The Beauty of Bivalves

When Sally was selling seashells by the seashore, it’s safe to say she could have charged a steeper price, because her wares weren’t just wondrous things to look at. In fact, shells and the bivalve beasts that inhabit them hold valuable keys to unlocking the natural world’s remaining mysteries, from why some animals can think without brains to how the ocean’s chemistry has changed over the centuries.

“They’re the canaries of the sea,” said Paul Valentich-Scott, who’s worked at the Santa Barbara Museum of Natural History since 1982. “They’re essentially sampling the water daily, even hourly.” This year, along with Eugene Coan, Valentich-Scott coauthored what must be one of the heaviest marine biology volumes ever assembled, a nine years-in-the-making, nearly 1,300-page guide titled Bivalve Seashells of Tropical West America: Marine Bivalve Mollusks from Baja California to Northern Peru. It’s the second in a series that started with a bivalve guide for California to Alaska (that one took 12 years), and it will be followed by a third edition, stretching from Peru to the tip of South America (which is already underway and which he hopes to finish in six years).

“I’m the curator of shells, which is pretty fun,” he explained one recent morning while showing off some of the museum’s more than 2.5 million specimens, which he calls a “biodiversity library” and is used by researchers all over the world: bright green swirly cones from Papau New Guinea, trippy triangular shells from Japan, watermelon-sized snails from Western Australia, giant wheel-shaped clams from the South Pacific, tiny bits that could be confused for grains of sand from Mexico. “A lot of life on the planet, especially that which we don’t know about, is that size,” said Valentich-Scott, noting that as much as 95 percent of life in earth is not yet known. “For things with big eyes and fur, we know a lot. But spineless creatures? Very little.”

Though Valentich-Scott’s new guide details each of nearly 900 species, identifies about 16 new species (though hints at dozens more), and extensively describes their habitats, he said that it represents the “very smallest step of understanding” these species and simply provides a base from which future researchers can grow their own studies. And there’s also plenty of potentially practical and medical functions that may arise from studying bivalves, including learning how mussels tell the glue-like substance in their beards to harden at times, and relax its grip at others. “They really don’t even have a brain,” said Valentich-Scott. “It’s almost magic. We don’t understand it at all.”

Sounds like Sally’s got another selling point down by the seashore.

See sbnature.org.