The most powerful and fearsome predatory reptile of all time

[theropod]

At mere 20t they would not approach the sperm whale in size, however if their body shape was somewhat deeper than a Shastasaurus or Cymbospondylus, more like the Shonisaurus reconstruction from Berkeley, it is plausible at such a lenght they would indeed approach the sperm whale (as stated in the paper) or Livyatan and Carcharocles for that matter.

[coherentsheaf]

Jun 22, 2013 15:16:21 GMT 5 theropod said:

For now it seems:
Kronosaurus, P. funkei/kevani/grandis=10-11m | following the description paper 10-13m for the first two
Megalneusaurus: 11-12m
P. macromerus=12-13m | originally 15-18m (proportionally smaller skull)
NHM symphysis= probably 10-13,5m
Peterborough vertebra(?)= 13-15m (unsure whether it is really pliosaurian, originally 15-18m based on now-downssized Harvard mount)
MoA= 11-16m(?extremely unsure and we need to have better understanding of all the remain's size first)

I would rather suspect Megalneusaurus to be about 10m long.

Peterbrough vertebra is likely a Cetiosaur (If two interpretations are possible, one being that it is a rather typical vertebra of a Cetiosaur and the other that it is a pliosaur outside the established size range, the first possiility is more parsimonious).

MoA is probably not 16m long. McHenry gives a best estimate of about 12m and around 15 tonnes based on the size of the pectoral vertebrae, making it the largest pliosaur where size can be reliably estimated from unrestored remains.

Regarding giant teeth, do you have any info on them? I think I can dig up comparative data on pliosaur tooth size.

[Grey]

Can you give me a good example were this was the case?

Orca/white shark.
Mosasaurs/Ginsu.

There were ecological battles between groups of predators, of course strength wasn't the only factor but it was part too.

I suppose you haven't read Darwin, 1859

I guess McHenry did...
Please, improve your posts with some space, that's suffocating to read you sometimes.

This is not speculation on some potential size. It is somewhat speculative, yes, but is is not supported either that all but one marine apex predator were below 20t. It was different before Livyatan was described, and I think McHenry wasn't aware of Himalayasaurus or the Liassic giant ichthyosaurs either.

Liyatan is specific just like megalodon because of its particular era and marine ecological situation.
Nothing says that Himalaysaurus are strictly well above the 20 tons marks, we don't know at now. But like I said in my post earlier, it is possible that they may have exceeded it, at least a bit. The main thing is that through all the evolutionnary history marine predators above 10 tons are rare, and those that we know to have exceeded 20 tons are as we know only two (the Miocene critters) and were related to their specific era and their coevolution with whales. This does not mean it could have occured elsewhere but we have no direct indication of it at now.
But I can live if you want to believe so. This does not change these actual observations of evolutionnary history of oceanic apex carnivores. Especially when keeping in mind that all the giants (including my "beloved" megalodon) are downsized or likely to be downsized with time.

[coherentsheaf]

Jun 22, 2013 16:39:07 GMT 5 theropod said:

I suppose you haven't read Darwin, 1859

Who has?
Modern evolutoinary synthesis is much deeper than Darwin's work ever was.

[Grey]

A good complement to this, McHenry did this in 2002, which will be further explained in his 2009 thesis.

dml.cmnh.org/2002Jun/msg00105.html

[theropod]

Jun 22, 2013 16:48:40 GMT 5 coherentsheaf said:

Jun 22, 2013 15:16:21 GMT 5 theropod said:

For now it seems:
Kronosaurus, P. funkei/kevani/grandis=10-11m | following the description paper 10-13m for the first two
Megalneusaurus: 11-12m
P. macromerus=12-13m | originally 15-18m (proportionally smaller skull)
NHM symphysis= probably 10-13,5m
Peterborough vertebra(?)= 13-15m (unsure whether it is really pliosaurian, originally 15-18m based on now-downssized Harvard mount)
MoA= 11-16m(?extremely unsure and we need to have better understanding of all the remain's size first)

I would rather suspect Megalneusaurus to be about 10m long.

