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A 25-year-old PhD student at Trinity has just discovered that sharks used to eat their own young

Dubliner Aodhán Ó Gogáin travelled to Canada to collect 300 million-year-old ‘shark poop’ before making his discovery.

SCIENTISTS HAVE DISCOVERED macabre fossil evidence suggesting that sharks who lived 300 million years ago ate their own young.

TCD researchers, led by 25-year-old Aodhán Ó Gogáin, found ‘fossil poop’ of prehistorica adult orthacanthus sharks which contained the tiny teeth of juveniles.

These fearsome marine predators, which existed before the age of dinosaurs, used protected coastal lagoons to rear their babies.

But it seems they also resorted to cannibalising them when other food sources became scarce.

Three hundred million years ago, Europe and North America lay on the equator and were covered by steamy jungles, the remains of which are now compacted into coal seams.

The top predators of these so-called ‘coal forests’ were not land animals, but huge sharks that hunted in the oily waters of coastal swamps.

Aodhán Ó Gogáin, a PhD candidate at Trinity’s School of Natural Sciences, made the extraordinary discovery.

Poop Image of a thin-section through an Orthacanthus coprolite, or poop fossil, with a black box indicating the tooth of the shark's own offspring.

“It is a brilliant feeling making this discovery and being able to contribute to a field I am passionate about,” the 25-year-old told TheJournal.ie.

“I did my Masters over in Bristol, and someone had already collected some specimens of the shark poop.

I eventually went over there to Canada and collected some new samples in the field, and we cut through the sections and found a baby shark’s tooth.

Aodhán, from Glasnevin, is currently researching tetrapods found in Kilkenny in the 1800s.

The fossil evidence for shark cannibalism was found in distinctive spiral-shaped coprolites (fossil poop) found by Aodhán and others in the Minto Coalfield of New Brunswick, Canada.

Corkscrew

The poop is known to have been excreted by Orthacanthus because this shark had a special corkscrew rectum that makes identification easy.

The poop is packed full of the teeth of juvenile Orthacanthus, confirming that these sharks fed on their own babies – a phenomenon known as “fillial cannibalism”.

Ó Gogáin’s findings have just been published in the journal Palaeontology. He added: 

Orthacanthus was a three-metre-long xenacanth shark with a dorsal spine, an eel-like body, and tricusped teeth.

“There is already evidence from fossilised stomach contents that ancient sharks like Orthacanthus preyed on amphibians and other fish, but this is the first evidence that these sharks also ate the young of their own species.

Orthacanthus was probably a bit like the modern day bull shark, in that it was able to migrate backwards and forwards between coastal swamps and shallow seas.
This unusual ecological adaptation may have played an important role in the colonisation of inland freshwater environments.

“It’s such a privilege to work with such influential palaeontologists as my co-authors.”

Eating its own young

A co-author of the study, Professor Mike Benton of the University of Bristol, said: “As palaeontologists cannot observe predator-prey relationships directly in the way that a zoologist can, they have to use other methods to interpret ancient food webs.

One method is by probing the contents of coprolites [fossil poop] as we have done here.

Dr Howard Falcon-Lang of the Royal Holloway University of London is another co-author. He said:

We don’t know why Orthacanthus resorted to eating its own young.
“However, the Carboniferous Period was a time when marine fishes were starting to colonise freshwater swamps in large numbers.
It’s possible that Orthacanthus used inland waterways as protected nurseries to rear its babies, but then consumed them as food when other resources became scarce.

The Minto Coalfield in Canada, where the fossils were discovered, was the first place in North America where settlers mined coal in the early 17th Century.

Read: New 80 million-year-old ‘giant thief’ dinosaur found in Argentina

Read: So it turns out that dinosaurs were neither warm nor cold blooded

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    Mute Aurelio Na Fodhla
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    Jun 30th 2022, 6:55 AM

    It’s like a repeat of a bad dream I had…

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    Mute Handsome McWonderful
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    Jun 30th 2022, 9:01 AM

    @Aurelio Na Fodhla: Leo will be quoting movies again. Zoom parties will be had. Tony will get the band back together. Curves will be flattened and sourdough baked.

