Translated from L1 regional radio in the Netherlands:
The rest of the skeleton had probably already been excavated during the marl extraction in the ENCI quarry and so, it disappeared.
The scientists are pleased that most of the head has been recovered. In addition, they found, inter alia, the collar-bone and a so-called bud tooth of a few millimeters in size.
This is a new tooth hidden in the jaw which only emerges as an old tooth falls out.
Daily De Telegraaf again makes the mistake of calling the fossil a dinosaur. While mosasaurs are much closer related to, eg, monitor lizards of today then to dinosaurs.