Peterbrough vertebra is likely a Cetiosaur (If two interpretations are possible, one being that it is a rather typical vertebra of a Cetiosaur and the other that it is a pliosaur outside the established size range, the first possiility is more parsimonious).

MoA is probably not 16m long. McHenry gives a best estimate of about 12m and around 15 tonnes based on the size of the pectoral vertebrae, making it the largest pliosaur where size can be reliably estimated from unrestored remains.

Regarding giant teeth, do you have any info on them? I think I can dig up comparative data on pliosaur tooth size.

I noted the incertainities in those cases, and did not imply these were the most likely. On the peterborough vertebra, it would be interesting to see a picture of it somewhere, any clue where to find one?
I remember we discussed a 45cm tooth on carnivora, tough I'm unsuser were the size originally came from. the lenght jsut based on isometric scaling based on the minimum estimate of 10m cited for P. grandis (33cm tooth)

[Grey]

Regarding giant teeth, do you have any info on them? I think I can dig up comparative data on pliosaur tooth size.I noted the incertainities in those cases, and did not imply these were the most likely. On the peterborough vertebra, it would be interesting to see a picture of it somewhere, any clue where to find one?
I remember we discussed a 45cm tooth on carnivora, tough I'm unsuser were the size originally came from. the lenght jsut based on isometric scaling based on the minimum estimate of 10m cited for P. grandis (33cm tooth)

The 45 cm teeth are referred on plesiosaur.com.

[theropod]

Orca/white shark.
Mosasaurs/Ginsu.

There were ecological battles between groups of predators, of course strength wasn't the only factor but it was part too.

Orcas and white sharks don't have the same niche, merely overlapping ones, are totally different int erms of size and both extant.

There is no sufficient evidence suggesting Mosasaurs repressed sharks because they were more powerful.

Strenght is a factor, but only one in many and usually not that important.

I guess McHenry did...

But I am replying to your arguments. If you say you don't understand what I mean, please read it more carefully!

Liyatan is specific just like megalodon because of its particular era and marine ecological situation.

And you think for some reason all other marine ecosystems in the history of the planet are likely to have less prey?

Nothing says that Himalaysaurus are strictly well above the 20 tons marks, we don't know at now. But like I said in my post earlier, it is possible that they may have exceeded it, at least a bit. The main thing is that through all the evolutionnary history marine predators above 10 tons are rare, and those that we know to have exceeded 20 tons are as we know only two (the Miocene critters) and were related to their specific era and their coevolution with whales. This does not mean it could have occured elsewhere but we have no direct indication of it at now.

But a likelyhood. It is not feasible that all extinct animals were strictly restricted to the size known from fossils, even if you exclude somewhat enigmatic remains.
McHenry himself states the limits were only true for animals known of "substantially complete remains". That remains are fragmentary does not mean they cannot be considered indicative of larger sizes, they just have to be taken with a grain of salt.
In fact, I don't get the impression any major group of marine apex predators was limited to exactly 10 or 20t, and stating that as a fact would be very hapazard and no longer accurate nowadays.

[Grey]

Theropod read again McHenry please.

Prehistory evolution of predators is not a bunch of incoherent occurrences of large predators. I understand your thought but you ignore the importance of size in trophic systems.

If you want to think McHenry is wrong (another one) and that macropredators over 50 tons have been legion, do so. But just understand that I don't take you seriously in that case.

[creature386]

Jun 22, 2013 17:42:12 GMT 5 theropod said:

Orca/white shark.
Mosasaurs/Ginsu.

There were ecological battles between groups of predators, of course strength wasn't the only factor but it was part too.

Orcas and white sharks don't have the same niche, merely overlapping ones, are totally different int erms of size and both extant.

