Let's see your Monthly favourite fossil!

[IsaacTheFossilMan]

The title says it all!

 

Let's see all of you guys' favourite fossil of the week! Try to keep it to one per week per user, but, hey, some fossils are worth screaming about! They can belong to you, or anyone else! Feel free to have a nice small lecture to us about this week's coolest prehistoric creature, and teach us all the ins and outs! Lotsa pictures will go down a treat...

 

I look forward to seeing you guys' best!

[IsaacTheFossilMan]

I'm gonna start us off with returning to an old favourite of mine!

 

I'm going to be focusing on a really, really neat fossil from South Korea, originally discovered in 2004 by professor of vertebrate palaeontology at Seoul National University Yuong-Nam Lee. While fossil hunting, he came across nearly 30 lizard and pterosaur tracks in a mudstone slab, and quickly (in 4 years :P)

 published a paper in Cretaceous Research about this cool new pterosaurid tracks he found from the Hasandong Formation. He noted some lizard tracks, but, and I quote: "At the time, I thought they were just small animal tracks of little importance because I was more interested in pterosaur tracks," - I mean, fair enough! It wasn't until 2016, when he looked into the museum's collections again, and noted that they "have very typical pedal morphologies of modern lizards.". Pretty cool already, right? 110mya evidence of modern lizard feet! So, this new ichnotaxa Sauripes hadongensis already has a lot going for it, but, things got even cooler when he looked at trackway A... 

 

This is already the oldest group of lizard trackways known, but, even cooler, upon looking at this specific trackway, Lee discovered that the feet prints start as a mix of front and back feet, and end up as only back feet... You know what that means? Bipedalism! All the way back at the time of the dinosaurs! That's super super super cool, and I'm going to show you some pictures now!

 

 

There are some photos of the actual fossils, and here's an analysis:

 

 

Now, remember that pterosaur from before? It was named as Pteraichnus koreanensis, and on analysis of its prints, it's one of those snub-nosed ones (very scientific lexicon from me, there...). Now, one of these would want to get their hands on a teeny lizard for a snack, right? Well, captive lizards are known to run around on their back legs for fun (pretty cute), but, in nature, they run on their back legs to get away from things that are looking for a teeny lizard tasting snack... And, this lizard was running away from the direction of the prints of the pterosaur. Obviously, it's unprovable, butttt, it's a reasonable assumption to say that it was running from our pterosaur friend (or foe?)!

 

Now here's a super cool interpretation of this encounter, as a reward for reading me gushing about some cool rocks for a while!

 

 

Hope you guys enjoyed this!

Isaac

[IsaacTheFossilMan]

Let's be honest - I completely forgot about this thread... I'll put up something very cool later!

[IsaacTheFossilMan]

Uhhhhh... Guilty as previously charged - again.

 

Let's pretend it's the *monthly* favourite fossil, haha! @Fossildude19 would you mind changing the article to replace weekly with monthly? If it's no problem, of course. 

 

I will write up something tomorrow, I've got a big thing planned that some people here may have seen I loved before...

 

[IsaacTheFossilMan]

Sitting in my room in a secluded, now-sleeping corner of the Cotswolds, physics papers and maths proofs strewn on the carpet at my feet, I feel it is only fair that we turn to the more abstract to judge July's favourite fossil... The abstract that is - quantum physics!

 

Now, I'm not going to explain quantum physics or what the hell a quanta is right now - that's a job for an upcoming post on my website - but, I can give a brief explanation. Quantum physics is... weird physics. At a really, really small scale. To be precise, the study of quantum physics is looking at things so small that so-called "quantum effects" or "phenomena" begin to occur - these can include weird things from particles acting like waves, to particles vanishing from existence, only to coalesce as a different form such as light, even to particles TELEPORTING from one place to another - like, seriously. Quantum physics is weird. Weird particle physics.

 

Now, let's get into the rocks!

 

I was first introduced to this fossil via the paper, published in the Journal "Geology", in December 2021, by the extraordinary team from Cardiff University - but was reminded of its sheer scientific and geologic prowess by the lovely folks over at the ISIS Neutron and Muon Source, when I was lucky enough to study their technology and talk to them during a particle physics "masterclass". The instruments ISIS develop, and allow peer-reviewed teams beam-time to use, are surely phenomenal, and a massive feat by themselves.

