The Cretaceous Sea
from the Dinosaur Collector
Updated 4/21/2008 proof 100306 rjk
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Giant squids like Boreopeltis are known from Australia, where they show evidence of predation by Kronosaurus. Today’s giant squid live at depths of 600 – 1000 feet and are preyed on by Sperm whales.
In the Late Cretaceous, the interior seaway of North America was extremely active, and squid were seemingly common animals; five species have been described, but the largest of all were Niobrarateuthis bonneri, Niobrarateuthis walkeri and Tusoteuthis longa.
Squids are hard to identify as they gave up the shells, and their soft body parts don’t fossilize except in rare instances. Squid pens, or the gladius, are the internal remnants of the exterior shell of the primitive nautiloid ancestral cephalopods and they do leave fossils. “Fossil Teuthids” are largely identified and classified by variations in the shape of the gladius alone, and comparisons with living species of cephalopod. Tusoteuthis was large; it is neither a close relative nor a deep-sea dweller but was similar in size to modern giants.
Schleich Kronosaurus, and Safari Giant squid Architeuthis courtesy of Healthstones hobbies.
Kronosaurus is a pliosaur; a marine reptile that lived in the vast inland sea that covered western Queensland between 110 and 100 million years ago. Kronosaurus is named after Kronos, the Greek god of time. It had rounded rear teeth that were suited to crushing hard-shelled prey.
Kronosaurus, from the Cadbury Yowies series. Early Cretaceous Kronosaurus has been projected up to 13 meters (43 feet), but recent studies of its fossil skull and other parts, and comparisons with other pliosaurs, suggest that the true length was probably only 9–10 meters (30–33 feet).
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Kronasurus from Carnegie Safari.
In the Late Cretaceous, the Western Interior Seaway reached as far north as the Arctic Sea and as far south as the Gulf of Mexico; completely dividing the eastern and western landmasses of what we now call North America. Generally shallow, the waterway is estimated to have been less than 600 feet deep, with a flat, muddy bottom. Turtles, fish, mosasaurs, pleisosaurs, and aquatic birds swam the shallow seas and invertebrates, such as crinoids, echinoids, crabs, lobsters, ammonites, snails and clams were common.
A branch of the monitor lizard family went to sea; their descendants are snakes. Mosasaurs were extremely successful, and may have contributed to the disappearance of the ichthyosaurs and the decline of the plesiosaurs. Professor Bob Bakker has speculated based on skull comparisons that the plesiosaurs of the Cretaceous are not directly descended from the Jurassic plesiosaurs. Instead he has proposed that they re-evolved from the short-necked pliosaurs.
Elasmosaurus, (Thin plated Lizard) size: 46 feet long. It is thought that Elasmosaurus used its flippers to fly through the water like a penguin. Since no evidence of live birth has been found they are assumed to have returned to land to lay their eggs.
Mosasaurus (Meuse-River lizard) size 59 feet long.
A full-grown Mosasaurus had a 6-foot long skull with 4-foot jaws, capable of opening 3 feet apart. Like modern constrictors and other types of mosasaurs, the lower jaws were two separate units and could spread apart at the anterior end, stretching to give this amazing creature the ability to swallow huge prey.
Hydrotherosaurus (meaning "water beast lizard") is an elasmosaurid plesiosaur from the Late Cretaceous.
Hydrotherosaurus is from Procon CollectA . Dino Horizon Panorama series from Cog Ltd Ammonite.
Tylosaurus (Knot Lizard) lived in the Niobara sea during Late Cretaceous North America. It was 20 to 40 feet (6 to 12m) long and had a long, slim body. It had huge jaws; sharp, cone-like teeth, and flipper-like hands and feet. It was a savage hunter and ate fish, shellfish and one of the largest mosasaurs.
Tylosaurus from UHA Dino Tales and two Elasomsaurus from the Retro Classic collection.
Elasmosaurus had the longest neck of all the swan necked plesiosaurs, with over 1/2 of its length made up of neck. It ate fish, mollusks, and soft-bodied invertebrates. While often pictured with head rearing from the water this does not seem likely given the length of the neck. It seems to have been more flexible side to side than up and down. The long neck must have offered an advantage ambushing small faster prey, while limiting its speed and perhaps making it vulnerable to the newly evolving sharks and mosasaurs. The large size and extreme adaptations of the last plesiosaurs may be a sign they were under some kind of evolutionary stress.
Original Carnegie Safari Elasmosaurus is in the front, and the recent version looking forward in the back. Safari often seems to make unpublished changes to figures. This change could be a result of differences in the manufacturing process.
One idea is that plesiosaurs declined as modern types of sharks appear.
Carnegie Safari series repaint.
Tylosaurus (Swollen Lizard) was, at over 45 feet, one of the largest of the three types of mosasaurs. It lived in the vast Western Interior Seaway alongside several other species of mosasaurs, including the familiar Platecarpus and Plioplatecarpus, while other relatives of Tylosaurus, such as Mosasaurus, lived in Europe.
Elasmosaurus, Mosasaurus from Play Vision, and Tylosaurus from Starlux.
Ammonites, with their curled shells, and Belemnites were characteristic of the Late Cretaceous Seas, and their disappearance marks the end of the Mesozoic. Several sea going turtles existed in the Cretaceous. The giant sea turtle Archelon had a life style much like the present-day green back turtle.
Ammonites and a Belemnite from Bullyland, and a Plesiosaurus from the Laramie play set, strongly reminiscent of the Invicta figure.
Pachydiscus (actually now called Parapuzosia seppenradensis) is the largest ammonite yet discovered with a shell diameter of 2.2m.
from UHA Dino Tales Pachydiscus and Cadbury Yowie Ammonites.
Archelon ischyros lived about 70 million years ago in the Mid-American Seaway, during the Cretaceous period. At least occasionally they were food for the giant Mosasasurus; fossils of Archelon with teeth marks that match the bite of mosasaurs have been found. The shell of this turtle was reduced to a framework of struts made from bony ribs that grew from the backbone. It had weak jaws, a toothless beak, and probably fed on jellyfish.
Both of these are Kaiyodo products; the Mosasurus is from the 1/100 scale Dino Land series and the Archelon is from the UHA Dino tales premiums.
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