Remarkably Preserved ‘Lazarus’ Fossil Suggests Fish Evolved Based on Earth’s Crust

An past coelacanth—the benignant of food deemed a ‘living fossil’ erstwhile it was discovered successful 1938—may person evolved successful performance with tectonic activity, according to a caller paper.

In the work—published contiguous successful Nature Communications—a squad of researchers picture a caller coelacanth taxon from the precocious Devonian, astir 383 cardinal years ago. Using changes successful Earth’s subduction arsenic a proxy for past tectonic activity, the squad concluded that coelacanth taxon evolved much rapidly erstwhile determination was much activity.

“Our analyses recovered that tectonic sheet enactment had a profound power connected rates of coelacanth evolution,” said pb writer Alice Clement, an evolutionary biologist and paleontologist from Flinders University, successful a assemblage release. “Namely that caller taxon of coelacanth were much apt to germinate during periods of heightened tectonic enactment arsenic caller habitats were divided and created.”

Artist’s content of the coelacanth. Illustration Katrina Kenny (courtesy Flinders University)

The 2 fossil specimens, representing a azygous coelacanth, were collected during a 2008 expedition to what was erstwhile an past tropical reef. The caller squad CT-scanned them, giving them 3D images of the fish, which is remarkably preserved successful 3 dimensions; galore fossilized scales and skull bones are evident successful the acid-treated fossil.

Coelacanths are often called surviving fossils because, erstwhile discovered disconnected the South African seashore successful 1938, they uncannily resembled past food taxon from the fossil record. (It’s worthy noting that locals were astir surely alert of the coelacanth’s persistence anterior to 1938.) Today, determination are 2 known extant taxon of coelacanth, inhabiting the waters disconnected South Africa and Indonesia.

“We calculated the rates of improvement crossed their 410 million-year history,” said survey co-author John Long, a paleontologist astatine Flinders University, successful the aforesaid release. “This revealed that coelacanth improvement has slowed down drastically since the clip of the dinosaurs, but with a fewer intriguing exceptions.”

But caller probe has besides shaken up the “living fossil” trope. One 2021 paper recovered that coelacanth DNA has gotten a revamp successful the past 23 cardinal years—relatively caller changes erstwhile you see its ancestors, similar the Australian specimen, didn’t alteration overmuch implicit 300 cardinal years. The aforesaid year, a antithetic squad of researchers determined the food tin unrecorded up to 100 years, and apt doesn’t adjacent scope maturity until astir property 50.

The coelacanth continues to evolve, adjacent if it does truthful astatine a slower complaint than its pre-dinosaur days. But the caller assemblage of enactment suggests a straightforward story: conscionable due to the fact that an carnal whitethorn acceptable our accepted ideas of what prehistoric looks like, it doesn’t mean the carnal isn’t adaptable.