Note on $\mathcal{N}=8$ supersymmetric mechanics with dynamical and semi-dynamical multiplets

We give a Hamiltonian formulation of the new model of $\mathcal{N}=8$ supersymmetric mechanics recently proposed by S.~Fedoruk and E.~Ivanov and show that it possesses the dynamical $\mathcal{N}=8$ superconformal symmetry $osp(8\mathrm{\mid }2)$. The bosonic part of the Hamiltonian is just a free particle on eight-dimensional cone embedded in nine-dimensional pseudo-Euclidean space, while the fermionic part can be interpreted as a spin-orbit interaction term.