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Ask a Geologist- Mosasaurs Ask a Geologist: Mosasaurs By: Kiersten Formoso About Me Kiersten Formoso ● I grew up in Sussex County, New Jersey. I graduated from Rutgers in 2016 with a degree in Ecology & Evolution ● I am a PhD studying Vertebrate Paleobiology in the Earth Sciences Dept. at USC, and am also a Graduate Student-in-Residence at the Natural History Museum of Los Angeles County ● My favorite Geologic Time Period is the Triassic Period Ask A Geologist Series Art by Charles R. Knight Ask A Geologist Series Ask A Geologist Series What are Mosasaurs? Mosasaurs are extinct aquatic squamates (lizards) We know they are lizards because of their anatomy They share characters with lizards, and have many characters shared with snakes Ask A Geologist Series Pterygoid teeth Ask A Geologist Series When did Mosasaurs live? Mosasaurs lived in the Late Cretaceous Period of the Mesozoic Era About 95 to 66 million years ago The latest mosasaurs lived at the same time as famous dinosaurs like T. Rex and Triceratops (but they were not dinosaurs!) They went extinct at the same time as the dinosaurs when the asteroid struck the Earth Ask A Geologist Series Ask A Geologist Series Mosasaurs started small Aigialosaurus Ask A Geologist Series Where did Mosasaurs live? Globally! Ask A Geologist Series What did mosasaurs eat? Whatever they wanted! Mosasaurs were predators and ate fish, sharks, ammonites, plesiosaurs, birds, turtles, and even other mosasaurs Ask A Geologist Series What did mosasaurs eat? Whatever they wanted! Mosasaurs were predators and ate fish, sharks, ammonites, plesiosaurs, birds, turtles, and even other mosasaurs Ask A Geologist Series What did mosasaurs eat? Mosasaur stomach contents Ask A Geologist Series What did Mosasaurs look like? Tylosaurus reconstruction Scott Hartmann, 2015 Ask A Geologist Series What did Mosasaurs look like? Lindgren et al. 2013 Ask A Geologist Series Ask A Geologist Series Mosasaur skin! Ask A Geologist Series Konishi et al. 2014 Ask A Geologist Series Tylosaurus Ask A Geologist Series Art by Mark Witton Ask A Geologist Series Art by Andrey Atuchin Ask A Geologist Series How did Mosasaurs swim? (This is what I study!) Types of body-caudal fin propulsion Anguilliform Sub-carangiform Carangiform Ask A Geologist Series Mosasaur family tree Mosasaur relatives that are less aquatically specialized Halisaurus Mosasaurs more related mosasaurs like Mosasaurus and Halisaurus than to Tylosaurus Mosasaurus Mosasaurs more related to mosasaurs like Tylosaurus than to Mosasaurus and Halisaurus Tylosaurus Ask A Geologist Series Mosasaur family tree Mosasaurinae Russellosaurina Simões et al., 2017 Ask A Geologist Series My favorite Mosasaur: Plotosaurus Ask A Geologist Series Mosasaur Fun Facts v Mosasaurs were discovered before dinosaurs (1764 near Maastricht, Netherlands) v They’re the biggest lizards to ever live v They probably had forked tongues Ask A Geologist Series Schulp et al., 2005 Ask A Geologist Series Mosasaurus at the Rutgers Geology Museum! Ask A Geologist Series Why Do We Care? v Mosasaurs are great models for understanding secondarily aquatic evolutionary transitions (four-limbed vertebrates that evolved to go back into the water from terrestrial ancestors) v They have great fossil preservation across their whole evolutionary history, so we can ask detailed question about how they moved, their diet and ecology, and their morphology v They’re extinct, but very closely related to animals that we have living with us today Ask A Geologist Series Future work on mosasaurs v New fossils are always being found Recently a mosasaur from the Arctic was described v My co-authors and I are working on a broad comparison of mosasaur swimming changes through their evolution Ask A Geologist Series Question Time!.
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