  We show that $U(k)$-invariant hypercomplex structures on (open subsets) of
regular semisimple adjoint orbits in $\mathfrak{gl}(k,{\mathbb C})$ correspond
to algebraic curves $C$ of genus $(k-1)^2$, equipped with a flat projection
$\pi:C\to{\mathbb P}^1$ of degree $k$, and an antiholomorphic involution
$\sigma:C\to C$ covering the antipodal map on ${\mathbb P}^1$.
