An historical, armored worm will be the key to unraveling the evolutionary historical past of a various assortment of marine invertebrates.
Discovered in China, a roughly 520-million-year-old fossil of the newly recognized worm, dubbed Wufengella, may be the lacking hyperlink between three of the phyla that represent a cadre of sea creatures known as lophophorates.
Based on a genetic evaluation, Wufengella might be the widespread ancestor that connects brachiopods, bryozoans and phoronid worms, paleontologist Jakob Vinther and colleagues report September 27 in Current Biology.
“We had been speculating that [the common ancestor] may have been some wormy animal that had plates on its back,” says Vinther, of the University of Bristol in England. “But we never had the animal.”
Roughly half a billion years in the past, almost all main animal teams burst onto the scene in a flurry of evolutionary diversification throughout what’s often called the Cambrian explosion (SN: 4/24/19). During this time, lophophorates skilled a fast progress of species, which has obscured the group’s evolutionary historical past.
This Wufengella fossil, present in China, is roughly 520 million years previous and sports activities a number of options widespread to sea creatures often called lophophorates.Jakob Vinther and Luke Parry
One factor that ties collectively the totally different phyla of the group is their tentacle-like feeding tubes often called lophophores. But past that commonality, the phyla are all fairly totally different. Brachiopods are shelled animals that in the first place look resemble clams. Bryozoans — generally often called moss animals — are microscopic sedentary critters that stay in corallike colonies. And phoronids, or horseshoe worms, are unsegmented, soft-bodied creatures that stay in stationary, tubelike buildings. (More just lately, some researchers have decided that hyoliths — an extinct animal identified by their conical shells (SN: 1/11/17) — are additionally lophophorates due to the tentacled organ that surrounds their mouth.)
Wufengella doesn’t belong to any of those phyla, Vinther and his colleagues discovered. But the critter has traits just like these of brachiopods, horseshoe worms or bryozoans: a collection of uneven, armored again plates, a wormlike physique and bristles that stand out from lobes surrounding its physique.
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The fossil is a “great find,” says Gonzalo Giribet, an invertebrate zoologist at Harvard University who was not concerned within the analysis. Still, the scientists’ evaluation doesn’t verify that Wufengella is the long-sought lacking hyperlink, he cautions, however reasonably suggests it.
Some researchers had hypothesized that lophophorates’ widespread ancestor can be a stationary creature that sat on the seafloor and fed solely by way of tubes, just like its trendy kin. The Wufengella fossil may refute this concept; the animal’s physique plan suggests as an alternative that it crawled round, the researchers say.
A fossil like Wufengella had lengthy been excessive on Vinther’s bucket listing of fossils that he and his colleagues hoped to search out. But “we always thought, ‘Well, we probably will never see that in real life,’” he says. Typically, such a creature would have spent its life in shallow water. Organisms don’t are likely to protect nicely there, decaying sooner as a consequence of publicity to a number of oxygen. Vinther means that the Wufengella that his group discovered in all probability washed out to deep water in a storm.
Now that the researchers have discovered one Wufengella, they hope to search out extra, partially to see if there are different varieties. And maybe the group may determine much more distant ancestors additional again on the tree of life which may join lophophorates with different animal teams comparable to mollusks, Vinther says, additional fleshing out how life on Earth is linked.