Tylosaurus vs. Orca

[Infinity Blade]

Mar 8, 2014 2:10:09 GMT 5 theropod said:

Source?

I said those two statements were clickable. They direct you to the source.

[Vodmeister]

Mar 7, 2014 22:03:28 GMT 5 coherentsheaf said:

Mar 7, 2014 21:51:54 GMT 5 Vodmeister said:

How heavy was Tylosaurus?

Estimates of Alexander would put the largest specimen at about 3-5 tonnes. However recent evidence suggests deeper whale like bodies in some mosasaur species. It is unclear though if Tylosaurus had it too.

In the most likely case, I give it to the Orca. It's bulkier and more powerfully build than the Tylosaurus.

[Infinity Blade]

If it weren't for its superior girth, I wouldn't be leaning towards the mammal.

Though, if Tylosaurus had a deeper whale-like body as now being hinted, then this match is roughly a 50/50.

[blaze]

Mar 7, 2014 19:17:54 GMT 5 creature386 said:

The six foot skull yields a 14.2 m animal? That's a true monster!
Although the orca probably is overall no less massive (when comparing small to small and large to large in your comparison). The average for the orca is probably somewhat lower, but a 7.3 m specimen should still be fine as a representative.

That's what it ended up at from my scaling but I'll prefer to stick to the 1:7.7 ratio seen in a complete 8.8m specimen, so 13.9m long, the difference will not look that big though, it's a body 2.5% smaller.

[creature386]

Still above the normally stated 12-13 m.

[coherentsheaf]

Re ramming:

The article by ingham Soliar is here. I do not have access:
onlinelibrary.wiley.com/doi/10.1111/j.1502-3931.1998.tb00520.x/abstract

[Infinity Blade]

Neither do I.

For now, I give a bit of an edge to the orca, but only due to its greater bulk and girth (and there's a chance even that might not have been the case).

[creature386]

The girth would be equal when picking 13 v 7 m. Are you talking about a chance of Tylosaurus being bulkier than thought? I know that this maybe applied to Mosasaurus, but I am not sure about Tylosaurus.

[Infinity Blade]

1.) Yes.
2.) I looked at the size comparison again, and you're right. Roughly 50/50 or close to it. 

[elosha11]

Orcas are very powerful rammers as well. See the recent video recorded case where an adult female orca rammed a fkw from below, sending the animal hurtling ten meters into the air. There's little doubt that either animal could inflict major injury by ramming or biting.

[Infinity Blade]

So 50/50 sounds logical?

EDIT: I realized I never gave much of an explanation. At similar weights, I go with the Tylosaurus for its much larger skull & jaws, serrated teeth, bone-crushing properties in its bite, and superior maneuverability/agility thanks to its sub-carangiform locomotion (vs the orca's thunniform locomotion) and possible use of pectoral flippers for additional propulsion. Likely matches the orca in speed and ramming capabilities too.

[Grey]

A slight edge for Tylosaurus IMO. Larger skull and jaws, with its relatively slender built, I see it not so vulnerable to orca's ramming.

[Deleted]

Interesting subject on mosasaur ramming abilities. I kind of share the thought with Theropod that Tylosaurus could have rammed in an almost woodpecker style. I actually wonder though how much damage a mosasaur can take by ramming at such a force? Orcas have rather thick heads, so I can see how they can ram quite well.

This probably depends on the actual weight of the Tylosaurus. I see it being likely that a rather slender Tylosaurus around an Orca's size would actually be somewhat at advantage, because it could be more agile underwater and probably harder to catch underwater while the orca is very quick, but quite rigid and Tylosaurus could possibly grab hold of the more robust Orca with it's larger jaws and a wider gape compared to the orca's relatively small gape. A smaller Tylosaurus might have troubles getting a good hold on the Orca though... I say Tylosaurus wins this, at a win ratio of about 55/45 or 60/40.

[theropod]

Mar 8, 2014 15:06:28 GMT 5 coherentsheaf said:

Re ramming:

The article by ingham Soliar is here. I do not have access:
onlinelibrary.wiley.com/doi/10.1111/j.1502-3931.1998.tb00520.x/abstract

I’ve got access now, it appears. So if someone wants the paper, let me know.

