Fossil Friday: Glyptops

A small turtle basks on a ginkgo log overhanging the lazy river.

Species: Glyptops plicatulus (glip-tops plee-cat-you-lus)

What it means: Grooved face

Other Species: G. utahensis?

Where I live: Western U.S.A.- The Morrison Formation

When to find me: The Late Jurassic period, about 155 million years ago.

My favorite food: All sorts of grubs, fish, snails, and plants! I’m an omnivore.

My neighborhood: The Morrison Formation covers a huge expanse of land with a variety of different habitats teaming with life. Most of it was very much like the Serengeti of modern day Africa, only with prairies of drought-tolerant ferns and cycad relatives instead of grass. Dense woodlands of tall conifers like the modern araucaria, ginkgoes, and tree ferns would only lie in places of plentiful water such as the few permanent rivers. Other areas had far more sparse and shrubbier vegetation like the open woodlands of acacia trees in the Serengetti.

Life in this environment would’ve adapted to long months of harsh drought, followed by a few months of monsoon that flooded the rivers. Many of the larger herbivores may have migrated like the herds in Africa do today, while most carnivores stayed behind to feast on the dead and dying, or else become opportunistic hunters of less traditional diets for lean times, such as fish or turtles in the rivers.

A few of my neighbors: First let me share the plant-eating giants…

  • Long-necked sauropods like Brachiosaurus, Camarasaurus, Diplodocus, Barosaurus, Apatosaurus, Suuwassea, Supersaurus, Haplocanthosaurus, and Dystrophaeus.
  • Armored dinosaurs like Stegosaurus, Hesperosaurus, Mymoorapelta, and Gargoyleosaurus.
  • Two-legged ornithopods like Dryosaurus, Camptosaurus, and Nanosaurus

There are also giant, meat-eating monsters to worry about, including dinosaurs like Allosaurus, Torvosaurus, Ceratosaurus, Saurophaganax, Marshosaurus, Stokesosaurus, Ornitholestes, Coelurus, Tanycolagreus, Elaphrosaurus, and Koparion.

Not to mention the countless lizards, crocodile relatives on land and water, mammals, frogs, turtles, fish, and all the pterosaurs flying in the sky!

Fun Facts:

  • A partial skull of Glyptops was originally named by famous paleontologist Othniel Charles Marsh, who named the fossils Glyptops ornatus. The type species, and the fossils upon which all other Glyptops fossils are compared with, was described by his equally famous rival, Edward Drinker Cope, who found a partial shell around the same time and named it Compsemys plicatulus. The fossils were later determined to be the same animal, and so the names were combined into Glyptops plicatulus.
  • Glyptops is a type of turtle known as a cryptodire, or arch-necked turtle. They fold their necks vertically to tuck their heads inside their shell like modern box turtles and tortoises. Side-necked turtles fold the neck sideways to tuck their heads under the rim of their shells.
  • Glyptops turtles have ridges on the surface of the shell that makes them easy to tell apart from the other three turtles of the Morrison Formation. The ridges are more pronounced in juveniles.
  • The shells of these turtles can grow to about a foot long, or about 30 centimeters.

Fossil Finds: One or two nearly complete skulls, and one or two complete and nearly complete shells from adults and juveniles. Plus lots, and lots, and lots of shell pieces. This turtle was everywhere, and was by far the most common.

References:

“Glyptops plicatulus.” National Park Service, https://www.nps.gov/dino/learn/nature/glyptops-plicatulus.htm

JAMES M. CLARK, A new shartegosuchid crocodyliform from the Upper Jurassic Morrison Formation of western Colorado,Β Zoological Journal of the Linnean Society, Volume 163, Issue suppl_1, December 2011, Pages S152–S172,Β https://doi.org/10.1111/j.1096-3642.2011.00719.x

Foster, John. Jurassic West: The Dinosaurs of the Morrison Formation and Their World. Indiana University Press, 2007

“Glyptops.” Wikipedia, https://en.wikipedia.org/wiki/Glyptops

Foster, J.R. and Lucas, S.G., eds., 2006, Paleontology and Geology of the Upper Jurassic Morrison Formation: Glyptops (testudines, pleurosternidae)from the upper Jurassic Morrison formation, New Mexico. New Mexico Museum of Natural History and Science Bulletin 36. https://libres.uncg.edu/ir/asu/f/Heckert_A_2006_36_Glyptops.pdf

6 thoughts on “Fossil Friday: Glyptops

  1. Glyptops looks very happy on his branch. πŸ˜€ I would totally get a prehistoric turtle! Just cause it’s prehistoric. πŸ˜› I think it’s actually really cool how turtles seem to have stayed mostly the same over the years.

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    1. A pet Glyptops would be cool, even if it was just because it’s prehistoric lol. For the most part we see a greater diversity of body plans and strategies in older turtles, like with crocodilians, but even then it’s pretty interesting that they are all easily recognizable as turtles. What we have today are the ones that survived the various extinction events, and diversified from those limited body plans. The two other turtles in the Morrison have different strategies for tucking their heads in their shells. πŸ™‚ They’ll be coming along soon!

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  2. Very interesting the different ways they folded their neck into the shell. It is amazing how the ribs evolved into what is now the shell. And how the the ribs (the shell) became more and more specialized to evolve into the large shell that it is now – even protecting the underside of the turtle.

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    1. Turtles are fascinating! I had to look at a few diagrams to figure out how their necks work. πŸ˜€ Glyptops looks very much like modern turtles. It has an under-shell as well as a top shell. The modern box turtle definitely took the concept an extra step though, I’ve always thought it was really cool how they can completely “box” themselves in!

      I want to draw more turtles, so we may be seeing the other two Morrison Formation turtles in between the next couple of dinos coming up.

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  3. It’s good to see Glyptops get some representation. The only other media that I believe it has been represented in was Dinosaur Train, and there needs to be more attention to prehistoric chelonians. Amazing work, I’m looking forward for some future profiles.

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    1. Thank you, I’m glad you like it Angel! πŸ™‚

      Yes, the only media representation I know of is Dinosaur Train, though I believe it was also mentioned in the wiki of a Jurassic Park game, but that doesn’t really count lol. πŸ˜€

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