Editing Mosasaur (section)

===Soft tissue===
[[Image:Tylosaurus skin.jpg|thumb|left|Scales of ''Tylosaurus proriger'' (KUVP-1075)]]
Despite the many mosasaur remains collected worldwide, knowledge of the nature of their skin coverings remains in its early stages. 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. 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]]<ref name=Kaddumi>{{cite book |last=Kaddumi |first=H.F. |year=2009 |chapter=On the latest scale coverings of mosasaurs (Squamata: ''Mosasauridae'') from the Harrana Fauna in addition to the description of s new species of Mosasaurus |title=Fossils of the Harrana Fauna and the Adjacent Areas |publisher=Eternal River Museum of Natural History |location=[[Amman]] |pages=80–94}}</ref> 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.<ref name=Snow>{{cite journal |last=Snow |first=F. H. |year=1878 |title=On the dermal covering of a mosasauroid reptile |journal=Transactions of the Kansas Academy of Science |volume=6 |pages=54–58 |doi=10.2307/3623557 |jstor=3623557 }}</ref>

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. Much like those of modern reptiles, mosasaur scales varied across the body in type and size. In Harrana specimens, two types of scales were observed on a single specimen: keeled scales covering the upper regions of the body and smooth scales covering the lower.<ref name=Kaddumi/> As ambush predators, lurking and quickly capturing prey using stealth tactics,<ref name=Massare>{{cite journal |doi=10.1080/02724634.1987.10011647 |last=Massare |first=J. A. |year=1987 |title=Tooth morphology and prey preference of Mesozoic marine reptiles |journal=Journal of Vertebrate Paleontology |volume=7 |issue=2 |pages=121–137|bibcode=1987JVPal...7..121M }}</ref> they may have benefited from the nonreflective, keeled scales.<ref name=Kaddumi/> Additionally, mosasaurs had large pectoral girdles, and such genera as ''Plotosaurus'' may have used their front flippers in a breaststroke motion to gain added bursts of speed during an attack on prey.<ref>{{Cite web | url=https://www.sciencedaily.com/releases/2019/09/190923140812.htm |title = Did mosasaurs do the breast stroke?}}</ref> 
[[Image:Soft tissue structures in Platecarpus.png|thumb|Soft tissues in the head and neck of ''Platecarpus tympaniticus'' specimen LACM 128319: Tracheal rings are shown in the bottom three photographs.]]
More recently, a fossil of ''[[Platecarpus|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. The trachea is also preserved, along with part of what may be the [[retina]] in the eye. The placement of the kidneys is farther forward in the abdomen than it is in monitor lizards, and is more similar to those of [[cetacean]]s. As in cetaceans, the [[bronchi]] leading to the lungs run parallel to each other instead of splitting apart from one another as in monitors and other terrestrial reptiles. In mosasaurs, these features may be internal adaptations to fully marine lifestyles.<ref name=LCKC10/>
[[File:Prognathodon tissue.jpg|thumb|left|Fibrous tissues and microstructures recovered from ''Prognathodon'' specimen IRSNB 1624]]

In 2011, [[collagen]] protein was recovered from a ''[[Prognathodon]]'' humerus dated to the [[Cretaceous]].<ref>{{Cite journal |last1=Lindgren |first1=Johan |last2=Uvdal |first2=Per |last3=Engdahl |first3=Anders |last4=Lee |first4=Andrew H. |last5=Alwmark |first5=Carl |last6=Bergquist |first6=Karl-Erik |last7=Nilsson |first7=Einar |last8=Ekström |first8=Peter |last9=Rasmussen |first9=Magnus |date=29 April 2011 |title=Microspectroscopic Evidence of Cretaceous Bone Proteins |journal=[[PLoS ONE]] |language=en |volume=6 |issue=4 |pages=e19445 |doi=10.1371/journal.pone.0019445 |issn=1932-6203 |pmc=3084868 |pmid=21559386 |first10=Desirée A. |last10=Douglas |first11=Michael J. |last11=Polcyn |first12=Louis L. |last12=Jacobs|bibcode=2011PLoSO...619445L |doi-access=free }}</ref>

In 2005, a [[case study]] by A.S. Schulp, E.W.A Mulder, and K. Schwenk outlined the fact that mosasaurs had paired [[fenestra]]e in their palates. In monitor lizards and snakes, paired fenestrae are associated with a [[forked tongue]], which is flicked in and out to detect chemical traces and provide a directional sense of [[Olfaction|smell]]. They therefore proposed that mosasaurs probably also had a sensitive forked tongue.<ref>{{Cite journal |last1=Schulp |first1=A. S. |last2=Mulder |first2=E. W. A. |last3=Schwenk |first3=K. |date=2005-09-01 |title=Did mosasaurs have forked tongues? |journal=Netherlands Journal of Geosciences |volume=84 |issue=3 |pages=359–371 |doi=10.1017/S0016774600021144 |doi-access=free |bibcode=2005NJGeo..84..359S }}</ref>