Carbon dating live mollusk
Holes have been found in fossil shells of some ammonites, mainly Pachydiscus and Placenticeras.
These were once interpreted as a result of limpets attaching themselves to the ammonites, but the triangular shape of the holes, their size, and their presence on both sides of the shells, corresponding to upper and lower jaws, is evidence of the bite of medium-sized mosasaurs.
More recently, a fossil of Platecarpus tympaniticus has been found that preserved not only skin impressions, but also internal organs.
Several reddish areas in the fossil may represent the heart, lungs, and kidneys. Schwenk outlined the fact that mosasaurs had paired fenestrae in their palates.
Few mosasaurid specimens collected from around the world retain fossilized scale imprints.
This lack may be due to the delicate nature of the scales, which nearly eliminates the possibility of preservation, in addition to the preservation sediment types and the marine conditions under which the preservation occurred.
Mosasaur bones have also been found with shark teeth embedded in them.
One of the food items of mosasaurs were ammonites, molluscs with shells similar to those of Nautilus, which were abundant in the Cretaceous seas.
Mosasaurus hoffmannii, the largest known species, may have reached up to 17 m (56 ft) in length.Until the discovery of several mosasaur specimens with remarkably well-preserved scale imprints from late Maastrichtian deposits of the Muwaqqar Chalk Marl Formation of Harrana in Jordan, knowledge of the nature of mosasaur integument was mainly based on very few accounts describing early mosasaur fossils dating back to the upper Santonian–lower Campanian, such as the famous Tylosaurus specimen (KUVP-1075) from Gove County, Kansas.Material from Jordan has shown that the bodies of mosasaurs, as well as the membranes between their fingers and toes, were covered with small, overlapping, diamond-shaped scales resembling those of snakes.The smaller genera, such as Platecarpus and Dallasaurus, which were about 1–6 m (3.3–19.7 ft) long, probably fed on fish and other small prey.The smaller mosasaurs may have spent some time in fresh water, hunting for food.