Arthur Conan Doyle's "The Lost World" may be the most famous novel
about an isolated area where dinosaurs survived their apparent
extinction, but Burroughs' Pellucidar novels, and also one of his
Tarzan novels also had surviving dinosaurs, and this idea was, I
believe, used by many other authors.

While the only creatures that survived the Cretaceous-Tertiary
extinction that were in the dinosaur family were birds, various
types of reptile still did manage to survive.

What I just learned today was that, for a short time after the
extinction, the apex predator in the new order of things was still
a reptile, one related to the crocodile.

Its name was Dentaneosuchus.

For reasons that are still not known, it eventually disappeared, and
then mammals were free to take over the apex predator position.

But now, all of a sudden, the plot of some caveman rescuing
Carole Landis or Raquel Welch from something that at least
*looks* vaguely like a dinosaur has become a _little_ more plausible.

Of course, Dentaneosuchus missed the human race by millions of
years; it thrived in the middle Eocene, and apparently completely
disappeared at the end of the Eocene. 34 million years ago may be
less than 65 million years ago, but it's still long before the first
hominids appeared.

John Savard

On 2023-05-07, Quadibloc <jsavard@ecn.ab.ca> wrote:

> While the only creatures that survived the Cretaceous-Tertiary
> extinction that were in the dinosaur family were birds, various
> types of reptile still did manage to survive.

Conversely, the K-T extinction also wiped out a number of other
charismatic reptilian clades: pterosaurs, plesiosaurs, and mosasaurs.

> What I just learned today was that, for a short time after the
> extinction, the apex predator in the new order of things was still
> a reptile, one related to the crocodile.
>
> Its name was Dentaneosuchus.

30 million years is not "a short time after".

During their long history, the crocodylomorphs have spawned a number
of remarkable forms. More or less a contemporary of Dentaneosuchus,
the smaller Boverisuchus was a long-limbed running form with
"hoof-like toes, suggesting that it lived more on land than in the
water, and that it therefore probably hunted terrestrial mammals."
(Wikipedia). It, or something like it, appeared in episode 3.01
of _Primeval_.

> But now, all of a sudden, the plot of some caveman rescuing
> Carole Landis or Raquel Welch from something that at least
> *looks* vaguely like a dinosaur has become a _little_ more plausible.

You can get a lot closer in time, even if it doesn't close the gap
completely and it's a different continent, by having her rescued
from a Titanis terror bird.

--
Christian "naddy" Weisgerber naddy@mips.inka.de

On Saturday, May 6, 2023 at 8:01:34 PM UTC-7, Quadibloc wrote:
> Arthur Conan Doyle's "The Lost World" may be the most famous novel
> about an isolated area where dinosaurs survived their apparent
> extinction, but Burroughs' Pellucidar novels, and also one of his
> Tarzan novels also had surviving dinosaurs, and this idea was, I
> believe, used by many other authors.
>
> While the only creatures that survived the Cretaceous-Tertiary
> extinction that were in the dinosaur family were birds, various
> types of reptile still did manage to survive.
>
> What I just learned today was that, for a short time after the
> extinction, the apex predator in the new order of things was still
> a reptile, one related to the crocodile.
>
> Its name was Dentaneosuchus.
>
> For reasons that are still not known, it eventually disappeared, and
> then mammals were free to take over the apex predator position.
>
> But now, all of a sudden, the plot of some caveman rescuing
> Carole Landis or Raquel Welch from something that at least
> *looks* vaguely like a dinosaur has become a _little_ more plausible.
>
> Of course, Dentaneosuchus missed the human race by millions of
> years; it thrived in the middle Eocene, and apparently completely
> disappeared at the end of the Eocene. 34 million years ago may be
> less than 65 million years ago, but it's still long before the first
> hominids appeared.
>
> John Savard

I really have a paleontology degree but hadn't heard of this. From basic Wikipedia info, I wouldn't say it stands out a lot. What was most interesting is that there is a reconstruction that seems to show it with an upright gait like Pristichampsus (I see already mentioned in this thread). If this is the case, it would indicate that it was also capable of running down prey on land, as well as a possible reclassification since the pristichampsids are currently listed in a different lineage. However, I have not yet sorted out the source of this image or what if any anatomical basis there is for it.