They share some prey, for example both kill beaked whales:
calhoun.nps.edu/public/bitstream/handle/10945/697/NPS-OC-08-001.pdf?sequence=1

[Grey]

Orcas and white sharks don't have the same niche, merely overlapping ones, are totally different int erms of size and both extant.

There is no sufficient evidence suggesting Mosasaurs repressed sharks because they were more powerful.

Strenght is a factor, but only one in many and usually not that important.

Orcas and white sharks share a similar niche as ocean apex predators, only orcas because of their social behavior can rely on a wider range of preys.

Still today, the apex predator in the sea is the most powerful, excluding the teuthophagous sperm whale.

Mosasaurs repressed the sharks because they evolved faster, grew bigger and were better at reproducing (Everhart, pers. comm).

The dominant apex predators outclassing the other is normally the most powerful incidentally.

But I am replying to your arguments. If you say you don't understand what I mean, please read it more carefully!

Please, make your texts more spaced and easier to read, we're not born english-speakers both...

And you think for some reason all other marine ecosystems in the history of the planet are likely to have less prey?

Less large, less related to. Livyatan and megatooth evolved that big for this.

But a likelyhood. It is not feasible that all extinct animals were strictly restricted to the size known from fossils, even if you exclude somewhat enigmatic remains.
McHenry himself states the limits were only true for animals known of "substantially complete remains". That remains are fragmentary does not mean they cannot be considered indicative of larger sizes, they just have to be taken with a grain of salt.
In fact, I don't get the impression any major group of marine apex predators was limited to exactly 10 or 20t, and stating that as a fact would be very hapazard and no longer accurate nowadays.

Fossil record is not complet but still we have a good indication of the ancients ecosystems allowing comparisons with modern ones.
Fossil records indicate that at any time, the largest predators were below 10 tons, some above 20 tons, and the very exception above 20 tons during the Miocene and evolution of baleen whales.

This does not mean we're not going to found others predators above 20 tons in others eras, but that will be still limited. And for now, we cannot establish that as a fact.

[theropod]

Jun 22, 2013 17:46:58 GMT 5 Grey said:

Theropod read again McHenry please.

Prehistory evolution of predators is not a bunch of incoherent occurrences of large predators. I understand your thought but you ignore the importance of size in trophic systems.

If you want to think McHenry is wrong (another one) and that macropredators over 50 tons have been legion, do so. But just understand that I don't take you seriously in that case.

You never take me seriously or even try to properly understand what I write as soon as it doesn't seem to please you. You seem to believe everything not strictly in agreement with your ideas is a completely ridiculous idea. Of course feel free to read my posts again and correct yours, then I will delete the quote.

Exactly, predator evolution, just like evolutionary ecology, follows some patterns. Therefore it is unlikely that in one time there were predators 2-3 times larger than in any other time, just because there were some baleen whales swimming around. Concrete evidence for such large predators or not. You can of course easily deny everything

coherentsheaf: This is the original information from carnivora:

Grey said:

Richard Forrest talked about this, unfortunately in a part of his website which doesn't work anymore (the Questions and Answers). He reported 45 cm isolated teeth, to be compared with the teeth reaching 20 cm for Liopleurodon ferox...

We'll really have to get a better info.

creature386: Yes, that's were they overlap. Up to now, neither has repressed the other tough. Orcas are the top predators in the oceans today, they even prey on great whites in some cases. Clearly those two are not animals with the exact same niche, and if they were, it wouldn't be mere power determining which animal survives.

[creature386]

But when they overlap, that is still some competition. Orcas of course have a wider range of prey (large whales), but they still share quite a lot of prey with great whites (fish, seals, beaked whales).

[Grey]

Jun 22, 2013 18:02:46 GMT 5 theropod said:

Jun 22, 2013 17:46:58 GMT 5 Grey said:

Theropod read again McHenry please.

Prehistory evolution of predators is not a bunch of incoherent occurrences of large predators. I understand your thought but you ignore the importance of size in trophic systems.

