Fossil Friday: Kayentavenator

Species: Kayentavenator Elysiae (Kah-yen-tah-veh-nay-ter Eh-lee-see-eye)

What it means: Kayenta hunter

Other species: none

Where I live: Arizona in the U.S.A.- The Kayenta formation

When to find me: The Early Jurassic period, about 196 million years ago.

My favorite food: Meat! I’m a carnivore.

My neighborhood: The Kayenta formation used to be a tropical floodplain, a bit like African savannah today- but no grass or flowers. Ferns cover the open plains, dotted with islands of spiky cycad groves. Rivers crisscross the land with lush tree ferns, ginkgo trees, and conifers. Every year during the wet season the plains turn into a flooded marsh, but the hottest months bring no rain, and the rivers shrink until the plains are almost as dry as the great desert that lies to the north.

A few of my neighbors: Sarahsaurus (an early sauropod) is a tough neighbor. We don’t talk much. But if I’m lucky, little Scutellosaurus (small armored dinosaur) might join me for lunch. Dilophosaurus is the biggest carnivore around, but Coelophysis (smaller meat-eater) is happy to take a few leftovers or join me on a quick chase after frogs, turtles, or a crocodile cousin or two. They like to stay close to the rivers. A long-tailed pterosaur patrols the skies for insects like beetles, dragonflies, an ancient cousin of the moth, and something called a snakefly.

Fun Facts: 

  • Paleontologists don’t really know how big I could grow, because the only fossils found are of a juvenile, with a lot of growing left to do!
  • There’s been a bit of discussion back and forth about what family I should be in. I was first described as a Tetanuran, which is a group that includes dinosaurs like Tyrannosaurus rex, Allosaurus, Ornithomimus, and even birds, just to name a few. Others suggested I was related to the local Coelophysis k. or possibly a young Dilophosaurus, but the Dilophosaurus idea was quickly ruled out since other fossils of young Dilophosaurus have been found, and mine don’t look exactly like them. All in all there are not very many bones to go on, and it can be difficult to figure out where the puzzle pieces go when they are broken and squashed with time!
  • A lot of dinosaurs are named after the place they’re found, like me! Kayenta + venator (latin for hunter). Hunter of the Kayenta Formation.

Fossil Finds:

Only one partial, juvenile skeleton with part of the pelvis, some vertebrae, and pieces of hind legs.


Gay, Robert. 2010. “Kayentavenator elysiae“, a new tetanuran from the early Jurassic of Arizona” In: Notes on Early Mesozoic Theropods. Lulu Press. p. 27-43. ISBN 978-0-557-46616-0

Mortimer, Mickey. “Kayentavenator is not a tetanurine.” The Theropod Database Blog, Blogger, 30 September 2010,

Mortimer, Mickey. “Is Kayentavenator a young ‘Megapnosaurus’ kayentakatae?” The Theropod Database Blog, Blogger, 1 October 2010,

These two websites were a huge help in knowing where to start when finding research material and basic information.

“Kayentavenator.” Prehistoric wildlife

“Kayentavenator.” Wikipedia,

23 thoughts on “Fossil Friday: Kayentavenator

  1. Thanks for the research Patricia. For novices like me it would help in a future post if you included a reference page of all the prefixes and suffixes used when paleontologists decide to name a dinosaur. Also, include the meanings of the prefixes and suffixes. For example, I might have a better idea why and how Scelidosaurus or Kayentavenator got their names. Thanks for your time in doing the research and keeping us up to date.

    Liked by 1 person

    1. Hi Dad, thank you for stopping by! I can certainly look into the precise words used to get the name. Since I often do that sort of research to figure out how a name is supposed to be pronounced, I can add that as one of the tidbits of info.

      I’ve been getting faster at doing these, and with greater efficiency have been thinking about other simple facts to include. For example, if there is more than one species of the critter, and how many there are if that is the case. 🙂


  2. To be honest with you, I want to see an adult specimen of this dinosaur to be found. Though some can argue that it could be the same as Coelophysis k. I want us to know how big it may have been with just juvenile fossils found so far. Thanks for this entry, Patricia. How many Kayenta Formation critters left?


