Uncommon fossil clam found alive

Rare fossil clam discovered alive

A stunning play of colours highlights Southern California’s lengthy misplaced clam. Credit score: Jeff Goddard

Discovering a brand new species is at all times thrilling, however so is discovering one alive that everybody assumed had been misplaced to the passage of time. A small clam, beforehand recognized solely from fossils, has just lately been discovered residing at Naples Level, simply up the coast from UC Santa Barbara. The invention seems within the journal Zookeys.

“It is not all that widespread to seek out alive a species first recognized from the fossil documentparticularly in a area as well-studied as Southern California,” stated co-author Jeff Goddard, a analysis affiliate at UC Santa Barbara’s Marine Science Institute. “Ours would not return anyplace close to so far as the well-known Coelacanth or the deep -water mollusk Neopilina galatheae—representing a complete class of animals thought to have disappeared 400 million years in the past—however it does return to the time of all these wondrous animals captured by the La Brea Tar Pits.”

On a day low tide in November 2018, Goddard was turning over rocks trying to find nudibranch sea slugs at Naples Level, when a pair of small, translucent bivalves caught his eye. “Their shells have been solely 10 millimeters lengthy,” he stated. “However once they prolonged and began waving a few brilliant white-striped foot longer than their shell, I spotted I had by no means seen this species earlier than.” This stunned Goddard, who has spent a long time in California’s intertidal habitats, together with a few years particularly at Naples Level. He instantly stopped what he was doing to take close-up pictures of the intriguing animals.

With high quality photographs in hand, Goddard determined to not acquire the animals, which gave the impression to be uncommon. After pinning down their taxonomic household, he despatched the photographs to Paul Valentich-Scott, curator emeritus of malacology on the Santa Barbara Museum of Pure Historical past. “I used to be stunned and intrigued,” Valentich-Scott recalled. “I do know this household of bivalves (Galeommatidae) very properly alongside the coast of the Americas. This was one thing I might by no means seen earlier than.”

He talked about a number of potentialities to Goddard, however stated he’d must see the animal in-person to make a correct evaluation. So, Goddard returned to Naples Level to assert his clam. However after two hours combing only a few sq. meters, he nonetheless hadn’t caught sight of his prize. The species would proceed to elude him many extra instances.

Rare fossil clam discovered alive

It takes a eager eye to identify the minuscule clam (backside heart), sitting subsequent to this chiton within the tidepools of Naples Level. Credit score: Jeff Goddard

9 journeys later, in March 2019, and practically prepared to surrender for good, Goddard turned over one more rock and noticed the needle within the haystack: A single specimen, subsequent to a few small white nudibranchs and a big chiton. Valentich-Scott would get his specimen finally, and the pair might lastly set to work on identification.

Valentich-Scott was much more stunned as soon as he bought his palms on the shell. He knew it belonged to a genus with one member within the Santa Barbara area, however this shell did not match any of them. It raised the thrilling chance that they’d discovered a brand new species.

“This actually began ‘the hunt’ for me,” Valentich-Scott stated. “After I suspect one thing is a brand new species, I want to trace again by means of all the scientific literature from 1758 to the current. It may be a frightening process, however with expertise it could actually go fairly shortly.”

The 2 researchers determined to take a look at an intriguing reference to a fossil species. They tracked down illustrations of the bivalve Bornia cooki from the paper describing the species in 1937. It appeared to match the trendy specimen. If confirmed, this is able to imply that Goddard had discovered not a brand new species, however a form of residing fossil.

It’s price noting that the scientist who described the species, George Willett, estimated he had excavated and examined maybe 1 million fossil specimens from the identical location, the Baldwin Hills in Los Angeles. That stated, he by no means discovered B.cooki himself. Relatively, he named it after Edna Cook dinner, a Baldwin Hills collector who had discovered the one two specimens recognized.

Rare fossil clam discovered alive

The kind specimen that George Willett used to initially describe the species. Credit score: Valentich-Scott et al

Valentich-Scott requested Willett’s authentic specimen (now categorized as Cymatioa cooki) from the Pure Historical past Museum of Los Angeles County. This object, known as the “kind specimen,” serves to outline the species, so it is the last word arbiter of the clam’s identification.

In the meantime, Goddard discovered one other specimen at Naples Level—a single empty shell within the sand beneath a boulder. After fastidiously evaluating the specimens from Naples Level with Willett’s fossil, Valentich-Scott concluded they have been the identical species. “It was fairly outstanding,” he recalled.

Small dimension and cryptic habitat however, all of this begs the query of how the clam eluded detection for therefore lengthy. “There’s such an extended historical past of shell-collecting and malacology in Southern California—together with of us within the tougher to seek out micro-mollusks—that it is onerous to consider nobody discovered even the shells of our little cutie,” Goddard stated.

He suspects the clams might have arrived right here on currents as planktonic larvae, carried up from the south throughout marine heatwaves from 2014 by means of 2016. These enabled many marine species to increase their distributions northward, together with a number of documented particularly at Naples Level. Relying on the animal’s development fee and longevity, this might clarify why nobody had observed C. cooki on the web site previous to 2018, together with Goddard, who has labored on nudibranchs at Naples Level since 2002.

“The Pacific coast of Baja California has broad intertidal boulder fields that stretch actually for miles,” Goddard stated, “and I believe that down there Cymatioa cooki might be residing in shut affiliation with animals burrowing beneath these boulders.

Data:
Paul Valentich-Scott et al, A fossil species discovered residing off southern California, with notes on the genus Cymatioa (Mollusca, Bivalvia, Galeommatoidea), ZooKeys (2022). DOI: 10.3897/zookeys.1128.95139

citations: Uncommon fossil clam found alive (2022, November 7) retrieved 8 November 2022 from https://phys.org/information/2022-11-rare-fossil-clam-alive.html

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