When Sea Scorpions Ruled The Seas! GEO GIRL

[@sjzara]

There’s a tendency (for me at least) when introduced to ancient animals like sea scorpions to think of one animal called a sea scorpion. It’s amazing to see the huge variety of this group in this video.

[@LorenStClair]

When I was young I hated adults talking down to me, GEO GIRL you are awesome there are kids that respect your show, I do

[@GEOGIRL]

So glad to hear that! Thank you so much! That means a lot to me :)

[@shadeen3604]

Excellent DR GEO GIRL

[@GEOGIRL]

Thank you!

[@lethargogpeterson4083]

I've long thought that a eurypterid should make an appearance on an episode of the cartoon Scooby Doo, just so Scooby can say, "Raggy, rit's ra rurypterid!"

[@GEOGIRL]

Oh my gosh, yes!

[@stevenbaumann8692]

I didn't even know these things existed! Thanks!

[@claytonshearer1582]

Thank you for making this!!

[@GEOGIRL]

Of course! So glad you enjoyed it ;D

[@rursus8354]

Apex predator is kind of a curse: if your prey disappears, you're toast. You have to be big and then the next extinction event will toast you. Better to "multiply" faster than the others.

[@iamsuzerain3987]

Another great video. Thanks GeoGirl👍

[@punditgi]

Geo Girl has it all! Many thanks for this video! ❤🎉😊

[@MrSiwat]

Wow! I wasn't one of the folks to ask for this but this is so interesting. I didn't even know these critters existed! Amazing! So big!! I'm in Cyprus and my local mountains (Troodos range) was uplifted from the Tethys Ocean after the Mesozoic Era. We have some good fossils but nothing like that. Thanks so much. Great video. Love your channel.)

[@donaldbrizzolara7720]

Rachel: Love Eurypterids! They have always been on my bucket list to find. Eurypterids are chelicerate arthropods, and apparently until recent were put into the Class Merostomata with the Xiphosura (horseshoe crabs). I guess it is now believed that the Eurypterida is the sister group to the Arachnida, making the sea scorpions closer relatives of the scorpions and spiders than to horseshoe crabs. Wonderful discussion Rachel…as usual!!

[@Dragrath1]

Technically based on some phylogenetic evidence modern Xiphosurans appear to be highly derived arachnids forming a sister group to the hooded tick spiders and certain morphological and developmental characteristics appear to back this up in the context of say Xiphosurans still needing to return to land because their eggs and young are obligate air breathers. Interestingly due to trace fossils mostly reproductive molts we even know that early Eurypterids and all later egg laying genera shared this characteristic of obligate air breathing needing to complete their first molt instar before they could survive in the water. Later giant Eurypterids appear to have gotten around this limitation through the same mechanism sea snakes plesiosaurs ichthyosaurs mosasaurs Thalattosuchians among other marine reptiles and the mammalian cetaceans all independently evolved. Additionally given that we also know due to well preserved fossil molts that all Xiphosurans and Eurypterids have the same kind of UV fluorescence found within all extant or fossil arachnids, because the UV fluorescence appears to be due to structural crystals within their cuticles which generally survives fossilization, it stands to reason that the UV fluorescence trait was important early on in their evolutionary history. But even more curious is that the fluorescence within arachnids is tuned particularly to shorter UV B and UV C radiation which no longer regularly reach Earth's surface due to the Ozone layer which suggests if their fluorescence evolved for a beneficial reason it would have had to have occurred then before they radiated out when the ozone layer had not yet formed. All of this genetic evidence is of course complicated by the upwards of a half a billion years since their evolutionary radiation and effects such as long branch attraction but the UV fluorescence and obligate air breathing eggs and offspring characteristics only really make sense from the perspective of a terrestrial lineage returning to the water. There is also the fact that chelicerates as well as myriapods appear to be conspicuously severely underrepresented and or absent from the fossil record prior to the Ordovician and Silurian respectively where they appear suddenly in the fossil record already having a diverse well differentiated radiation of lineages. And molecular clock estimates while crude suggest by best fit a Cambrian origin. Mites at the very least based on many of these phylogenetic studies seem to be not only under sampled/studied but to likely be basal and or polyphyletic with a large fraction of them living within the soil. which seems to potentially approximate a good candidate niche for a tiny animal which adapts to come on shore where the group of green algae which would later become plants has begun to colonize the land at least in costal wet environments. After all we know from modern biodiversity that high rates of competition like seen within the Cambrian explosion tends to push some organisms to colonize marginal habitats. Given the subterranean soil dwelling habits of many of their extant descendants and the absence of related marine organisms Occam's razor seems to pretty strongly favor a origin of chelicerates/arachnids from tiny arthropods which moved into the marginal shore terrestrial environments to escape the high rates of competition in the oceans. Ergo Eurypterids have a pretty good chance of having been highly derived arachnids or at least some post terrestrial adapted sister group which returned to the ocean after a wave of major extinctions opened up vacant ecological niches.