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    Mute Anna Carr
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    Jun 30th 2022, 8:01 AM

    Will it ever go away? I’m so over it. No one’s even listening to advice anymore, it’s just us all sort of winging it. I’m going for jab no. 4. How many others are? Just curious.

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    Mute The Ghost of Dublin
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    Jun 30th 2022, 8:24 AM

    @Anna Carr: I have had four jabs, was following mask protocols, and as far as I know I’ve never had Covid.

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    Mute Anna Carr
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    Jun 30th 2022, 9:28 AM

    @The Ghost of Dublin: I’ve done the same but I got covid…. Very mild…. Still going for number 4 though

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    Mute Michael McGrath
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    Jun 30th 2022, 2:06 PM

    @Anna Carr: Are you not starting to question the fact that you need 4 injections of the one “vaccine” in little over 12 months and still got covid anyway. If your healthy the likelyhood is you would only have got a mild dose of covid in any case. This putting down to only getting a mild dose of covid because your vaccinated is ridiculous when the vast majority of cases are mild anyway vaccinated or not(this is not having a go at you personally it’s the narrative that’s being put out constantly in the media) . Now if you are in anyway immunocompromised I stand corrected and apologise.

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    Mute Fiona Fitzgerald
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    Jun 30th 2022, 4:00 PM

    @Michael McGrath: I’d still say that anything we do to reduce exposure is healthy. I’ve heard several people who were runners before and can barely get around the house now. The less viral load the better.

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    Mute Michael McGrath
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    Jun 30th 2022, 4:41 PM

    @Fiona Fitzgerald: So your in agreement that we continue taking injections every three months can’t see it happening tbh and the infrastructure just isn’t there to do it, it’s not even really there to do it every twelve months. Since the EUCDC is saying its not worth a jot against the new strains what’s the point

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    Mute Brendan Odonnell
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    Jun 30th 2022, 9:02 AM

    Really annoyed as my daughter had to ring the Coombe maternity hospital after contacting Covid to find out that pregnant women with covid are at risk of blood clots and need to be put on blood thinners as a precaution. Why is this not mentioned anywhere ????

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    Mute Anna Carr
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    Jun 30th 2022, 9:30 AM

    @Brendan Odonnell: wow I had no idea of this. I hope everything goes well for your daughter and impending grandchild.

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    Mute Brendan Odonnell
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    Jun 30th 2022, 11:54 AM

    @Anna Carr: thanks and please God all goes well for them both. It affects those under 26 weeks and so mad that she had to ring after a neighbour mentioned it to her in passing. Thanks once again

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    Mute Kayleigh Furlong-Folan
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    Jun 30th 2022, 12:12 PM

    @Brendan Odonnell: Not sure if this is possibly just isolated to your daughter or the coombe now maybe have introduced this. I caught covid at 7weeks, and I was under the Coombe and did ask about blood thinners and they said no. They will monitor more closely towards the end however! I hope she keeps well!!

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    Mute Maeve O'Sullivan
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    Jun 30th 2022, 10:48 AM

    I’m sorry I barely got past the first line … “as we head into the summer months” …. It’s nearly July and not even a hint of summer yet!

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    Mute Damien Leen
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    Jun 30th 2022, 7:59 AM

    Seriously…bloody isolate then go from there.

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    Mute Dave Barrett
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    Jun 30th 2022, 8:38 AM

    @Damien Leen: Just drive on. No more than a bad cold now. Rate of rising prices, petrol and mortgages no one will be able to afford stay home from work.

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    Mute lelookcoco
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    Jun 30th 2022, 8:40 AM

    @Dave Barrett: A bad cold for some but not all. And why even put up with a bad cold of it can be avoided

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    Mute Thomas O' Donnell
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    Jun 30th 2022, 9:14 PM

    @Dave Barrett: When did a bad cold ever lead to such high absenteeism in summer months?

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    Mute Stanley Marsh
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    Jun 30th 2022, 1:25 PM

    Given that we are now literally at the height of ‘summer’ where are all those who claimed Covid was purely a seasonal virus?

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