Fossil Friday: Amphicotylus

Amphicotylus ambles to the river’s edge for an afternoon swim.

Species: Amphicotylus lucasii (Am-fee-koe-tih-lus Loo-kas-eye)

What it means: two-sided cup

Other Species: A. gilmorei, A. stovalli, “Goniopholis” Felix

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: Meat and fish! I’m a carnivore.

Amphicotylus is about 10 feet long, so kinda average. It’s perfectly content in its averageness.
Amphicotylus was about 10 feet long.

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 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:

  • Amphicotylus gets it’s name from the Greek amphis (both ways) + kotyle (cup).
  • Amphicotylus is not a dinosaur, but a croc-relative known as a neosuchian. It was discovered and named by famous paleontologist Edward Drinker Cope in 1878.
  • Amphicotylus was first named as a species of Goniopholis, a European relative, before it was determined to be a separate animal. It’s waffled back and forth between the two, but most recently the name Amphicotylus is here to stay.
  • It’s possible that too many species are named. More fossils can help determine if the slight differences in the skulls are due to differences in individuals or different species. It would be like figuring out if the the stripe pattern between two zebras is simply the “fingerprint” between two individuals, or the drastically different stripe pattern of two different types of zebra (and yes, there are several, and clearly different when seen next to each other) 🙂 It’s most likely that there is only one species, A. lucasii.

Fossil Finds: Several complete and partial skulls to determine different species, along with scutes and fragmentary remains from the rest of the body.


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

4 thoughts on “Fossil Friday: Amphicotylus

  1. Yay, another croc cousin! I like his face. 😀 I also like how you suggested the density of the foliage–any artsy tips on that?

    It’s pretty amazing to see the variety of wildlife that can thrive in such a barren area! But then you look at all the diversity of places like the Serengeti in Africa. Nature adapts really well! 🙂


    1. Hi Brownie! I’m glad you like him. I’m having quite a bit of fun with all these crocs, and I think this guy has a very nonchalant attitude. 🙂 I might name him Corrin if he ever gets featured in the shop. 😀

      This illustration was a great excuse to practice drawing dense foliage like this! There’s an art instructor I follow on Instagram, and I followed his advice. Basically, you break it down to layers and basic shapes. Typically three layers so it’s not too crowded or busy. The hindmost layer is the basic silhouette of what the edges of the grass/horsetails/dense shrubs look like. Thin, light lines, or no lines in my case. The middle layer is darker, with thicker/darker lines to show that it’s closer, but it’s still just a silhouette like the back layer. The front layer is where you draw the shapes of the isolated elements of plant, horsetails in this case. 🙂 It doesn’t have to be many, and is actually best if there are only a few. The idea is to give the viewer a few shapes, and then give a hint of more complexity with lights and darks for the brain to fill in. Drawing out each individual reed or leaf makes for a busy scene that distracts from the primary character.

      It’s pretty amazing how some places you’d think would be so barren are so full of life!


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