1

People and ecosystems

Understanding of the links between coral reef ecosystems, the goods and services they provide to people, and the wellbeing of human societies.

2

Ecosystem dynamics: past, present and future

Examining the multi-scale dynamics of reefs, from population dynamics to macroevolution

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Responding to a changing world

Advancing the fundamental understanding of the key processes underpinning reef resilience.

Coral Bleaching

Coral Bleaching

Coral Reef Studies

ARC Centre of Excellence for Coral Reef Studies
James Cook University Townsville
Queensland 4811 Australia

Phone: 61 7 4781 4000
Email: info@coralcoe.org.au

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New DNA techniques are being used to understand how coral reacted to the end of the last ice age in order to better predict how they will cope with current changes to the climate.

James Cook University’s Dr Ira Cooke was senior author of the study. He said when corals become stressed they often bleach and die, but not all corals experience stress equally.

“This is often due to genetic differences between species, but it’s usually very difficult to determine which genes are responsible. In situations where the differences evolved relatively recently – thousands not millions of years ago – it’s much easier to do so,” said Dr Cooke.

He said the end of the last ice age is relatively recent in evolutionary terms and it sometimes forced corals to adapt to stresses similar to those projected under future climate change.

“Until now it hasn’t been possible to look at this period in coral evolution because most of the techniques available have provided information about much older events. But by sequencing the whole genomes of many individuals within a single species we have now been able to access this crucial period of coral evolutionary history,” said Dr Cooke.

JCU PhD candidate Jia Zhang, lead author of the study, said sea-level change has reshaped the Kimberley coral communities many times in the past.

“This study examines how these historical changes have influenced coral population sizes, how far they disperse, and their ability to adapt,” said Ms Zhang.

She said the researchers compared the genomes of corals from the inshore Kimberley with those inhabiting more benign offshore locations (Ashmore Reef and Rowley Shoals).

“We found there were clear genetic distinctions, akin to races, between corals from the three locations we studied but most obviously between the inshore and offshore reefs, and that these genetic groups had arisen around the time the last ice-age ended.

“This was when sea levels rose dramatically allowing corals to colonise the Kimberley region, and to re-establish themselves on the tops of offshore atolls,” said Ms Zhang.

Co-author of the study, Dr Zoe Richards from Curtin University’s School of Molecular and Life Sciences said as the sea-level rose between 20 and 10 thousand years ago, corals dispersed to new habitats.

“But only those individuals with the right genetic makeup were able to survive. This selective process is visible in the genomes and tells us which genes were important for survival,” said Dr Richards.

She said corals from the Kimberley had tell-tale patterns in their genomes revealing genes that were modified through natural selection around the time of the last ice-age when they colonised this tough inshore habitat.

Dr Cooke said one specific type of genes called peroxinectins have been under especially strong and recent evolutionary pressure (natural selection) in inshore Kimberley corals.

“These genes clearly evolved different versions in inshore corals and it’s likely that this helps them cope with the extreme environmental conditions there. These genes provide a roadmap to help further understand how corals can survive turbid, hot and exposed conditions like those in the Kimberley”

This study was funded by ARC Linkage Project LP160101508.

PAPER

Zhang J, Richards Z, Adam A, Cheong XC, Shinzato C, Gilmour J, Thomas L, Strugnell J, Miller D, Cooke I. 2022. ‘Evolutionary responses of a reef-building coral to climate change at the end of the last glacial maximum’. Molecular Biology and Evolution. DOI: https://doi.org/10.1093/molbev/msac201

IMAGES

A selection of images can be used for media stories with credit to the photographer as stated in the file name. Please note these are for single use with this story only, not for any other story. No archival permissions are granted.

CONTACT

Dr Ira Cooke (Townsville, AEST)
P: +61 (0)429 105 999
E: ira.cooke@jcu.edu.au

Dr Zoe Richards (Perth, AWST)
P: +61 (0)487 213 021
E: zoe.richards@curtin.edu.au

Ms Jia Zhang (Townsville, AEST)
P: +61 (0)431 819 701
E: jia.zhang2@my.jcu.edu.au

Prof David Miller (Townsville, AEST)
P: +61 (0)418 671 768
E: david.miller@jcu.edu.au

An international team of researchers have described a remarkable new species of fish that lived in the sea in the time of the dinosaurs in the late Jurassic about 150 million years ago.

