Episode 319 is all about Dilong, a small feathered tyrannosaur.
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In this episode, we discuss:
News:
- The Museum of Discovery and Science in Fort Lauderdale, Florida is holding a free online speaker event about dinosaurs on Jan 7 source
Best of 2020 (266-318):
Best New Sauropod: Bagualia (318)
HM – Best New Sauropod: Bravasaurus (314)
HM – Best New Sauropod: MCF-PVPH-87 (302)
Best New Theropod: Oksoko (307)
HM – Best New Theropod: Paraxenisaurus (300)
Best New Ornithopod: : Ajnabia odysseus (312)
HM – Best New Ornithopod: Changmiania (306)
Best Re-description: Dilophosaurus (296)
HM – Best Re-description: Scelidosaurus (307)
Gnarliest Pathologies: Worms in sauropod leg (316)
HM – Gnarliest Pathologies: Osteosarcoma in a Centrosaurus (307)
Best Early Dinosaur Discovery: Dinosauromorph Kongonaphon (294)
Best Gut Contents: Borealopelta (295)
Best Dinosaur Nest: Protoceratops (& Mussaurus) (292)
Best Biomechanics Study: Spinosaurus tail (284 & interview in 300)
Best Paleoart: Zuul cake (278 & interview in 281)
Best Dinosaur Art: Quarry rocks in England (282)
Best Video (Short): Avatar Airbender dinosaur video (312)
Best Unexpected Place to Find Dinosaurs: SpaceX astronauts brought a dinosaur to space (289)
Best Dinosaur Thought: Turtles are murderers (308)
Best Dinosaur Impression: Evan Johnson-Ransom’s T. rex impression (293)
Best Dinosaur Sound: Penguins walking around the Field Museum (294)
Best/Worst Dinosaur Auction (ever): Stan the T. rex (305 & 307)
Biggest Court Case: Montana ruling that the Dueling Dinosaurs and other dinosaur fossils are not minerals (287, 291 & 313)
Best Augmented Reality: National Geographic Re-imagining Dinosaurs on Instagram. Search for filter “natgeo” to find them (314)
Best Dinosaur Game: Animal Crossing (297)
HM – Best Dino Game: Path of Titans
The dinosaur of the day: Dilong
- Basal tyrannosauroid that lived in the Cretaceous in what is now Liaoning province in China (Yixian Formation)
- Holotype is nearly complete, semi-articulated skeleton, and includes a nearly complete skull
- Type and only species is Dilong paradoxus
- Genus name means emperor dragon (??)
- Genus name refers to the relationship of Dilong to T. rex, the king tyrannosaurid
- Species name means “against received wisdom” or “against accepted wisdom”, and according to the original description, refers “to the surprising characters of this animal” (protofeathers on a tyrannosauroid)
- Described in 2004 by Xu Xing and others
- Holotype was about 5.2 ft (1.6 m long) but may be a juvenile
- Estimated to be more than 6.6 ft (2 m) long as an adult
- Had a long skull and slender neck
- Had a Y-shaped skull crest, with two ridges along its snout
- Had relatively long arms and three fingers on each hand
- Had large jaw with tightly packed front teeth
- Had short legs, so probably not a fast runner
- Probably active
- Probably went after lizards, mammals, and birds
- Similar looking to Eotyrannus, which lived in the Cretaceous in what is now the Isle of Wight, UK
- Closely related to Yutyrannus
- Covered in protofeathers, which were found in fossilized skin impressions
- Four specimens found, but only one has protofeather impressions
- Protofeathers found around the tail and the back of the head
- Protofeathers were up to 0.4 in (3 cm) long, and were simple and filamentous
- Probably covered in a downy coat
- Most likely used for insulation, not for flight
- Tyrannosauroid, and lived much earlier than T. rex
- First direct evidence that tyrannosauroids had protofeathers
- Feathers on Dilong may mean that T. rex and other later tyrannosaurs had feathers
- Had some advanced skull features like later tyrannosaurs, including fused nasal bones and a rounded snout with front teeth that are D-shaped in cross section, which would give it a “cookie cutter” bite
- Had a small skull compared to later tyrannosaurs
- Pelvis is not as robust as other tyrannosauroids
- Skull is less robust than other tyrannosauroids, but could be because it’s smaller
- In other ways, Dilong looked like juveniles of later, bigger tyrannosaurs
- Dilong shows tyrannosaurs had some distinctions before they became large like T. rex
- Adult tyrannosaurs in Alberta, Canada and Mongolia have skin impressions that show pebbly scales. Xu Xing and others suggested tyrannosauroids may have had different skin coverings on different parts of their bodies (scales and feathers). Also suggested juveniles may have had feathers and adults had scales because they got large enough they didn’t need insulation to keep warm
- Scans of the braincase found Dilong had an S-shaped brain with thin meninges (three membranes that line the skull and vertebral canal and enclose the brain and spinal cord). T. rex had a more linear brain with thicker meninges
- Based on the scans, found Dilong was probably agile and had good balance, but didn’t have good a sense of smell as T. rex
- Lived in an area with early flowering plants, rivers, and streams, with nearby volcanoes
- Dinosaurs that lived around the same time and place included Yutyrannus, Beipiaosaurus, Sinornithosaurus, Psittacosaurus, Tianyuraptor, and Sinocalliopteryx
Fun Fact: Dilong is the name of a dinosaur and it’s also a name used to mean “earthworm” in traditional Chinese medicine and Geosaurus (a marine crocodyliform).
