  Evidence is mounting that a significant fraction of the early-type galaxy
population contains substantial reservoirs of cold interstellar gas and dust.
We investigate the gas and dust in NGC 5485, an early-type galaxy with a
prominent minor-axis dust lane. Using new Herschel PACS and SPIRE imaging data,
we detect 3.8 x 10^6 Msun of cool interstellar dust in NGC 5485, which is in
stark contrast with the non-detection of the galaxy in sensitive HI and CO
observations from the ATLAS3D consortium. The resulting gas-to-dust ratio upper
limit is Mgas/Md < 14.5, almost an order of magnitude lower than the canonical
value for the Milky Way. We scrutinize the reliability of the dust, atomic gas
and molecular gas mass estimates, but these do not show systematic
uncertainties that can explain the extreme gas-to-dust ratio. Also a warm or
hot ionized gas medium does not offer an explanation. A possible scenario could
be that NGC 5485 merged with an SMC-type metal-poor galaxy with a substantial
CO-dark molecular gas component and that the bulk of atomic gas was lost during
the interaction, but it remains to be investigated whether such a scenario is
possible.