[@ansfridaeyowulfsdottir8095]

Excellent video! I've seen some incredible footage of camouflaged octopus. I didn't even know it was there until it moved and created a flurry of sand! Then the colours and patterns all leached out of it and it was plainly visible! {:o:O:}

[@GEOGIRL]

I know right, octopuses are so incredible!! We are so lucky to have them living on modern Earth :D

[@UnionYes1021]

Thank you doctor for another excellent lecture. It is a delight to attend every one of yours. You are generous to share your knowledge and expertise. It’s a bit of an intellectual desert out here in general society. You are an inspiration. Thank you for all the work you do. Much appreciated.

[@wavemaker54]

Another fascinating video. Thank you so much for sharing your experience and knowledge with everyone. I look forward to viewing all the videos you mentioned in this one, and eventually watching your entire catalog. Thanks!

[@GEOGIRL]

Thank you so much! :D So glad to hear that!

[@wavemaker54]

You're very welcome. I just wanted to let you know your work is really wonderful. It's captivating, understandable, and entertaining. You're an excellent disseminator of our knowledge, science, and our natural history.@@GEOGIRL

[@GEOGIRL]

@@wavemaker54 Thank you so much! This really means so much to me! :)

[@kayakman2024]

Rachel, thank you for your excellent work. I have watched many of your GEO Girl videos and think they are great. Several months ago, I began a focused effort to become better educated on all aspects of earth's climate history, and your climate related videos have been extremely helpful in this endeavor. To make this task easier, I have created a personal, interactive "climate project" which helps me visualize time-synced relationships between earth's temperature, sea level, and CO2, covering the period of time from the present, back 550 million years. This private climate project uses reference materials I've derived from sources such as Wikipedia, and its backbone is a 5 panel series of graphs of earth's temperature, sea level, and CO2. I use this project to create screen-casted video tutorials. What I have now works, but I'd like to ensure the project's maximum accuracy. So I'm wondering if you could point me to where I might obtain the most accurate and up-to-date graphs of earth's historical temperatures, sea levels, and CO2, that would cover the time period of my project? Thanks again.

[@markmuller7962]

They still rule my nightmares 😳

[@Afridisamiullah776]

Interesting video. Learning so much knowledge, not from this video but from all your previous videos on your channel.

[@GEOGIRL]

Thank you so much! ;D

[@jonwashburn7999]

Thanks. This was pretty cool.

[@barbaradurfee645]

Nice work! We listened to you as we zoomed across west TX and one passenger was fixated on your voice 🐕❤️

[@GEOGIRL]

I miss him!! 💛🐕

[@Scottabamos]

Great Video!!! Thanks for making a video about eurypterids!!! Great overview, very informative!!!

[@davidniemi6553]

Thank you for a very thorough explanation of eurypterids. You provide a lot of useful context I had not seen before. Some minor notes: the creature labeled as an Anomalocarid around the 8:24 mark looks like the more primitive and bizarre Opabinia. Also -- the living arthropods most closely related to eurypterids are probably the arachnids, which does include modern scorpions but over 100,000 other species as well.

[@Hellbender8574]

Remember the guy getting pinched by the sea scorpion on the Walking with Dinosaurs documentary series? 🦂

[@neotericrecreant]

These guys are giving me "Seeker"(skyrim) vibes!

[@Miloun]

You deserve way more than 50K subscribers. I'm guessing in a year you'll easily have half a million. You produce great content and you have a top-notch way of presenting it. Thanks for making these videos! Best regards from Switzerland

[@GEOGIRL]

Wow thank you so much! This comment made my day! I hope you are right haha ;)

[@michaeleisenberg7867]

Rachel 🪁, I love 💕 this video. Thank you! Another interesting early Apex predator were arrow worms 🪱 or chaetognaths from the Cambrian.

[@GEOGIRL]

Thanks for the comment! I am going to read about chaetognaths right now!! They sound so interesting, hopefully I can find enough on them to make a video :D

[@michaeleisenberg7867]

@@GEOGIRL I think is what I read is since they're mainly soft body they didn't leave much in the fossil record. Maybe a tooth 🦷 here or there. Good luck. I hope you find something video-worthy 🎥.

[@EnRouteToMoon]

Nice story ! Interesting, did they ever try to live out of the ocean ? Who knows may be it was a chance for them to avoid extinction. 🤔

[@jackprier7727]

Wow nearly 200 million years of success. I had no idea they were so perfectly adapted--

[@trilobite3120]

3:58 Ironically, the earliest known Eurypterid, Pentecopterus, was among the largest.

