  Integrable deformations of the hyperbolic and trigonometric ${\mathrm{BC}}_n$
Sutherland models were recently derived via Hamiltonian reduction of certain
free systems on the Heisenberg doubles of ${\mathrm{SU}}(n,n)$ and
${\mathrm{SU}}(2n)$, respectively. As a step towards constructing action-angle
variables for these models, we here apply the same reduction to a different
free system on the double of ${\mathrm{SU}}(2n)$ and thereby obtain a novel
integrable many-body model of Ruijsenaars--Schneider--van Diejen type that is
in action-angle duality with the respective deformed Sutherland model.
