MI weekly selection #554

Spiral galaxy Andromeda, also called M31, in ultraviolet light. Source: NASA/Swift/Stefan Immler (GSFC) and Erin Grand (UMCP)

Fossils of 2 new mammal species clarify evolution’s path

Teeth, ears and jaws of two newly identified mammal species could help scientists understand mammals’ evolution from crocodilians, dinosaurs and lizards. Specimens of Feredocodon chowi, mouse-size members of the family shuotheriids from the Jurassic period, have molars more like reptiles than modern mammals, and the middle ears of early Jurassic fossils from rat-like species Dianoconodon youngi exhibit signs of a transition from reptiles’ single bone to modern mammals’ three bones.

Full Story: Popular Science

Dinosaurs’ reign may have relied on more than fast growth

Reptiles and other non-dinosaur animals of the Mesozoic era shared dinosaurs’ rapid growth rates, calling into question the concept that dinosaurs’ dominance was due to their speedy growth alone. Researchers, who examined leg bone fossils from Argentina of dinosaurs, non-dinosaur reptiles and an early mammalian relative, suggest that factors other than rapid growth contributed to dinosaurs’ success.

Full Story: Earth

How brown rats won the race in North America

Atlantic Ocean shipping networks doubled as “rat superhighways” to colonial North America, ferrying brown rats into coastal shipping centers before 1740, at least 35 years earlier than previous estimates. The findings are based on studies of rodent bones from the 1607 establishment of Jamestown through the early 1900s, as well as bones from ships that sank between 1550 and 1770, and the study suggests that the bigger, more aggressive brown rats took mere decades to take over from black rats, probably by eating their food.

Full Story: The Associated Press

Age propels galaxies into chaotic orbits

Aging is the reason chaos increases in galaxies as they transition from places of organized rotation that quickly generate stars into random orbits. Galaxies’ environment and mass play a role in the chaos, but age is the most important element.

Full Story: Popular Science

Ancient wood tools carve clearer picture of early hominins

Wooden tools, from broken spears to domestic implements, indicate that early hominins hunted horses 300,000 years ago at Germany’s Schoningen site and stayed long enough to establish a campsite or village. The tools point to cognitive abilities that allowed the hominins, likely early Neanderthals, to plan and execute complex carvings.

Full Story: Science

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