If you want to think McHenry is wrong (another one) and that macropredators over 50 tons have been legion, do so. But just understand that I don't take you seriously in that case.

You never take me seriously or even try to properly understand what I write as soon as it doesn't seem to please you. You seem to believe everything not strictly in agreement with your ideas is a completely ridiculous idea. Of course feel free to read my posts again and correct yours, then I will delete the quote.

Exactly, predator evolution, just like evolutionary ecology, follows some patterns. Therefore it is unlikely that in one time there were predators 2-3 times larger than in any other time, just because there were some baleen whales swimming around. Concrete evidence for such large predators or not. You can of course easily deny everything

:

Once you come in the realm of optimism or overenthusiasm and challenge any serious work done, I don't take seriously anymore it's true.
But in others contexts, I recognize your knowledge often surpassing mine. In terms of theropods I tend to contribute but not challenge most of your informations.


Nothing indicates a tremendeous size linked to the tremendeous size of prey evolution during the Mesozoic. McHenry searched that possibility for pliosaurs as analogous of megalodon (and incidentally Livyatan) and found it to be unlikely. You should read it again before arguing.

Another quote of him :

These two reasons may then explain why killer whales are the largest apex predators alive today, and why the fossil record strongly suggests that apex predators didnÂ’t get above 10 tonnes in weight. Firstly, most ocean habitats are not productive enough to support big apex predators. Secondly, those habitats that are productive enough to support large predators are coastal, and the nature of the physical environment means that any predator larger than a killer whale is not going to be agile enough to hunt effectively in a coastal environment.

[theropod]

Orcas and white sharks share a similar niche as ocean apex predators, only orcas because of their social behavior can rely on a wider range of preys.

And do you see either winning the evolutionary battle at the moment? I don't. What has at one time been suggested is that the typically smaller carcharhiniform sharks are possibly repressing the lamniforms...

Orcas and white sharks share a similar niche as ocean apex predators, only orcas because of their social behavior can rely on a wider range of preys.

Yes, exactly. Let's get back to the original question, did Pliosaurs repress Ichthyosaurs because they were more powerful?
Not necessarily. Again, if one group going extinct (temnodontosauridae) and another one taking over its niche (pliosaurs) would always mean the latter was simply more powerful, there would be quite some paradoxa.

Mosasaurs repressed the sharks because they evolved faster, grew bigger and were better at reproducing (Everhart, pers. comm).

We are not talking about one group growing bigger obviously.

The dominant apex predators outclassing the other is normally the most powerful incidentally.

But the apex predator surviving is an entirely different question. Today, orcas outclass Carcharodon, because they are two to three times bigger. That's logical, but it doesn't mean Carcharodon isn't still a large, macrophagous predator. If on the other hand two similar-sized animals compete for the same food source, it is not how formidable they are that decides which one wins, it is how efficient they function as predators.

Please, make your texts more spaced and easier to read, we're not born english-speakers both...

You mean insert a free line after every line of text?

Less large, less related to. Livyatan and megatooth evolved that big for this.

What do you mean by "less related to"?

There were analogous planktonivorous or parvipiscivorous animals in other times. There is no reason to suspect one time greatly outclassed another time in terms of prey abundance.

Fossil record is not complet but still we have a good indication of the ancients ecosystems allowing comparisons with modern ones.
Fossil records indicate that at any time, the largest predators were below 10 tons, some above 20 tons, and the very exception above 20 tons during the Miocene and evolution of baleen whales.

This does not mean we're not going to found others predators above 20 tons in others eras, but that will be still limited. And for now, we cannot establish that as a fact.

I was never talking about establishing something as a fact. Merely that it is unlikely that in all but one geological time periods predator size was limited to 20t or less. This is simply a size not commonly exceeded by any predator, and if, from most periods we have no well-preserved, often undiagnostic (eg. peterborough vertebra) remains, or the animals are at least not well studied (eg. temnodontosauridae? sp.).