Episode 563: Hadrosaur Hooves, Head Combs, Muscles, and More Soft Tissues. Lots of new discoveries of soft tissues in dinosaurs. Plus new studies to confirm old soft tissues and a new—controversial—iguanodont.

News:

• There’s a potentially new iguanodont, Paulodon galvensis (but it is controversial) source
• Soft tissues can be preserved in fossils regardless of the species, age of the bones, or where the animal was buried source
• A new method using Cross-polarized light microscopy (XPol) helps identify organic molecules in fossils source
• New Edmontosaurus “mummies” show hooves, small spikes down the tail, and a banded fleshy crest over the neck and back source
• Scientists re-evaluated the soft tissue crest of an edmontosaur hadrosaur dinosaur source
• Dinosaurs likely had muscles forming cheeks source
• New titanosaur sauropod tracks found in Mongolia show a lot of soft tissue details in the hands and feet source

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The dinosaur of the day: Santanaraptor

• Santanaraptor (saw it in a recent paper, thought it’d be interesting, and it is!)
• Coelurosaurian theropod that lived in the Early Cretaceous (about 112 million years ago) in what is now Brazil
• Lightweight and walked on two legs, had short ams, long legs, a long tail, and a long head
• Estimated to be 4.9 ft (1.5 m) long and weigh 33 lb (15 kg)
• Possibly covered in feathers
• Described in 1999 by Alexander Kellner
• Type and only species is Santanaraptor placidus
• Genus name means “Santana Formation thief”
• Fossils found in 1996 in the Romualdo Formation, in the Santana Group
• Lots of well preserved fossils found in the Romualdo Formation
• Fossils found near the town of Santana do Cariri, in Ceará, Brazil
• Species name refers to Placido Cidade Nuvens, who founded the Plácido Cidade Nuvens Paleontology Museum
• Fossils were found in a calcareous concretion (a hard mass of calcium carbonate)
• Fossils found are from a juvenile. It’s a partial skeleton, and includes four tail bones, parts of the hips, parts of the legs (lower legs including tibia and fibula and the thigh bone, or femur), parts of the feet, and soft tissue
• Soft tissue includes a thin epidermis (outer skin layer), muscle fibers, and possibly blood vessels. There are also skin impressions under the left foot, which show scales
• Had a thin epidermis, of about 0.04 mm that had a criss-cross pattern
• Two types of scales in the skin on the feet: large hexagonal scales (possibly scutellate scales, which can form a shield and protect the feet), and small diamond-shaped scales on the underside of the foot (likely reticulate scales (help provide friction). Together they form a podotheca (horny sheath on the legs and feet, like most birds (think of a crow’s feet, for example)
• Debate over the years about what type of theropod Santanaraptor was
• Had three large toes on its foot (so knew it was a theropod)
• Originally thought to be a maniraptoran (group that includes birds and dromaeosaurs)
• For a while considered to be a tyrannosauroid
• Then considered to be a basal coelurosaur, based on features of its femur
• A 2025 study found Santanaraptor to be either an early maniraptoromorph, along with Mirischia, Juratyrant, and Tanycolagreus, or as an early megaraptoran (the authors said their preferred hypothesis was as a maniraptoromorph)
• Lived in a semi-arid (semi dry) area with marine incursion (sea water levels rose for a while to create some brackish or saline lakes)
• Other dinosaurs that lived around the same time and place include spinosaurs like Angaturama and Irritator, coelurosaurs like Aratasaurus and Mirischia, and megaraptors
• Other animals that lived around the same time and place include crocodylomorphs, pterosaurs, turtles, and fish

Fun Fact:

Paleontologists have found the first evidence of color in a sauropod dinosaur (it may have been red!)

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