An ancient armed worm may be key to unraveling the evolutionary history of a diverse collection of marine invertebrates.
Found in China, a fossil about 220-million years old, recently identified as a worm, has been hailed. Wufengellathere could be a missing link between the three phyla that comprise the marine creatures called lophophorata.
Based on genetic analysis; Wufengella is probably a common ancestor that unites brachiopods, bryozoans and phoronid worms, paleontologist Jakob Vinther and colleagues report on September 27. Current Biology.
“He had been watching us [the common ancestor] It was some sort of wormy animal that had plates on its back,” said Vinther, of the University of Bristol in England. “But we never had an animal.”
About half a billion years ago, almost all major animal groups burst onto the scene in a flurry of evolutionary diversification in what is known as the Cambrian explosion (SN: 4/24/19). During this period, the lophophorates experienced a rapid increase in species, which obscured the evolutionary history of the group.
One thing that unites the different phyla of the group is their tentacle-like tubes that feed the lophophora. But beyond that commonality, the files are quite different. Brachiopods are test animals that are clear at first sight. Bryozoans — commonly known as fly animals — are microscopic, sedentary critters that live in coral colonies. And phoronids, or ungulate worms, are seamless, soft bodies that live in stationary, kinetic structures. (Recently, some researchers have established that the hyolith – an extinct animal known for its cones (SN: 1/11/17) – they are also lophophorate because of the tentacle organ that surrounds the mouth.
Wufengella The phyla of Vinther and colleagues does not agree. But the critter has characteristics similar to those of brachiopods, sole worms or bryozoans: an asymmetric series, an armored dorsal plate, a worm body and a set of lobes attached to the surrounding body.
The fossil is a “great find,” says Gonzalo Giribet, an invertebrate zoologist at Harvard University who was not involved in the research. However, physical analysis does not confirm this Wufengella the long-sought page is not wanting, he warns, but rather suggests.
Some researchers have suspected that the common ancestor of the lophophorate was a sedentary creature that sat on the sea floor and fed only through tubes, similar to its modern relatives. The Wufengella a fossil could refute this; The design of the animal’s body suggests a place where it crawls around, the researchers say.
Like a fossil Wufengella He had long hoped to find himself and his colleagues deep in the bucket list of fossils. But “we always think, ‘Well, we’ll probably never see it in our lifetime,'” he says. Normally, such a creature would have spent its life in the shallows. Organisms don’t tend to preserve well there, failing more quickly due to the exposed lots of oxygen. Vinther suggests that Wufengella His team was probably found when the storm washed away at high water.
Now researchers have found one Wufengellathey hope to find more, partly to see if there are other varieties. And perhaps the team could bring back even more ancestors in the tree of life that would connect lophophorates with other animal groups such as mollusks, Vinther says, to further excavate how life on Earth is connected.
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