摘要: Platybelodon is the predominant proboscidean of northern China’s Middle Miocene.
However, the cranial and cheek tooth morphologies are not clearly diagnosed. In particular, the
differential diagnoses between Platybelodon and Gomphotherium have not been comprehensively
examined. Here we restudied the cranium previously identified as Gomphotherium shensiense.
The upper tusks lack an enamel band, the rostrum is long and narrow, the facial part is rostrally
positioned, and a large “prenasal slope” is present. These characters are distinct from those of
any species of Gomphotherium, but fit well with some primitive species of Platybelodon, i.e.,
P. tongxinensis and P. danovi. The molars are also close to the type specimen of P. tongxinensis
in the tetralophodont M3 with mesiodistally wide interlophs, curved outline, and a tendency of
cementodonty. In this article, we synonymized Gomphotherium shensiense with P. tongxinensis.
Moreover, we recognized a new species, Platybelodon tetralophus, from the P. grangeri material
collected by the AMHN expedition in Tunggur region. Platybelodon tetralophus differs from P.
grangeri and the other species in the tetralophodont M2 and m2, representing the most derived
species within Platybelodon. It has only occurred in the uppermost horizon of the Tunggur
Formation, i.e., the Tamuqin Fauna (Platybelodon Quarry and Wolf Camp Quarry of AMHN).
This work is a comprehensive amending of the genus Platybelodon.