Aaron Woodruff

@cenozoicking.bsky.social

🦴🦣🎨 Paleontologist, paleoartist and scientific illustrator 📬 DM for commissions

An analysis of fossil mammals in Science suggests that Mexico served as a long-term evolutionary “holding pen” where North American species adapted and diversified for millions of years before sweeping into South America 2.8 million years ago. https://scim.ag/4fu2QKL

Pie charts of taxonomic representation for all taxa sampled in each indicated geographic region and time interval during five diversification events leading up to interchange pulses.

Based on the GI tract contents of the frozen mammoth calf Yana, and material between her front legs, Yakutia was dominated by sparse larch forests with a shrub layer of dwarf birch, alder, and willow. She primarily ate sedges and cotton grass. #FossilFriday

Image source: https://phys.org/news/2025-04-yana-year-baby-mammoth-scalpel.html
Ausarchosaur@ausarchosaur.bsky.social · 2mo ago

Astrodon is named for the fact that one of its teeth was cut open and revealed a vaguely star-shaped cross section. Here it is figured in Joseph Leidy's "Cretaceous reptiles of the United States" (1865). #FossilFriday

#fossilfriday although the end of the symphysis is damaged it clearly has a bilobed tuskless end and a huge anterior mental foramen. These features are shared with Megabelodon lulli, leading many (including me) to think T.phippsi is a junior synonym of M. lulli.

View from the mammal overlook down at DMNS 1261 showing the bilobed symphysis Anterior view of DMNS 1261 showing the bilobed symphysis and large anterior mental foraminaUp close on the bilobed symphysis and tube-like mental foramina

Giant sea monsters are trending with the newly described Cretaceous "kraken"*. So for #FossilFriday, a better known super predator named after myth: Livyatan melvillei! A true terror of the Miocene oceans, I was thrilled to see original fossils and a skull cast of this killer sperm whale in Lima.

Reconstructed skull of Livyatan melvillei, the giant killer sperm whale. To the left, a fossil jaw fragment, part of the holotype. In the background, an illustration of a dark-blue, adult Livyatan attacking a smaller whale from below. Exhibition at the Natural History Museum of Lima, Peru.The dorsally crushed holotype skull of Livyatan melvillei. Exhibition at the Natural History Museum of Lima, Peru.Reconstructed skull of Livyatan melvillei, the giant killer sperm whale. To the left, a fossil jaw fragment, part of the holotype. In the background, an illustration of a dark-blue, adult Livyatan attacking a smaller whale from below. Exhibition at the Natural History Museum of Lima, Peru.Diorama depicting Livyatan together with other prehistoic and modern marine superpredators: Otodus megaldon (an older, Carcharodon-based reconstruction) and a giant pliosaur below it, and an Orca and Great White shark to the right
Uri Wolkowski@deinocurious.bsky.social · 4mo ago

This #FossilFriday I'm moving over from giant marine reptiles to mammals! Starting with one of the biggest of them all: Perucetus collosus! First claimed to be potentially heavier than a blue whale, Perucetus had since been "downsized" drastically. It was nevertheless a mightily chonky beast >

Partial vertebral column of Perucetus, displayed in the Natural History Museum of Lima, Peru

#FossilFriday: The Pacific mastodon, Mammut pacificus, known from California and Idaho. This species was described in 2019. This is the second of two species of Mammut from North America, the other being Mammut americanum.

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