  Axisymmetric, orbit-based dynamical models are used to derive dark matter
scaling relations for Coma early-type galaxies. From faint to bright galaxies
halo core-radii and asymptotic circular velocities increase. Compared to
spirals of the same brightness, the majority of Coma early-types -- those with
old stellar populations -- have similar halo core-radii but more than 2 times
larger asymptotic halo velocities. The average dark matter density inside 2
reff decreases with increasing luminosity and is 6.8 times larger than in disk
galaxies of the same B-band luminosity. Compared at the same stellar mass, dark
matter densities in ellipticals are 13.5 times higher than in spirals.
Different baryon concentrations in ellipticals and spirals cannot explain the
higher dark matter density in ellipticals. Instead, the assembly redshift (1+z)
of Coma early-type halos is likely about two times larger than of comparably
bright spirals. Assuming that local spirals typically assemble at a redshift of
one, the majority of bright Coma early-type galaxy halos must have formed
around z = 2-3. For about half of our Coma galaxies the assembly redshifts
match with constraints derived from stellar populations. We find dark matter
densities and estimated assembly redshifts of our observed Coma galaxies in
reasonable agreement with recent semi-analytic galaxy formation models.
