First, biologist Mason Dean noticed a tiled pattern of hexagons and pentagons in the cartilaginous scales on a ray skeleton. The observation sparked a fruitful search for similar tiling patterns elsewhere in nature. Dean and his colleagues found these “tessellations” in diverse organisms and structures, including on the outer coatings of millet seeds, shark skin and even microscopic amoebae. Now, the team’s published catalog of so-called true tessellations throughout nature reveals how widespread they are.

How it works: Dean’s team defines true tessellations as discrete geometric plates connected by soft seams. They’re not purely visual, like the hexagons formed by the negative space in honeycomb. A typical example of true tessellation is reptile scales. They form polygonal shapes and are connected by soft tissue. A less obvious example is tree bark: the outer layer of most tree trunks consists of layered plates. These tessellations can form protective layers that are the perfect combination of stiff and flexible. Geometry and growth push vastly different life forms toward the same solutions, writes freelance journalist Anirban Mukhopadhyay.

What the experts say: The catalog could help more researchers recognize these patterns in nature, the authors hope. “Once you start paying attention to that, you see it everywhere,” Dean says. His colleague and co-author, zoologist Jana Ciecierska-Holmes, agrees: “You kind of go into the tessellation world.”

–Emma Gometz, newsletter editor

Amoebas, animals, plants, seaweeds and other cellular lifeforms with a membrane-bound nucleus are unable to survive in temperatures above 60 degrees Celsius. Or so scientists have long thought. Now, a newly discovered amoeba species can divide and reproduce at 63 degrees C, and even survive temperatures up to 70 degrees C, a team of scientists reported. The organism was discovered in hot, watery pits at Lassen Volcanic National Park in California.

Why this matters: The discovery of the so-called fire amoeba expands the definition of potentially habitable places in our universe. And insights into how organisms survive high heat could help researchers develop heat-tolerant proteins and enzymes for practical applications, such as more efficient laundry detergent.

The takeaway: “The difference between 60 and 63 degrees C may sound small but represents a relatively large shift in our current understanding of eukaryotic limits,” says microbial ecologist and astrobiologist Luke McKay, who was not involved with the study.

–Emma Gometz, newsletter editor