[@danielschechter8130]

Really fascinating stuff! Thanks.

[@A-K_Rambler]

Coffee Treat for U!

[@GEOGIRL]

Thank you so much! How kind! :D

[@philochristos]

I was kind of okay with them until you showed that picture of how big they were compared to a human. Now I'm like, "Oh, hell no!"

[@Alexnz935]

cat spotted, just chilling on the chair

[@GEOGIRL]

lol I didn’t even notice!

[@barbaradurfee645]

She’s a diva

[@Alexnz935]

@@GEOGIRL my part time job cat spotter lol

[@od1452]

Interesting. More successful than I thought. Still wondering about the first animal...but I can see that might be more interesting to qualify. ... comparing a sponge to an octopus or a tiger doesn't sound too fair. Maybe first mover, first walker , first flyer..etc.? Antway.. Great stuff Doc. ( We can call you that now..right? ) Thanks.

[@_andrewvia]

Just a small bit of feedback: When you press a key on your computer, I can hear it! Perhaps your microphone is connected to your desk? One solution would be that I should be the one who adapts - I could use headphones with weaker bass response (these really kick).

[@GEOGIRL]

Yea, I know, I have changed my set up recently, and that has been an issue, I try to cut them all out when I edit, but sometimes I press it so quick it overlaps with my speaking. I will try to be better about that! Sorry, I didn't realize it would be so noticeable! :)

[@_andrewvia]

@@GEOGIRL My headphones generate great bass, so I hear it more I think. Still, perhaps a hi-density quarter or half inch thick foam pad would help. Often you can get just the dimensions you want at a hardware store. amazon sells six-foot lengths.

[@GEOGIRL]

Thank you for the suggestion! I will certainly fix it for future videos (keep in mind I have about 6 more pre-filmed videos before I need to film more, so it may take over a month to tell the difference but I promise I will fix it!) ;) thanks again for the heads up!

[@JKTCGMV13]

🦂 🦂 🦂

[@i18nGuy]

Interesting that early sea scorpions had camouflage. Were there predators that had vision capabilities in the same period? It seemed that the ability to see might have developed later. In that case, was there some other benefit to camouflage or perhaps it reflected other changes in environment etc. (like tree rings...)

[@GEOGIRL]

Yep! There were the anomalocarids, trilobites (some of which were predators, potentially to the very small eurypterids), and of course fish, which had eyesight and increasing body sizes over this time range, so I could see why the eurypterids would have the camouflage, especially if the fish were swimming and looking down at the benthic eurypterids from above :)

[@trilobite3120]

​@@GEOGIRL There's also the giant Endoceratids that might have preyed on them.

[@Jason-xf3ym]

Stop talking about my ripterids! Lol. Im new to your videos, and i love them! Subscribed.

[@GEOGIRL]

Thanks so much! So glad to hear that ;D

[@terenzo50]

Okay, eeeeew! Evan as a misnomer, I don't like scorpions either in, out of or under the water. I'm a Seahorse man. Love those guys. It's a childhood thing. And sea otters. Seahorses and sea otters are like kittens and puppies to me.

[@asjenmensink2740]

They are MORE related to spiders, mites, scorpions and other arachnids (and the sistergroup to them and horseshoe crabs).

[@Afridisamiullah776]

Please make a video on coming Sunday "Biomarker analysis and how they are related to the Paleoclimate proxy". Hope my request is accepted.

[@GEOGIRL]

I have it on my list! But there's a lot more research I need to do before I can film, so it will probably be a few months, but I will try to rush it ;)

[@Afridisamiullah776]

@@GEOGIRL Thank you so much

[@ansfridaeyowulfsdottir8095]

Sorry for the Pedantic Brit Rant again, but it's "pincer", not "pincher". And it's "picture", not "pickshure". And it's _"I could NOT care less"_ not _"I could care less."_ {:o:O:}

[@GEOGIRL]

Haha Yea, sorry about that, I actually realized I said pincher in editing and I was going to correct it but figured it still gets the point across ;)

[@ansfridaeyowulfsdottir8095]

@@GEOGIRL 🤣 No worries! {:o:O:}

[@Afridisamiullah776]

My question is from the previous video "How Global Cooling increases the Salinity of the Ocean although river input is less and also less volcanism that drives the ions to the ocean".

[@GEOGIRL]

Global cooling leads to glaciation, and when glaciers and ice form and expand it locks up freshwater (ice does not take up salt), so the leftover liquid ocean water becomes saltier as the ice continues to take up freshwater, concentrating the salt in the liquid portion. Hope that makes sense! ;)

[@Afridisamiullah776]

@@GEOGIRL Thank you. Logical and interesting answer

[@naajilyons2872]

Sea scorpions are cool, but those anonymous carrots seem pretty neat too.

