ichthyosaurian

The assumed position of the naris in hupehsuchians as explained above can be taken as evidence for possible ichthyosaurian affinities, as it is in the same general area as those of ichthyosaurs.

It could be that the ichthyosaurian over-specialisation was a contributing factor to their extinction, possibly being unable to 'keep up' with the fast swimming and highly evasive new teleost fish, which had become dominant at this time, against which the sit-and-wait ambush strategies of the mosasaurs proved superior (Lingham-Soliar 1999).