  The half-Heusler rare-earth intermetallic GdPtBi has recently gained
attention due to peculiar magnetotransport phenomena that have been associated
with the possible existence of Weyl fermions, thought to arise from the
crossings of spin-split conduction and valence bands. On the other hand,
similar magnetotransport phenomena observed in other rare-earth intermetallics
have often been attributed to the interaction of itinerant carriers with
localized magnetic moments stemming from the $4f$-shell of the rare-earth
element. In order to address the origin of the magnetotransport phenomena in
GdPtBi, we performed a comprehensive study of the magnetization, electrical and
thermal magnetoresistivity on two single-crystalline GdPtBi samples. In
addition, we performed an analysis of the Fermi surface via Shubnikov-de Haas
oscillations in one of the samples and compared the results to \emph{ab initio}
band structure calculations. Our findings indicate that the electrical and
thermal magnetotransport in GdPtBi cannot be solely explained by Weyl physics
and is strongly influenced by the interaction of both itinerant charge carriers
and phonons with localized magnetic Gd-ions and possibly also paramagnetic
impurities.
