Platecarpus skull, Peabody Museum, Yaleo University,. Lestosaurus gracilis: YPM 1264, a partial skeleton. (1999). Caldwell. Platecarpus tympaniticus skull, dorsal view with lower jaws. Small structures in the retina, each around 2 µm long and observed by scanning electron microspectroscopy, may represent retinal melanosomes preserved in their original positions. Diet Platecarpus had a long, down-turned tail with a large dorsal lobe on it, steering flippers, and jaws lined with conical teeth. Platecarpus ("Flat wrist") is an extinct genus of aquatic lizard belonging to the mosasaur family, living around 75 million years ago during the end of the Cretaceous period.  In 1898, on further analysis of the remains, it was determined that the mosasaur be placed in the genus Platecarpus. Scales on the tip of the snout and the top of the skull are somewhat hexagonal in shape and do not touch one another. The scales on the jaws are longer and rhomboidal in shape, overlapping one another. 2012, Leidy 1873, Lindgren et al. 172152), Platecarpus gracilis Marsh 1872 (no. [note 1] LACM 128319 preserves matter within the sclerotic ring that may possibly be the retina of the eye. The early mosasauroid Vallecillosaurus also preserves body scales, but they are larger and more varied in shape, suggesting that the animal relied on undulatory movement in its trunk rather than just its tail. , Internal organs, or viscera, may also be preserved in the specimen as reddish areas.  Since then, fragmentary fossils and one complete skull have been uncovered in the same area, as well as possible specimens from Belgium and Africa. At the point of the tail where the fluke begins the vertebral centra are shortened and disk-like. Only one species, P. tympaniticus, is currently regarded as valid, but many other species have been named in the past. This type of reptile had hinged jaws like a snake and could swallow their prey whole. , The caudal, or tail vertebrae, are sharply downturned. , It was first believed that Platecarpus and other mosasaurs moved their bodies from side to side like an eel while swimming, and that they had straight tails. 172151), Lestosaurus curtirostris Cope 1871 (no. Platecarpus skull, Peabody Museum, Yaleo University.  In 1898, on further analysis of the remains, it was determined that the mosasaur be placed in a separate genus, Platecarpus. LACM 128319 preserves matter within the sclerotic ring that may possibly be the retina of the eye.  The type specimen underwent another taxonomic review in 1967, when paleontologist Dale Russell determined that the remains were too fragmentary to be placed within any genus, and deemed it to be a specimen of "uncertain taxonomic position". Based on its position, the organ in the thoracic cavity is probably the heart or liver, or even both of those organs. On the reptilian orders Pythonomorpha and Streptosauria. The small size and similar shape of these scales throughout the body would have stiffened the trunk, making it more resistant to lateral movement.  A well-preserved specimen of Platecarpus shows that it fed on moderate-sized fish, and it has been hypothesized to have fed on squid, and ammonites as well. Uploaded By lanem688. doi:10.1371/journal.pone.0011998. It grew up to 4.3 m (14 ft) long, with half of that length taken up by its tail. Williston 1898 - includes drawings of the skull of Platecarpus ictericus. Platecarpus probably fed on fish, squid, and ammonites. The ligaments were probably made of collagenous fibers that acted as springs to move the tail back into a resting position after energy was stored in them. The type specimen of Platecarpus planiforns was discovered by Professor B. F. Mudge and was classified by Edward Drinker Cope as Clidastes planiforns.  The type specimen underwent another taxonomic review in 1967, when paleontologist Dale Russell determined that the remains were too fragmentary to be placed within any genus, and deemed it to be a specimen of "uncertain taxonomic position". These substances are evidence of hemoglobin decomposition products that may have formed in the organs as they decomposed. The type specimen of Platecarpus (P. planiforms) was discovered by Professor B. F. Mudge and was classified by Edward Drinker Cope as Clidastes planiformes.