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Arrangement of fossils gives insights into mammal behavior at 75 million years ago


A sort of rodent called Filikomys primaevus. Eurekalert offers an artist’s concept:

A life-like reconstruction along with identified fossilized bones found of Filikomys primaevus. Its powerful shoulders and elbows suggest it was a burrowing mammal/
Misaki Ouchida

The evidence lies in the fossil record of a new genus of multituberculate—a small, rodent-like mammal that lived during the Late Cretaceous of the dinosaur era—called Filikomys primaevus (translates to “youthful, friendly mouse”). The fossils, which are the most complete mammal fossils ever found from the Mesozoic in North America, indicate that F. primaevus engaged in multi-generational, group-nesting and burrowing behavior, and possibly lived in colonies. University of Washington Biology and Burke Museum Graduate Student Luke Weaver, UW Professor of Biology and Burke Museum Curator of Vertebrate Paleontology Gregory Wilson Mantilla, and co-authors analyzed several fossils, extracted from a well-known dinosaur nesting site called Egg Mountain in western Montana, that are about 75.5 million years old.

Fossil skulls and skeletons of at least 22 individuals of F. primaevus were discovered at Egg Mountain, typically clustered together in groups of two to five, with at least 13 individuals being found within a 30 m2 area in the same rock layer. Based on how well preserved the fossils are, the type of rock they’re preserved in, and F. primaevus’ powerful shoulders and elbows that are similar to today’s living burrowing animals, Weaver, Wilson Mantilla, and co-authors hypothesize these animals lived in burrows and were nesting together. Furthermore, the animals found were a mixture of multiple mature adults and young adults, suggesting these were truly social groups as opposed to just parents raising their young.

News, “New Study Finds Earliest Evidence for Mammal Social Behavior” at Burke Museum

We learn more from bones all the time, especially as more of them are found. Some dinosaurs appear to have lived in social groups (herds) too. It prompts one to wonder, at what point did truly social behavior arise?

Truly social behavior was there from the start. Bacterial biofilms are social in every sense. polistra
75M YA current consensus strata was placed during the 1656 anno-mundi impacts year., as more recent strata is capped at under 70k and under 10k based on radio-metric dating and soft tissue. So just one of many strata laid down during the global flood of Noach, thus the conditions were in place for this fossil formation.. reference volume I of the YeC Moshe Emes series for Torah and science alignment. Pearlman

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