  We have studied a large number of elliptical galaxies and found a correlation
between their dark matter content and the ellipticity of their visible shape.
The galaxies were strictly selected so that only typical medium-size elliptical
galaxies were considered. Galaxies with unusual characteristics were rejected
to minimize point-to-point data scatter and avoid systematic biases. Data from
six different techniques of extracting the galactic dark matter content were
used to avoid methodological biases. A thorough investigation of the
interrelation between attributes of elliptical galaxies was carried out to
assess whether the correlation originates from an observational bias, but no
such origin could be identified. At face value, the correlation found implies
that at equal luminosities, rounder medium-size elliptical galaxies appear to
contain less dark matter than flatter elliptical galaxies, e.g. the rounder
galaxies are on average four times less massive than the flatter ones. This is
puzzling in the context of the conventional model of cosmological structure
formation.
