A reappraisal of the dwarfed mammoth Mammuthus lamarmorai (Major, 1883) from Gonnesa (south-western Sardinia, Italy)

The Gonnesa Quaternary deposits have been cited since the end of the 19th century due to the discovery, during the construction of a railway, of an incomplete postcranial skeleton belonging to an endemic dwarfed elephant, afterward described by Major as a new species (“Elephas lamarmorae” Major, 1883). Although the remains have since been reported in the literature as coming from the aeolian deposits outcropping at Funtana Morimenta, the precise provenance of the findings and their chronostratigraphical setting remained uncertain. Taking into account the route of the now disused railway, the stratigraphical successions of the Morimenta area, and the fact that the elephant bones were actually collected during a number of excavations spanning several decades, the location of the fossiliferous site is most likely on the northeast end slope of Guardia Pisano hill (Gonnesa), where aeolianites correlate with the Funtana Morimenta Formation (FMF) outcrop. The FMF is supposed to predate the onset of the MIS 5e climatic event and the Tyrrhenian “Panchina” overlies equivalent deposits cropping out along the Gonnesa Gulf coast. Therefore, the hypothesis that the elephant remains found in the “Morimenta” area were retrieved from late Middle Pleistocene deposits cannot be ruled out. The anatomical features of the bones suggest they represent a single individual, perhaps partially exposed and damaged before the discovery. New evidence, including a thus far unpublished tusk fragment from the Guardia Pisano hill (Gonnesa), whose Schreger angles fall within the range of Mammuthus, supports the systematic attribution of the incomplete Morimenta skeleton to a dwarfed mammoth. The size reduction of this Sardinian dwarfed mammoth is discussed in light of body-mass changes undergone by insular endemic elephants.