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Post by coherentsheaf on Apr 10, 2014 17:52:39 GMT 5
So, indication that some pliosaurs reached the meg/liv league but no serious hint of super-giants 5-meters headed monsters ? I would agree with this. The attacking pliosaurs were likely very large animals. One reason for this is that they engaged in potentially lethal conflict with the already whale sized Monster. Given that animals will more likely pick on something smaller than them than taking on a potentially lethal opponent suggests that the Monster was probably smaller than them. the other reason is that the suggested length of the crowns is very large. We can assume that the crowns are proportionally larger than in Kronosaurus and that the marks are enlarged by the dynamics of the engagement ad still get a very sizable animal. Eg: Assume at the size of Kronosaurus the attackers would have 15cm crowns. The crown was 20 cm long -> Attacker is about 14m long. This seems like a lower bound all other numbers I came up with are larger and I suspect the attackers may have been larger than 14m. |
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Post by Grey on Apr 10, 2014 21:22:37 GMT 5
The only issue I see with that is that we don't have an indication that the Monster had itself bigger crowns than in Kronosaurus. The only piece with teeth they had is lost so impossible to determine if that was the case. Assuming that the two pliosaurs that successively attacked the Monster were from the same species, which is very likely indeed.
So if the crown was truly 30 cm, that would suggest a pliosaur about 21 m.
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Post by Grey on Apr 17, 2014 16:36:26 GMT 5
The vertebra of the Aramberri pliosaur.  |
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Post by Grey on Apr 18, 2014 20:55:25 GMT 5
Have recently asked to Pat Druckenmiller.  |
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Post by Grey on Jun 1, 2014 2:08:01 GMT 5
A mysterious giant ichthyosaur from the lowermost Jurassic of Wales
Jeremy E. Martin, Peggy Vincent, Guillaume Suan, Tom Sharpe, Peter Hodges, Matt Williams, Cindy Howells, and Valentin Fischer Ichthyosaurs rapidly diversified and colonised a wide range of ecological niches during the Early and Middle Triassic period, but experienced a major decline in diversity near the end of the Triassic. Timing and causes of this demise and the subsequent rapid radiation of the diverse, but less disparate, parvipelvian ichthyosaurs are still unknown, notably because of inadequate sampling in strata of latest Triassic age. Here, we describe an exceptionally large radius from Lower Jurassic deposits at Penarth near Cardiff, South Wales (UK) the morphology of which places it within the giant Triassic shastasaurids. A tentative total body size estimate, based on a regression analysis of various complete ichthyosaur skeletons, yields a value of 12-15 m. The specimen is substantially younger than any previously reported last known occurrences of shastasaurids and implies a Lazarus range in the lowermost Jurassic for this ichthyosaur morphotype. www.app.pan.pl/archive/published/app59/app000622014_acc.pdf
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Post by Godzillasaurus on Jun 1, 2014 2:29:15 GMT 5
I wonder if that specific ichthyosaur was like shonisaurus or shastasaurus where it completely lacked teeth altogether and fed only on small fish and squid (or at the very most possessing a few small teeth), or if it was macropredatory in nature like a few genera of ichthyosaur (like thallatarchon).
Or possibly it could have been one of the more dolphin-like ichthyosaurs with smallish pointed teeth feeding on fish and squid in a similar way to modern dolphins
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Post by theropod on Jun 1, 2014 2:52:38 GMT 5
"One of the more dolphin-like ichthyosaurs" sounds very unlikely for a shastasaur, but there were shastasaurs that were macropredators with large, sharp teeth.
Since it is only a radius it is difficult to tell whether it is rather similar to Himalayasaurus (macrophagous) or to Shonisaurus (teutophagous).
But we do know that there were giant macrophagous ichthyosaurs in the lower Jurassic based on the presence of large teeth (McGowan 1996) and those may be referrable to this and/or one of the giant taxa described earlier.
The radius is about the same lenght as that of the largest specimen of Shonisaurus popularis listed in Motani et al. 1999 (though smaller than that of Himalayasaurus) so I’d say it is a good starting point to say it was also in that general size range. The estimated preflexural (I presume that means as much as "without the tail fin") lenght between 12 and 15m is consistent with that (especially if we tend towards the upper end, which, as explained by the authors, we probably should), even though it remains to be quantified how much the various clades of ichthyosaurs differ in forelimb and overall proportions.
I’d be no less fascinated if this actually was a squid-sucking type, that would definitely increase the structural diversity of ichthyosaurs in liassic seas!
Imagine a giant 15m Temnodontosaurus-like ichthyosaur preying on a giant 15m Shonisaurus-like one. An amazing thought.
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Post by Godzillasaurus on Jun 1, 2014 3:01:09 GMT 5
That would be amazing!
Although I do see this in reality, assuming that macrophagous ichthyosaurs and more docile ones established a similar predator-prey relationship such as lions and zebras/wildebeest for example
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Post by Grey on Jun 29, 2014 2:25:01 GMT 5
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Post by coherentsheaf on Jun 29, 2014 2:31:14 GMT 5
I have been trying to find this catalogue for ages. Thanks grey! |
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Post by Grey on Jun 29, 2014 8:24:54 GMT 5
You welcome. I remember I loved that chart once when I believed it. Would be cool it is accurate.  |
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Post by theropod on Jun 29, 2014 15:41:05 GMT 5
Seems we’ve got a new contestant for "worst scale chart". Yeah, would be cool if it was accurate–on some parts at least. I personally wouldn’t want T. rex to look like shown above though.
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Post by creature386 on Jun 29, 2014 17:53:07 GMT 5
How old is this? Because the images all look very old fashioned and the theropods lack feathers. Theropod already said what has to be said about T. rex stance. Not saying this is bad, I like such depictions, they remind of good old dino-book times (and also some animal books where for example the style of the whale depictions was similar).
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Post by Grey on Jun 29, 2014 23:29:45 GMT 5
Has anyone yet found pics or sources about the reported 40 cm Oxford Clay teeth ?
I know that novelist Max Hawthorne uses them to justify a +20 m pliosaur but this guy is anything but a clown playing with paleontological facts much like Steve Alten.
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Post by coherentsheaf on Jun 29, 2014 23:53:20 GMT 5
Has anyone yet found pics or sources about the reported 40 cm Oxford Clay teeth ? I know that novelist Max Hawthorne uses them to justify a +20 m pliosaur but this guy is anything but a clown playing with paleontological facts much like Steve Alten. Unfortunately I dont. Given the comprehensiveness of McHenry (2009) I am somewhat doubtful of their existence. I suspect he would not have missed them. |
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