[@GEOGIRL]

Oh my gosh! I just noticed that the auto captions that youtube put said anonymous carrots instead of anomalocarids, that is hilarious!! I am literally going to call them that from now on🤣

[@patkelley8293]

I had a friend that kept scorpions as pets. Apparently they like cheese. Honestly I have no idea what they like.

[@johnbaker1256]

Did they sting the cheese, or just eat it ?

[@patkelley8293]

@@johnbaker1256 I don't know. I was down in Mexico. This guy had it in a cassette case and fed it cheese or flies. Memories from a strange life. 🤕

[@cfmcguire]

Many years ago, I had one. I named him Herman for some reason and fed him flies.

[@sjzara]

I don’t know if this is your subject, but I would love to see something about the Cambrian explosion and associated fossils. This is because there’s said to be a large number of now extinct phyla. I find it hard to look up what these phyla were or how they were identified in fossils.

[@GEOGIRL]

Check out my previous video on the Cambrian explosion here: kzbin.info/www/bejne/nKrJo5WNfpWemZI And I am actually working on a video about the preceding ediacaran fauna right now that I hope to put out in the next few weeks! :)

[@nicholasmaude6906]

Now that you've uploaded this interesting video about Eurypterids (A fascinating order), Rachel, are you going to do a couple of videos concerning Eusthenopteron and the Placoderms?

[@FrancisFjordCupola]

I think it's supposed to be: you can't beat the effishiency.

[@GEOGIRL]

Omg I wish I'd thought of that! haha

[@cafiend]

You can’t spell “efishent” without “fish!” 😄

[@Pikkugen]

The effishency of fish is great.

[@scottwootten1848]

G'day Geo Girl (Rachel)! I was wondering if you are planning to do a presentation on the Hawaiian Islands specifically? I read they are just a bleeding volcanic vent that bursts through the overlaying/moving Pacific Plate, which is why all the islands, atolls and seamounts are lined up along the northern/northwestern Pacific. I also read that seismic data has found the subducted flood basalts beneath eastern Siberia, which the Hawaiian volcanic vent originally gave rise to. How old this flood basalt event was, I don't recall (Triassic or Permian), but it may be another contributing factor to the Permian Mass Extinction or something???? Either way, all this just another idea for a new presentation.

[@kunalroy9735]

I❤U

[@k4x4map46]

Ammonites; liking them of the Carboniferous period!!

[@jareg4033]

Please please before you show a picture of a spider across the whole screen, give us a few seconds notice! My heart jumped and I couldn't concentrate on anything for 10 minutes 🤦

[@nicholasmaude6906]

It's a pity the Eurypterids didn't survive the Permo-Triassic extinction, Rachel, as they were a fascinating order.

[@jimbojones247]

geo babe

[@joseph96345]

Can't help but wonder if they taste any good.

[@Troy-ol5fk]

how do structures like pinchers/fingers evolve?

[@chaosopher23]

Very lobster-like! That makes me want to bring them back from extinction. I bet they'd be good with butter. I still want to know everything about them. I know of no branch of science that lets you eat the experiment than some branches of biology.

[@nicholasmaude6906]

They're fascinating, extinct order, Rachel, anyway what do you think of the BBC's portrayal of Eurypterids in its' excellent 2005 TV series "Walking with Monsters" (en.wikipedia.org/wiki/Walking_with_Monsters)? When you love to have in an aquarium a pet gene-engineered analogue of Brontoscorpio Anglicus, Rachel, if they were available? No doubt using the latest advances in genetic-engineering an analogue of a Sea Scorpion could be made from a gene-engineered Horseshoe crab.

[@marble296]

The real question is how edible were they?

[@reidflemingworldstoughestm1394]

Proto shark

[@francoislacombe9071]

I wonder what they tasted like. 🤔

[@uncleanunicorn4571]

Instead of church, Why not go somewhere on sundays to learn about Eurypterids?

[@GEOGIRL]

Absolutely ;)

[@nicholasmaude6906]

With recent advances in genetic-engineering, Rachel, would you like to have as a pet a modern analogue of a Brontoscorpio Anglicus (kzbin.info/www/bejne/moGmm3SIhsZ1gbM) created from a gene-edited Horseshoe Crab?

[@aps340]

You are so beautiful,, in a goodway😂also intelligent

[@iansanford6544]

"...up against fish, y'know, you just can't beat the e-fish-iency" 🤌

[@GEOGIRL]

Omg I wish I'd thought of that! haha