Bird brain from the age of dinosaurs reveals roots of avian intelligence

sc604 — Wed, 13 Nov 2024 14:20:58 +0000

A ‘one of a kind’ fossil discovery could transform our understanding of how the unique brains and intelligence of modern birds evolved, one of the most enduring mysteries of vertebrate evolution.

‘Missing’ sea sponges discovered

sc604 — Wed, 05 Jun 2024 12:56:30 +0000

At first glance, the simple, spikey sea sponge is no creature of mystery.

No brain. No gut. No problem dating them back 700 million years. Yet convincing sponge fossils only go back about 540 million years, leaving a 160-million-year gap in the fossil record.

In a paper released in the journal Nature, an international team including researchers from the ̽��ֱ�� of Cambridge, have reported a 550-million-year-old sea sponge from the “lost years” and proposed that the earliest sea sponges had not yet developed mineral skeletons, offering new parameters to the search for the missing fossils.

̽��ֱ��mystery of the missing sea sponges centred on a paradox.

Molecular clock estimates, which involve measuring the number of genetic mutations that accumulate within the Tree of Life over time, indicate that sponges must have evolved about 700 million years ago. And yet, there had been no convincing sponge fossils found in rocks that old.

For years, this conundrum was the subject of debate among zoologists and palaeontologists.

This latest discovery fills in the evolutionary family tree of one of the earliest animals, connecting the dots all the way back to Darwin’s questions about when the first animals evolved and explaining their apparent absence in older rocks.

Shuhai Xiao from Virginia Tech, who led the research, first laid eyes on the fossil five years ago when a collaborator texted him a picture of a specimen excavated along the Yangtze River in China. “I had never seen anything like it before,” he said. “Almost immediately, I realised that it was something new.”

̽��ֱ��researchers began ruling out possibilities one by one: not a sea squirt, not a sea anemone, not a coral. They wondered, could it be an elusive ancient sea sponge?

In an earlier study published in 2019, Xiao and his team suggested that early sponges left no fossils because they had not evolved the ability to generate the hard needle-like structures, known as spicules, that characterise sea sponges today.

̽��ֱ��team traced sponge evolution through the fossil record. As they went further back in time, sponge spicules were increasingly more organic in composition, and less mineralised.

“If you extrapolate back, then perhaps the first ones were soft-bodied creatures with entirely organic skeletons and no minerals at all,” said Xiao. “If this was true, they wouldn’t survive fossilisation except under very special circumstances where rapid fossilisation outcompeted degradation.”

Later in 2019, Xiao’s group found a sponge fossil preserved in just such a circumstance: a thin bed of marine carbonate rocks known to preserve abundant soft-bodied animals, including some of the earliest mobile animals. Most often this type of fossil would be lost to the fossil record. ̽��ֱ��new finding offers a window into early animals before they developed hard parts.

̽��ֱ��surface of the new sponge fossil is studded with an intricate array of regular boxes, each divided into smaller, identical boxes.

“This specific pattern suggests our fossilised sea sponge is most closely related to a certain species of glass sponges,” said first author Dr Xiaopeng Wang, from Cambridge’s Department of Earth Sciences and the Nanjing Institute of Geology and Palaeontology.

Another unexpected aspect of the new sponge fossil is its size.

“When searching for fossils of early sponges I had expected them to be very small,” said co-author Alex Liu from Cambridge’s Department of Earth Sciences. “ ̽��ֱ��new fossil can reach over 40 centimetres long, and has a relatively complex conical body plan, challenging many of our expectations for the appearance of early sponges”.

While the fossil fills in some of the missing years, it also provides researchers with important guidance about what they should look for, which will hopefully extend understanding of early animal evolution further back in time.

“ ̽��ֱ��discovery indicates that perhaps the first sponges were spongey but not glassy,” said Xiao. “We now know that we need to broaden our view when looking for early sponges.”

Reference:
Xiaopeng Wang et al. ‘A late-Ediacaran crown-group sponge animal.’ Nature (2024). DOI: 10.1038/s41586-024-07520-y

Adapted from a Virginia Tech press release.

̽��ֱ��discovery, published in Nature, opens a new window on early animal evolution.

Xiaopeng Wang

Heliocolocellus fossil

̽��ֱ��text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

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Earth’s earliest forest revealed in Somerset fossils

sc604 — Thu, 07 Mar 2024 10:27:02 +0000

̽��ֱ��oldest fossilised forest known on Earth – dating from 390 million years ago – has been found in the high sandstone cliffs along the Devon and Somerset coast of South West England.

̽��ֱ��largest penguin that ever lived

sc604 — Thu, 09 Feb 2023 08:21:23 +0000

Fossil bones from two newly-described penguin species, one of them thought to be the largest penguin to ever live – weighing more than 150 kilograms, more than three times the size of the largest living penguins – have been unearthed in New Zealand.

Bird beak evolved before dinosaur extinction

sc604 — Wed, 30 Nov 2022 15:18:58 +0000

Fossilised fragments of a skeleton, hidden within a rock the size of a grapefruit, have helped upend one of the longest-standing assumptions about the origins of modern birds.

Shaking the dinosaur family tree: how did ‘bird-hipped’ dinosaurs evolve?

sc604 — Wed, 21 Sep 2022 14:57:37 +0000

Researchers have conducted a new analysis of the origins of ‘bird-hipped’ dinosaurs – the group which includes iconic species such as Triceratops – and found that they likely evolved from a group of animals known as silesaurs, which were first identified two decades ago.

What did Megalodon eat? Anything it wanted — including other predators

sc604 — Thu, 23 Jun 2022 16:32:36 +0000

New research involving the ̽��ֱ�� of Cambridge shows that prehistoric megatooth sharks — the biggest sharks that ever lived — were the ultimate top predators, operating higher up the food chain than any other marine predators through history.

Millipedes ‘as big as cars’ once roamed England

sc604 — Tue, 21 Dec 2021 05:50:30 +0000

̽��ֱ��largest-ever fossil of a giant millipede – as big as a car – has been found on a beach in the north of England.

̽��ֱ�� of Cambridge - Palaeontology