New Fossil Reveals Early Evolution of Mammal-like Traits

Megaconus mammaliaformis, illustration by April Isch

Megaconus mammaliaformis, illustration by April Isch

A newly discovered fossil reveals the evolutionary adaptations of a 165 million-year-old proto-mammal, providing evidence that traits such as hair and fur originated well before the rise of the first true mammals. UChicago scientists including Zhe-Xi Luo, PhD, described the biological features of this ancient mammalian relative, named Megaconus mammaliaformis, in the Aug. 8 issue of Nature.

Zhe-Xi Luo, PhD

Zhe-Xi Luo, PhD

Discovered in Inner Mongolia, China, Megaconus is one of the best-preserved fossils of the mammaliaform groups, which are long-extinct relatives to modern mammals. Dated to be about 165 million years old, Megaconus co-existed with feathered dinosaurs in the Jurassic era, nearly 100 million years before Tyrannosaurus rex roamed Earth. Kevin Jiang has more at the UChicago News site:

“We finally have a glimpse of what may be the ancestral condition of all mammals, by looking at what is preserved in Megaconus. It allows us to piece together poorly understood details of the critical transition of modern mammals from pre-mammalian ancestors,” said Zhe-Xi Luo, professor of organismal biology and anatomy.

The discovery has been covered widely in national and international media, including:

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Zhou C.F., Wu S., Martin T. & Luo Z.X. (2013). A Jurassic mammaliaform and the earliest mammalian evolutionary adaptations, Nature, 500 (7461) 163-167. DOI:

About Matt Wood (513 Articles)

Matt Wood is a senior science writer at the University of Chicago Medicine and nonfiction editor for Another Chicago Magazine.

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