Episode 307 is all about Sinocalliopteryx, a dinosaur that may have specialized at hunting birds.

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In this episode, we discuss:

News:

• New oviraptorosaur from Mongolia named Oksoko only had two fingers on each hand source
• The first ever ankylosaur, Scelidosaurus, finally got a complete description over 150 years after it was excavated source
• A Centrosaurus has the “first confirmed case of malignant bone cancer in a dinosaur” source
• Stan the T. rex went to auction and sold for $31.8 million to an anonymous bidder source
• Dinosaur eggshells from 68 million years ago were recently found in Huesca Province, Spain source
• The Phil Currie Dinosaur Museum has a free virtual speaker series every other Saturday about dinosaurs and paleontology source
• In Australia, Tasmania Zoo has recently reopened and has a new T. rex model source
• The Korea Minting, Security Printing & ID Card Operating Corp made a new commemorative medal of Koreanosaurus source
• If you need a Halloween costume, here are 15 DIY dinosaur costume ideas source
• Universal Orlando is updating their “Jurassic Coaster” to “VelociCoaster” by adding many dinosaur eggs and Velociraptor source
• The Jurassic World: Dominion release date has been delayed for a year to June 10, 2022 source

The dinosaur of the day: Sinocalliopteryx

• Compsognathid theropod that lived in the Cretaceous in what is now China (Yixian Formation)
• Bipedal and carnivorous
• Type specimen was about 7.78 ft (2.37 m) long
• Estimated to weigh 44lb (20 kg)
• Had an elongated head and a pointed snout
• Had long hands compared to its arms (hands were as long as the ulna and upper arm)
• Arms and hindlimbs were longer compared to other compsognathids
• Also had relatively long feet
• Had protofeathers (hairlike structures that covered its skin)
• Had protofeathers on the upper part of its foot, which showed foot feathers or something like them occurred in more basal dinosaurs than previously thought (like Microraptor, which lived later than Sinocalliopteryx)
• Protofeathers helped with insulation
• Type species is Sinocalliopteryx gigas
• Genus name means “Chinese beautiful feather”
• Species name means “giant” and refers to it being a large compsognathid
• Described and named in 2007 by Ji Shu-an and others
• Holotype is a nearly complete adult specimen with a skull
• A second specimen was found that was even larger the holotype (skull was about 10% longer)
• Similar to Huaxiagnathus, but bigger
• Its large size may show compsognathids as a group getting larger
• One of the reasons Sinocalliopteryx may be so large is because it’s one of the few compsognathid species probably represented by adult specimens
• Holotype had gut contents: a partial dromaeosaurid leg in the abdominal cavity (complete lower leg and foot, with toes and claws articulated)
• Leg was found in between the ribs, so very likely Sinocalliopteryx ate the leg
• Also found feathers thought to be from a bird and were with the leg in the gut contents
• Four irregular shaped stones were found in the holotype’s abdomen as well, and originally thought to be gastroliths to help aid in digestion. But no gastroliths were found in the second specimen and in 2012 thought that the stones in the holotype were swallowed by accident
• In 2007, Ji and others said this may mean it preyed on a smaller, bird-like dinosaur, and Sinocalliopteryx may have been agile and active and fierce
• In 2012 the dromaeosaurid found in Sinocalliopteryx was thought to be from a Sinornithosaurus that was about 3.9 ft (1.2 m) long. Also found feathers above the dromaeosaurid leg, and other prey animal remains
• Second specimen also had gut contents, including undigested bones from two Confuciusornis specimens (primitive avialian), and a scapula from an ornithischian, such as Yueosaurus or Psittacosaurus. The ornithischian scapula had more corrosion which shows it had been partially digested, so may mean the birds were eaten more recently and quickly together, which may mean Sinocalliopteryx had a high metabolism and needed lots of food
• Gut contents in the second specimen were found in a C-shape, which may be the shape of the digestive tract
• Having three undigested dinosaurs in its stomach (of the second specimen) suggests it ate a lot of food and was an active hunter
• Probably couldn’t fly or climb trees, but may have been stealthy when attacking
• May have ambushed prey, like cats such as servals
• Being an early bird, Confuciusornis probably could only fly for short periods and would have been slow to take off
• Bones of Confuciusornis don’t take long to digest, and the bones in Sinocalliopteryx’ gut were not damaged by any stomach acid
• Based on how quickly modern alligators digest their food, scientists think the ornithischian bones were in the gut of Sinocalliopteryx for 13 days (based on the corrosion of the bones), and that birds would be dissolved in the gastric tract in less than 12 hours
• Whether it actually was an active stealth hunter is considered speculative/not all scientists agree (possible it could have scavenged its gut contents)
• If the Sinornithosaurus in the holotype specimen was hunted and not scavenged, then Sinocalliopteryx would have been able to go for prey more than a third its size
• Based on the two Confuciusornis specimens found in the second Sinocalliopteryx specimen and the bird feathers found in the holotype, may mean Sinocalliopteryx specialized in bird-like prey
• Not all the Confuciusornis bones were in the gut contents (missing the skull, ribs, vertebrae, and more), so it’s not clear if those parts weren’t eaten, if they were digested more quickly, if they were eaten but then preserved and obscured in the preservation, or if they were preserved in another block of fossils not yet found
• Lived in a warm, wet forest, in an area with lots of volcanic activity
• Lived among birds and crocodiles, in addition to many dinosaurs including tyrannosauroids Yutyrannus and Dilong, Therizinosaurus Beipiaosaurus, troodontid Mei, and dromaeosaurid Tianyuraptor

Fun Fact: Adult ankylosaurs are usually presented as being solitary creatures. But some may have lived in groups, especially when young.

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