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Smithsonian National Museum of Natural History
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Artist’s reconstruction of a new fossil species Hemignathus vorpalis (bottom), based on its probable resemblance to adult males of its genus: H. wilsoni (Akiapola’au, above) and H. lucidus hanepepe (Kauai Nukupu’u, middle). Illustration © J. Hume


Artist’s reconstruction of a new fossil species Hemignathus vorpalis (bottom), based on its probable resemblance to adult males of its genus: H. wilsoni (Akiapola’au, above) and H. lucidus hanepepe (Kauai Nukupu’u, middle).

Illustration © J. Hume

 

Gene Hunt
Gene Hunt in the lab.

Gene Hunt, PhD, is curator of Ostracoda, which are crustaceans like shrimp and crabs, but tinier—only about 1 mm (1/25 in.) long.


I find it gratifying that an insight made more than 150 years ago can still contribute to understanding living things today.

Like Charles Darwin, I sometimes spend a lot of time thinking about natural selection. Most often, that’s because I observe fossil evidence of change over time, and considering natural selection can help make sense of these patterns.

I was puzzled that one group of ostracodes evolved larger bodies over millions of years until I remembered that natural selection often favors larger bodies in colder climates. The ostracodes lived more than 1 km (3,300 ft) deep in the ocean, which has grown colder over millions of years, by about 10oC (18oF). I hypothesized that ostracodes had evolved larger sizes as an adaptation to increasingly cold temperatures.

Colleagues and I tested this idea, and we found that ostracodes grew larger when the ocean cooled but not when ocean temperatures stayed the same.

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