We study the spin Calogero model of D N type with polarized spin reversal operators, as well as its associated spin chain of Haldane-Shastry type, both in the antiferromagnetic and ferromagnetic cases. We compute the spectrum and the partition function of the former model in closed form, from which we derive an exact formula for the chain's partition function in terms of products of partition functions of Polychronakos-Frahm spin chains of type A. Using a recursion relation for the latter partition functions that we derive in the paper, we are able to numerically evaluate the partition function, and thus the spectrum, of the D N -type spin chain for relatively high values of the number of spins N . We analyze several global properties of the chain's spectrum, such as the asymptotic level density, the distribution of consecutive spacings of the unfolded spectrum, and the average degeneracy. In particular, our results suggest that this chain is invariant under a suitable Yangian group, and that its spectrum coincides with that of a Yangian-invariant vertex model with linear energy function and dispersion relation.paper, we shall extend the above results to spin Calogero models and their corresponding spin chains of Haldane-Shastry type based on the D N root system.In order to present our work in an appropriate context, let us briefly recall the origin and significance of the latter models. The Haldane-Shastry (HS) spin chain, introduced independently by these authors in the late eighties [4,5], is perhaps the best known example of an exactly solvable one-dimensional lattice model with long-range interactions. More precisely, this model describes a circular array of equispaced spins with two-body interactions inversely proportional to the square of the (chord) distance between the spins. The motivation for introducing this chain was the construction of a simple model with an exact ground state given by the U → ∞ limit of Gutzwiller's variational wavefunction for the ground state of the one-dimensional Hubbard model [6][7][8]. Over the years, the HS chain has appeared in many areas of interest both in Physics and Mathematics, such as fractional statistics and one-dimensional anyons [9-12], quantum entanglement [13], characterization of integrability vs. quantum chaos [14][15][16][17], quantum integrability via the asymptotic Bethe ansatz [18][19][20], Yangian quantum groups [12,[21][22][23], and conformal field theory [18,[24][25][26].One of the key properties of the HS chain -already noted by Haldane and Shastry in their original papers-is its intimate connection with the scalar (trigonometric) Sutherland model [27,28]. This connection was subsequently elucidated by Polychronakos in Ref. [2], who showed how to derive the HS chain from the spin Sutherland model [29][30][31] by a technique that he called the "freezing trick". The main idea behind this technique is to note that when the coupling constant in the spin Sutherland model goes to infinity the particles tend to concentrate on the coordinates of the (essential...