Most dangerous extinct predators for humans ?

[theropod]

Otodus obliquus and Parotodus could be the approximate right size (to easily be able to kill and eat a human, but still have interest in it), and perhaps they were very agressive, like later members of the lineage.

[blaze]

Off topic but relevant to Redondasaurus, Heckert et al. (2003) gives measurements of the skull of the male specimen of Redondasaurus (the biggest one), it's 80cm in DCL (dorsal cranial length), but 80% of that is just the snout as its ODCL (orbito-cranial length) is just 15cm, the paper gives estimates of its mass and total length based on those measures but they recognize that those measurements, either underestimate the mass by about 50% (ODCL) or grossly overestimated it by an order of magnitude (DCL) but I think is safe to assume that the biggest Redondasaurus was around 4.5m long and ~400kg because those are the best estimates for an almost complete specimen of Pseudopalatus that has similar skull measurements (ODCL of 14cm and DCL of 88cm).


How Redondasaurus became a 12m giant I think we'll never know, it isn't even the largest know phytosaur skull, that honor goes, as far as I know, to the specimen AMNH 3060 of Smilosuchus gregorii, which is 142cm long from premaxilla to squamosals (Colbert, 1947), DCL seems to be 120cm and ODCL around 20cm (Colbert, 1947; plate. 4) so maybe not even this giant was much more than 6m long and 1 tonne.

References:
Heckert et al. 2003. Body mass estimates of phytosaurs (archosauria: parasuchidae) from the Petrified Forest Formation (Chinle Group: Revueltian) based on skull and limb bone measurements.
Colbert, E.H. 1947. Studies of the phytosaur Machaeroprosopus and Rutiodon. Bulletin of the American Museum of Natural History Vol. 88 (2).

[Grey]

Jul 19, 2013 22:48:45 GMT 5 theropod said:

Leedsichthys was pretty extreme too.

Yes but at least it as based on a published size estimate, not a loosely extrapolation of an extrapolation of an extrapolation !

[Grey]

Jul 20, 2013 1:13:30 GMT 5 Life said:

Some ancient sharks (including Megatoothed species) would have been very dangerous to humans. C. chubutensis and C. megalodon may have topped the list perhaps.

Rigorously speaking, I don't see a human being of interest of a meg ~700-900 times heavier ! Pups and juveniles would be certainly very dangerous though. The smaller Carcharocles species too, and I expect the Ginsu to have been a terribly dangerous foe for a human-sized animal.

[Runic]

After some thinking I really think the main predators of humans would have perhaps been between dromaeosaurids, Larger Birds of Prey (on juvenile humans), big cats (long history of primates having an innate fear of cats), Wolves & Hyenas etc. I really doubt the more fancy and larger predators would waste time running after a human (or swimming). It's even been said humans taste bad to predators.

[theropod]

Probably because we're too bony for many of them. But this depends on the feeding habits.

Just like with JP Velociraptor and Deinonychus, we have to keep in mind the BBC Liopleurodon was actually based on the enigmatic Peterborough vertebra (does anyone have a picture of that fossil?) and prematurely attributed to Liopleurodon. Either way it was oversized, but that's quite a difference.

[Grey]

Yes it was based on the famous vertebra but the vertebra itself didn't indicate 25 m. Naish and Martill presumed a size in at 15-18 m but Tim Haines extrapolated in that the largest individual of that kind was 25 m. Much like if they had used T. rex and hypothesized a record freak of 14-15 m. The raptors from JP on the other hand are simply large Deinonychus based on the size (in height especially) expected to them at the time. The oversizing of Liopleurodon (5-7 m) and the isolated centra (15-18 m) is much worse by comparison when they built from this a 25 m behemoth, still poisoning the general knowledge of prehistoric enthusiasts today.

[theropod]

Of course. I just meant that exagerations was within the normal boundaries, while of course if one only has a 7m Liopleurodon in mind it is not.

It is very much like 20m Peck's rex or 27m Leedsichthys

[Grey]

20 m Peck rex ? What is that joke...

Leedsichthys was at least a published estimate at one given time, though no wonder, it wasn't listed very long being that large, but the mainstream and the poorly educated enthusiasts kept in mind mostly that estimate, of course...Thanks BBC again for that. They could have used a 40 m ichthyosaur as well...

[theropod]

It was in a luckily very unpopular documentary I once saw, that seemed to mostly be a compilation of paleoworld episodes.

[Derdadort]

The first time I saw Leedsichthys was in "Sea Monsters". They did not say anything about the size, but then there were those tiny Liopleurodon and I had of course still that 25m-beast in mind. For long time I thought Leedsichthys was a kind of blue whale sized fish...

Back to topic: What about Andrewsarchus? I know, there is only a skull so far, but it probably hunted the early megaherbivorous mammals like Brontotheriids and was still small enough to chase for human sized prey.

[theropod]

In sea monsters they said 27 metres, their Liopleurodon was the 25m giant you had in mind. They also stated "...bigger than most whales..."

[Derdadort]

But not in the German version? Well, I have no idea, I havn't watched it for a long time.

[theropod]

There too, "...werden bis zu 27m lang und sind damit größer als die meisten wale...". I don't actually remember the line in the english version, but it has been some time since I watched it.

[Fragillimus335]

Since Salties are the most prolific human eaters of today, an extinct ~5-6 meter croc could still have the top spot when it comes to "munchin monkeys".