World News – US – Chinless fish sticky in the mud who was one of the ‘earliest ancestors of man’


Posted: 4:00 PM EDT October 1, 2020 | Update: 4:25 p.m. BST, October 1, 2020

One of the earliest human ancestors – who lived 400 million years ago – was a jawless ‘fish’ that used thorns on its head to move through water, study finds

Researchers at the University of Bristol used computer simulations to create ‘avatars’ of our former parents to explore how they moved in water

Named Cephalaspis, the creature was about a foot long – about the size of a modern trout – and was heavily armored with a thick bone from snout to tail

The study suggests that jawless aquatic creatures began to diversify body and head shapes to adapt to different environments much sooner than expected

The team behind the study hopes to use the same computer modeling technique to understand the full diversity of « early » vertebrates and their evolution

Impression of Cephalaspis, a typical osteostracan, swimming on the substrate The creature was about a foot long – about the size of a modern trout – and was heavily armored with thick bone from snout to tail

Cephalaspis was part of the osteostracans species – considered to be «  lazy bumps  » that were found at the bottom of rivers and seas feeding on algae and worms in the mud

A remarkable feature of the fish is that it lacked chin, fins and legs, but had striking spikes on its head – the Bristol team say they used it to change positions in the ‘water

The creatures had sensors in their skin that could detect the smallest vibrations in the water

Recent studies have revealed that they may be good swimmers and widely adapted to different aquatic environments

This contrasts with previous studies which suggested that they were « lazy pieces » that remained at the bottom of a river or sea

The new study found the species to be much more water-loving than previously thought – some being able to move on the bed and others freely in open water

They allowed animals to passively generate lift from water currents flowing through their bodies – allowing them to move through water

The different head shapes of the different species have allowed them to thrive in a variety of positions in the water – from seabed to open water

Groundbreaking discovery shows that they were already ecologically diverse – long before the arrival of jawed vertebrates

Co-author Dr Humberto Ferron, University of Bristol, said the evolution of jaws and fins was conventionally seen as the key inventions that allowed vertebrates to diversify their way of life

Jawed vertebrates were previously thought to compete with «  lumpy  » species and eventually dominate and move to land

« In this context, the jawless ancestors, characterized by the presence of heavy rigid bumpers, were supposed to be bulky fish-like creatures, living at the bottom of rivers and seas, with poor maneuverability », Ferron said

The results published in Current Biology contradict the classic version of events by shedding new light on osteostracans and their evolution

Dr Ferron and his colleagues have used cutting-edge computer engineering techniques to mimic their behavior based on fossilized remains

Co-author Dr Imran Rahman of the Museum of Natural History at the University of Oxford said the use of computational fluid dynamics enabled them to study the swimming performance of extinct vertebrates long without a modern equivalent species

« Our main finding confirms that the adaptations that enabled vertebrate diversification into aquatic environments occurred before the jaws evolved, » Dr Ferron told MailOnline

‘This challenges the widely accepted paradigm that the earliest jawless fish-like vertebrates were essentially sessile organisms living on the substrate’

It also shows that ‘the emergence of paired jaws and fins triggered the diversification of lifestyles in vertebrates’

The ancient fish-like creatures were not only adaptable – they were also intelligent – with brains capable of retaining memories of breeding grounds

They are also said to have fallen prey to large arthropods – monster sea scorpions and giant crabs and used sensors on their skin as an early warning system

A digital recreation of an ostracoderm The different head shapes of different species have allowed them to thrive in a variety of positions in the water – up and down

The researchers used ostracoderm fossils to produce their computer simulation and determine how they could swim

As the breeding season arrived, the Cephalaspis gathered in the one place they could escape the scorpions – the inland freshwater – with their convoy moving slowly upstream

They returned to the spawning grounds where they hatched, thanks to one of the first complex brains that allowed them to remember the location

He was much more developed than his rivals who had no memory and allowed Cephalaspis to process information – and escape

The team hopes to use the same computer simulation techniques developed for this study on other ancient vertebrates

« We plan to apply this technique to more groups spanning the full diversity of ‘early’ vertebrates to further test other classical hypotheses about the early evolution of this group, » Dr Ferron told MailOnline

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‘This is a really fascinating methodology because it allows very broad analyzes and it is still a fairly new approach in paleontology’

Life on Earth may have started with a modified version of modern DNA sister molecule, scientists say

DNA is the backbone of life and almost our entire planet depends on it, but on primordial Earth a primitive version of its lesser-known sister – RNA – was the focal point of evolution, say the experts

RNA is structurally similar to DNA, except that one of the four basic building blocks, thymine, is replaced by uracil

This changes the shape and structure of the molecule, and researchers have long believed that this chemical is vital for the development of Earth’s earliest life forms

Accidental discovery by Harvard academics published in December 2018 revealed that a slightly different version of RNA may have been the key ingredient in allowing life on Earth to flourish

Scientists claim a chemical called inosine may have been present in place of guanine, allowing life to develop

This slight change in bases, known as nucleotides, may provide the first known evidence for the « RNA world hypothesis » – a theory that claims RNA was an integral part of life forms primitives – they say

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World News – United States – Chinless fish that crawled through mud and was one of the «  earliest ancestors of man  »



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