We have observed with XMM-Newton the extended 4 Mpc filament detected by the ROSAT PSPC in the neighbourhood of the cluster of galaxies Abell 85 .
We confirm that there is an extended feature , aligned at the same position angle as the major axis of the central cD , the bright cluster galaxies , and nearby groups and clusters .
We find that the X-ray emission from the filament is best described by thermal emission with a temperature of \sim 2 keV , which is significantly lower than the ambient cluster medium , but is significantly higher than anticipated for a gas in a weakly bound extended filament .
It is not clear whether this is a filament of diffuse emission , a chain of several groups of galaxies , or stripped gas from the infalling south blob .