Episode 196 is all about Scelidosaurus, the first dinosaur described based on a mostly complete skeleton, and an important ancestor to Stegosaurus and Ankylosaurus.

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In this episode, we discuss:

News:

• Over 260 dinosaur tracks (mostly sauropodomorph) were found in southwest China and may show sauropodomorphs swimming source
• In Alaska, therizinosaur and hadrosaur tracks were found together for the first time source
• Dinosaur footprints have been found for the first time on the Scottish mainland source
• A closed mine in Grand Staircase-Escalante National Monument may reopen, risking damage to dinosaur fossils source
• The University of Alberta is holding a “Dinosaur Dentistry” event on Saturday, September 22 source
• The Philip J. Currie Dinosaur Museum is looking for volunteers for their fossil preparation lab, to help clean and prepare Pachyrhinosaurus fossils source
• National Fossil day is coming up, October 17 this year here’s a list of some of the events scheduled so far source
• Scotty the T. rex celebrated her birthday at the Discovery Centre in Easton, Saskatchewan, Canada, with a fun mock interview source
• Mary Anning is getting a statue in Lyme Regis, at the request of a 10-year-old girl source
• Paleontologist Xing Lida has a science fiction book out in China, called You Long Ji: Prehistoric Intruder source
• Earth Science in Cinema at the University of Utah, will explore the relationship between storytelling and scientific accuracy in Hollywood source
• Jurassic Outpost created a visual guide to the dinosaurs in Jurassic Park(s) and Jurassic World(s) source
• Jurassic Park will be in 500 theaters around the U.S. next month to celebrate its 25th anniversary source

The dinosaur of the day: Scelidosaurus

• Thyreophoran ornithischian that lived in the Jurassic in what is now England (fossils found in Dorset)
• Name means “limb lizard” (Greek word skelis means “rib of beef”)
• Found in the 1850s
• Named by Richard Owen in 1859
• Only one species considered valid: Scelidosaurus harrisonii
• Richard Owen named Scelidosaurus harrisonii in 1861
• In the 1850s, James Harrison, who owned a quarry in Dorset, England, found fossils. He gave some of those fossils to Henry Norris, a collected and retired general surgeon. In 1858, both men sent some fragments to Richard Owen (including a left thighbone)
• Owen named Scelidosaurus in an paleontology entry in the Encyclopedia Britannica, though no specimens had yet been identified
• Owen meant to call the dinosaur “hindlimb saurian” but used the Greek word “skelis” instead of “skelos” (which means hindlimb)
• Named because of its strong hindleg
• Harrison sent more fossils (knee joint, claw, juvenile specimen, and skull) to Owen, which Owen described in 1861 (named Scelidosaurus harrisonii)
• Species name was in honor of Harrison
• That skull was found to be part of a nearly complete skeleton, which Owen described in 1863
• Owen did not indicate a holotype, and in 1888 Richard Lydekker designated hindlimb fragments (lower part of femur, upper part of tibia and fibula, which formed the knee joint) described in 1861 as the type specimen (which became the lectotype). He didn’t say why he chose this as the type specimen. However, in 1968 Bernard Newman found that the femur and tibia from a theropod. Newman also thought the rest was from a dinosaur related to Megalosaurus, and he suggested the lectotype be officially rescinded. Alan Jack Charig filed the request for this in 1992, and the International Commission on Zoological Nomenclature agreed in 1994 and decided a different specimen (which included skull, lower jaws, and skeleton) would be the neotype. In 1995 that knee joint from the former lectotype was informally assigned to Merosaurus by Samuel Welles and others, though some scientists think it was some sort of Coelophysoidea or Neoceratosauria
• The neotype came from marine deposits of the Charmouth Mudstone Formation, and is nearly complete (only the tip of the snout, the neck base, forelimbs, and tail end are missing). Many articulated osteoderms were found. Ronald Croucher prepared most of the fossils starting in the 1960s. Charig said in 1992 only one block was left to prepare, but he passed before the results were published. Norman published some new details in 2004, but there hasn’t been a full modern description yet
• A second partial juvenile was described in 1968 (found in 1959, by James Frederick Jackson)
• Another partial skeleton excavated in 1985
• There are more undescribed specimens, but they’re in private collections (including one thats 7 ft (2 m) long, found in 2000)
• Another species was Scelidosaurus oehleri, described in 1965 by David Jay Simmons, though Simmons described it as Tatisaurus (Spencer G. Lucas reclassified it in 1996 to Scelidosaurus). However, this classification was not accepted, so it’s still considered to be Tatisaurus
• Scelidosaurus was one of the earliest complete dinosaurs, and the most completely known dinosaur from the British Isles
• One of the most primitive thyreophorans
• First dinosaur academically described based on a mostly complete skeleton (before that, most descriptions were based on isolated bones and fragments)
• Richard Owen thought it was semi-aquatic and ate fish, and may have been ovoviviparous (had eggs that hatched in its body), which was odd because it was large and Owen had put forward the idea that dinosaurs were quadrupedal and active
• Lived on Laurasia
• Medium sized for its time, about 13 ft (4 m) long
• Quadrupedal herbivore, with longer hindlimbs than forelimbs
• May have been sometimes bipedal (but mostly quadrupedal)
• Feet were large and wide (had four large toes, and one small toe on each foot)
• Had flat, hoof-shaped claws that curved to the inside
• Tail was about half the length of its body
• Had a small, elongated head, and its snout was flat on top
• Probably had a short beak
• Probably cropped vegetation with its primitive teeth and had a simple up-and-down jaw movement
• Ate low plants
• May have reared up on hind legs to get leaves off trees, though probably not
• Had a large gut
• Had light armor, with long horizontal rows of oval scutes on its back and tail, and possibly neck (three rows on each side of its body), scutes were different sizes, and had four rows of large scutes on the tail
• Did not have continuous plating, or spikes or a pelvic shield
• Had two rows of large osteoderms on each side of its neck
• Hip and tail base had lots of ossified tendons
• Some specimens have osteoderms that looked thorny or spiky, as well as small horns on the back of their heads
• May have had skin ossifications on the skull and lower jaws
• David Martill and others in 2000 said they found soft tissue in a Scelidosaurus specimen. They show the presence of a layer of skin over the scutes, so the authors suggested that basal armored dinosaurs had osteoderms covered in a tough, keratinous layer of skin
• Osteoderms were probably for defense
• Can see a Scelidosaurus cast at the Dinosaur Discovery Site museum in St. George Utah. In 2011, local resident Virginius Dabney covered most of the cost ($7,000) for the replica, because his 9 grandkids urged him to. The dinosaur is known as the “Dabney Scelidosaurus replica”

Fun Fact:

The feet of the hadrosaurs from the herd trackway recently described in Alaska roughly range in size from a US infant size 2 to a Men’s size 54

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This episode is brought to you in part by TRX Dinosaurs, which makes beautiful and realistic dinosaur sculptures, puppets, and animatronics. You can see some amazing examples and works in progress on Instagram @trxdinosaurs