  We observed the coexistence of superconductivity and antiferromagnetic order
in the single-crystalline ternary pnictide HoPdBi, a plausible topological
semimetal. The compound orders antiferromagnetically at $T_N =$1.9 K and
exhibits superconductivity below $T_c =$0.7 K, which was confirmed by magnetic,
electrical transport and specific heat measurements. The specific heat shows
anomalies corresponding to antiferromagnetic ordering transition and
crystalline field effect, but not to superconducting transition. Single-crystal
neutron diffraction indicates that the antiferromagnetic structure is
characterized by the (1/2, 1/2, 1/2) propagation vector. Temperature variation
of the electrical resistivity reveals two parallel conducting channels of
semiconducting and metallic character. In weak magnetic fields, the
magnetoresistance exhibits weak antilocalization effect, while in strong fields
and temperatures below 50 K it is large and negative. At temperatures below 7 K
Shubnikov-de Haas oscillations with two frequencies appear in the resistivity.
These oscillations have non-trivial Berry phase, which is a distinguished
feature of Dirac fermions.
