The Prehistoric Croc Thread- Anything crocodilian related

Adam Khor · 07-05-2012 1:01am #1

Its name is Crocodylus thorbjarnarsoni, and it is, according to its describers, the largest true crocodile ever found, at 8.2 meters long. Its skull was so heavy that it took four men to lift it.

This croc lived during the Pliocene and Pleistocene in Kenya along with our hominin ancestors and it probably dined on them- and any other thing it could catch. Appearance-wise, it was basically a larger version of today's Nile croc. It was closely related to the also huge C. anthropophagus from Olduvai Gorge.

http://zeenews.india.com/news/eco-news/largest-known-crocodile-could-swallow-a-human_773404.html

Galvasean · 09-05-2012 2:48pm

National Geographic's headline of 'Biggest Crocodile Found' made me think we were getting another 40+ footer

http://news.nationalgeographic.com/news/2012/05/120508-biggest-crocodile-early-humans-science-animals/

Adam Khor · 09-05-2012 7:45pm

Galvasean wrote: »

National Geographic's headline of 'Biggest Crocodile Found' made me think we were getting another 40+ footer
http://news.nationalgeographic.com/news/2012/05/120508-biggest-crocodile-early-humans-science-animals/

It's a very interesting discovery, tho. Now it seems that the modern day Nile crocodile didn´t appear until after these big guys (C.thorbjarnarsoni and C. anthropophagus) dissappeared... plus the fact that the Nile crocodile seems to be more closely related to American crocodiles than to any of those ancient giants (or to modern day sacred crocodiles Crocodylus suchus which was actually believed to be the same as the Nile croc!) seems to indicate that Nile crocodile ancestors swam from the New World to Africa and took over the niche left vacant by the native giants!

Galvasean · 09-05-2012 9:24pm

Not so sure about intercontinental swimming migration en-mass. I'd say more likely their ancestor already lived there (albeit in smaller form).

Adam Khor · 14-05-2012 12:11am

Not a new creature, but a study confirming that the awesome Dakosaurus, a marine "crocodile" that looked rather like a cross between a theropod and a shark, was perfectly adapted to hunt and eat large sea reptiles- perhaps larger than itself.
The study shows that the teeth of Dakosaurus would interlock when it closed its jaws, and this would cause a shearing effect, allowing the "croc" to slice large chunks of flesh from a carcass (or live prey?) more like a great white shark than a crocodile.

http://onlinelibrary.wiley.com/doi/10.1002/ar.22491/abstract

Galvasean · 26-05-2012 11:18pm

I still think Dakosaurus is a theropod dinosaur that evolved to live in the sea...

Adam Khor · 06-08-2012 5:12am

Believed to have been 8-12 meters long or so, the creature belongs to already known genus Pallimnarchus, but was much bigger than any previous specimen found. It may represent a new species.

http://www.heraldsun.com.au/news/national/croc-and-awe-over-dino-mite-fossil/story-fndo45r1-1226442903133

Rubecula · 06-08-2012 6:52pm

There have been so many mega crocs in the past it makes me wonder when the next one will evolve.

Adam Khor · 07-08-2012 12:01am

Im pretty sure we would have some super crocs today if they were left alone and allowed to grow to their maximum size

Kess73 · 07-08-2012 2:14pm

Adam Khor wrote: »

Im pretty sure we would have some super crocs today if they were left alone and allowed to grow to their maximum size

Yep Salties have shown over the past 30 or so years that their average sizes, in areas were they are left be, increase to a sizeable degree. Even the maximum accepted size of Salties has increased in the last decade or so as larger live specimens to what were found in the past appear.

If we look again at the last few decades, the largest maximum size that I just mentioned has actually increased by between a half metre to a full metre with the 7m range now being seen the maximum size much as the 6m range was in the past. Who is to say that with another few decades of unhindered habitats that the 8m range may not replace the 7m one.

Galvasean · 09-08-2012 12:27am

Pleistocene eh? Reasonable chance it may have munched a few people so.

Galvasean · 09-08-2012 10:31pm

Rubecula wrote: »

There have been so many mega crocs in the past it makes me wonder when the next one will evolve.

