We present time-resolved optical spectroscopy and photometry of the nova-like cataclysmic variable V348 Puppis .
The system displays the same spectroscopic behaviour as SW Sex stars , so we classify V348 Pup as a new member of the class .
V348 Pup is the second SW Sex system ( the first is V795 Herculis ) which lies in the period gap .
The spectra exhibit enhanced He ii \lambda 4686 emission , reminiscent of magnetic cataclysmic variables .
The study of this emission line gives a primary velocity semi-amplitude of K _ { 1 } \simeq 100 km s ^ { -1 } .
We have also derived the system parameters , obtaining : M _ { 1 } \simeq 0.65 M _ { \sun } , M _ { 2 } \simeq 0.20 M _ { \sun } ( q \simeq 0.31 ) , i \simeq 80 \degr and K _ { 2 } \simeq 323 km s ^ { -1 } .
The spectroscopic behaviour of V348 Pup is very similar to that of V795 Her , with the exception that V348 Pup shows deep eclipses .
We have computed the “ 0.5-absorption ” spectrum of both systems , obtaining spectra which resemble the absorption spectrum of a B0 V star .
We propose that absorption in SW Sex systems can be produced by a vertically extended atmosphere which forms where the gas stream re-impacts the system , either at the accretion disc or at the white dwarf ’ s magnetosphere ( assuming a magnetic scenario ) .