Fossil Friday: Prosalirus


Species: Prosalirus bitis (Pro-sah-lee-rus bee-tis)

What it means: Leaping forward

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: Bugs! I’m an insectivore.

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: Since I’m a tiny, froggish guy, I have to watch out for all sorts of predators like Dilophosaurus, Kayentavenator, Coelophysis (meat-eating dinosaurs), and crocodile cousins. In the sky, flying pterosaurs with long tails would love a snack. More friendly neighbors are Sarahsaurus (an early sauropod), and little Scutellosaurus (smaller armored dinosaur). I like to hang out on the riverbank with the turtles and keep an eye out for insects like beetles, dragonflies, an ancient cousin of the moth, and something called a snakefly.

Fun Facts: 

  • I am one of the very first frogs, and the first frog we know that could actually jump! Most of the tail my ancesters had is gone, and my legs are a bit shorter than modern frogs.
  • The name Prosalirus comes from the Latin verb prosalire, which means “to jump forward.” Bitis is Latin for the verb “to go.”
Put your hand up to the silhoette. It should be life size!

Fossil Finds: Partial skeletons of at least two individuals, including various parts of the body, head, and legs.


Hecht, Jeff. “Jurassic frog leaps into the record books.” New Scientist, New Scientist Ltd., 16 sept. 1995.

Farish A. Jenkins Jr. & Neil H. Shubin (1998) Prosalirus bitis and the anuran caudopelvic mechanism, Journal of Vertebrate Paleontology, 18:3, 495-510, DOI: 10.1080/02724634.1998.10011077

Stocker Michelle R., Nesbitt Sterling J., Kligman Ben T., Paluh Daniel J., Marsh Adam D., Blackburn David C. and Parker William G.. 2019 The earliest equatorial record of frogs from the Late Triassic of Arizona. Biol. Lett. 15:20180922.

Neil H. Shubin and Farish A. Jenkins, Jr (7 September 1995). “An Early Jurassic jumping frog”. Nature

(The Nature article is hidden behind a paywall. Luckily everything else I found was free and frequently quoted from the paper published in Nature.)

18 thoughts on “Fossil Friday: Prosalirus

    1. All in good time! These Fossil Friday posts will cover every animal possible in its formation. If I can find enough information I might even feature a few insects or plants! 🙂


  1. Great! Cool to see Prosilarus, an amphibian, get a debut on the site, probably the first time it’s mentioned on a the main part of a webpage on WordPress. I’d like to see one (probably called Silas) on a COTM page. I remembered the suggestion of Vieraella before and I’m glad we get to see an amphibian on the site. I want to know, what’s your opinion on it, Patricia?


    1. Hi! thank you so much! I’m glad you like the little guy. 😀 It was very interesting to do research and find out more about it, since I know absolutely nothing about prehistoric frogs. It was cool to find out that it’s the first truly jumping frog that we know of. 🙂 I don’t think it’s a “true frog” though.

      I completely forgot about Vieraella, but if it’s the first “true frog” known it’ll certainly find a place in Pete’s Petshop at some point. That’s an important traight! 🙂


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