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Richard Dearden @euphanerops.bsky.social · 18/09/2026

Fan of weird end-Permian-surviving fossil sharks? Check out our preprint describing the first endoskeletal fossils of Carnian jalodontiform Keuperodus brodiei. #FossilFriday doi.org/10.64898/202... Led by Ryan Tokeley (no bsky), based on his great masters project work @nitroshutter.bsky.social

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Richard Dearden @euphanerops.bsky.social · 16/09/2026

Haha excellent. Look forward to basking in Diplacanthus energy at PalAss! commons.wikimedia.org/wiki/File:Di...

A fossil fish with pronounced fin spines: fossil is dark preserved in light rock

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Richard Dearden @euphanerops.bsky.social · 13/06/2026

Had a great time at Euroevodevo in Glasgow featuring lots of cool talks and people, a ceilidh, and even a celebrity fossil shark #EED2026

Tower of Glasgow University seen over river and trees

Big dinner and ceilidh in Glasgow science centre

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Richard Dearden @euphanerops.bsky.social · 22/05/2026

Spent the last couple of days in the @ntlmuseumsscot.bsky.social , so is only right to share some Old Red Sandstone fishes for #fossilfriday

A completely preserved lobe finned fish (Trisyichopterus I think) with intact bread, body, and fins

Afossil of jawless fish Cephalaspis, with a horseshoe-shaped head shield and scaly body

A large armoured placoderm head (Homostius I think) peeking out from beneath a shelf.

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Richard Dearden @euphanerops.bsky.social · 08/05/2026

Strange guitarfish-esque Mesozoic holocephalan Squaloraja for #Fossilfriday to celebrate the end of my first week @unibirmingham.bsky.social as a NERC Independent Research Fellow! Lots of weird fossil cartilaginous fishes to come over the next few years I hope! 🦈

Red brick university campus with tall clock tower

3d model of elephant sharks with long snout

Fossil of long snouted extinct telephant shark Squaloraja in grey stone

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Richard Dearden @euphanerops.bsky.social · 17/02/2026

Check out our new #OpenAccess paper in @commsbio.nature.com redescribing bewhiskered Jurassic shark Bavariscyllium, led by Sebastian Stumpf. Although relationships hard to pin down, its catshark-esque form shows sharks explored varied body shapes from the start. 🦈〰️ www.nature.com/articles/s42...

Flattened fossils in a pale sandstone showing a long, catshark-shaped shark from the Jurassic. Below are grey silhouettes of these body shapes and a palaeoart reconstruction of the shark in life

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Richard Dearden @euphanerops.bsky.social · 11/11/2025

Excellent day out on the #2025SVP Warwickshire Triassic field trip to Guy's Cliffe! Feat. Saxon hermits, Anisian channel deposits, and lots of temnospondyls!

Someone talking in front of an ~8m tall sandstone section with cross bedding and channel deposits.

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Richard Dearden @euphanerops.bsky.social · 10/11/2025

Centre of Birmingham looking suitably sparkling and ready to welcome palaeontologists to #SVP2025 #2025SVP!

A Ferris wheel at night, lit up by illumination

The ICC convention centre lit up at night

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Richard Dearden @euphanerops.bsky.social · 25/09/2025

Living sharks have innumerable tiny scales, but their earliest relatives somehow grew larger bony plates. In our new Biology Letters @royalsocietypublishing.org, we work try and out how, arguing they grew by fusing and remodelling spines and scales. doi.org/10.1098/rsbl...

Reconstruction of an early shark relative, a fish with a blunt head and with fins supported by spines. Image by Plamen Andreev.

Images of growth of the bony plate of an early shark relative.

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Richard Dearden @euphanerops.bsky.social · 08/08/2025

For #fossilfriday the toothplates of the LARGE Cretaceous elephant shark Edaphodon (L), from @sedgwickmuseum.bsky.social. Living elephant sharks (R) can get a little over a metre long, but Edaphodon's toothplates suggest it was elephantine in scale as well as trunkage, growing to over 3 metres! 🐘🦈

A photograph of the fossilised toothplates of the Cretaceous of the UK. Displayed in a glass dome in an old-style museum exhibit.

A photograph of an elephant shark, genus Callorhinchus, with its distinctively plough-shaped snout. Image from Wikipedia.