I'd say it will be quite some time (if at all) before we get another crocodilian that gets to the 10meter+ cut off point usually associated with 'super crocs'. A population of super crocs needs a surplus of very large prey. Generally for the prey items to grow so large en-mass there would need to be more 'room for expansion', ie: larger consistent habitats for them to live in. Currently most habitats are getting smaller due to manmade interference, limiting the opportunity for much land based or semi-aquatic gigantism.

Adam Khor · 09-08-2012 10:33pm

Galvasean wrote: »

I'd say it will be quite some time (if at all) before we get another crocodilian that gets to the 10meter+ cut off point usually associated with 'super crocs'. A population of super crocs needs a surplus of very large prey. Generally for the prey items to grow so large en-mass there would need to be more 'room for expansion', ie: larger consistent habitats for them to live in. Currently most habitats are getting smaller due to manmade interference, limiting the opportunity for much land based or semi-aquatic gigantism.

Unless some saltwater tolerant crocodiles moved to the sea and became true marine animals

Ok no

Rubecula · 10-08-2012 11:09pm

Adam Khor wrote: »

Unless some saltwater tolerant crocodiles moved to the sea and became true marine animals

Ok no

Cue a megalodon sized croc?

It could happen that crocs become more marine orientated but that would take a huge amount of time by our reckoning. (A mere blip to geological time of course) I would think that either a big stable river system or a vast lake/inland sea with mega fauna living around the boundaries.

Galvasean · 11-08-2012 1:24pm

Hey, it nearly worked for the spinosaurids...
That said though, every time the crocs attempted to become purely aquatic down through the years their success was somewhat limited.

Adam Khor · 11-08-2012 10:12pm

Galvasean wrote: »

Hey, it nearly worked for the spinosaurids...
That said though, every time the crocs attempted to become purely aquatic down through the years their success was somewhat limited.

I wouldn´t say sea croc success was limited... they lasted from the middle Jurassic to the Cretaceous, they were found all around the world, and the most derived ones seemingly spent their entire lives in the sea, probably giving birth to live young. As if that wasn´t enough, they gave rise to creatures as huge as Machimosaurus (11 meters or so) and as un-croc-like as Dakosaurus, basically the reptilian version of a great white shark. I'd say they were quite succesful really. :cool:

Galvasean · 12-08-2012 2:19pm

11 meters!?!? Why the heck isn't Machimosaurus more famous? I had to look it up just now!

Rubecula · 12-08-2012 3:29pm

And I had to look up the Dakosaurus :mad:

I am ashamed, a marine reptile I never knew about.

Adam Khor · 20-09-2012 8:41pm

Bigger than Dakosaurus, at about 7 meters long, but smaller than Machimosaurus, although better adapted to a marine lifestyle.

http://www.nhm.ac.uk/about-us/news/2012/september/ancient-crocodiles-ate-like-killer-whales114204.html

Creatures like this make me happy.

Galvasean · 25-09-2012 3:32pm

I guess we can ad suction feeding to the rapidly growing list of feeding techniques employed by crocodilians down through the ages.

Adam Khor · 10-02-2013 2:29am

Was found in Spain so I'm translating the good parts as usual:

Researchers from the universities of Zaragoza and Edinburghhave described another sea crocodile of the Jurassic, found in Ricla (Zaragoza), which coexisted with dinosaurs. Maledictosuchus riclaensis (Ricla's cursed crocodile) is the oldest and best preserved sea crocodile found in the Iberian peninsula.
...
The researches have noted that Maledictosuchus is known only through the specimen from Ricla, and is a practically perfect skull, excepcionally well preserved.
The specimen belongs to Metrorhynchidae, a group of sea crocodiles typical of the Jurassic which went extinct during the early Cretaceous, about 130 million years ago, having coexisted with dinosaurs.
The fossil was found in 1994 during the (...) building of the AVE railroad. This crocodile inhabited the seas 164 million years ago during the Middle Jurassic (Callovian).

