Sources: Extinction of South American sparassodontans (Metatheria): environmental fluctuations or complex ecological processes? South American Endemic Mammalian Predators (Order Sparassodonta) Image Sources: Velizar Simeonovski
Actually, sparassodonts IN GENERAL went extinct before placental competition could appear, not just Thylacosmilus. Thylacosmilus was the very last sparassodont (it was the only one to survive into the Pliocene), and it went extinct around 3 million years ago. The Great American Biotic Interchange had not happened at this point, so when carnivoran competitors entered South America later down the line they actually didn’t run into any sparassodonts to outcompete and displace (and few native predators period-only a few terror bird species were left, and most of those were small-bodied, Titanis being the only South American apex predator left by the time placental competitors showed up). Furthermore, South American predators in general had been in a chronic decline since the Late Miocene, losing much of their diversity even before the Pliocene. So it DIDN’t boil down to carnivorans outcompeting sparassodonts in the end. And the entire idea of placentals outcompeting metatherians is debatable, partially because this whole case study of “carnivorans outcompeting sparassodonts” never actually happened. Australia is not a good case study of placental mammals outcompeting marsupials, either: the biggest impact of placentals in Australia is actually predation by cats and foxes on small marsupials that they do not compete with, and Australian ecosystems were already heavily damaged by human activity before Europeans started bringing invasive species over, which skewed the tables in favour of invasive species (as a rule, successful invasive species are species that do well in damaged or disturbed ecosystems). Even the dingo vs. thylacine example is questionable, because it has been found that thylacines were much smaller than previously reported to be, meaning they were hunting much smaller prey than those regularly taken by dingoes, thus not resulting in serious competition. On top of that, rodents had already made it into Australia by the Pliocene and they didn’t end up outcompeting marsupials then.
You're correct, that's my bad. They just barely miss each other as save for a few species. It could be attributed to climate change or other factors then. There was also a trend of particular sparassodont groups becoming very common and then leaving the fossil records throughout the cenozoic up to their extinction long before carnivorans entered. Thank you for providing this information.
Between the decline and extinction of the three apex predator groups of south america and the American Biotic Interchange were some pretty weird animals filling the niches of the predators, for example the carnivorous armadillo Macroeuphractus
@@pyrogamerpredator1016 Yep (though at that point Thylacosmilus was still around, but the traditional SA predator lineages had still declined to the point predatory niches had opened up)
5:41 has to be the most badass looking reconstruction of thylacosmilus I’ve ever seen. Great work btw, this feels like one of the most in-depth videos on the sparassodonts.
@@gamervox1707 Funny thing is, you wouldn't be surprised I'm alive if RU-vid had the decency to show my community post to most of my subs lol...anyways, you're very welcome and thank you for the complement on Grey's Guide! 😊
@@gamervox1707 Yes, the community section. IIRC post made to the community section will almost always show up in your subscribers' sub box/feed if they've hit the bell icon.
Just wanted to say how much I appreciate this channel. I used to be super into zoology when I was younger, but I fell out of it over time. These videos have really rekindled my love for the subject. Great stuff!
There is a relatively new theory about what Smilodon (classic La Brea tar pits sabertooth cat) looked like in life concerning their canine teeth. The classic artists rendering of Smilodon has been the canines fully exposed with mouth closed. New theory that Smilodon had fleshy pad upper lip extensions that covered the saber canines. This makes more sense as the canines if exposed as shown in renditions the tooth enamel would dryout and check without moisture contact from saliva. This happens with teeth from preserved skulls. Fleshy pads would not interfere in the function of saber canines they would simply passively be exposed/retracted by the simple act of biting into a prey animal. The canines while they have penetrative strength they are fragile with lateral or torque/twisting forces. The belief is that Smilidon or other sabertooth felines/marsupials killed prey not by biting spinal cord as lions(struggling prey and hard neck vertebrae could easily break such canine teeth) do but rather severe windpipe/jugular veins. Those rhino horn handle knives from Arabia are designed the same as the saber canine and are designed to puncture the skin of throat and due to their curvature they slice/slash in one motion. Those Arabic knives are designed to cut a victims throat from ear to ear. I think that sabertooth predators ambushed their prey rather than chasing them down as their teeth were too fragile compared to lions and no need for balance thus the bob-tail. One more thought on specialized anatomy is that Smilodons top and bottom incisors exhibit exaggerated prognathism (extending out forward of canines) Their sabers would otherwise prohibit ability to take bites of meat using molars in a sideways scissor fashion.