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Richard Dearden @euphanerops.bsky.social · 09/07/2025

(I say sorcerer but the real stars are the minions)

An enigmatic armoured chaos minion holding a massive sword

A purple lizard minion toots a horn in the ear of a blue wizard who clutches some scrolls. Behind them lurks a hungry toothed cauldron.

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Richard Dearden @euphanerops.bsky.social · 09/07/2025

Finally finished a #Warhammer chaos sorcerer I've been chipping away at for ages! #miniatures

A painted Warhammer miniature with a chaos sorcerer standing on a rock surrounded by nefarious minions

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Richard Dearden @euphanerops.bsky.social · 02/05/2025

For #FossilFriday Pararhincodon torquis: a new species of Cretaceous stem-group collared carpet shark we redescribed earlier this week based on CT data of skeletal fossils (see thread below). Nice writeup on the @nhm-london.bsky.social website here www.nhm.ac.uk/discover/new...

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Richard Dearden @euphanerops.bsky.social · 30/04/2025

Huge thanks to all co-authors for their contributions, without which this sharky detective work would have come to naught. Thanks to Martin Rücklin @naturalis.bsky.social who hosted me, the @ec.europa.eu #MSCA for funding, and @nhm-london.bsky.social for specimens (and prep permission!) (13/13)

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Richard Dearden @euphanerops.bsky.social · 30/04/2025

More generally this shows the Chalk's potential as a repository of 3D fossil sharks which can explicitly tie the tooth record to gross anatomy and spans the gap between the earliest crown-group sharks from the Jurassic and Cenozoic ones. More 3D Chalk sharks exist so hopefully more to come! (11/13)

Chalk cliff and houses at Seven Sisters. Wikipedia.

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Richard Dearden @euphanerops.bsky.social · 30/04/2025

Fossil teeth show that carpet sharks moved from what is now the Chalk to their modern Indo-Pacific hotspot via the Tethys. Our data shows parascylliids had locked in some of their strange anatomy (e.g. braincase) before they split but aspects like weird pectoral fins had yet to evolve. (10/13)

Comaprison of anatomy of fossil parascyllid (a-c,f,h) to a living parascylliid (d,e,g,i) based on CT data

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Richard Dearden @euphanerops.bsky.social · 30/04/2025

We named this new species Pararhincodon torquis n. sp. Pararhincodon = "near-whale shark". Our species name is for the torc, a collar associated with the European iron age, tying things back to collared carpet sharks. @lacerdajulio.bsky.social did a lovely reconstruction for us feat. collar! (9/13)

A torc (twisted metal collar) from the European Iron Age of France (Wikimedia)

A reconstruction of a Cretaceous collared carpet shark menacing a crab in a shallow sea, crinoids, ammonites, and belemnites in background. Credit: Julio Lacerda

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Richard Dearden @euphanerops.bsky.social · 30/04/2025

These teeth can be attributed to a new species of the extinct genus Pararhincodon. Pararhincodon was thought, tentatively, to be a parascylliid based on a single published, articulated Lebanese specimen. We show conclusively that it is a stem-group parascyllid based on skeletal characters. (8/13)

Plate from Cappetta 1980 showing a Lebanese specimen of Pararhincodon

Phylogenetic tree showing Pararhincodon is a parascylliid

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Richard Dearden @euphanerops.bsky.social · 30/04/2025

Rough models of the teeth and helpful colleagues gave us clues as to what these teeth could be. To be sure though we needed high-resolution data. Incredibly, co-author Kieran Miles was able to extract one specific tooth from each specimen, located in the CT data, allowing us to SEM them (7/13)

CT data of fossil shark with rough tooth models highlighted in orange

SEMs of fossil shatk teeth, they are pointy without serrations

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Richard Dearden @euphanerops.bsky.social · 30/04/2025

But what about those missing teeth? After looking more closely at the scan data we realised that teeth were there in both specimens: they were just tiny (1-2mm across) and scattered amongst the very similar-looking dermal denticles in the Chalk matrix (small white things in video below). (6/13)

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Richard Dearden @euphanerops.bsky.social · 30/04/2025

Skeletal detective work led us to collared carpet sharks (parascylliids): small, beautifully patterned, eel-like sharks from Australia/Indo-Pacific. CSIRO colleagues (inc. co-author Helen O'Neill) helpfully scanned an extant one, confirming these had the same weirdly-shaped braincase. (5/13)

CT scan of an extant collared carpet shark with head skeleton inset

Small collared carpet shark hiding on seabed. Shark is spotted with distinctive collar. Image from GBIF, via Bruce Deagle

