A brown Parasaurolophus cyrtocristatus skeleton is posed in a walking position in the Evolving Planet exhibition at the Field Museum in Chicago, Illinois.

#FossilAdventCalendar day #25:
Parasaurolophus cyrtocristatus.

This GORGEOUS specimen in Evolving Planet at the Field Museum 🏛 is a special specimen - it’s the holotype, or the specimen🦴 used to describe the species.

I hope you've enjoyed the Fossil Advent Calendar. Stay tuned for more #scicomm!

A skull of Daeodon faces the camera with large canines, forward facing eyes, and large jaw flanges.

A side view of the same Daeodon skull showing its huge canine teeth and pig-like skull.

#FossilAdventCalendar day #24: Daeodon, the "Hell 🔥 pig".

One of my all-time favorite fossil mammals, these HUGE, fast, fearsome, omnivorous, pig-like 🐗 ungulates ate their way through North America 29-15.97 million years ago.

Specimen housed at the UNL Morill Hall Museum in Lincoln, Nebraska.

A tan jawbone from Brachylophosaurus with a row of flat teeth sits against a black background next to a specimen label.

#FossilAdventCalendar day #23: Brachylophosaurus lower jaw (MOR 1071-7-15-98-226).

My, that's a lot of teeth you have! Hadrosaurs, or duck-billed dinosaurs, had rows full of teeth that created a grinding surface for shredding tough plants 🪴.

This specimen is housed at Museum of the Rockies.

A diamond shaped osteoderm, or bony scute with a ridge down the center, sits against a black background at Museum of the Rockies.

#FossilAdventCalendar day #22: Ankylosaur scute.

Ankylosaurs had osteoderms, or scutes made of bone 🦴, embedded in their skin that worked together as a form of protection against toothy predators 🦖.

This specimen from Glacier County, Montana (MOR 419) is housed at Museum of the Rockies.

A dark brown skeleton of Smilodon fatalis, the sabertoothed cat, shows its long, banana-sized sabers to the camera.

#FossilAdventCalendar day #21: #Smilodon fatalis.

The La Brea Tar Pits in Los Angeles 🌴🌊, has the largest collection of Smilodon skeletons in the world, all from within Hancock Park.

This specimen, on display at the UNL Morill Hall Museum, is one of many that reside at museums worldwide.

A large Bison latifrons statue with brown fur and large, curved horns, stands atop an exhibit at the UNL Morill Hall Museum in Lincoln, Nebraska.

#FossilAdventCalendar day #20: Bison latifrons.

Large and in-charge, this Pleistocene bison 🦬 was MUCH larger than the bison we see in the American west today.

The horns of Bison latifrons measured 84 in. tip to tip, compared to 26-35 in. in modern bison.

UNL Morill Hall Museum, Lincoln, NE.

A large Columbian mammoth molar sits atop a piece of gray foam in the Morill Hall Museum in Lincoln, Nebraska.

#FossilAdventCalendar day #19: Mammuthus columbi molar.

Columbian mammoth, wooly mammoth's larger cousin 🐘, had 4 large molars in their mouth that were replaced 6 times over their lifetime!

Mammoth remains have been found in ALL 93 counties in Nebraska 🌽.

Specimen at the UNL Morill Hall Museum.

A brown Jefferson's ground sloth skull sits sideways on two black foam blocks with a specimen label on display at the Nebraska State Museum in Lincoln, NE.

#FossilAdventCalendar day #18: Megalonyx Jefferson, the Jefferson's ground sloth.

We live with many Ice Age 🧊 megafauna that persevered into present day, like coyote and American pronghorn, but these large sloths 🦥 went extinct, unfortunately!

Specimen UNSM 145000 at UNL Morill Hall Museum.

Overhead view of a large nest of oblong shaped Troodon eggs in a gray mudstone nest.

#FossilAdventCalendar day 17: Troodon formosus nest and eggs 🪺 (MOR 393)!

Over 75 million years ago, Troodon, medium-sized meat-eating dinosaurs, nested in the same area as Maiasaura, large hadrosaurs, or duck-billed dinosaurs.

Museum of the Rockies is still actively studying this important site.

Close-up of a leaf impression in brown mudstone at Museum of the Rockies.

#FossilAdventCalendar day 16: fossil leaf impression (MOR PB 72).

The study of plants is called paleobotany 🌿, a subfield of paleontology.

Between 66 and 58 million years ago, a leaf fell from a tree 🍁 and left its impression in the mud, only to be discovered by curious fossil hunters in 1936.

#FossilAdventCalendar day 15: Dromaeosaur hand claw (MOR 484).

Dromaeosaurs, or "raptors," had recurved hand claws that assisted them in holding and grasping their struggling prey.

