"Mammut" borsoni

"Mammut" borsoni was first described by American naturalist Isaac Hays in 1834 as Mastodon borsoni, for a tooth discovered near Villanova d'Asti in Piedmont, Italy. It was named after professor , who had originally attributed the tooth to the species Mastodon giganteum. Since its description it has been attributed to both the genera Zygolophodon and Mammut. The attribution of "M". borsoni to Mammut has been considered questionable, as the type species for Mammut, the American mastodon (Mammut americanum) is known from North America, and there is no clear evidence that there was a migration of Mammut from Eurasia to North America (a hypothesis historically favoured by some authors such as Günther Schlesinger and Heinz Tobien, and still favoured by some modern authors) or vice versa after the initial dispersal of Zygolophodon from Eurasia to North America c. 16 million years ago, with the generally accepted (though not universally so It has been suggested that "M." borsoni derives from the lineage of Zygolophodon turicensis. Some authors choose to segregate some late Miocene fossils into the species "Mammut" obliquelophus, which has molars essentially identical to the Pliocene "Mammut" borsoni; however, the mandibular symphysis (the fused front-most part) of the lower jaw is somewhat more elongated with larger lower tusks, and the upper tusks are probably shorter. == Description ==

(Mammut americanum, bottom right), to tall human figures|275x275px Like many other proboscideans including living elephants, the species is suggested to have been sexually dimorphic, with considerably larger males than females. with an estimated mass in life of around . Females are suggested to have probably had smaller tusks than males, similar to modern elephants. The anatomy of the ulna, radius, femur, and foot bones of "Mammut" borsoni are more morphologically similar to those of the American mastodon (Mammut americanum) than to Zygolophodon turicensis, though the converse is true for the humerus and tibia, The humerus has a distinctly convex outline in medial view (when viewed from the inner side respective to life position), with the shaft being triangular shaped in cross section. The olecranon process of the ulna where it articulates with the elbow is very robust and projects out to the side (laterally). The intercondylar fossa of the femur is narrower in "M." borsoni than in the American mastodon and more similar to Z. turicensis. The condylus medialis of the tibia where connects to the knee joint with the femur is large. The fibula shaft is relatively thin. with the brain of the Moldovan specimen estimated to have weighed approximately . == Ecology ==

(upper left), rhinoceros Stephanorhinus etruscus, the pig Sus minor and the bovine Leptobos stenometopon,'' alongside pikas, ptarmigans and grouse.|350x350px Dental microwear and mesowear analysis of specimens from the Pliocene of Romania and England (Red Crag), respectively, as well as isotopic analysis of specimens from Milia, suggest that "M". borsoni was primarily a browser on leaves and twigs of woody plants. In Pliocene Europe, it coexisted with other proboscidean species, including the mammoth Mammuthus rumanus and the "tetralophodont gomphothere" Anancus arvernensis, which also had browsing-based diets. == Distribution and chronology ==

"Mammut" borsoni is known from localities across Europe, spanning from the Iberian Peninsula in the west to Greece and Ukraine in the east. and Shanxi in northern China, though it has been argued by some authors that the Chinese remains should be assigned to the separate species M. shansiense. The oldest specimens of the "Mammut" borsoni lineage sensu lato date to the late Miocene (around 9-7 million years ago), while the youngest date to the earliest Pleistocene, around 2-2.5 million years ago (Mammal Neogene zone 17). == References ==