Based in Oxfordshire, by pulsing two types of particles known as "neutrons" (one of - sort of - two particles in the nucleus of atoms) and "muons" (the supermassive fake electron ), scientists (overseen by instrument specialist scientists) can study microscopic properties of specimens, ranging from subatomic in size (things like muons, photons, protons, quarks), to macromolecular (things like proteins). Every year, a whopping 600 experiments are carried out by 1600 users, the control rooms stationed 24 hours a day, every. single. day. Did I mention that the users and parent institutions of users get to use these £11,000 per-instrument-per-day services for free? That's over 20 instruments. That's... a lot of money.

 

Okay, now, seriously, into the rocks!

 

The specimen we are going to be looking at today is a spectacular ammonite collected from the humble Cotswold gravel pit by a certain Neville Hollingworth all the way back 23 years ago, in 1998. Although the locality may be unsuspecting, such gravel pits in the Cotswold are no stranger to extraordinary fossils - the Jurassic limestone being crammed full of spectacular critters, once thriving in a warm shallow sea - this particular one was buried rather quickly, and was presumed to have retracted its body into the living chambers and sealed shut for defence. Now clamped inside, the unfortunate beastie could not escape, being plunged into a cement pile of mud and silt, slowly decaying in anoxic conditions. Little did it know, this brutal and merciless death would prove itself invaluable to a troublesome species of hominin some 165ma later.

 

These anoxic conditions led to a conclusion us fossilers are attuned to - a partial decay, resulting in exceptional preservation. This resulted in calcification of some semi-decayed internal features and soft-tissue, the shell and organs alike being preserved in calcium carbonate (much like the brachiopod in my profile picture at the time of writing!). For those of you that may not be aware, the internal features of ammonoids are vastly unknown, being scanty in the fossil record - which is why this specimen was so important, and priceless. Yes, this single, mature adult Sigaloceras (Catasigaloceras) enodatum (Nikitin, 1881) from the Lower Callovian "is the first specimen where we have substantial three-dimensional preservation of internal organs and muscles" - quote from Imran A. Rahman, one of the authors of this paper.

 

 

Now is a good time to note that this fossil isn't in fact the "shell", but instead a "steinkern" (internal mould) of calcium carbonate - the shell is instead deposited in Cardiff's collections in two halves, in-situ in consolidated matrix.

 

Upon back-lighting of the specimen, it is clear there is something inside (dark mass, left) - but an unobtrusive means of exploring that something  was not yet known to the researchers - that is, until they stumbled upon ISIS. All the stars seemed to align, and the team was not only able to obtain high resolution images of the mass, but also to construct a three-dimensional model of the tissues and organs, which were studied with correlative tomography, and identified to their purposes. 

 

The team, led by Lesley Cherns, a lecturer at Cardiff since 1989, found that the paired dorsal muscles were used to draw and push the body out of the shell - if you're sharp with your spiralled cephalopod anatomy, you'll know this is unfamiliar with our oft-compared-with-ammonites extant nautiloids - which use their dorsal muscles to control propulsion, in a synergy with the funnel. This means that they must have swam differently to Nautilus, something the researchers "infer evolved early in the ammonoid-coleoid lineage".

 

Using the IMAT Beamline at ISIS was not only helpful, but a necessity - the dark mass of the organs is apatitic in nature - meaning it has very, very poor contrast with the rest of the fossil being CaCO₃ in purely X-Ray tomography. IMAT was used to fire neutrons at the specimen, resulting in this fabulous 3D scan that you can see below, and tinker with yourself! Noteworthy are the bonus gastropods and bivalves in the living chamber of the specimen, which were flushed there during the burial.

 

 

The specimen can be accessed at the National Museum Wales, Cardiff; NMW.2002.69G.1

 

The paper can be read below:

Correlative tomography of an exceptionally preserved Jurassic ammonite implies hyponome-propelled swimming | Geology | GeoScienceWorld

 

Now, it really is sleeping time over here, I appear to have been writing this up for over an hour and a half now, and its technically tomorrow here... Oops!

 

Isaac, over and out...