A study by Mauricio Anton in 2022 actually disproved the theory that Smilodon's teeth were covered by lips or any sort of fleshy pad, though cats with smaller teeth like Homotherium would be able to fully hide theirs. Also Smilodon skulls have been found with puncture wounds made by other Smilodon, which proves their teeth were at least strong enough to pierce bone.
Interestingly sparassodont sabre teeth are structurally different than sabertooth cat teeth. They're meatier in cross section, and the roots go way back into the skull. The reason for their weird shaped heads is because their sabre teeth roots go all the way back to pretty much the braincase, making for a much more robust tooth.
Can't believe it took me this long to stumble across Animal Origins,but man I am glad to find you! I have been looking for something which falls in-between the corporate gloss of PBS Eons and some of the spirited by amateur looking videos on the topic and I think your going to fit the bill perfectly 🤘
Initial thoughts before watching it: So, South American Carnivorous Fauna gave up meat for Lent and just never went back, but Australia's Marsupial Lion accidentally put meat on its buffet plate, and decided to go full carnivore, developing quite a dangerous cigar cutter of a mouth to shear limbs clean off. It's like two teams traded players.
the sparassodonts are some of my favorite prehistoric alongside the phorusrhacids and sebecids. I really hope the next documentary after Prehistoric Planet takes place in Cenozoic South America.
Spotted hyenas are not exclusive scavengers. They are active, pursuit predators first and foremost. On average, they have a higher success rate in hunting relative to lions, leopards and cheetahs (only the African wild dog has a higher success rate ). Furthermore, more often than not, lions scavenge from hyena kills instead of the reverse. Anyway, just wanted to point that out. Great content otherwise.
If sparassodonts weren't marsupials, then what were they? Were born undeveloped, or fully formed? Did they had pouches or placentas? Opossums still live all over South America today occupying a variety of niches. I always that these were cousins to the borhyenadae carnivores and thylacosmilus.
ahh, glad someone covered these boys on YT, they are underrappreciated and forgotten save for thylacosmilus. Plust it will come in handy for any future projects.
Do note that they actually completely went extinct before placental competitors showed up: Thylacosmilus was the very last one and the only one to make it into the Pliocene, and even it went extinct during the Early Pliocene: the Great American Biotic Interchange only happened in the Late Pliocene. So this video is wrong.
Wow. This was really cool. I'm loving extinct mammals more and more each day. By the way, you showed some wonderful Paleo art. Could you put the names of the artists who made them, to look them up?
@@pyrogamerpredator1016 yah,know. However, it seems once large Carnivorans enter an area the gradual extinction of non-Carnivoran land predators occurs. E.g. Enteledonts, Terror Birds, and large terrestrial reptilian predators all got outcompeted by Carnivorans.
Actually, there were carnivorans that lived alongside the sparassodonts but did not outcompete them, especially carnivorans like Cynonasua, Chapalmalania, and Parahyaenodon, which were members of the family Nasuidae and closest living relatives of the genera Cynonasua, Chapalmalania, and Parahyaenodon are the coatis, olingos, olinguito, and kinkajou, Nasuidae is a very unique family of carnivorans that originated from South America, they coexisted with the sparassodonts and other mammalian predators native to South America like the armadillos of the genus Macroeuphractus, with Macroeuphractus outesi being its type species and the largest armadillo that ever lived, while the coatis, olingos, olinguito, and kinkajou are the only surviving members of the family Nasuidae, all other members such as Cynonasua, Chapalmalania, and Parahyaenodon which filled ecological niches occupied by dogs, bears, and hyenas went extinct along with the other South American mammalian predators like the sparassodonts and Macroeuphractus armadillos, the sparassodonts, Macroeuphractus armadillos, and most members of the carnivoran family Nasuidae went extinct due to direct competition with invaders such as dogs, bears, skunks, raccoons, weasels, huros, grisons, tayras, and cats, this makes sense as the carnivorans of the family Nasuidae were the first carnivorans to colonize South America, while most members of this family are extinct such as Cynonasua, Chapalmalania, and Parahyaenodon, its only surviving members are the coatis, olingos, olinguito, and kinkajou.
Would be intersting if Antarctica was more northern than its current placement and Australia became more southern and dipped near the south pole instead. I wonder what group of animals would've arose or remained to today.
