Episode 417: Thescelosaurus had spikes popping out of its forearms. Plus extra information from SVP together with why tyrannosaurs had small arms; how raptors had been like cheetahs; and potential theropod embryos with palatal tooth, osteoderms, and pores and skin.
Information:
- Displays from the Dinosaur Macroevolution/Macroecology session of SVP 2022 supply
- The Smooth Tissues and Taphonomy talks from SVP 2022 supply
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The dinosaur of the day: Caenagnathus
- Caenagnathid oviraptorosaur that lived within the Late Cretaceous in what’s now Alberta, Canada (Dinosaur Park Formation)
- Massive, and should have been about as large as Anzu
- Appeared much like Anzu
- Appeared hen like, with feathers and lengthy legs
- Additionally had an extended tail, and s-shaped neck, and possibly had a crest on its head
- Considered across the identical measurement as Anzu due to the recognized specimens of Anzu and Caenagnathus, the pubes are about the identical measurement
- Anzu was about 11 ft (3.5 m) lengthy
- Anzu should have been bigger (recognized specimens could not symbolize its max physique measurement, and the specimens discovered could have nonetheless been rising)
- Estimated to weigh as much as 212 lb (96 kg)
- Had an extended, flattened, toothless decrease jaw
- Had a shallow jaw, which is completely different from different oviraptorosaurs which might be extra like an upturned beak. Could imply it ate extra crops
- Caenagnathids most likely had been generalist feeders that ate crops, small animals, and possibly eggs
- Fossils discovered embody decrease jaws, tail vertebra, bones from the hand and limbs
- Sort species is Caenagnathus collinsi
- Genus title means “latest jaw”
- Species title “in honor of the late Dr. W. H. Collins, for a few years director of the Geological Survey of Canada”
- Described by R. M. Sternberg in 1940
- At first regarded as a toothless hen
- Jaws had been present in 1936 and it was named Caenagnathus
- Sternberg wrote that “The holotype is an admirably preserved decrease jaw, full apart from the ventral border of the proper ramus”
- Holotype was discovered in the summertime of 1936, a area celebration from the Nationwide Museum of Canada, underneath the route of C.M. Sternberg
- In 1988, a unique specimen that had been in storage since 1923 was rediscovered and studied, and it helped hyperlink a number of fragments of an oviraptorosaur into one dinosaur: Chirostenotes (coated in episode 404)
- Plenty of debate and subsequent research discovering Chirostenotes and Caenagnathus to be separate
- In 2010, Phil Senter did a phylogenetic evaluation of Coelurosauria and located Caenagnathus and Chirostenotes to be separate, “casting doubt on their synonymy”
- Extra full caenagnathid specimens present in 2014 and 2015, like the invention of Anzu, helped present extra variations within the fragmentary specimens
- In 2015, Funston and others re-examined caenagnathid fossils from Dinosaur Park Formation, and located extra Caenagnathus collinsi fossils, together with a tail vertebra, femur, and elements of the toes
- Funston and Currie in 2020 described one other Chirostenotes specimen with a decrease jaw, that supported Chirostenotes and Caenagnathus being separate
- Variations within the toes and toes, between Caenagnathus and Chirostenotes
- In 2020, Gregory Funston re-examined caegnagthid materials and redescribed Caegnathus collinsi (some disagreement over the range of caenagnathids)
- One of many specimens was no less than 12 years previous and practically completed rising
- In all probability grew shortly at first, then slowed down
- In 1993, Phil Currie and others named “Caenagnathus” sternbergi, primarily based on new specimens discovered within the Judith River Formation, however in a 2014 evaluation it was discovered to be a sister taxon
- Different dinosaurs that lived across the identical time and place embody ankylosaurs, ceratopsians, ornithopods, pachycephalosaurs, ornithomimids, oviraptorosaurs, paravians, tyrannosaurs
- Different animals that lived across the identical time and place embody amphibians, crocodylians, lizards, plesiosaurs, pterosaurs, turtles, mammals, fish
Enjoyable Reality:
Generally you will discover progress marks in ribs to calculate a dinosaur’s age when the legs don’t have progress marks.
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