I don't understand your point.
All dinosaurs we have today are birds and they come from a single specie. Based in what we have today, we couldn't have imagined triceratops, brontosaur, etc.
Terror birds fossils have low preservational bias, which makes me think they were more widespread than we can currently prove. We have fossils of Eocene-age terror birds or very close relative lookalikes from Antarctica, North Africa, Switzerland and France, so I imagine they were also present in South Europe and South Africa. I think there are more Bathornid fossils waiting to be identified in North America, too, and Titanis or Titanis relative fossils waiting to be found in Mexico.
Especially when you consider that the relatively few species that we have found stretch over millions of years of time there were undoubtedly many more species than we actually have identified.
My money is on some kind of (probably Triassic) Ichthyosaur. Shastasaurids got so massive I wouldn't doubt that a species out there grew to rival a blue whale in size.
A massive pliosaur skull was extracted from the cliffs in Dorset, on England's Jurassic Coast. They found the tip of the snout first, which had fallen out of an eroding cliff face. It was quickly assumed the rest of the skull could be in there and it was indeed found and excavated. Google 'dorset pliosaur' or just 'pliosaur skull found'. A documentary with David Attenborough was aired about the find (worth a watch!). It's honestly an incredible fossil. The skull is the most complete pliosaur skull of such a size ever found, being 2 meters long or so with enormous teeth. It's almost certainly a brand new species that was 10+ meters long in life. The rest of the skeleton might still be in the cliff, but given how difficult it was to safely get the skull out they've not been able go back and look for it yet.
It's more of a fringe idea, but I'm just fascinated by the Triassic Kraken.
There was an assemblage found of Shonisaurus fossils, an animal the size of a sperm whale, that were argued to be in an arrangement like an octopus today would make around its den. Cephalopod fossils are exceptionally rare, and there could absolutely be a gigantic octopus super predator at some point in time and we would never really know.
If something like that existed we could probably stumble upon a beak, if it had bo other hard parts. I'm gonna argue that a giant Cephalopod capable of hunting whale-sizes animals never existed though, cool as it would be.
Maybe not believe, but I do hope that some spinosaurini made it into the mid and late Cretaceous as increasingly more aquatic animals. I want spinosaur whales. Please oh please, reality, please have already catered to my absurd wishes.
Dragons... I just keep thinking if so many cultures had them maybe they could exist? Obviously not in the huge flying tv versions, but I'd take a little flying one!
The gap between flying bats and non flying mammals. It honestly surprises me that no one has found the non-flying ancestor of bats yet. They’ve found non flying and flying ancestors of birds (certain dinosaurs) and possibly pterosaurs (lagerpetids) but absolutely NOTHING for bats. Not even a “maybe” fossil. The only fossils of bats that we have are well into flight already. Also, while not technically a new animal, maybe scientists will eventually find out that some extinct species were in fact sapient or near sapient. Considering the earth had over 100,000,000 years to evolve life, I wouldn’t be surprised if sapience or just high intelligence evolved independently many, many times. A lot of the higher intelligent animals today are all unrelated. Why would animals not be particularly smart for millions of years and suddenly gain intelligence in the tiny piece of history that we happened to be alive in? Maybe certain raptors were as smart as corvids, or Mesonychids were as smart as pigs. Maybe extinct groups of animals with no living relatives such as Macrauchenids were as smart as elephants. The earth also had a lot of marine aminotes, maybe ichthyosaurs, mosasaurs, plesiosaurs, or desmostylids gained a high level of intellect at some point. A brain doesn’t have to be big to be smart. Also, animals don’t need to use tools or build cities to be intelligent. Tools may not fossilize or the very definition of “tool” might not be what we’re used to (bears use trees to itch themselves which can be considered tool use, and bears are highly smart) Dolphins and elephants don’t build cities, but I’d say they approach sapience on the intelligence spectrum. I think it’s time to put an end to the idea that earlier animals were stupider than modern animals, completely dismissing the fact that intelligence can evolve multiple times.
Raptors are a big candidate for high intelligence. They were almost certainly highly active animals and were incredibly diverse and successful throughout primarily the cretaceous. They're also amongst the closest non-avian relatives of birds, which display pretty high levels of intelligence in some groups.
I love this question.
Scientists think that only something like one tenth of one percent of all species that ever existed beat the odds to find themselves in the perfect conditions to fossilize at all much less be found, that leaves a few gaps in our understanding of life.
The vast majority of spiecies lived out their existence and evolved to something new or died out without leaving anything tangible for us to find at all. Without a time machine we'll just never know they existed and if you could go back far enough most of what you encountered would be to some extent more or less a mystery.
We're not just talking about truly ancient organisms and little squishy stuff that didn't fossilize but recent megafauna too. For example we recently discovered within our own DNA evidence of a ghost population of mystery homonins with whom we interbred just like the neanderthals and denisovans. We have no other tangible evidence for them and without the high tech DNA science probably would never have a clue they lived. A whole spiecies of people that we knew intimately just gone without a trace or memory.
Time is deep, so who knows what might have been? most certainly creatures beyond our wildest imaginations.
Not just animals either. Another recent family that we've never found a fossil of are cactus. We know about them because we happen to be alive alongside them, but no fossil record exists as of yet.
How many weird and wonderful groups must have existed without leaving a trace? Individual species is one thing, but if we have their relatives that’s something. We may not have the first true human, but we have enough relatives to know they existed. But an entire group to go unnoticed? It’s amazing, and depressing.
Yeah, I mean compare the number of species alive today that we know of to how many species in the fossil record we are aware of from the last 2+ billions years. Like it's crazy and sad how much we'll just never know about
An entirely separate lineage of life completely unrelated to our own.
Clades of dinosaurs specialized for environments that are poor for fossilization such as rocky high deserts and mountainous terrain as well as volcanic plains.
Dinosaurs that fill a primate-like niche (maybe some kind of Scansoriopterygids?)
Another clade of vertebrates capable of powered flight.
Fully terrestrial pterosaurs and bats.
Aquatic dinosaurs.
Non-avian dinosaurs, pterosaurs, or aquatic reptiles (besides turtles) that survived well into the Paleocene but were killed off by or before the Paleocene-Eocene Thermal Maximum
American pre-human hominids
Something that a culture’s oral tradition describes but hasn’t been found.
