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Doug Henderson's Marine Paleo-Life Art

Copyright 1999-2011 by Mike Everhart and Doug Henderson

Last Revised 05/09/2011

 

 

 

 

 

LEFT: Primitive toothed birds called Ichthyornis dispar rest near the large crocodile Deinosuchus while a herd of hadrosaurs (Claosaurus agilis Marsh) passes by in the background  in this paleo-life art by Doug Henderson. Copyright Doug Henderson; used with permission of Doug Henderson. While Deinosuchus remains have not yet been found in Kansas, another similar but smaller crocodile called Dakotasuchus kingi is found here.  See David Schwimmer's book, "King of the Crocodylians" for more information on Deinosuchus.


In 1991, Patricia Lauber's Living with Dinosaurs was published by Maxwell Macmillan International Publishing Group. The book was written about life during the late Cretaceous (75 million years ago) and was illustrated with 26 new paleo-life artworks created by Douglas Henderson. Marine creatures, birds and Pteranodons were the subjects of many of his paintings. Doug Henderson has generously given me permission to use these pictures as illustrations on the Oceans of Kansas Paleontology webpage. They will soon be found on various pages on the Oceans of Kansas website, but I wanted to show all of them together in one place so that the reader can get a feel for the variety of creatures that Doug re-created in his pictures. I also wanted to be able to give some background about the animals shown in the pictures in the context of the fossils that we find represented in the Smoky Hill chalk and Pierre Shale. All the pictures are Copyright by Doug Henderson, and may not be used in any form without his permission. 'Click' on the thumbnails below to see the larger version.

Two adult male Pteranodons soar on the air currents rising above the western shore of the late Cretaceous Western Interior Seaway. While their coloration is not preserved in the fossil record, it is reasonable to assume that they had the same variety of colors as modern sea birds. Although they were reptiles and did not have feathers, there is evidence that their skin was covered with fine, hair-like fibers. From stomach contents preserved with some specimens, it appears that Pteranodon fed almost exclusively on fish.
Here, a full grown,  adult male Pteranodon is shown in flight over the seaway.  According to research done by Chris Bennett, male Pteranodons were substantially larger than the females. Based on his measurements of hundreds of specimens, Bennett concluded that the adult males were about 50% larger than the females, with wing spans of up to 24 feet. Only the males had the large crests on their heads.  The purpose of this the crest is unknown and is the subject of a lot of speculation.
This picture shows a group of large, flightless marine birds called Hesperornis  riding the crest of a wave in mid-ocean. Their legs were highly adapted for swimming; so much so that they probably could not walk upright on land.   They fed on small fish and probably lived in colonies much like modern penguins. In the background, two female Pteranodons skim low over the surface in search of food.
Protostega gigas was a giant, leatherback-like sea turtle that grew to lengths of nine feet or more during the deposition of the Smoky Hill chalk. Xiphactinus audax was the largest fish in the seaway, growing to as large as 20 feet in length.  It was a voracious predator, often swallowing fishes almost half its length. Apparently, its appetite was frequently its undoing because many specimens have been found with the undigested prey still inside, indicating that the larger fish died shortly after swallowing the smaller one.  Swarms of squid and other invertebrates provided food for many other species. 
Here a small Clidastes mosasaur dives in search of a meal.   Clidastes was one of the smaller varieties of mosasaurs (less than 20 feet) and probably stayed fairly close to shore where it was less vulnerable to being eaten by pliosaurs or the bigger mosasaur species such as Tylosaurus.  Coiled ammonites use jets of water to move through the beds of sea weeds looking for food.  Ammonites were an old and and very successful group of invertebrates which became extinct about the same time as the dinosaurs, and the marine reptiles such as mosasaurs and plesiosaurs.
The plesiosaurs, including this long-necked Elasmosaurus, used their rigid, bony paddles like wings to 'fly' through the water.   This half-grown juvenile is swimming rather close to a huge (18') shark called Cretoxyrhina mantelli.  Whether or not these sharks attacked living prey or only scavenged the carcasses of the dead is not known for certain, but the marks made by their large, sharp teeth have been found on mosasaur and plesiosaur bones.
Fossils provide evidence that  at least one large species of squid lived in the Western Interior Seaway.  It is possible that they were a favorite prey for the mosasaurs and pliosaurs.  Here the squid Tusoteuthis has foiled the initial attack of a diving Tylosaurus by jetting away and releasing a cloud of black ink into the water.  The squid may be able to escape by going deeper than the mosasaur is able to dive.  "Microscopic evidence found by Martin and Rothschild in the fossilized bones of mosasaurs indicates that they were susceptible to decompression sickness (also known as 'the bends'), a condition caused by the formation and expansion of nitrogen bubbles in the blood and tissues during a rapid ascent from a deep dive." (Duane K. Dougal, 1999, personal communication)
A large pliosaur (a short-necked plesiosaur) called Brachauchenius lucasi swims slowly near the surface of the ocean while an ancestor of Hesperornis chases after another that has managed to catch a small plesiosaur.  Some of the pliosaurs, like Kronosaurus, were huge with skulls as much as 10 feet long. While the smaller plesiosaurs probably fed on small fish and invertebrates, the larger pliosaurs apparently ate whatever they wanted, including other plesiosaurs.
Here Doug has painted a picture of something that probably didn't happen. In his defense, until recently, most paleontologists believed that mosasaurs laid eggs in beach sand like sea turtles.  Studies have shown, however, that it would be very difficult for a female mosasaur weighing several thousand pounds to pull herself up on a beach to lay eggs. According to a report made by Gordon Bell in 1996, a fossil of a Plioplatecarpus mosasaur was found in South Dakota with the remains of at least  two baby mosasaurs inside.  This specimen provided convincing proof that mosasaurs, like Ichthyosaurs and modern sea mammals, gave live birth to their young.  Nearby, a flock of Ichthyornis  shore birds gathers around the carcass of a dead sawfish.

All pictures on this page are Copyright by Doug Henderson, and may not be used in any form without his permission.