This picture was produced for a new paper about Brancasaurus, by far not a new genus, but one was hasn't been touched in many years.

The remains of Brancasaurus represent the most complete remains of an early cretaceous plesiosaur from Europe and will hopefully be on display again when the renovation 
of the Geomuseum Münster is finished. The animal was described by Wegner in 1914 and went to much trouble over the years, 2013 Gronausaurus was described but as the authors of the new paper show this is probably just a junior synonym of Brancasaurus.

In case you wonder about the color of the water: Brancasaurus, Gronausaurus and several other plesiosaur remains were found continental deposits of the shallow, brakish inland sea which was characterized by regular algae blooms and little influence from the rest of the Tethys; also found here were sharks like Hybodus the blunt snouted pycnodontiformes or the predatory fish Caturus.

In terms of coloration I originally had something reddish brown in mind, with striking contrasts but otherwise rather known, but I was encouraged to work more speculative and so this unusual pattern is inspired now by some coral fishes.

Reappraisal of Europe’s most complete Early Cretaceous plesiosaurian: Brancasaurus brancai Wegner, 1914 from the “Wealden facies” of Germany

Here the paper: peerj.com/articles/2813/

Edit: I need to thank Jahn Hornung as a main consultant, he had the idea for this unusual perspective and was a great help with providing information about the environment. In addition: I uploaded this, and another picture on Wikipedia for the new entry for this genus, it shows you how our picture of this animal evolved and gives you a idea how my first ideas for the coloration of this animal were: en.wikipedia.org/wiki/Brancasa…