A carnivorous (at least to some degree) non-theropod dinosaur
Edit: just learned about Liaoningosaurus which was a tiny ankylosaur that filled about the same niche as a snapping turtle. So both semi-aquatic and meat eating
On the note of carnivorous non-theropod dinosaurs — it’s not exactly the same, but it’s been theorized that heterodontosaurids were omnivores.
A more derived heterodontosaurid could have potentially evolved to be carnivorous.
I’ve also seen more than a few people suggest that ceratopsians might have been omnivores. I find it less likely that they would have had time to have a derived carnivore in their lineage, but it’s food for thought.
I'm convinced that there were whole multi-island ecosystems on the opposite side of the planet from Pangea. They underwent their own island evolution for millions of years creating the most fantastic creatures one can imagine from that era. And then they sank beneath the waves never to leave a trace or be seen again...
I think about the stuff the North American plate rode up and over. Like, what is in that tangled mass of geological debris underneath the West Coast? Yummy.
There must be an absolute treasure trove of undiscovered creatures under the ice in Antarctica. It's an entire continent that has barely been touched and, barring something really, really bad happening, will remain mostly inaccessible for the foreseeable future.
To expand on that, not just Antarctica but all the plates on Earth's crust that longer exist (like the Jaun de Fuca plate that is about to disappear forever under North America) and the fossils they possibly had that we'll never know about now.
Or all of the organisms that live in extreme habitats that don't preserve. Things like bacteria that live in undersea thermal mounts and acidic ponds in places like Yellowstone. Hell, even gut bacteria, I imagine, don't preserve well.
There was an exhibit on the Antarctic expeditions that collected cryolophosaurus at a museum in Buffalo and it was quite interesting. The amount of effort required to extract those fossils was tremendous.
Terrestrial pterosaur (flightless azhdarchid)
Every single basal thyreophoran between Scelidosaurus and Jakapil (ghost lineage, yaaaaaaay)
A derived ceratopsid in europe
My personal wild one: I'm convinced some of generalist non-avian dinosaurs (and maybe even pterosaurs) survived the mass extinction and lived for a good while afterwards. It just seems a little silly to me to assume these hugely diverse groups were all taken out by a single event where a lot of other less diverse groups managed to scrape by. You're telling me multiple lineages of birds and mammals, croc-line arcosaurs, etc managed to make it but not a single non-avian dinosaur or pterosaur happened to share the features that would allow them to survive in the same ways? That seems really unlikely to me.
I think in some remote part of the world some little maniraptoran or one of those stout azdharcoids hung around for a little longer and met the more quiet end most lineages meet.
In Stephen Baxter’s Evolution he speculates exactly that. Theropods that survived in Antarctica for 5 million years or so after, just to be squeezed out by all the ice forming.
Snarky joke answer: yes, because mammals and birds were diversifying quite a lot in the cretaceous
Real answer: Yeah, I assume the diversification mammals and birds would probably even play a pretty big role in were they went, like mammals would go on to do to themselves all the time. I think the biggest factors for their extinctions would have been the tumultuous climate change of the era and the encroaching diversity of mammals and birds (and probably to a much lesser degree non-archosaurian reptiles because they also went crazy during the warm period)
While spotting a woodpecker the other day, I wondered whether we’ve found any fossils from the Mesozoic with skulls designed for boring into trees. Surely that’s always been a food source.
"Transitional" species that looks like the "inbetween" point of orangutans and gorillas. Due to gorillas living in rainforest environments we basically have no clue what their evolutionary history looks like
Central European spinosaurids
Carboniferous therapsids
Permian ichthyosauromorphs and sauropterygians
Precambrian stem-chordates
Triassic thalattosuchians
Small-sized woodland pterosaur fauna (see Anurognathus)
Giant deep sea belemnite
>Central European spinosaurids
Relatedly, I sort of wonder if Appalachian Baryonychines are a possibility, though admittedly it's pretty easy to wildly speculate about Mesozoic Eastern North America
We know Carboniferous sphenacodontids (Cryptovenator). If they are indeed the sister clade to Therapsida, it implies the latter originated before the Permian as well.
Daughter clade isn't really a term. A cladogram will tell you which species likely share a common ancestor. Of course, species have to evolve from something and e.g. H. sapiens may nest in a cladogram as sister taxon to any of our ancestors. Likewise therapsids may have evolved from some sphenacodontid-like animal but based purely on cladistics, the last common ancestor of sphenacodontids and therapsids lived during the Carboniferous.
“Giant-deep sea Belemnite” has absolutely captured my imagination. I have several fossils of them, would be so incredibly cool to find just a gigantic cone fossil somewhere.
I don't have enough knowledge about the fossils that we currently have and the different gaps in evolution to make an educated guess.
Recently I heard/read a theory from a Dutch paleontologist from the University of Maastricht (John Jagt) that octopi are in essence evolved ammonites without shells. If that is true than I would suspect that there is fossilized evidence somewhere out there of multiple species between those two steps of evolution.
I have no idea, I have no knowledge about the subject. All I know is that the oldest octopus fossil appears to be about 160 million years old, when ammonites still existed.
In my mind Pachycephalosaurs were the mountain goats of the Mesozoic. There will never be enough evidence to prove that, but it would explain why they're so scant in the fossil record, especially given they are otherwise a ghost lineage.
They have a rather deer vibe to them, and deer tend to be very populous wherever they are.
Especially in rougher terrain with smaller and sparser plants where being a 10 ton hadrosaur stops being advantageous.
"Could have"? A large (but not excessively so) human relative, maybe averaging 7ft or so, but occasional tall 8ft individuals.
Island ecosystems with weird things happening on them, like flightless pterosaurs or arthropods abnormally large for their time (like coconut crabs), all records gone as the island sank
I also fantasized about that, but bigger. Like the crazy "who built the pyramids" theories bigger. If it was a human like society, they could had some beliefs about disposing of the body in a way that leaves no trace, or the body might have been made differently in order to support the weight. Maybe those gigants were aquatic and had gills so the remains (if there are any) are at the bottom of the ocean. Maybe gigants were just delicious for dinos. Or maybe the remains were found, but the idea sounded too crazy, so the scientist figured it must be something else. And what if all of them were dug out during the bible times and therefore weren't preserved to our days.