#FossilAdventCalendar day 14: #Edmontosaurus maxilla!

This partial maxilla, or upper jaw, belongs to one of the largest Cretaceous hadrosaurs, Edmontosaurus.

As their teeth 😬 wore down, they were replaced throughout their life, giving them an endless supply of teeth and zero dental bill.

#FossilAdventCalendar day 13: #Edgarosaurus muddi holotype (MOR 751).

Plesiosaurs like Edgarosaurus were air breathing marine reptiles that swam the seas 🌊 while dinosaurs lived on land.

The bountiful Western Interior Cretaceous Seaway teemed with life 🐟 that supported these large marine animals.

#FossilAdventCalendar day 12: Diplodocid 🦕 fossilized skin (MOR 637)!

Skin fossils discovered at the Mother's Day Quarry in Montana exhibit a vast amount of scale diversity. They vary in shape, size, orientation, and 3-dimensional relief depending on their location on the integument.

#FossilAdventCalendar day 11: #Hypacrosaurus stebingeri holotype (MOR 549):

These 75 million year old crested hadrosaurs lived with Maiasaura, Troodon, and other Cretaceous dinosaurs across what is now Montana and Alberta.

This stunning specimen resides at Museum of the Rockies.

#FossilAdventCalendar day 10: Tenontosaurus tilletti (MOR 682).

Not only is this a GORGEOUS specimen, but 11 sharp, serrated teeth were discovered with it, leading researchers to believe it was killed by a pack of Deinonychus.

Discovered by Dr. David Varricchio in 1991 on BLM land in Montana.

#FossilAdventCalendar day 9: #Troodon embryo (MOR 993)!

Dinosaurs hatched from eggs 🥚 and sometimes we can still find tiny bones 🦴 of unhatched embryos inside.

This little one never made it, but it’s helping us unlock secrets of how Troodon grew, and adds to our knowledge of dinosaur reproduction.

#FossilAdventCalendar day 8: #Ornithomimus foot (MOR 1105)!

This gorgeous ~66 mya foot belongs with the hand 👋, covered in my last post. The metatarsals, or foot bones, elongate the leg, making this animal an excellent runner 🏃‍♀️.

Visit this and other fossil specimens at Museum of the Rockies 🦖!

#FossilAdventCalendar day 7: #Ornithomimus "Ostrich mimic" hand (MOR 1105)!

Ornithomimids were bird-like dinosaurs with sleek bodies built for speed!

If you saw one alive, you'd swear it was an ostrich, complete with wings 🪶 and a toothless beak.

Learn more: www.newscientist.com/article/dn22...

#FossilAdventCalendar day 6 AND #FossilFriday! Meet "Montana's T.rex"!

Museum of the Rockies 🏛️ here in Bozeman, Montana has the largest collection of T.rex 🦖 in the world!

This adult T.rex (MOR 980) was found near Fort Peck Lake in 1997 and is one of the most complete T. rex specimen ever found.

#FossilAdventCalendar day 5: Meet #Maiasaura peeblesorum, state dinosaur of Montana and "good mother lizard".

Museum of the Rockies cares for a 75 million year old dinosaur nesting ground where Maiasaura, #Troodon, and others laid their eggs 🥚🥚🥚.

Learn more: www.nps.gov/articles/mes...

#FossilAdventCalendar day 4: This GORGEOUS 😍 ammonite!

Look closely 🔎: Can you see the intricately preserved structures? The sutures and septa have been beautifully preserved!

Ammonites thrived for in the world's oceans 🌊 for 140 million years until they went extinct ☄️ with nonavian dinosaurs 🦖.

#FossilAdventCalendar day 3: Meet the #Daspletosaurus 🦖horneri holotype (MOR 590)!

These GORGEOUS, large tyrannosaurs roamed what is now Montana ~10 MILLION years before Tyrannosaurus rex.

Want to learn more? Watch this video from tyrannosaur expert Dr. Thomas Carr: youtu.be/4D3aHIFOtMk?...

#FossilAdventCalendar Day 2:

#Promerycochoerus synonymized now with #Merycochoerus, were oreodonts, affectionately referred to as "sheep🐏-camel🐪-pigs🐖".

Though they've been studied fairly well, there's still not a great #paleoart depiction.

Drop your favorite depiction in the comments ⬇️:

Hey, everyone! I'll be posting a fossil every day starting TODAY! #FossilAdventCalendar

Say hi to Big Al MOR 693: #Allosaurus jimmadseni 🦖.

This specimen is housed at Museum of the Rockies in Bozeman, Montana. This specimen is famous for their many pathologies, or injuries 🩹 sustained during life.