He first concludes that the damage to the braincase of a M. hoffmanni specimen was probably the result of a powerful blow to the skull. The following is what it states about mosasaur ramming:

It is interesting to consider the predator that could have delivered such a well pin-pointed and lethal blow to a large animal such as Mosasaurus hoffmanni. Fishes, primarily swordfish, and marine crocodiles are unlikely, since to my knowledge they have not been found in the Maastrichtian localities in which Mosasaurus hoffmanni is known. Ichthyosaurs were already extinct by the Maastrichtian. Pliosaurs are infrequent but, in addition, are broad-snouted, and a blow to the braincase of Mosasaurus hoffmanni would have caused widespread damage to virtually the whole posterior part of the skull. However, it is among the last group considered, the mosasaurs themselves, that the most likely attacker, Hainosaurus bernardi, is found. H. bernardi was a gigantic 15 m long tylosaurine mosasaur (Lingham-Soliar 1992) and known from Maastrichtian localities close to those of M. hoffmanni. Significantly, they possessed a large solid bony rostrum at the tip of their snout that was evidently used in the ramming of prey (Lingham-Soliar 1992) either to kill or to stun. Tylosaurines were ideally designed to deliver a powerful blow with the rostrum by rapid acceleration from a virtually stationary position. The attack, probably from an ambush (Massare 1987), was enhanced by a long powerful tail adapted for burst speeds, as in crocodiles. These mosasaurs are also known to have had enormous diets. The gastric contents of a single specimen in the South Dakota School of Mines consisted of the small mosasaur Clidastes, the marine fish Bananogmius, a shark and the diving bird Hesperornis (Martin & Bjork 1987).

The solid bony rostrum of tylosaurines is unique among marine vertebrates, and hence it is hard to find close analogues among living forms for the kind of behavior described above. However, bottle-nosed dolphins (Tursiops truncatus) use their beaks in defence to kill or see-off lemon sharks (Triakis semifasciata) (Watson 1988), and crocodiles show some form of ramming behavior in male-male fights (Lingham-Soliar 1995). With our knowledge of mosasaurs it seems reasonable to associate the large rostrum in tylosaurine mosasaurs with the kind of offensive behavior described above.

Obviously that’s just Lingham-Soliar’s side of the story. I’d feel more confident in this hypothesis if there was some independent confirmation, and best of all some quantitative testing.

This (pdf download link)→ is his other paper, the one regarding Hainosaurus and Tylosaurine ramming abilities. I haven’t found the time to look into it yet.
EDIT: It does go into some further detail regarding the rostral anatomy.

[Infinity Blade]

What I find really interesting is how it says that male crocodiles apparently engage in some kind of ramming behavior with each other.

Edit (2/23/17): so recently I decided to look up mosasaur ramming some more, and people from another forum seem to have had their criticisms of it. While I cannot conclusively say that mosasaurs rammed prey or foes right now (although I'm inclined to believe it), I do not agree with their criticisms.

With all the nerve endings on the premaxilla (and it is chock-a-block loaded with them) I'd think a Tylosaurus snout-ramming something would be like you attacking something with your testicles.

.... but I have to agree that a tylosaur's snout was much more of a sensory organ than a weapon...

This is just plain invalid as an argument. Sperm whales use their junk for echolocation, and are thus sensitive, yet there's no doubt that this organ is a formidable ramming weapon. Great white sharks have hundreds, if not thousands, of ampullae of Lorenzini on their faces, yet they've rammed into fiberglass boats, which in some cases were much larger than themselves. As pointed out above, Lingham-Soliar also claims some form of ramming behavior in crocodiles, and their faces have an abundance of multi-sensory organs. Lastly, narwhal tusks are actually sensitive organs too, but they can and have been used in aggressive encounters at least sometimes (Silverman & Dunbar, 1980; Struzik, 2009). Granted, narwhal tusks are still pretty poor weapons, but that has more to do with their great elongation and fragility.

Why would the biggest predator in the ocean need to be ramming his head into much smaller prey when he can just crunch it instead?

Ask this question to modern orcas.

In this case, a large (10 m) Tylosaurus proriger ran into something solid (a rock?), gouging out a quarter sized chunk of bone from the right side of the premaxilla.... jamming the premax into the the right maxilla so hard that the first two teeth of the maxilla are crushed together. Ouch! .... and probably fracturing the nasal....

[followed by pictures of a broken mosasaur snout and textual descriptions thereof]

A close-up of the gouged area on the right side of the premaxilla also shows some exostitial bone growth... the wound was healing but the mosasaur didn't live long enough for it to finally close.

Well, sure, but even a structure designed to withstand a strenuous activity can fail during performance. For example, Tyrannosaurus' incrassate teeth still sometimes broke off during a struggle with prey.