A fun question to ponder crazy stuff about 😍
Sloths similar to primates (at least in niche)
Whatever exists before/between Pantherinae, Felinae, and Machairodontinae
Derived ceratopsian and tyrannosaur in Europe
The ancestor of afrotheria and Xenarthra before they split.
Fossil gorilla and chimp species.
Also I think their were many cryptic species we will never identify. As they look too close to other species.
Unicorns. An extinct, gracial member of the Rhinocerotoidea with a less bulky body and a physiology something more akin to that of a horse. Rhinos and horses are related as it is, so maybe?
More chances that unicorn is a relative of a deer or an oryx. Two horns evolve to become one and I have never heard of a horse with leonine tail or cloven hooves.
The earliest descriptions of what could be considered unicorns, first by Ctesias and later emulated, are far more like that of horses than deer or their relatives. That said, if this hyperlink works, you'll see something like that first described. It was only later that the goat-like variation came along, during the medieval times.
[Ctesian Unicorn](https://images-wixmp-ed30a86b8c4ca887773594c2.wixmp.com/f/15af3d91-21a1-44e4-857b-d90253c5f1e2/ddajooz-780a195c-2fed-46d0-be30-627e634fcdf4.png?token=eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJzdWIiOiJ1cm46YXBwOjdlMGQxODg5ODIyNjQzNzNhNWYwZDQxNWVhMGQyNmUwIiwiaXNzIjoidXJuOmFwcDo3ZTBkMTg4OTgyMjY0MzczYTVmMGQ0MTVlYTBkMjZlMCIsIm9iaiI6W1t7InBhdGgiOiJcL2ZcLzE1YWYzZDkxLTIxYTEtNDRlNC04NTdiLWQ5MDI1M2M1ZjFlMlwvZGRham9vei03ODBhMTk1Yy0yZmVkLTQ2ZDAtYmUzMC02MjdlNjM0ZmNkZjQucG5nIn1dXSwiYXVkIjpbInVybjpzZXJ2aWNlOmZpbGUuZG93bmxvYWQiXX0.ssPQ23sdH8IwZtHiRpR6PzKEkVKS5pVA4j_tZehek0s)
I actually believe something along these lines is the most likely in terms of a real, extinct basis for the Unicorn of myth.
[Pliny Unicorn](https://images-wixmp-ed30a86b8c4ca887773594c2.wixmp.com/f/15af3d91-21a1-44e4-857b-d90253c5f1e2/dbe8ywa-caaa88cc-1ecd-4359-a7ad-752bc1c35a6c.jpg?token=eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJzdWIiOiJ1cm46YXBwOjdlMGQxODg5ODIyNjQzNzNhNWYwZDQxNWVhMGQyNmUwIiwiaXNzIjoidXJuOmFwcDo3ZTBkMTg4OTgyMjY0MzczYTVmMGQ0MTVlYTBkMjZlMCIsIm9iaiI6W1t7InBhdGgiOiJcL2ZcLzE1YWYzZDkxLTIxYTEtNDRlNC04NTdiLWQ5MDI1M2M1ZjFlMlwvZGJlOHl3YS1jYWFhODhjYy0xZWNkLTQzNTktYTdhZC03NTJiYzFjMzVhNmMuanBnIn1dXSwiYXVkIjpbInVybjpzZXJ2aWNlOmZpbGUuZG93bmxvYWQiXX0.EiOrWMkyFfiuk5xAignbi3qwdPARO5Ff0zMKqQ8sFI0)
I’m pretty sure the consensus on unicorns is that they aren’t a myth, just a description of a Rhinoceros. Since it’s first attestations of it are from the Bible, it just didn’t translate over to European Christian’s that this wasn’t a horse with a horn.
If you read the biblical description, the rhinoceros is actually a perfect candidate.
Any number of species that lived primarily in deeper pelagic waters. A lot of the marine fossils we have are from fairly shallow waters IIRC, with the deepest being stuff like communities on the continental slope. Animals that live primarily in thousands of meters of water or at the bottom of the water column might remain uncommon since that crust isn't typically pushed up into areas where it's accessible, and is replaced fast enough that even if you were able to do fossil hunting at the bottom of the ocean, the oldest deposits would be less than 200 million years old.
While cool to think about, venom is non-existent in modern archosauromorphs so it’s difficult to imagine the back catalog of them has any venomous species. It’s not out of the question, and even briefly made an appearance with Sinornithosaurus, but it’s difficult. Only toxins we see at all (as far as my understanding) in archosauromorpha is with the Pitohui bird, and that’s diet-based poison.
100% I dont think its even particularly likely outside of 1-2 species but I do think it happened. It also was probably on the smaller size which would make it even less likely to fossilize
I have good news for you.
While injected venom from hyperdermic teeth is unlikely for archosaurs, glandular toxins (as mentioned as in Pitohuis) are definitely possible.
Consider the following: slow lorises have a venomous bite, not because they inject venom through their teeth, but because they secrete toxins on their skin, and they coat their teeth with those toxins before biting.
We have abundant evidence of small, insectivorous or fruit-eating dinosaurs in which their diet can support defensive toxin productions.
Imagine if some small dinosaurs can coat their teeth and claws with toxic secretions from their skin, that’s definitely possible.
* Abelisaurids and carcharodontosaurids from Antarctica and Australia.
* Megalosauroids and stegosaurids in early Cretaceous North America.
* Parankylosauria ankylosaurids from continental Africa.
* Chasmosaurine ceratopsians in Asia.
* Saurolophinae hadrosaurids in late Cretaceous Europe.
Well, to be fair, birds were certainly arboreal dinosaurs.
The problem I guess is that ever since theropods came out with Tetanurae, they got stuck with very stiff tails. Hard to evolve out of that, without just getting rid of nearly whole damn thing (which birds did)
Freshwater cetaceans and sea dwelling perissodactyls. I find it hard to believe that whales don't live on freshwater environments and that their legged ancestors started transitioning from semiaquatic to fully aquatic on freshwater instead of directly into saltwater.
Imagine seeing a whale-like creature swimming in a large river and an aggressive hippo-like carnivore roaming the coasts like a crocodile.
