  T Pyx is a recurrent nova which has undergone eruptions on an almost regular
basis every 20 years until reaching a long lasting quiescence between 1967 and
2011. We observed the long awaited 2011 explosion in the optical and near
infrared with intermediate spectral resolution. In this paper we report on the
change in the spectral type of the nova (both during its rise and during its
fading), as well as the observed changes in the expansion velocities. We also
present an interpretation of these changes and set them in the general
framework of a new understanding of nova classification.