    1. Hi Angel, thank you for stopping by! Wouldn’t it be great to have more fossils? I would’ve posted a size comparison for the juvenile at least, but I couldn’t find anything definite to make one. The best guess I could find was that it was almost as big as the Coelophysis k. fossil material, but it wasn’t an “official source” and would only be a guess. If it was at least the same size or bigger as Coelophysis, then we’d know for sure that it wasn’t of the same genus, since it still has growing to do, but at the moment we just don’t know.

      It’ll be at least one more month of Kayenta creatures. 🙂 I still have planned (not in order) Calsoyasuchus, Eopneumatosuchus, Rhamphinion, Dinnebitodon, Kayentatherium, and possibly a special post on insects and other invertebrates and plants. Upon further research I discovered that the supposed Scelidosaurus material may not even be Scelidosaurus, so I will not be doing a post on it.

      Liked by 1 person

      1. I’m glad that you’ll wait to do Scelidosaurus. I always view it as a dinosaur from the U.K. Either way, I want to see adult material that officially makes Kayentavenator separate from the other theropods in the formation, and that gives us a good estimate on how big it could grow up to. Have you planned a name for the individual that will show up in a long-ish while?


        1. There are so many Jurassic critters that have better material, I don’t think I’ll include Kayentavenator officially in the shop. If more material is found, and we find out more about it, particularly if any adult fossils are found, then I’d consider it. But until that happens I didn’t plan on including it as an official member of the shop.


              1. Coelurus is one of my favorite meat eating dinosaurs. This little guy had somewhat of an underground following during the 1980s and early 1990s – it was featured in nearly every dinosaur book during that time.


  3. Is it possible that Kayentavenator might be an elaphrosaur? That would place it within the family Noasauridae, within the super-family Abelisauroidea, within the clade Ceratosauria. I think that there are similarities in the vertebra structure of both Kayentavenator and Elaphrosaurus. However, the overwhelming majority of noasaurid fossils have been found in the Southern Hemisphere (I’m including India in this, because the Subcontinent was located much further south during the early Jurassic). Limusaurus, an elaphrosaurine noasaurid, was found in China, and this is the only northern noasaurid to my knowledge. Making a claim that Kayentavenator is an elaphrosaur is sketchy due to geography and due to the incomplete nature of fossils, but still, I think that it might be worth considering.


    1. Thank you for stopping by Jason! I am far from knowledgeable on the particulars concerning most dinosaurs, and certainly don’t pretend to know anything about cladistics, but I’d highly recommend reading Mortimer’s very knowledgeable posts on Kayentavenator.

      She admits that there isn’t enough fossil material to know for sure, but all published evidence seems to point to Kayentavenator being a Coelophysoid. At least certain characters appear unique enough for Kayentavenator to be a valid genus.

      I’m afraid I know nothing about Noasauridae or Elaphrosaurs aside from a quick look to Wikipedia to at least know what you’re talking about lol. (I’m rather focused on the current critters and timeline, and do research as I come across them.) I think any hypothesis is always worth considering. It appears that remains from a possible relative to Elaphrosaurus were uncovered in the Morrison Formation, but I don’t know if there was ever anything definite assigned to these remains. Ultimately we need more fossils, and it seems the best evidence thus far (at least according to one source) points to Kayentavenator being a Coelophysoid. Mortimer’s series of posts are very thorough, at least to a complete novice like me.

      I’ve only recently started doing further research into the characters of bones and actually reading the papers describing these animals, so I’m still learning the terminology. I’m getting better at it though! 😀 Phylogeny is still a bit of a mystery aside from the absolute basics lol. I know about Ceratosauridae and Abelisauridae, but I had to look up what Elaphrosaurs and Nosauridae were. 😀

      Liked by 1 person

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