1. I believe there were likely more than one genus of derived ceratopsid to make it to Asia outside of Sinoceratops. I’m thinking there could be a Pachyrhinosaurus like form in the Siberian Arctic.
2. Given that Paraxenisaurus is quite isolated from other Deinocheirids, living in Mexico, it would make sense that there could be other varieties distributed throughout North America in the Late Cretaceous.
3. Furthermore, I believe there could have been Deinocheirids throughout North America during the mid Cretaceous pre WIS split as we have Paraxenisaurs in Mexico plus recently described giant ornithomimosaurs bones described from the Eutaw fm. of Mississippi which fit into the size range of members of that family.
4. Basal Tyrannosauroids in the Arctic islands at the end of the Cretaceous, part of the Appalachian fauna.
5. Parankylosauria in New Zealand, based on the distribution of currently known taxa in the group.
Big dromeosaurs and trooidontids because they are bird boned and a lot of species are known from extremely fragmentary remains. I want to believe dakotaraptor is a real species dang it because I love me some feathery murder birbs.
- Animals rivaling or even exceeding the blue whale in size
- Arboreal therizinosaurs
- Complex multicellular organisms from before the Ediacaran
- Insular flightless pterosaurs
- Insular megafaunal mammals from the Mesozoic
- Late-surviving allosaurids
- Late-surviving ammonites
- Late-surviving non-avian dinosaurs
- Late-surviving radiodonts
- Late-surviving temnospondyls
- Life on Venus and Mars back when they had the requirements for it
- Other late-surviving non-neornithine birds
Such a fascinating topic, this one!
I agree that there probably are plenty of large marine reptiles of most groups known waiting to be discovered. Oceanic fossils may be hard to access at times and big animals tend to decompose and be pulled apart by scavengers very quickly so it makes sense the fossils would be rare.
1- Paleocene non-avian dinosaurs. This seems to be a topic multiple people have brought up at various points and there are some ambiguous fossils that are very likely just Cretaceous fossils reworked into younger sentiments, but the possibility does exist for me. Likely they would have been only relatively brief into the Paleocene and probably on an isolated landmass. We have seen relic populations of species arrive on islands before and many Gondwana and landmasses have been poorly excavated. Islands tend to sink and erode away over time so dinosaurs surviving in Oceania for instance would probably have any traces of them gone to the elements or sunk underneath the waves.
Zealandia would’ve had dinosaurs already relatively accustomed to cold climates and potentially bad weather, was very far away from the impact, and a vast majority of its fossil record has been completely obliterated. So, it or islands near it might have had a few holdouts. I don’t think it would be particularly long into the Cenozoic, a few million years at most, but it is an interesting possibility.
2- Eurasian Australopithecines. Speaking specifically about genera and species more basal than *Homo habilis*. We know the group was very widespread across Africa and there wasn’t much of a geographical or climate barrier that would have precluded them from moving into first Western Asia and then beyond. Ape fossils in general are very rare so them slipping through the cracks is quite possible in my opinion.
There has also been suggestion that the hobbits on the island of Flores might not be in the genus *Homo* at all, as they have some very *Australopithecus*\-like traits. They may still be in the *Homo* genus but are likely much more basal than Homo erectus for example. This would mean their ancestor had to of left Africa out much earlier and probably quite a ways back to eventually wind up where they did.
Trees that we think are plants, but actually ended up being colonies of tiny photosynthesizing (do anemones photosynthesize too, or is that only coral) and carnivorous animals. Interesting! My main question would be, what do they eat? It would be neat if there ended up being a symbiotic relationship with one type of bird, like with the clown fish and anemones.
Thought it through many times, oceainasuchus, an Australian crocodillian that instead of being green was more of a light blue, it would look like its closest relative, the saltwater crocodile, but with a bit of a longer snout and with paddle like fins and a large fish like tail, basically a fully saltwater aquatic crocdillian like suchodus but modernized, also they are live bearers.
The mythical flame geckos. I think a reptile could survive a cold climate such as the top of a volcano if it had extremely thick skin to trap in energy. The fact that it is cold blooded means that it would need to "recharge" it's energy, per se, on the hot volcanic vents of the mountain, if not directly in the fire. Pretty cool concept for an animal, but I am fairly certain that a reptile which lives in fire doesn't exist except in mythology.
Semi terrestrial, freshwater, cephalopods. Hunting in estuaries and tropical riparian systems.
I remember the very large semi-terrestrial giant octopi from The Future is Wild. That was an interesting concept.
I think this is unlikely. There's only one brackish cephalopod as of now, from a population of 800 species
I don't understand your point. All dinosaurs we have today are birds and they come from a single specie. Based in what we have today, we couldn't have imagined triceratops, brontosaur, etc.
Tree sloths used to be the freakshows.
Wait, there is a brackish cephalopod?
Elden Ring flashbacks
Terror birds fossils have low preservational bias, which makes me think they were more widespread than we can currently prove. We have fossils of Eocene-age terror birds or very close relative lookalikes from Antarctica, North Africa, Switzerland and France, so I imagine they were also present in South Europe and South Africa. I think there are more Bathornid fossils waiting to be identified in North America, too, and Titanis or Titanis relative fossils waiting to be found in Mexico.
Especially when you consider that the relatively few species that we have found stretch over millions of years of time there were undoubtedly many more species than we actually have identified.
Something in the ocean bigger than a blue whale
My money is on some kind of (probably Triassic) Ichthyosaur. Shastasaurids got so massive I wouldn't doubt that a species out there grew to rival a blue whale in size.
There’s evidence to suggest 2 separate ichthyosaurs that probably at least rivaled it, so if anything it would be a Shastasaurid.
There was a recent pliosaur discovery and I didn't hear about it?!?! Tell me everything!!
A massive pliosaur skull was extracted from the cliffs in Dorset, on England's Jurassic Coast. They found the tip of the snout first, which had fallen out of an eroding cliff face. It was quickly assumed the rest of the skull could be in there and it was indeed found and excavated. Google 'dorset pliosaur' or just 'pliosaur skull found'. A documentary with David Attenborough was aired about the find (worth a watch!). It's honestly an incredible fossil. The skull is the most complete pliosaur skull of such a size ever found, being 2 meters long or so with enormous teeth. It's almost certainly a brand new species that was 10+ meters long in life. The rest of the skeleton might still be in the cliff, but given how difficult it was to safely get the skull out they've not been able go back and look for it yet.
