May 2, 2024

Ancestry of Three Major Animal Groups Revealed by 518-Million-Year-Old Armored Worm

Surrounding the asymmetrical armor of the worm was a fleshy body with a series of flattened lobes forecasting from the sides. In between the lobes and the armor, bundles of bristles emerged from the body. The numerous lobes, packages of bristles, and the range of shells on the back are proof that the worm was initially serialized or segmented, like an earthworm.
The findings were published in the journal Current Biology on September 27. Study co-author, Dr. Jakob Vinther from the University of Bristols School of Earth Sciences, stated: “It appears like the not likely offspring in between a bristle worm and a chiton mollusk. Interestingly, it belongs to neither of those groups.”
The fossil Wufengella and a drawing outlining the major elements of the organism. Credit: Jakob Vinther and Luke Parry
The animal kingdom consists of more than 30 major body plans categorized as phyla. Each phylum includes a distinct set of functions that set them apart from one another. Just a few functions are shared across more than one group, which is a testimony to the extremely fast rate of development during which these significant groups of animals come from. This was during a period called the Cambrian Explosion, around 550 million years earlier.
Brachiopods are a phylum that ostensibly resembles bivalves (such as clams) in that they have a set of shells and live connected to the seafloor, rocks, or reefs. When looking inside, brachiopods reveal themselves to be substantially different in lots of respects. In fact, brachiopods filter water using a set of tentacles folded into a horseshoe-shaped organ.
Such an organ is called a lophophore and brachiopods share the it with two other major groups called the phoronids (” horseshoe worms”) and bryozoans (” moss animals”). Molecular studies– which reconstruct evolutionary trees utilizing amino acid sequences– concur with physiological proof that brachiopods, bryozoans, and phoronids are each others closest living relatives. This is a group called Lophophorata after their filter-feeding organ.
A schematic outline of how tommotiids tell us about the evolution of body strategies throughout the tree of Life. Credit: Luke Parry
Co-author Dr. Luke Parry from the University of Oxford included: “Wufengella belongs to a group of Cambrian fossils thats vital for understanding how lophophorates progressed. Theyre called tommotiids, and thanks to these fossils we have actually had the ability to understand how brachiopods evolved to have 2 shells from ancestors with many shell-like plates arranged into a cone or tube.
” We have known for a very long time about this tommotiid group called camenellans. Paleontologists have thought that those shells were connected to a nimble organism– crawling around– rather than being fixed in one place and feeding with a lophophore.”
The team, which includes paleontologists from the University of Bristol, Yunnan University, the Chengjiang Museum of Natural History, University of Oxford, the Natural History Museum in London, and the Muséum nationwide dHistoire Naturelle in Paris, demonstrate that Wufengella is a total camenellan tommotiid. This means that it exposes what the long popular wormy forefather to lophophorates looked like.
Dr. Parry added: “When it initially became clear to me what this fossil was that I was taking a look at under the microscopic lense, I couldnt believe my eyes. This is a fossil that we have actually often hypothesized about and hoped we would one day lay eyes on.”
While the fossil satisfies the palaeontological forecast that the lophophorates ancestral family tree was a nimble, armored worm, the look of its soft anatomy brings into focus some hypotheses about how lophophorates might be related to segmented worms.
Dr. Vinther stated: “Biologists had long kept in mind how brachiopods have multiple, paired body cavities, special kidney structures, and bundles of bristles on their back as larvae. These resemblances led them to see how carefully brachiopods resemble annelid worms.”
” We now can see that those resemblances are reflections of shared origins. The typical ancestor of lophophorates and annelids had an anatomy most closely resembling the annelids.
” At some point, the tommotiid forefather to the lophophorates became sessile and evolved suspension feeding (capturing particles suspended in the water). A long, wormy body with numerous, repetitive body units became less helpful and was minimized.”
Co-author Greg Edgecombe from the Natural History Museum said: “This discovery highlights how essential fossils can be for reconstructing development.
” We get an incomplete image by just taking a look at living animals, with the relatively couple of physiological characters that are shared between various phyla. With fossils like Wufengella, we can trace each family tree back to its roots, understanding how they when looked entirely various and had really various modes of life, often unique and often shown more far-off loved ones.”
Referral: “A Cambrian tommotiid maintaining soft tissues exposes the metameric ancestry of lophophorates” by Jin Guo, Luke A. Parry, Jakob Vinther, Gregory D. Edgecombe, Fan Wei, Jun Zhao, Yang Zhao, Olivier Béthoux, Xiangtong Lei, Ailin Chen, Xianguang Hou, Taimin Chen and Peiyun Cong, 27 September 2022, Current Biology.DOI: 10.1016/ j.cub.2022.09.011.

Named Wufengella and discovered in China, the fossil worm determines about half an inch long. It belongs to an extinct group of shelly organisms called tommotiids.

A restoration of how Wufengella would have appeared like in life. Credit: Illustration made by Roberts Nicholls, Paleocreations.com
An unspoiled fossilized worm dating from 518-million-years-ago resembles the ancestor of three major groups of living animals.
A worldwide team of researchers has found that an unspoiled fossilized worm dating from 518-million-years-ago looks like the forefather of three significant groups of living animals. The research study team consisted of scientists from the University of Bristol, the University of Oxford, and the Natural History Museum.
Named Wufengella and unearthed in China, the fossil worm measures about half an inch long. It was a stubby animal covered in a thick, frequently overlapping selection of plates on its back. It comes from an extinct group of shelly organisms called tommotiids.

Research study co-author, Dr. Jakob Vinther from the University of Bristols School of Earth Sciences, stated: “It looks like the unlikely offspring in between a bristle worm and a chiton mollusk. Only a few functions are shared throughout more than one group, which is a testimony to the really fast rate of evolution throughout which these major groups of animals stemmed. Such an organ is called a lophophore and brachiopods share the it with 2 other significant groups called the phoronids (” horseshoe worms”) and bryozoans (” moss animals”).