Champsosaurus in Cobra Pose at the Science Museum of Minnesota

Champsosaurus FTW!

I like the cobra yoga pose, gets that lower back nice and stretched :-).

Champsosaurus is a #choristodere, a group not related to #crocodiles other than by virtue of both being in the group #Reptilia. They split from the main #reptile line over 250 mya, in the #Permian it is thought, and were quite successful in their niches.

#Champsosaurus died out in the #Paleocene and shows up in the Late Cretaceous. The last choristodere seems to have died out 11 mya. Talk about a long run!

All members of this group seem to have a #neomorphic bone, meaning a net-new bone (think #pteroid bone in #pterosaurs). Such bones are always awesome as they help #paleontologists figure out who goes in what clade. Have the right bone and you are in the club, like how arostral bone makes one a #ceratopsian (you are welcome #Psittacosaurus, a bipedal #ceratopsian :-)).

Champsosaurus is the most famous choristodere, living in the Late #Cretaceous and surviving into the Age of #Mammals, too! It makes me wonder what it was doing that let it survive the Big Impact when so many others didn’t. #Aestivation? #Brumation? Luck (which we have few ways to categorize so we don’t write about it enough in my opinion)?

It has massive temporal fenestrae, which gives it a unique, heart-shaped skull look when observed from above.

Differences in sacral morphologies suggest sexual dimorphism, with one sacrum type suggesting its possessors could crawl ashore to lay eggs. The other type doesn’t possess the same feeling of biomechanical strength.

The long, #gharial-like snout suggests it ate #fish. They are only known from freshwater and the longest reached 12’ but just about all I have ever touched were much, much smaller, closer to 4’. Convergent #evolution is amazing!

Skin impressions of Champsosaurus indicate tiny scales. Close cousins have been found with webbed feet and no osteoderms.

Science Museum of Minnesota in St. Paul @SMMPaleo @sciencemuseummn is legendary for its #Borealosuchus, #Champsosaurus, and various #crocodile skeletons in their collections. During my sauropod study visit I met three researchers studying these long-snouted beauts!

#FossilCrates

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