In the broader perspective, there are already a lot of strange crocs from the Mesozoic and Cenozoic. The weirdest for the group was Simosuchus, which was terrestrial and herbivorous. The most interesting question is whether any of the Cretaceous terror crocs lasted into the Paleocene or later, which I would consider not easily ruled out. Another thing that's important to bear in mind is that the crocodilians are still dominant predators in the ecosystems that will support them at all. If it comes to that, the saltwater croc is the biggest purely predatory tetrapod vertebrate still extant outside the whales, and would probably still hold that title with geologically recent mammalian carnivores like the cave lion and short faced bear included.. The bottom line is that the semi-aquatic ambush predator niche is too effective not to be occupied at any given time.

On Sunday, May 7, 2023 at 9:40:09 PM UTC+1, David Brown wrote:
> On Saturday, May 6, 2023 at 8:01:34 PM UTC-7, Quadibloc wrote:
> > Arthur Conan Doyle's "The Lost World" may be the most famous novel
> > about an isolated area where dinosaurs survived their apparent
> > extinction, but Burroughs' Pellucidar novels, and also one of his
> > Tarzan novels also had surviving dinosaurs, and this idea was, I
> > believe, used by many other authors.
> >
> > While the only creatures that survived the Cretaceous-Tertiary
> > extinction that were in the dinosaur family were birds, various
> > types of reptile still did manage to survive.
> >
> > What I just learned today was that, for a short time after the
> > extinction, the apex predator in the new order of things was still
> > a reptile, one related to the crocodile.
> >
> > Its name was Dentaneosuchus.
> >
> > For reasons that are still not known, it eventually disappeared, and
> > then mammals were free to take over the apex predator position.
> >
> > But now, all of a sudden, the plot of some caveman rescuing
> > Carole Landis or Raquel Welch from something that at least
> > *looks* vaguely like a dinosaur has become a _little_ more plausible.
> >
> > Of course, Dentaneosuchus missed the human race by millions of
> > years; it thrived in the middle Eocene, and apparently completely
> > disappeared at the end of the Eocene. 34 million years ago may be
> > less than 65 million years ago, but it's still long before the first
> > hominids appeared.
> >
> > John Savard
> I really have a paleontology degree but hadn't heard of this. From basic Wikipedia info, I wouldn't say it stands out a lot. What was most interesting is that there is a reconstruction that seems to show it with an upright gait like Pristichampsus (I see already mentioned in this thread). If this is the case, it would indicate that it was also capable of running down prey on land, as well as a possible reclassification since the pristichampsids are currently listed in a different lineage. However, I have not yet sorted out the source of this image or what if any anatomical basis there is for it.
>
> In the broader perspective, there are already a lot of strange crocs from the Mesozoic and Cenozoic. The weirdest for the group was Simosuchus, which was terrestrial and herbivorous. The most interesting question is whether any of the Cretaceous terror crocs lasted into the Paleocene or later, which I would consider not easily ruled out. Another thing that's important to bear in mind is that the crocodilians are still dominant predators in the ecosystems that will support them at all. If it comes to that, the saltwater croc is the biggest purely predatory tetrapod vertebrate still extant outside the whales, and would probably still hold that title with geologically recent mammalian carnivores like the cave lion and short faced bear included. The bottom line is that the semi-aquatic ambush predator niche is too effective not to be occupied at any given time.
Fortunate for me that this appears to be true only in warmer areas of the world, or some of my favourite walks by canals, streams, and the sea-side would have been taken in an entirely idfferent frame of mind.