Top Dog

[creature386]

Because I can't quite follow you, are you talking about the graph on page 24 of the "Megalodon size" thread?

[theropod]

The mean or median of the maximum sizes for each of the strata (in all likelyhood these represent adults) still isn’t unrealistically huge, and those are more likely unusually large than unusually small. Obviously there are points to criticise about the method, but in a sufficiently large sample individual errors from tooth position will tend to compensate for one another–even if there were a systematic overestimates or underestimates that’s more likely attributable to that than to some different logarithm being used.

creature386: This one:

It’s probably best to wait for the paper, if it’s due soon anyway. Nonetheless I find it hard to believe that the final results in terms of average and maximum sizes will differ vastly from these, unless the preliminary samples in were ridiculously skewed. But perhaps we are going to see larger samples and ranges for some of the periods that appear to have smaller size ranges here.

[Grey]

I suspect the max size will level off at 18 m, though I'm curious to see if there are any outliers well above this mark.

[creature386]

theropod
Yup, that's the one I meant.

Grey
I am curious, too, but I doubt it because the largest teeth are mostly the ones one thinks of first, so I guess they are already in the tentative box plot (where the maximum weight fits well to an 18 m Meg).

[Grey]

My point is that some very large posterior teeth could suggest larger sizes than some very large anterior teeth.

But I doubt it, I think the max will be established at ~18 m with this method.

[Grey]

A temporary summary of the question.

Physeter macrocephalus : maximum length about 24 m (McClain 2015) but is it representative of the "normal" max reached by the species ? Ellis for his part (2011) doubts of these figures. Maximum-sized bulls are usually listed either at 18.3 m (Trites and Pauly 1998) or 20.5 m (Whitehead, marinebio.). Physeter has the largest gullet on Earth, large enough to swallow a human being. However its status as a macro-predator is debattable; while not planktonivore, the largest of its preys, Mesonychoteuthis hamiltoni, is known to weigh up to 500 kg, only 1 % the body mass of a large bull. Plus, it appears Physeter does not use its teeth for killing and feeding.

I would personnally put it aside because of these questions. Plus, using small-game/teuthivore predators, I should include as well S. sikanniensis in the list.

Basilosaurus : B. isis : 16 m (Gingerich 1990). B. cetoides : 18 m (McCormick 2008 from Kellogg 1936). 23 m (?). Slender build.

Carcharocles megalodon : 20.2 m (?) (Gottfried 1996), 18 m (Pimiento 2013, 2014).

Livyatan melvillei : 13.5-17.5 m (Lambert 2010).

Mosasaurus hoffmanni : 17.6 m (?) (Lingham-Soliar 1999). Probably less massive than a whale or lamnid shark of the same length, upper body mass estimate at 30 tonnes (McHenry 2009).

UANL FCT-R2 'The Monster of Aramberri' : 15 m (Buchy 2003, 2006, 2007); 11.7-12.4 m (McHenry 2009); 12-14 m (Frey 2014). Debattabe juvenile/subadult/adult status.

PETMG R272, the pliosaurid Peterborough vertebra : 15-18 m (McHenry 1996), 11.6-14.1 m (McHenry 2009). Uncertain identification, could be a sauropod (or not).

OUM J.10454, 'The Cumnor Monster', 'Megapleurodon' : 18 m (Naish 2001), 12.8 m (McHenry 2009). Possibly over-reconstructed mandible leading to overestimates.

Himalaysaurus tibetensis : 15 m (Motani 1999).

Giant Temnodontosaurus platyodon : 15 m (McGowan 1996).

These ones represent those which have been usually considered as candidates for the status of largest macropredator, Mosasaurus and Basilosaurus are exception because of their more slender built but their sheer length above 15 m forced me to list them among the largest marine carnivores ever to exist.

[richard]

I'd like to see the actual source for any sperm whales over 20m, I don't buy the 24m sperm whale just yet as there's nothing to confirm it.

[Grey]

Apr 10, 2015 6:35:22 GMT 5 richard said:

I'd like to see the actual source for any sperm whales over 20m, I don't buy the 24m sperm whale just yet as there's nothing to confirm it.