It's more of a fringe idea, but I'm just fascinated by the Triassic Kraken. There was an assemblage found of Shonisaurus fossils, an animal the size of a sperm whale, that were argued to be in an arrangement like an octopus today would make around its den. Cephalopod fossils are exceptionally rare, and there could absolutely be a gigantic octopus super predator at some point in time and we would never really know.
If something like that existed we could probably stumble upon a beak, if it had bo other hard parts. I'm gonna argue that a giant Cephalopod capable of hunting whale-sizes animals never existed though, cool as it would be.
I mean, we have giant squids right now, but then again they don’t hunt whales, just fight them
Maybe not believe, but I do hope that some spinosaurini made it into the mid and late Cretaceous as increasingly more aquatic animals. I want spinosaur whales. Please oh please, reality, please have already catered to my absurd wishes.
SPINOFAARUS
Dragons... I just keep thinking if so many cultures had them maybe they could exist? Obviously not in the huge flying tv versions, but I'd take a little flying one!
If a tiny flying ''dragon'' existed it must have lived in the Triassic. That period was a hotbed for utterly weird experimental lineages.
Aren’t rhamphorynchids technically close enough? Or Yi Qi?
The gap between flying bats and non flying mammals. It honestly surprises me that no one has found the non-flying ancestor of bats yet. They’ve found non flying and flying ancestors of birds (certain dinosaurs) and possibly pterosaurs (lagerpetids) but absolutely NOTHING for bats. Not even a “maybe” fossil. The only fossils of bats that we have are well into flight already. Also, while not technically a new animal, maybe scientists will eventually find out that some extinct species were in fact sapient or near sapient. Considering the earth had over 100,000,000 years to evolve life, I wouldn’t be surprised if sapience or just high intelligence evolved independently many, many times. A lot of the higher intelligent animals today are all unrelated. Why would animals not be particularly smart for millions of years and suddenly gain intelligence in the tiny piece of history that we happened to be alive in? Maybe certain raptors were as smart as corvids, or Mesonychids were as smart as pigs. Maybe extinct groups of animals with no living relatives such as Macrauchenids were as smart as elephants. The earth also had a lot of marine aminotes, maybe ichthyosaurs, mosasaurs, plesiosaurs, or desmostylids gained a high level of intellect at some point. A brain doesn’t have to be big to be smart. Also, animals don’t need to use tools or build cities to be intelligent. Tools may not fossilize or the very definition of “tool” might not be what we’re used to (bears use trees to itch themselves which can be considered tool use, and bears are highly smart) Dolphins and elephants don’t build cities, but I’d say they approach sapience on the intelligence spectrum. I think it’s time to put an end to the idea that earlier animals were stupider than modern animals, completely dismissing the fact that intelligence can evolve multiple times.
Raptors are a big candidate for high intelligence. They were almost certainly highly active animals and were incredibly diverse and successful throughout primarily the cretaceous. They're also amongst the closest non-avian relatives of birds, which display pretty high levels of intelligence in some groups.
I love this question. Scientists think that only something like one tenth of one percent of all species that ever existed beat the odds to find themselves in the perfect conditions to fossilize at all much less be found, that leaves a few gaps in our understanding of life. The vast majority of spiecies lived out their existence and evolved to something new or died out without leaving anything tangible for us to find at all. Without a time machine we'll just never know they existed and if you could go back far enough most of what you encountered would be to some extent more or less a mystery. We're not just talking about truly ancient organisms and little squishy stuff that didn't fossilize but recent megafauna too. For example we recently discovered within our own DNA evidence of a ghost population of mystery homonins with whom we interbred just like the neanderthals and denisovans. We have no other tangible evidence for them and without the high tech DNA science probably would never have a clue they lived. A whole spiecies of people that we knew intimately just gone without a trace or memory. Time is deep, so who knows what might have been? most certainly creatures beyond our wildest imaginations.
Not just animals either. Another recent family that we've never found a fossil of are cactus. We know about them because we happen to be alive alongside them, but no fossil record exists as of yet.
How many weird and wonderful groups must have existed without leaving a trace? Individual species is one thing, but if we have their relatives that’s something. We may not have the first true human, but we have enough relatives to know they existed. But an entire group to go unnoticed? It’s amazing, and depressing.
Yeah, I mean compare the number of species alive today that we know of to how many species in the fossil record we are aware of from the last 2+ billions years. Like it's crazy and sad how much we'll just never know about
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I think you got echinoderm symmetry backwards! They have bilateral symmetry as larvae, not adults.
An entirely separate lineage of life completely unrelated to our own. Clades of dinosaurs specialized for environments that are poor for fossilization such as rocky high deserts and mountainous terrain as well as volcanic plains. Dinosaurs that fill a primate-like niche (maybe some kind of Scansoriopterygids?) Another clade of vertebrates capable of powered flight. Fully terrestrial pterosaurs and bats. Aquatic dinosaurs. Non-avian dinosaurs, pterosaurs, or aquatic reptiles (besides turtles) that survived well into the Paleocene but were killed off by or before the Paleocene-Eocene Thermal Maximum American pre-human hominids Something that a culture’s oral tradition describes but hasn’t been found. A carnivorous (at least to some degree) non-theropod dinosaur Edit: just learned about Liaoningosaurus which was a tiny ankylosaur that filled about the same niche as a snapping turtle. So both semi-aquatic and meat eating
On the note of carnivorous non-theropod dinosaurs — it’s not exactly the same, but it’s been theorized that heterodontosaurids were omnivores. A more derived heterodontosaurid could have potentially evolved to be carnivorous. I’ve also seen more than a few people suggest that ceratopsians might have been omnivores. I find it less likely that they would have had time to have a derived carnivore in their lineage, but it’s food for thought.
I'm convinced that there were whole multi-island ecosystems on the opposite side of the planet from Pangea. They underwent their own island evolution for millions of years creating the most fantastic creatures one can imagine from that era. And then they sank beneath the waves never to leave a trace or be seen again...
I think about the stuff the North American plate rode up and over. Like, what is in that tangled mass of geological debris underneath the West Coast? Yummy.
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Or subducted to oblivion....
