MOSASAURINAE, Gervais, 1853

Caldwell, M. W., 2007, Ontogeny, anatomy and attachment of the dentition in mosasaurs (Mosasauridae: Squamata), Zoological Journal of the Linnean Society 149 (4), pp. 687-700 : 692

( MOSASAURINAE )

The illustrated maxillary dentition ( Fig. 3A, B ) is part of a well-preserved skull of Mosasaurus hoffmanni that shows minute details of the surface textures of the differing dental and cranial bony tissues ( Fig. 3B ). There are only a few empty alveoli indicating the loss of the adult tooth from that tooth position, whereas most tooth positions have an adult tooth fixed in the socket and a replacement tooth (merely a crown tip in most cases) positioned vertically within the posterolingually positioned replacement pit/crypt. Of importance to note with this specimen is that none of the replacement teeth are in a recumbent position in the developing crypt; all are vertically aligned. It is also important to note that the tooth crown settled within each pit is extremely small and is nothing more than the tip of the crown at this stage.

Development of the resorption pit is exemplified by the tooth position at the centre of Figure 3B : the crown–cement contact is clear; the textural features of the exposed cement portion of the root are demarcated; there is a thin, featureless zone of cement below the level of the alveolus; and the margin of the alveolus (alveolar bone), resembling a small crater, is also well preserved. The incipient replacement crown is vertically positioned within a replacement pit/crypt that has resorbed a portion of the alveolar bone tissue forming the margin, and is encroaching into the cement of both the contact zone and the root.

Figures

Figure 3. A, palatal view of right and left maxillae and vomeropalatines of Mosasaurus hoffmanni (IRScNB R12). B, close up of ‘A’ showing vertical position of all replacement teeth sitting in posterolingually positioned resorption pits. C, lateral view of right pterygoid of holotype specimen of Mosasaurus hoffmanni (MNHM 9648).