The new species of bony fish had teeth like a piranha, which the researchers from the ARC Centre of Excellence for Coral Reef Studies (Coral CoE, Australia) and Jura-Museum Eichstätt (Germany), suggest they used as piranhas do: to bite off chunks of flesh from other fish.

As further support for that notion, the team also found the victims – other fish that had apparently been nibbled on – in the same limestone deposits in South Germany (the quarry of Ettling in the Solnhofen region) where this piranha-like fish was found.

“We have other fish from the same locality with chunks missing from their fins,” said Prof David Bellwood of Coral CoE at James Cook University.

“This is an amazing parallel with modern piranhas which feed predominantly not on flesh but the fins of other fishes. It’s a remarkably smart move as fins regrow, a neat renewable resource. Feed on a fish and it is dead; nibble its fins and you have food for the future.”

The newly described fish is part of the world famous collections in the Jura-Museum in Eichstätt. It comes from the same limestone deposits that contained the first feathered proto-bird known as Archaeopteryx.

Careful study of the fossilized specimen’s well preserved jaws revealed long, pointed teeth on the exterior of the vomer, a bone forming the roof of the mouth, and at the front of both upper and lower jaws. Additionally, there are triangular teeth with serrated cutting edges on the pre-articular bones that lie along the side of the lower jaw.

The tooth pattern and shape, jaw morphology and mechanics suggest a mouth equipped to slice flesh or fins, the international team of researchers report. The evidence points to the possibility that the early piranha-like fish may have exploited aggressive mimicry in a striking parallel to the feeding patterns of modern piranha.

“We were stunned that this fish had piranha-like teeth,” Dr Martina Kölbl-Ebert of Jura-Museum Eichstätt (JME-SNSB) said.

“It comes from a group of fishes (the pycnodontids) that are famous for their crushing teeth. It is like finding a sheep with a snarl like a wolf. But what was even more remarkable is that it was from the Jurassic.”

“Fish as we know them, bony fishes, just did not bite flesh of other fishes at that time. Sharks have been able to bite out chunks of flesh, but throughout history bony fishes have either fed on invertebrates or largely swallowed their prey whole. Biting chunks of flesh or fins was something that came much later,” Kölbl-Ebert explained

Or, so it had seemed.

“The new finding represents the earliest record of a bony fish that bit bits off other fishes, and what’s more, it was doing it in the sea,” Bellwood said, noting that today’s piranhas all live in freshwater.

“So when dinosaurs were walking the earth and small dinosaurs were trying to fly with the pterosaurs, fish were swimming around their feet tearing the fins or flesh off each other.”

The researchers call the new find a “staggering example of evolutionary versatility and opportunism.” With one of the world’s best known and studied fossil deposits continuing to throw up such surprises, they intend to keep up the search for even more fascinating finds.

Citation: Kölbl-Ebert, M, Ebert, M, Bellwood, DR & Schulbert, C (2018) A Piranha-like Pycnodontiform Fish from the Late Jurassic. Current Biology 278(21): 3516 – 3521 DOI: 10.1016/j.cub.2018.09.013

 

Author Contact:

Prof David Bellwood (AUSTRALIA) – on leave until Nov.
david.bellwood@jcu.edu.au

Dr Martina Kölbl-Ebert (GERMANY)
Koelbl-Ebert@jura-museum.de

 

For More Information:

Catherine Naum, Communications Manager
ARC CoE for Coral Reef Studies
catherine.naum1@jcu.edu.au
P: +61 (0) 7 4781 6067 (AEST, +10 UTC)
M: +61 (0) 428 785 895

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Coral Reef Studies

ARC Centre of Excellence for Coral Reef Studies
James Cook University Townsville
Queensland 4811 Australia

Phone: 61 7 4781 4000
Email: info@coralcoe.org.au