Gregorio, 1886), elemento villafranchiano nella fauna di Monte Pellegrino (Palermo, Sicilia)

Abstract

The species Mustela arzilla was discovered by De Gregorio in a fossiliferous deposit on the top of Monte Pellegrino (Palermo, Sicily) in 1886. The species was reexamined and compared, on the basis of osteological studies, to the remains of the very similar fossil mustelids of the genus Pannonictis Kormos, 1931 and Enhydrictis Major,1901. More specifically, the skull characteristics - curved profile, downward-inclined snout, compact and roundish cranium, a forking of the sagittal crest at the narrowest interorbitai point, triangular tympanic bullae converging toward the mesopterygoid fossa -were consistently recognised in the species of the Pannonictis genus and correspond fairly well to the description of genus Kormos. The Sicilian species also shows a very close resemblance and affinity to Pannonictis nestii from the Villafranchian deposit of Upper Valdarno and to recently discovered fossil mustelid finds from the Upper Villafranchian Pietrafitta fossiliferous deposit. The analysis of the jaws of these two forms reveals a clear resemblance to those of the Sicilian species, as the very similar shape and pattern of the mandibular branch, the ascending branch, the coronoid process, ecc. and their relative size indicate. Analysis of teeth and particularly of the M1, also show an exstraprdinary resemblance to the Sicilian species. The comparison should attribute the Monte Pellegrino species to the Pannonictis genus; however, we prefer to attribute the Sicilian species for the priority rule to Mustelercta arzilla because De Gregorio introduced the Mustelercta genus already in 1925. The affinity of the Sicilian genus to the Pannonictis genus contributes to a better definition of the biochfohological collocation of the Monte Pellegrino fauna, which had been attributed in the literature to an age ranging from the late Pliocene to the early Pleistocene. In fact, this affinity points to the the early Pleistocene as the chronological attribution of the Monte Pellegrino faunal complex (characterized by the endemic rodent Pellegrinia panormensis), and suggests that this fauna is the oldest continental fauna of the Pleistocene in Sicily.