The skull of Maledictosuchus is streamlined, with huge eye sockets and very small, numerous teeth. It was mostly a fish-eater, although it may have eaten cephalopods and other sea invertebrates. The research suggests that Maledictosuchus is the basalmost and oldest member of the rhacheosaurines, a group of specialized metriorhynchids, fish-eaters, very well adapted to the open sea. Therefore, the study of this last crocodile proves that metriorhynchids were more diverse than previously thought and that their adaptation to life in the open sea started during the Middle Jurassic, 10 million years before the accepted date

Well, it seems we are in a sort of golden age of sea-crocodile discoveries :O

Adam Khor · 04-03-2013 11:24pm

Two new crocodilians found in Panama appear to be transitional between gators and caimans:

http://www.livescience.com/27613-crocodilian-species-fill-fossil-gap.html

Capt'n Midnight · 06-03-2013 5:38pm

could they have rafted over ?
crocs can live a long time without food

Adam Khor · 07-03-2013 12:32am

Capt'n Midnight wrote: »

could they have rafted over ?
crocs can live a long time without food

The thought did cross my mind... then again, Deinosuchus was an alligatoroid (more caiman or gator than crocodile) and it was seemingly able to live in saltwater, so maybe we shouldn´t rule out the possibility that these guys were able too...

Adam Khor · 17-10-2014 8:04pm

Possibly the largest marine crocodile known to date. And it ate dinosaurs. :pac:

http://www.dailymail.co.uk/sciencetech/article-2793913/the-ancient-crocodile-large-bus-terrifying-giant-predator-ripped-prey-shreds-160-million-years-ago.html

Rubecula · 18-10-2014 7:47pm

Just to give an idea of the size of these beasts:

The saltwater crocodile (Crocodylus porosus), also known as saltie, estuarine or Indo-Pacific crocodile, is the largest of all living reptiles, as well as the largest terrestrial and riparian predator in the world. The males of this species can reach sizes of up to 6.7 m (22 ft)[2] and weigh as much as 2,000 kg (4,400 lb)

However, an adult male saltwater crocodile is generally between 4.3 and 5.2 m (14 and 17 ft) in length and weighs 400–1,000 kg (880–2,200 lb), rarely growing larger

Adam Khor · 11-01-2016 6:15am

There's a fourth species, Machimosaurus rex; it's from the early Cretaceous of Tunisia, being the last known teleosaurid as well as the biggest known thus far:

http://www.sciencedirect.com/science/article/pii/S0195667115301178

1-s2.0-S0195667115301178-fx1.jpg

Rubecula · 12-01-2016 11:09pm

I was about to post this too lol

Adam Khor · 25-04-2016 9:35pm

http://www.sci-news.com/paleontology/miocene-crocodilian-gryposuchus-pachakamue-03803.html

Adam Khor · 26-09-2016 2:23am

http://www.sci-news.com/biology/american-alligators-lineage-04204.html

Adam Khor · 26-09-2016 3:25am

Needed 20 times as much food as the American alligator:

http://www.eartharchives.org/articles/the-powerful-bite-of-super-croc-purussaurus/

[img]http://scienceblogs.com.br/colecionadores/files/2015/03/Purussaurus_divulga o_com-aveDesprevenida.jpg[/img]

Adam Khor · 26-09-2016 3:43am

It appears that they had relatively huge heads and most of them did not exceed 7 meters long.

http://palaeo-electronica.org/content/2016/1554-teleosaurid-size-estimation

Capt'n Midnight · 29-09-2016 5:14pm

It's hard to believe that the Amazon used to flow into the Pacific, before the Andes rose up. Or that the Congo used to be a tributary, before the Atlantic opened up.

Adam Khor · 29-09-2016 8:19pm

What was that about the Congo?

Capt'n Midnight · 29-09-2016 11:36pm

Adam Khor wrote: »

What was that about the Congo?

Back in the days of Gondwanaland it used to flow into the Pacific Ocean.

Adam Khor · 04-07-2017 6:55pm

This animal has been known for a while now but only today it's been formally announced. At first it was believed it could've been a giant theropod in the same size class as Tyrannosaurus, but it turns out to be a notosuchian (a land crocodile). It would've been around 7 meters long, although its jaws and teeth are still comparable to those of T. rex.
http://www.newsweek.com/ancient-giant-crocodie-t-rex-teeth-madagascar-631590

Fathom · 07-07-2017 3:32am

Razanandrongobe. Scavenger or predator or both?