Probably more marsupials, I reckon if we were to dig up the bones underneath all that ice there would be tones of marsupials ranging in shapes of sizes and shapes
I want to see 2 other videos on the other dominant predatory animals of south america the terror birds which were fast moving predatory birds and the sebecids which if you didn't know we're terrestrial apex predator crocodiles
The hyenas you used as examples in this video are not scavengers. Spotted hyenas hunt most of their food and sometimes steal kills from lions and other carnivores, as lions steal kills from spotted hyenas and other carnivores
So, they are not marsupials, but they are closely related. Do we know weather they were placental, still early birthing like marsupials, or somewhere in-between?
Why am I still hearing that thylacosmilus was a large prey specialist? This thing had sabers that weren't flattened or serrated. It didn't have big incisors to eat meat with, in stark contrast to the placental smilodon, and only had semi-retractable claws to grapple with. I personally believe in an insectivorous diet supplemented by the occasional scavenging.
*THYLACOSMILUS DID NOT FILL THE SAME NICHE AS SMILODON.* This is a common misconception that unfortunately spreads faster than it can be corrected. While it would seem that they convergently evolved because "big canines" their skull anatomies are drastically different. For starters those famous "saber teeth" on Thylacosmilus had a triangle shaped cross-section and they slightly splayed out, these were not efficient killing weapons and were more like tusks than saber teeth. Also Thylacosmilus had no upper incisors, reduced lower incisors and small blunt molars, meaning it couldn't even _eat_ a carcass once if it somehow managed to kill something. There are also lots of other little differences such as no bony symphysis connecting the two halves of the lower jaw, further weakening it and a small infraorbital opening, meaning this animal lacked the fine whiskers most predators have to sense their environment. Even Smilodon relied on its whiskers to pinpoint the exact spot to bite and drive in its famous sabers. If Thylacosmilus wasn't a carnivore, what was it? No one knows entirely for sure but the most likely to be correct hypothesis was it was an insectivore feeding on eusocial insects because it has missing incisors like Sloth Bears and reduced molars like Aardwolves. Other wild theories range from it being a "guts specialist" feeding on only the organs and soft tissues of its prey, to it being a venomous "vampire" that would inject its prey with venom that would liquify its preys innards for a liquid diet to a worm specialist that specialized in feeding on giant species of earthworm like Rhinodriles which can grow to the size of snakes. It is also entirely possible that Thylacosmilus could have filled an entirely unique niche unlike anything alive today, we really can't say until we have more evidence. Like I said my money is on an insectivorous niche.
An isotope ratio study, using stable isotopes of carbon and oxygen from the tooth enamel of several mammals from the Pampean region from the Late Miocene to Late Pleistocene, was published by Domingo et al. in 2020 and indicates that the favoured prey of Thylacosmilus were grazers, mainly notoungulates from open areas. This diet seems to coincide with the expansion of vast grasslands of C4 plants in southern South America and the increasing of aridity and lower temperatures, in the interval between 11-3 million years ago known as Edad de las Planicies Australes ("Age of the Southern Plains", in Spanish).[29]
@@chrishohl6141 wouldn't grass-feeding termites also have such isotopes? The types of termite Aardwolves primarily prey on feed exclusively on grass. Also given the long list of anatomy I just listed it doesn't add up, couldn't there be a mistake? Like I said, this thing lacks the tools to eat meat efficiently; no shearing teeth, no incisors, tusks that don't line up for a killing bite and so on.
@@reeyees50 Many species of termite feed on grass, in fact the Aardwolf only feeds on grass-eating termite species. I know the venomous interpretation is highly unlikely, I was just listing it alongside gut specialist as one of the "wild" theories. Like I said eusocial insect feeder is the most likely based on skull anatomy. It is way to similar to other insect-eating specialists and without incisors or cutting teeth of some sort this thing couldn't dream of processing a carcass.
The English pronunciation of smilodon is incorrect, as the correct pronunciation is smylodon, Actually, on second thought, you have a great difficulty in pronouncing, names in Portuguese, like tapeja, which you pronounce tapehara, Ubirajara you pronounce ubirahara, it's not that difficult Understand that Spanish and Portuguese are different languages, with different pronunciations. The video isn't about any of the aforementioned animals, but my incorrectly pronounced Smilodon detector ear ❤️
Taxonomy is just some way of clasifying stuff we see. It aint a big deal if its wrong because its just to kinda sort the stuff. Thats how I view it. Its an imperfect science that will never be perfected. Evolution and genetics are all over the place
@@Dr.IanPlect I meant that there's still taxonomic groups that are just piled together even though the advances in genetics. I wanted to get into that.
Actually marsupial an sparassadonts must have evolved on gondwanan land mass before its split up into Australia,Antarctica an south America hence Australia and south America having a higher number of marsupials the origin of marsupials is gondwana not north America
