Episode 184 is all about Segisaurus, a small Jurassic theropod which was so small that it probably ate insects

Thank you! Thank you to all our patrons! Your support means so much to us and keeps us going! If you’re a dinosaur enthusiast, join our growing community on Patreon at https://www.patreon.com/iknowdino.

You can listen to our free podcast, with all our episodes, on Apple Podcasts at:

https://itunes.apple.com/us/podcast/i-know-dino/id960976813?mt=2

In this episode, we discuss:

News:

The dinosaur of the day: Segisaurus

Featured in the Jurassic Park brochure

Coelophysoid theropod that lived in the Jurassic in what is now Arizona

Name means “Tsegi canyon lizard”

Found in the Tsegi Canyon, in Arizona, and is the only dinosaur excavated from there

Max Littlesalt and Robert Thomas found Segisaurus in 1933, in sandstone (Max kept livestock in the canyon where it was found, and pointed out the fossils to archeologists who were on an expedition)

Probably buried in sand and then died, based on being found in sandstone

Lived in something similar to modern sand dunes

Tracks are more common in the formation than skeletons

Described in 1936 by Charles Lewis Camp

Found parts of the limb, pelvis, and vertebrae (no skull)

Type species is Segisaurus halli

Found a sub-adult

About 3.3 ft (1m) long (probably grew bigger)

Weighed about 9-15 lb (4-7 kg)

Ate insects, may have also scavenged for meat

Primitive, bipedal

Had long tail, long forearms, and long, powerful legs, with three toes

Found in a roosting position, similar to modern birds

Camp said its posture was like a “sitting hen” the way it was found. May have been in that position because it was sleeping or sheltering from sand and ash storms

Bird like, with a long neck and stout body

Found fused clavicles, which have not been found in other dinosaurs that lived at the same time

Charles Lewis Camp said it may have had a “splint-like” neck to support a fold of skin that may have helped it move quickly

Segisaurus shows that clavicle was in early theropods (interesting because there was debate in the 1930s whether dinosaurs had shoulder girdle bones, and how birds evolved)

Gerhard Heilmann, a Danish artist and paleontologists, published The Origin of Birds in 1926. He argued that though many dinosaurs looked bird-like, they did not have clavicles (precursors to wishbones) and they seemed ot have lost them over time, and could not have re-evolved them. So he said that thecodonts (crocodylian types) where ancestors to birds and dinosaurs, and the shared ancestry was why there appeared to be convergent evolution between dinosaurs and birds. Many paleontologists agreed with this until the Dinosaur Renaissance of the 1970s

Unfortunately, Segisaurus was largely ignored for many years (wasn’t reexamined until 2005), so didn’t play a role in the Dinosaur Renaissance

Seems related to Coelophysis, but it was thought to have had solid bones instead of hollow bones

Some scientists were unsure if it was a theropod because of its solid bones

The re-examination in 2005 found that it did have hollow bones, and it was a coelophysoid, probably closely related to Procompsognathus

Fun Fact:

Dinosaur in mandarin is 恐龙 (Kǒnglóng) literally translates to afraid-dragon (or scary dragon) similar to Dinosaur which literally means terrible-lizard (or could be scary lizard)

This episode was brought to you by:

TRX Dinosaurs, which makes beautiful and realistic dinosaur sculptures, puppets, and exhibits. You can see some amazing examples and works in progress on Instagram @trxdinosaurs.

Enter to win a TRX Dinosaurs-made 1:1 scale Velociraptor sculpture. It’s open to anyone in the US or Canada (except Quebec) ages 18 and older to win. Complete rules are at https://iknowdino.com/velociraptor-sculpture-sweepstakes-official-rules

This week’s link to enter is http://bit.ly/Dinosaur184