Adam Khor · 07-07-2017 3:58am

Among big animals today, all predators are occassional scavengers. The exceptions are few- cheetahs for example rarely if ever scavenge, but that may have more to do with their need to avoid larger predators (lions, hyenas) than any actual dislike for carrion. If they only fed on prey killed by themselves, all captive cheetahs would starve.
Likewise, even the most dedicated scavengers- vultures- will kill live prey if pushed by hunger and presented with an opportunity. All things considered, I'd imagine Razanandrongobe was no different from modern meat eaters.

Fathom · 07-07-2017 8:14pm

A link between crocodylomorphs and theropods?

Adam Khor · 07-07-2017 8:20pm

Convergent evolution. The crocodylomorph's answer to theropods, you could say.

Fathom · 07-07-2017 8:26pm

Adam Khor wrote: »

Convergent evolution. The crocodylomorph's answer to theropods, you could say.

These organisms evolved? Did not suffer extinction as many species of dinosaurs?

riffmongous · 07-07-2017 8:37pm

What an awful name, that will never catch on.

Adam Khor · 07-07-2017 8:41pm

Did Razanandrongobe specifically evolve into something else? That I don´t know, since no remains of potential descendants have been found, at least to my knowledge. But its Notosuchian relatives continued to exist until the late Cretaceous, and another branch of land-crocs (Sebecosuchians) even made it to the Miocene, where some forms (Barinasuchus, for example) also reached pretty large sizes.

And then after that, you had land crocs again, this time more closely related to modern crocodiles, such as the Australian Quinkana which was as large as today's saltwater crocodiles and like Razanandrongobe and Barinasuchus had serrated, blade like teeth to deal with land prey. Quinkana lasted until about 40.000 years ago, meaning it may have been seen the first humans to arrive to Australia (who knows, maybe ate a few too).

But again, convergent evolution- same basic design, three different linneages.

Fathom · 07-07-2017 9:03pm

If there had been a major dinosaur extinction event millions of years ago. One that ended many species. Razanandrongobe may have been lucky. Evolved.

Adam Khor · 07-07-2017 9:15pm

Large animals in general tend to be the first to go with major extinction events, unfortunately.

Adam Khor · 07-07-2017 9:15pm

Large animals in general tend to be the first to go with major extinction events, unfortunately.

Fathom · 10-07-2017 6:36pm

Adam Khor wrote: »

Large animals in general tend to be the first to go with major extinction events, unfortunately.

Comparatively speaking. Read (somewhere) that primates were at first advantaged by their small size. Many later evolved into larger-sized species.

Adam Khor · 10-07-2017 7:35pm

That is my point; during times of ecological crisis in which food is scarce and competition fierce, small animals (say, small primates) are more likely to survive, especially if they're not very specialized, whereas the larger animals that need a lot more food, space etc tend to go extinct. Then later the smaller ones may evolve into larger species when and if the conditions go back to being favourable, but by doing so they risk extinction the next time there's a crisis.

Fathom · 11-07-2017 3:49pm

65 million years ago. All animals with 25 kg body weights become extinct. Suggests Chandra Wickramasinghe in Where Did We Come From: Life of an Astrobiologist.

Adam Khor · 16-07-2017 7:21pm

Not really true- some animals larger than that survived, including the 2-3 meter crocodile Borealosuchus and the 4-5 meter long Thoracosaurus (a sea crocodile), as well as Champsosaurus (which actually grew bigger after the end of the Cretaceous). The crocodiles can be explained because they're capable of surviving a long time without feeding, but the seemingly warm-blooded champsosaurs are more difficult to explain.

Fathom · 17-07-2017 3:34pm

Adam Khor wrote: »

Not really true- some animals larger than that survived, including the 2-3 meter crocodile Borealosuchus and the 4-5 meter long Thoracosaurus (a sea crocodile), as well as Champsosaurus (which actually grew bigger after the end of the Cretaceous). The crocodiles can be explained because they're capable of surviving a long time without feeding

Borealosuchus and Thoracosaurus exceeded Chandra Wickramasinghe's body weight claims. Both aquatic. Champsosaurus was mostly aquatic too?

The Prehistoric Croc Thread- Anything crocodilian related

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