Post by Grey on Jan 14, 2015 9:59:42 GMT 5
Famous question.
Few species have been variously considered as the largest predator that ever lived, some more than others and I'm not sure yet if there is any consensus about that, most likely because all scientists are not experts on all animals groups.
I'm going to list here the contenders with what we actually know or strongly suggest about their size and body mass. Give your opinion about which creature was the biggest of the meat-eaters and most likely the most virtually invincible one in the sea (against any other individual opponent).
Physeter macrocephalus :
A paper published yesterday ( peerj.com/articles/715/ ) reports that the largest confirmed individual was a male about 24 m, caught in 1933. Eigth others individuals in their data sample are between 21 and 23 m. If that is true my guess estimate is that a 24 m Physeter should weigh at the least 100 tonnes and likely more.
However 95 % of the sperm whales reported are apparently under 15 m. So can we consider these giants still representative of the normal maximum size of the species ?
Carcharocles megalodon :
Pimiento is the scientists working mainly on meg these times. Her next paper with Balk is not yet published but so far the maximum size she reports for meg is about 18 m. As she follows Gottfried eight regression, a weight of 70 metric tons can be expected for a 18 m meg based on this. Others scientists suggest or indicate sizes up to 20-21 m possible or likely. At 20 m, uper range considered plausible by Gottfried, a body mass of 100 tonnes is expected. Like for any fossils, we can always guess the largest megalodons remains have not been found and that even the largest teeth found are not necessarilly representative of the largest individuals ever.
Livyatan melvillei :
The holotype is estimated in the range of 13.5-17.5 m. As it's only a holotype, larger individuals are of course expected though the possibility this particular individual was in the upper side still exists. However, isolated larger teeth can (maybe) suggest larger individuals. Several teeth from Chile are reported up to 40 cm and 12-15 cm in diameter. The question is still, do these teeth can suggest larger individuals and if yes, larger than which size for the holotype ? Another point is that Livyatan is often compared in size to Physeter (but with bigger teeth). It's rather unscientific but if we acknowledge Physeter at 24 m, can we reastically guess that the largest Livyatan individuals could have reach as well such sizes or this vast potential size range would be only exclusive to Physeter ?
Pliosaurs :
Yes, the largest well studied pliosaurs are all in the 10-13 m range. McHenry's thesis concluded that no pliosaur above 13 m is a serious claim. However, the possibility remains that McHenry wasn't aware of all the various isolated large pieces or that his thesis is somewhat outdated on some aspects.
Martill recently said me in mail :
If you go to the NHM in London you will find some undescribed specimens that are portions of Liopelurodon jaws with teeth. Some of these are massive. You may be able to derive some tooth measurements form these. One tooth in the NHM from Peterborough collected by Alfred Leeds in the late 19th C is certainly big enough to be from an animal of ~20 m.
Most estimates based on scaling form near complete skeletons suggest a size of 18 to 20 m with 20m being the upper end. However, the data set for determining these sizes is a very small one, and it is fragmentary material. There is room for error. Also, the chances of us haveing found the largest examples is very slim indeed.
The problem is about the size of these teeth and if Martill isn't a bit optimistic regarding pliosaurs proportions.
Another indication I had from Leslie Noé is that the ratio skull/body size for Jurassic pliosaurs is more about 1/6 than 1/4-1/5 for the Cretaceous pliosaurs which would make the Cumnor mandible (if correct in its size) belonging to a 17 m+ pliosaur.
Again, this is assuming that isometric scaling is good enough.
Another point is about the Monster of Aramberri :
- was it or not a subadult ?
- do the massive bite mark really indicated a 300 mm crown length like suggested by the authors ? is there any tooth known that could fit such a size ?
So, what your educated best opinion about this ? I'd appreciate objective insights, I assume the members of the forum are very mature now from this viewpoint.
Few species have been variously considered as the largest predator that ever lived, some more than others and I'm not sure yet if there is any consensus about that, most likely because all scientists are not experts on all animals groups.
I'm going to list here the contenders with what we actually know or strongly suggest about their size and body mass. Give your opinion about which creature was the biggest of the meat-eaters and most likely the most virtually invincible one in the sea (against any other individual opponent).
Physeter macrocephalus :
A paper published yesterday ( peerj.com/articles/715/ ) reports that the largest confirmed individual was a male about 24 m, caught in 1933. Eigth others individuals in their data sample are between 21 and 23 m. If that is true my guess estimate is that a 24 m Physeter should weigh at the least 100 tonnes and likely more.
However 95 % of the sperm whales reported are apparently under 15 m. So can we consider these giants still representative of the normal maximum size of the species ?
Carcharocles megalodon :
Pimiento is the scientists working mainly on meg these times. Her next paper with Balk is not yet published but so far the maximum size she reports for meg is about 18 m. As she follows Gottfried eight regression, a weight of 70 metric tons can be expected for a 18 m meg based on this. Others scientists suggest or indicate sizes up to 20-21 m possible or likely. At 20 m, uper range considered plausible by Gottfried, a body mass of 100 tonnes is expected. Like for any fossils, we can always guess the largest megalodons remains have not been found and that even the largest teeth found are not necessarilly representative of the largest individuals ever.
Livyatan melvillei :
The holotype is estimated in the range of 13.5-17.5 m. As it's only a holotype, larger individuals are of course expected though the possibility this particular individual was in the upper side still exists. However, isolated larger teeth can (maybe) suggest larger individuals. Several teeth from Chile are reported up to 40 cm and 12-15 cm in diameter. The question is still, do these teeth can suggest larger individuals and if yes, larger than which size for the holotype ? Another point is that Livyatan is often compared in size to Physeter (but with bigger teeth). It's rather unscientific but if we acknowledge Physeter at 24 m, can we reastically guess that the largest Livyatan individuals could have reach as well such sizes or this vast potential size range would be only exclusive to Physeter ?
Pliosaurs :
Yes, the largest well studied pliosaurs are all in the 10-13 m range. McHenry's thesis concluded that no pliosaur above 13 m is a serious claim. However, the possibility remains that McHenry wasn't aware of all the various isolated large pieces or that his thesis is somewhat outdated on some aspects.
Martill recently said me in mail :
If you go to the NHM in London you will find some undescribed specimens that are portions of Liopelurodon jaws with teeth. Some of these are massive. You may be able to derive some tooth measurements form these. One tooth in the NHM from Peterborough collected by Alfred Leeds in the late 19th C is certainly big enough to be from an animal of ~20 m.
Most estimates based on scaling form near complete skeletons suggest a size of 18 to 20 m with 20m being the upper end. However, the data set for determining these sizes is a very small one, and it is fragmentary material. There is room for error. Also, the chances of us haveing found the largest examples is very slim indeed.
The problem is about the size of these teeth and if Martill isn't a bit optimistic regarding pliosaurs proportions.
Another indication I had from Leslie Noé is that the ratio skull/body size for Jurassic pliosaurs is more about 1/6 than 1/4-1/5 for the Cretaceous pliosaurs which would make the Cumnor mandible (if correct in its size) belonging to a 17 m+ pliosaur.
Again, this is assuming that isometric scaling is good enough.
Another point is about the Monster of Aramberri :
- was it or not a subadult ?
- do the massive bite mark really indicated a 300 mm crown length like suggested by the authors ? is there any tooth known that could fit such a size ?
So, what your educated best opinion about this ? I'd appreciate objective insights, I assume the members of the forum are very mature now from this viewpoint.
