  The (2+1)-dimensional spherical Kadomtsev-Petviashvili (SKP) equation of
J.-K. Xue [Phys. Lett. A 314:479-483 (2003)] fails the Painleve test for
integrability at the highest resonance, where a nontrivial compatibility
condition for recursion relations appears. This compatibility condition,
however, is sufficiently weak and thus allows the SKP equation to possess an
integrable (1+1)-dimensional reduction, which is detected by the Weiss method
of truncated singular expansions.