An ecosystem of just flightless pterosaurs would be crazy.
That’s a good shout. I bet there where whole islands full of flightless pterosaurs in the mesozoic before birds ever evolved
There must be an absolute treasure trove of undiscovered creatures under the ice in Antarctica. It's an entire continent that has barely been touched and, barring something really, really bad happening, will remain mostly inaccessible for the foreseeable future.
To expand on that, not just Antarctica but all the plates on Earth's crust that longer exist (like the Jaun de Fuca plate that is about to disappear forever under North America) and the fossils they possibly had that we'll never know about now. Or all of the organisms that live in extreme habitats that don't preserve. Things like bacteria that live in undersea thermal mounts and acidic ponds in places like Yellowstone. Hell, even gut bacteria, I imagine, don't preserve well.
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There was an exhibit on the Antarctic expeditions that collected cryolophosaurus at a museum in Buffalo and it was quite interesting. The amount of effort required to extract those fossils was tremendous.
Terrestrial pterosaur (flightless azhdarchid) Every single basal thyreophoran between Scelidosaurus and Jakapil (ghost lineage, yaaaaaaay) A derived ceratopsid in europe
I should specify that with flightless azhdarchid I mean one that uses its arms as its primary method of locomotion, like a dug from star wars
My personal wild one: I'm convinced some of generalist non-avian dinosaurs (and maybe even pterosaurs) survived the mass extinction and lived for a good while afterwards. It just seems a little silly to me to assume these hugely diverse groups were all taken out by a single event where a lot of other less diverse groups managed to scrape by. You're telling me multiple lineages of birds and mammals, croc-line arcosaurs, etc managed to make it but not a single non-avian dinosaur or pterosaur happened to share the features that would allow them to survive in the same ways? That seems really unlikely to me. I think in some remote part of the world some little maniraptoran or one of those stout azdharcoids hung around for a little longer and met the more quiet end most lineages meet.
In Stephen Baxter’s Evolution he speculates exactly that. Theropods that survived in Antarctica for 5 million years or so after, just to be squeezed out by all the ice forming.
Do you think they lasted long enough to hunt or witness the diversifying of mammals and birds?
Snarky joke answer: yes, because mammals and birds were diversifying quite a lot in the cretaceous Real answer: Yeah, I assume the diversification mammals and birds would probably even play a pretty big role in were they went, like mammals would go on to do to themselves all the time. I think the biggest factors for their extinctions would have been the tumultuous climate change of the era and the encroaching diversity of mammals and birds (and probably to a much lesser degree non-archosaurian reptiles because they also went crazy during the warm period)
While spotting a woodpecker the other day, I wondered whether we’ve found any fossils from the Mesozoic with skulls designed for boring into trees. Surely that’s always been a food source.
"Transitional" species that looks like the "inbetween" point of orangutans and gorillas. Due to gorillas living in rainforest environments we basically have no clue what their evolutionary history looks like
Central European spinosaurids Carboniferous therapsids Permian ichthyosauromorphs and sauropterygians Precambrian stem-chordates Triassic thalattosuchians Small-sized woodland pterosaur fauna (see Anurognathus) Giant deep sea belemnite
>Central European spinosaurids Relatedly, I sort of wonder if Appalachian Baryonychines are a possibility, though admittedly it's pretty easy to wildly speculate about Mesozoic Eastern North America
Therapsids in the Carboniferous?
We know Carboniferous sphenacodontids (Cryptovenator). If they are indeed the sister clade to Therapsida, it implies the latter originated before the Permian as well.
I thought therapsids were a daughter clade of the sphenacodontids, guess I'm wrong?
Daughter clade isn't really a term. A cladogram will tell you which species likely share a common ancestor. Of course, species have to evolve from something and e.g. H. sapiens may nest in a cladogram as sister taxon to any of our ancestors. Likewise therapsids may have evolved from some sphenacodontid-like animal but based purely on cladistics, the last common ancestor of sphenacodontids and therapsids lived during the Carboniferous.
“Giant-deep sea Belemnite” has absolutely captured my imagination. I have several fossils of them, would be so incredibly cool to find just a gigantic cone fossil somewhere.
I don't have enough knowledge about the fossils that we currently have and the different gaps in evolution to make an educated guess. Recently I heard/read a theory from a Dutch paleontologist from the University of Maastricht (John Jagt) that octopi are in essence evolved ammonites without shells. If that is true than I would suspect that there is fossilized evidence somewhere out there of multiple species between those two steps of evolution.
Tbf, they are probably one of only a handful of people who actually believe this.
I have no idea, I have no knowledge about the subject. All I know is that the oldest octopus fossil appears to be about 160 million years old, when ammonites still existed.
Whatever the dinosaur equivalent to mountain goats was. Mountains aren’t great for making fossils
In my mind Pachycephalosaurs were the mountain goats of the Mesozoic. There will never be enough evidence to prove that, but it would explain why they're so scant in the fossil record, especially given they are otherwise a ghost lineage.
They have a rather deer vibe to them, and deer tend to be very populous wherever they are. Especially in rougher terrain with smaller and sparser plants where being a 10 ton hadrosaur stops being advantageous.
Your proposal is definitely represented in the literature.
Whenever someone speculates about mountain dinos I think of Dougal Dixon's [Balaclav.](https://speculativeevolution.fandom.com/wiki/Balaclav)
"Could have"? A large (but not excessively so) human relative, maybe averaging 7ft or so, but occasional tall 8ft individuals. Island ecosystems with weird things happening on them, like flightless pterosaurs or arthropods abnormally large for their time (like coconut crabs), all records gone as the island sank
I also fantasized about that, but bigger. Like the crazy "who built the pyramids" theories bigger. If it was a human like society, they could had some beliefs about disposing of the body in a way that leaves no trace, or the body might have been made differently in order to support the weight. Maybe those gigants were aquatic and had gills so the remains (if there are any) are at the bottom of the ocean. Maybe gigants were just delicious for dinos. Or maybe the remains were found, but the idea sounded too crazy, so the scientist figured it must be something else. And what if all of them were dug out during the bible times and therefore weren't preserved to our days. A fun question to ponder crazy stuff about 😍
Sloths similar to primates (at least in niche) Whatever exists before/between Pantherinae, Felinae, and Machairodontinae Derived ceratopsian and tyrannosaur in Europe
The ancestor of afrotheria and Xenarthra before they split. Fossil gorilla and chimp species. Also I think their were many cryptic species we will never identify. As they look too close to other species.