The source is a recent study : peerj.com/articles/715/

But McClain reports this about the blue whales size :


However, there is some uncertainty about how the lengths were recorded in earlier years (before the 1920s), as outlined by Branch et al. (2007). The official method of measuring was from the tip of the snout to the notch between the tails, since the tails were usually cut off after being killed (to prevent currents shifting the bodies before they could be brought to the processing ships). In addition, some early measurements may have been made in Norwegian feet (0.314 m) instead of British feet (0.3048 m), and there is additional estimation error during years when blue whales were processed alongside vessels. For these reasons, early length measurements in excess of 30.5m should be treated with suspicion.


Maybe that's also the case for the sperm whales.

Even if valid, bull Physeter above 21 m only represent 0.0017% of all catched. So can we say they would represent a valid, normal maximum size ?

Plus, despite their battering-ram, I guess they're quite poorly armed compared to Carcharocles and Livyatan. Physeter is in grey zone as macropredator.

I also know that Richard Ellis doubts about such specimens in his 2011 book, but I cannot say more yet, I don't have the book.

[richard]

Yes I've read that recent paper, I want to see where they get their figures from? One of the best sources for record sized cetacean individuals is Gerald Wood's "Guinness Book of Animal Facts and Feats", I have the last edition (1982) and the largest sperm whale mentioned in it is 20.7 m long, caught by Russian whalers. In an earlier edition (1976) there was an apparently 71 feet male individual caught in the waters around the Aleutians in 1921 but Wood reckoned that individual was measured "over curves". Nowhere is any sperm whales longer than this mentioned, so I have a feeling they're probably quoting inaccurate reports by whalers.

[Grey]

That's possible. I also remember that Cameron McCormick on his blog had somewhat debunked the basic estimates of the owner of the Nantucket Museum 5.5 m jawbone, most likely coming from a 70 feet individual, not 80 feet.

But McClain 2015 seemed to me confident in their work, although they express some doubts (blue whales) and report that if anything such large sperm whales would be infinitely small in number.

I know about the bull killed by Soviets whales (I think it was in the 50's), seemed to me that it was 20.5 m, not 20.7 m but whatever...and 90 short tons.

Could Woods have overlooked these whalers reports ?

(Don't hesitate to present yourself here : theworldofanimals.proboards.com/board/14/members-introduction )

[blaze]

McClain et al. (2015) do mention their source, the whaling records of the International Whaling Commission so yes, those measurements are definitely from whalers.

Jonsgard and Lyshoel (1969) say that when they measured orcas that had their length estimated beforehand by whalers even though most estimates were correct or almost correct there were cases where the whalers where wrong by as much as 0.6m, that's an error of ~7% an animal up to 9m long, the difficulty on measuring them accurately will definitely make the error bars grow exponentially the bigger the whale is. According to MacClain et al. (2015) there are only 9 individuals said to be larger than the official record, 9 out of a sample of over half a million, seems like the likelihood of their lengths being the result of whalers measuring/estimating them wrong is higher than them being genuine giants.

[Grey]

Well, seems like McClain et al. results are not all conclusive at this point. Once I get Ellis book I'll report what he says about the sperm whale sizes.



Nothing really new but related to this thread about ancient marine giants predators, I've found again this.

Ben Creisler 1999 article about giants pliosaurs : web.archive.org/web/19990222030450/http://www.isgs.uiuc.edu/dinos/dispatches/19981108001.html

Mike Siversson 2010 article about super predatory lamniforms : web.archive.org/web/20110303141026/http://www.biodiversity2010.org.au/2010/10/the-rise-of-super-predatory-sharks-2/

[Grey]

Is there some good data about the probable maximum speed in pliosaurs ?

Just sayin, some fanboy novelist says they would max at 80 kph or more, based on the analogy that leatherback turtles can max at 35 kph...

[theropod]

Absolute figures for the speed of an extinct taxon are always problematic. I don't know any estimate for pliosaurs.

Anyway, the conclusion doesn't fit the analogy. I'd expect pliosaurs to be in a similar ballpark as fast extant sea turtles (I remember reading somewhere that they are the fastest extant reptiles, but I don't know how reliable that is).

[Grey]

I guess he bases this on the premise that a larger animal with a similar body plan becomes faster, albeit less maneuvrable.

But by comparison megalodon is expected to merely have a similar speed than the great white...