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Home , Aigialosaurus, Halisaurus, Mosasaurinae, Mosasaurus, Plotosaurus, Tylosaurus

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By: Kiersten Formoso About Me Kiersten Formoso ● I grew up in Sussex County, . I graduated from Rutgers in 2016 with a degree in Ecology &

● 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 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 ()

We know they are lizards because of their anatomy

They share characters with lizards, and have many characters shared with

Ask A Geologist Series Pterygoid teeth

Ask A Geologist Series When did Mosasaurs live?

Mosasaurs lived in the Late Period of the Era

About 95 to 66 million 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

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Where did Mosasaurs live? Globally!

Ask A Geologist Series What did mosasaurs eat? Whatever they wanted!

Mosasaurs were predators and ate , sharks, ammonites, plesiosaurs, birds, , 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? 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

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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 and 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:

Ask A Geologist Series Mosasaur Fun Facts v Mosasaurs were discovered before dinosaurs (1764 near , ) 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 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 that we have living with us today

Ask A Geologist Series Future work on mosasaurs v New 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!