Cambrian Explosion: early skeletal form found (Introduction)

by David Turell , Monday, November 07, 2022, 18:46 (537 days ago) @ David Turell

In China, a tubular animal with evidence of skeletal parts:

https://www.sciencealert.com/incredible-discovery-has-finally-revealed-the-first-animal...

"Several fortuitous fossils from China have defied the odds and are now providing archeologists with a real glimpse into early lifeforms that lived about 514 million years ago.

"The fossils have preserved the soft tissue of four worm-like marine creatures belonging to the species Gangtoucunia aspera.

"Initially, scientists thought this extinct genus was a relative of living annelid worms (such as earthworms), which are horizontally segmented. However, these new results suggest Gangtoucunia is more closely related to polyp cnidarians, like jellyfish, sea anemones, and coral.

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"'This really is a one-in-million discovery. These mysterious tubes are often found in groups of hundreds of individuals, but until now, they have been regarded as 'problematic' fossils because we had no way of classifying them," says paleobiologist Luke Parry from the University of Oxford.

"'Thanks to these extraordinary new specimens, a key piece of the evolutionary puzzle has been put firmly in place."

"'This really is a one-in-million discovery. These mysterious tubes are often found in groups of hundreds of individuals, but until now, they have been regarded as 'problematic' fossils because we had no way of classifying them," says paleobiologist Luke Parry from the University of Oxford.

"'Thanks to these extraordinary new specimens, a key piece of the evolutionary puzzle has been put firmly in place."

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"'Intriguingly," the authors note, "we do not recover a close relationship between Gangtoucunia in a clade with other medusozoans with calcium phosphate exoskeletons, suggesting that tube-building materials could have a complex early evolutionary history, possibly due to convergent losses and reduction of calcium phosphate in skeletons as it became less available through the Palaeozoic."

"In other words, external skeletons probably didn't arise just once but probably evolved several times in multiple different lineages.

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"Even from the little evidence scientists have found, it is clear that tube-shaped animals were popping up before the explosion of animal diversity that once took our life by storm. What triggered their expansion remains an open question, though predation is one possibility.

"'A tubicolous mode of life seems to have become increasingly common in the Cambrian, which might be an adaptive response to increasing predation pressure in the early Cambrian," says paleobiologist and study author Xiaoya Ma from Yunnan University in China and the University of Exeter in the UK.

"'This study demonstrates that exceptional soft-tissue preservation is crucial for us to understand these ancient animals.'"

Comment: China is still the best source for new Cambrian discoveries.