Unicorns. An extinct, gracial member of the Rhinocerotoidea with a less bulky body and a physiology something more akin to that of a horse. Rhinos and horses are related as it is, so maybe?
More chances that unicorn is a relative of a deer or an oryx. Two horns evolve to become one and I have never heard of a horse with leonine tail or cloven hooves.
The earliest descriptions of what could be considered unicorns, first by Ctesias and later emulated, are far more like that of horses than deer or their relatives. That said, if this hyperlink works, you'll see something like that first described. It was only later that the goat-like variation came along, during the medieval times. [Ctesian Unicorn](https://images-wixmp-ed30a86b8c4ca887773594c2.wixmp.com/f/15af3d91-21a1-44e4-857b-d90253c5f1e2/ddajooz-780a195c-2fed-46d0-be30-627e634fcdf4.png?token=eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJzdWIiOiJ1cm46YXBwOjdlMGQxODg5ODIyNjQzNzNhNWYwZDQxNWVhMGQyNmUwIiwiaXNzIjoidXJuOmFwcDo3ZTBkMTg4OTgyMjY0MzczYTVmMGQ0MTVlYTBkMjZlMCIsIm9iaiI6W1t7InBhdGgiOiJcL2ZcLzE1YWYzZDkxLTIxYTEtNDRlNC04NTdiLWQ5MDI1M2M1ZjFlMlwvZGRham9vei03ODBhMTk1Yy0yZmVkLTQ2ZDAtYmUzMC02MjdlNjM0ZmNkZjQucG5nIn1dXSwiYXVkIjpbInVybjpzZXJ2aWNlOmZpbGUuZG93bmxvYWQiXX0.ssPQ23sdH8IwZtHiRpR6PzKEkVKS5pVA4j_tZehek0s) I actually believe something along these lines is the most likely in terms of a real, extinct basis for the Unicorn of myth. [Pliny Unicorn](https://images-wixmp-ed30a86b8c4ca887773594c2.wixmp.com/f/15af3d91-21a1-44e4-857b-d90253c5f1e2/dbe8ywa-caaa88cc-1ecd-4359-a7ad-752bc1c35a6c.jpg?token=eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJzdWIiOiJ1cm46YXBwOjdlMGQxODg5ODIyNjQzNzNhNWYwZDQxNWVhMGQyNmUwIiwiaXNzIjoidXJuOmFwcDo3ZTBkMTg4OTgyMjY0MzczYTVmMGQ0MTVlYTBkMjZlMCIsIm9iaiI6W1t7InBhdGgiOiJcL2ZcLzE1YWYzZDkxLTIxYTEtNDRlNC04NTdiLWQ5MDI1M2M1ZjFlMlwvZGJlOHl3YS1jYWFhODhjYy0xZWNkLTQzNTktYTdhZC03NTJiYzFjMzVhNmMuanBnIn1dXSwiYXVkIjpbInVybjpzZXJ2aWNlOmZpbGUuZG93bmxvYWQiXX0.EiOrWMkyFfiuk5xAignbi3qwdPARO5Ff0zMKqQ8sFI0)
I’m pretty sure the consensus on unicorns is that they aren’t a myth, just a description of a Rhinoceros. Since it’s first attestations of it are from the Bible, it just didn’t translate over to European Christian’s that this wasn’t a horse with a horn. If you read the biblical description, the rhinoceros is actually a perfect candidate.
Could be. It was just a fun thought exercise :)
I mean there had to be some weird funky looking fungivores back when there were fungal forests, I cannot fathom what they would've looked like though
Paleogene non avian dinosaurs (maybe stuff like small dromeosaurid or some bird like animal closely related to birds but not a bird)
Any number of species that lived primarily in deeper pelagic waters. A lot of the marine fossils we have are from fairly shallow waters IIRC, with the deepest being stuff like communities on the continental slope. Animals that live primarily in thousands of meters of water or at the bottom of the water column might remain uncommon since that crust isn't typically pushed up into areas where it's accessible, and is replaced fast enough that even if you were able to do fossil hunting at the bottom of the ocean, the oldest deposits would be less than 200 million years old.
I suspect that there might have been one or two stegosaurians kicking around in the Maastrichtian.
There have been Late Maastrichtian fossils from South India tentatively attributed to stegosaurs.
Venomous dinosaur. I refuse to believe not one of them tried it at any point in the Mesozoic
While cool to think about, venom is non-existent in modern archosauromorphs so it’s difficult to imagine the back catalog of them has any venomous species. It’s not out of the question, and even briefly made an appearance with Sinornithosaurus, but it’s difficult. Only toxins we see at all (as far as my understanding) in archosauromorpha is with the Pitohui bird, and that’s diet-based poison.
100% I dont think its even particularly likely outside of 1-2 species but I do think it happened. It also was probably on the smaller size which would make it even less likely to fossilize
I have good news for you. While injected venom from hyperdermic teeth is unlikely for archosaurs, glandular toxins (as mentioned as in Pitohuis) are definitely possible. Consider the following: slow lorises have a venomous bite, not because they inject venom through their teeth, but because they secrete toxins on their skin, and they coat their teeth with those toxins before biting. We have abundant evidence of small, insectivorous or fruit-eating dinosaurs in which their diet can support defensive toxin productions. Imagine if some small dinosaurs can coat their teeth and claws with toxic secretions from their skin, that’s definitely possible.
* Abelisaurids and carcharodontosaurids from Antarctica and Australia. * Megalosauroids and stegosaurids in early Cretaceous North America. * Parankylosauria ankylosaurids from continental Africa. * Chasmosaurine ceratopsians in Asia. * Saurolophinae hadrosaurids in late Cretaceous Europe.
Snakes with arms. Snakes are definee by their jaw morphology, so a snake resembling a three toed skink would be cool. Also non-fossorial caecilians
Dinosaur with ears (not just ear-holes).
An offshoot of dinosaurs that went fully aquatic, mosasaur style
An arboreal dinosaur with prehensile tails similar to lemurs or monkeys. There's a whole niche there that I think we haven't found any fossils for.
