  Quantum oscillation measurements can provide important information about the
Fermi surface (FS) properties of strongly correlated metals. Here, we report a
Shubnikov-de Haas (SdH) effect study on the pnictide parent compounds
EuFe$_{2}$As$_{2}$ (Eu122) and BaFe$_{2}$As$_{2}$ (Ba122) grown by In-flux.
Although both members are isovalent compounds with approximately the same
density of states at the Fermi level, our results reveal subtle changes in
their fermiology. Eu122 displays a complex pattern in the Fourier spectrum,
with band splitting, magnetic breakdown orbits, and effective masses
sistematically larger when compared to Ba122, indicating that the former is a
more correlated metal. Moreover, the observed pockets in Eu122 are more
isotropic and 3D-like, suggesting an equal contribution from the Fe $3d$
orbitals to the FS. We speculate that these FS changes may be responsible for
the higher spin-density wave ordering temperature in Eu122.