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Richard Dearden @euphanerops.bsky.social · 30/04/2025

Around this time we found a second Chalk specimen, @nhm-london.bsky.social, this time labelled even less informatively "Chondrichthyes" (i.e. sharks + friends). CT showed this rather unpromising fossil had the same weird braincase, and preserved the whole body back to the pectoral fins. (4/13)

A fossilised shark head and shoulders in chalk limestone, and CT data showing the 3D skull preserved inside

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Richard Dearden @euphanerops.bsky.social · 30/04/2025

Dear reader, we did not find out what Synechodus looked like, with it swiftly becoming clear this this thing looked nothing like Synechodus. It had a strangely-shaped braincase, the jaws were different and there was no sign of any teeth, Synechodus-like or otherwise. So what was it? (3/13)

A fossilised shark head in chalk limestone, and CT data showing the 3D skull preserved inside

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Richard Dearden @euphanerops.bsky.social · 30/04/2025

This project spun off another project, redescribing extinct Chalk shark Synechodus. This @nhm-london.bsky.social specimen below, was labelled "Synechodus sp.", despite no teeth being visible. Fool that I was, I believed the label and we CT scanned it to find out what Synechodus looked like. (2/13)

A fossilised shark head in Chalk limestone. Scale bar in mm.

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Richard Dearden @euphanerops.bsky.social · 30/04/2025

New #OA paper in @royalsocietypublishing.org #RSOS: we use CT to describe a 3D shark from the Cretaceous Chalk, giving a rare skeletal perspective on shark evolution. A bit of the backstory in 🧵below featuring 🦴 MYSTERY FOSSILS 🦈 CUTE SHARKS 🦷 CHALK DENTISTRY doi.org/10.1098/rsos... (1/13)

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Richard Dearden @euphanerops.bsky.social · 18/03/2025

Like fossil #sharks? Check out our new preprint from work @naturalis.bsky.social where we combine digital/hands on approaches with fossil/extant taxa to describe the 3D skeletal anatomy of Cretaceous collared carpet sharks from the English Chalk. Paper out soon, thanks to all collaborators! 🦈

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Richard Dearden @euphanerops.bsky.social · 13/12/2024

Sadly Ischyodus lost its nose: here's the full picture

A fossil elephant shark in sand-coloured rock

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Richard Dearden @euphanerops.bsky.social · 13/12/2024

Had an amazing time at #PalAss24: Awesome job by the organisers @rachelwarnock.bsky.social, @taphonomist.bsky.social and @emmadnn.bsky.social, as well as all volunteers! For #fossilfriday some lovely Jurassic chondrichthyans from Solnhofen I saw on the preconference fieldtrip

A fossil angel shark in sand-coloured rock

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Richard Dearden @euphanerops.bsky.social · 29/11/2024

Sad #FossilFriday as it's my last day as a postdoc at @naturalis.bsky.social. In tribute here are four excellent fossil fishes I got to see while doing my research here.

Flat fossil of an angel shark from Nusplingen

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Richard Dearden @euphanerops.bsky.social · 15/11/2024

Nose-on view of Devonian long boi Elpistostege, a stem-group tetrapod from the Escuminac Formation, Quebec. Amazing fossil and beautiful reconstruction . #fossilfriday

Image of a reconstruction of long fossil fish

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Richard Dearden @euphanerops.bsky.social · 30/10/2024

Happy International Ghost Shark day to all those who celebrate! 👻🦈 Check out our new, well-timed paper in Proceedings B, led by @chasebrownstein.bsky.social, combining fossils and genes to understand how and when they invaded the deep sea. doi.org/10.1098/rspb...

Phylogeny of ghost sharks from academic paper

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Richard Dearden @euphanerops.bsky.social · 18/10/2024

In the spirit of trying to use Bluesky here's a sharky #fossilfriday. The living nurse shark Ginglymostoma and the amazingly intact fossil of Cantioscyllium, an Upper Cretaceous nurse shark in the collections of the NHM, London preserved in Chalk.

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Richard Dearden @euphanerops.bsky.social · 31/05/2024

🚨New paper in Zoo. Jour. Linn. Soc. 🚨 Early shark relative Acanthodes is one of few Palaeozoic fishes to preserve the gill skeleton, but its mouldic fossils have proved difficult to interpret. In our paper we try and get to grips with this using CT. doi.org/10.1093/zool...

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