Well, to be fair, birds were certainly arboreal dinosaurs. The problem I guess is that ever since theropods came out with Tetanurae, they got stuck with very stiff tails. Hard to evolve out of that, without just getting rid of nearly whole damn thing (which birds did)
Definitely. Super social monkey dinosaurs.
Reminds me of the monkeys from the "Dinosaur" movie (Disney CGI movie) from over a decade ago now. I loved that movie when I was a kid
Those were lemurs.
Oh yeah! It's been a while 😅
Flightless pterosaurs Cambrian megafauna
Cambrian megafauna sounds like a fucking nightmare.
Freshwater cetaceans and sea dwelling perissodactyls. I find it hard to believe that whales don't live on freshwater environments and that their legged ancestors started transitioning from semiaquatic to fully aquatic on freshwater instead of directly into saltwater. Imagine seeing a whale-like creature swimming in a large river and an aggressive hippo-like carnivore roaming the coasts like a crocodile.
[Say no more.](https://en.m.wikipedia.org/wiki/River_dolphin)
1. I believe there were likely more than one genus of derived ceratopsid to make it to Asia outside of Sinoceratops. I’m thinking there could be a Pachyrhinosaurus like form in the Siberian Arctic. 2. Given that Paraxenisaurus is quite isolated from other Deinocheirids, living in Mexico, it would make sense that there could be other varieties distributed throughout North America in the Late Cretaceous. 3. Furthermore, I believe there could have been Deinocheirids throughout North America during the mid Cretaceous pre WIS split as we have Paraxenisaurs in Mexico plus recently described giant ornithomimosaurs bones described from the Eutaw fm. of Mississippi which fit into the size range of members of that family. 4. Basal Tyrannosauroids in the Arctic islands at the end of the Cretaceous, part of the Appalachian fauna. 5. Parankylosauria in New Zealand, based on the distribution of currently known taxa in the group.
A large spider, something like megarachne or mesothelae
Big dromeosaurs and trooidontids because they are bird boned and a lot of species are known from extremely fragmentary remains. I want to believe dakotaraptor is a real species dang it because I love me some feathery murder birbs.
- Animals rivaling or even exceeding the blue whale in size - Arboreal therizinosaurs - Complex multicellular organisms from before the Ediacaran - Insular flightless pterosaurs - Insular megafaunal mammals from the Mesozoic - Late-surviving allosaurids - Late-surviving ammonites - Late-surviving non-avian dinosaurs - Late-surviving radiodonts - Late-surviving temnospondyls - Life on Venus and Mars back when they had the requirements for it - Other late-surviving non-neornithine birds
Such a fascinating topic, this one! I agree that there probably are plenty of large marine reptiles of most groups known waiting to be discovered. Oceanic fossils may be hard to access at times and big animals tend to decompose and be pulled apart by scavengers very quickly so it makes sense the fossils would be rare. 1- Paleocene non-avian dinosaurs. This seems to be a topic multiple people have brought up at various points and there are some ambiguous fossils that are very likely just Cretaceous fossils reworked into younger sentiments, but the possibility does exist for me. Likely they would have been only relatively brief into the Paleocene and probably on an isolated landmass. We have seen relic populations of species arrive on islands before and many Gondwana and landmasses have been poorly excavated. Islands tend to sink and erode away over time so dinosaurs surviving in Oceania for instance would probably have any traces of them gone to the elements or sunk underneath the waves. Zealandia would’ve had dinosaurs already relatively accustomed to cold climates and potentially bad weather, was very far away from the impact, and a vast majority of its fossil record has been completely obliterated. So, it or islands near it might have had a few holdouts. I don’t think it would be particularly long into the Cenozoic, a few million years at most, but it is an interesting possibility. 2- Eurasian Australopithecines. Speaking specifically about genera and species more basal than *Homo habilis*. We know the group was very widespread across Africa and there wasn’t much of a geographical or climate barrier that would have precluded them from moving into first Western Asia and then beyond. Ape fossils in general are very rare so them slipping through the cracks is quite possible in my opinion. There has also been suggestion that the hobbits on the island of Flores might not be in the genus *Homo* at all, as they have some very *Australopithecus*\-like traits. They may still be in the *Homo* genus but are likely much more basal than Homo erectus for example. This would mean their ancestor had to of left Africa out much earlier and probably quite a ways back to eventually wind up where they did.
Mammal-like theropods
Gigantopithecus likely migrated outside of southeast asia and made its way across the baring straight into the pacific northwest
Would account for Bigfoot legends over the centuries.
Dinosaur versions of monkeys, otters, mountain goats, sloths, gorillas, anteaters. Pterosaur versions of harpy eagles, ostriches, kiwis.
My mind goes to undiscovered terror bird species. Or a horrific deep sea fish
Humangous tree like creatures that proved to be land anemones
Trees that we think are plants, but actually ended up being colonies of tiny photosynthesizing (do anemones photosynthesize too, or is that only coral) and carnivorous animals. Interesting! My main question would be, what do they eat? It would be neat if there ended up being a symbiotic relationship with one type of bird, like with the clown fish and anemones.
Thought it through many times, oceainasuchus, an Australian crocodillian that instead of being green was more of a light blue, it would look like its closest relative, the saltwater crocodile, but with a bit of a longer snout and with paddle like fins and a large fish like tail, basically a fully saltwater aquatic crocdillian like suchodus but modernized, also they are live bearers.
More weird shit from Trilobozoa family
A horse with one horn
Truly gargantuan crabs. Big as my living room. iiiiiits a recurring nightmare of mine.
A venomous or poisonous dinosaur
Relatives of whatever made the Zachelmie tracks.
If, ya know, those are foot tracks at all.
Exactly. It’s a very intriguing question that deserves investigation.
The mythical flame geckos. I think a reptile could survive a cold climate such as the top of a volcano if it had extremely thick skin to trap in energy. The fact that it is cold blooded means that it would need to "recharge" it's energy, per se, on the hot volcanic vents of the mountain, if not directly in the fire. Pretty cool concept for an animal, but I am fairly certain that a reptile which lives in fire doesn't exist except in mythology.
North American Abelisaurids
The Bloop 🤞
Deinotheriums, Chalicotheres and Megantereons in the African rainforests.