  We investigate magnetotransport on Bernal-stacked tetralayer graphene whose
band structure consists of two massive subbands with different effective
masses. Under a finite displacement field, we observe valley splitting of
Landau levels (LLs) only in the light-mass subband, consistent with a
tight-binding model. At low density, we find unexpected magnetoconductance
oscillations in bulk gaps which originate from a series of hybridizations
between electron-like and hole-like LLs due to band inversion in tetralayer
graphene. In contrast to a trivial LL quantization gap, these inverted
hybridization gaps can lead to a change in number of edge states which explains
the observed oscillations.
