False scientific claim rebuttal thread.

[creature386]

I'll answer your Discord question here for the reasons I DMed you.

Does phylogenetic equidistance equal genetic equidistance?
I'm personally unsure, since evolution rates are not always constant. We can assume that mutation rates are always constant (unless someone drops a nuke), which is why non-coding DNA similarity should also equal phylogenetic distance. Coding DNA is more complex, as it is subject to selective pressures which are not always constant.

Let's for the sake of the argument imagine that chimps were for some reason subject to higher selective pressures than bonobos after splitting up. Thus, chimp DNA is only 99.7% the same as chimp-bonobo LCA while bonobo DNA is 99.8% the same as chimp-bonobo LCA DNA. Since the chimp-bonobo LCA would be more similar to the Pan-Homo LCA than either of them would (due to less change having happened), bonobos would be more genetically similar to humans in this hypothetical scenario.

To give you an intuitive parallel:
Consider fish and humans. Both are equally close to their last common ancestor, but fish changed less.

Now, I'm not sure if a similar scenario applies to bonobos.
I've found this about bonobo-human similarity:

On average, the two alleles in single-copy, autosomal regions in the Ulindi genome are approximately 99.9% identical to each other, 99.6% identical to corresponding sequences in the chimpanzee genome and 98.7% identical to corresponding sequences in the human genome.

www.ncbi.nlm.nih.gov/pmc/articles/PMC3498939/
For humans and P. troglodytes, we have:

We calculate the genome-wide nucleotide divergence between human and chimpanzee to be 1.23%, confirming recent results from more limited studies

www.nature.com/articles/nature04072
In other words, 98.77% similarity. The figures are so similar that we should probably discuss measurement inaccuracies and methodological imprecisions before anything else.

Anatomically however, bonobos seem to be closer to our LCA than either chimps or humans:
www.nature.com/articles/s41598-017-00548-3

[dinosauria101]

creature386
Slightly off topic, but are you on Troop Panthera (Ferox's Discord)? If so, that may help with some certain things that must be discussed in the member's section

[creature386]

I'm in there. I've just wasted whoknowshowmany minutes scrolling through fascist nonsense to see who tagged me in the "serious matters" section today (I still have no answer).

[Infinity Blade]

Let's for the sake of the argument imagine that chimps were for some reason subject to higher selective pressures than bonobos after splitting up. Thus, chimp DNA is only 99.7% the same as chimp-bonobo LCA while bonobo DNA is 99.8% the same as chimp-bonobo LCA DNA. Since the chimp-bonobo LCA would be more similar to the Pan-Homo LCA than either of them would (due to less change having happened), bonobos would be more genetically similar to humans in this hypothetical scenario.

To give you an intuitive parallel:
Consider fish and humans. Both are equally close to their last common ancestor, but fish changed less.

What's the third thing we're comparing "fish" to? The case we're discussing here involves humans, chimps, and bonobos, which all share a common ancestor in the form of the Pan-Homo LCA, so I'm not sure how to make this parallel work. But if we stick with the case at hand, however, okay, bonobos are apparently phenotypically closer to the Pan-Homo LCA than humans and chimps are. I'm not sure if it follows that one is more genetically similar to us than the other is.

I did just realize this, though. Even if one is somehow genetically similar to us than the other is, I think that's kind of irrelevant to the original claim/point Adam Ruins Everything made. Cladistically bonobos and chimps are equally related to us, and I think this is what really matters, especially in the context of the original claim (i.e. what behavioral traits these species have).

As per your message to me that this is a discussion for knowledgable posters partake in, I'll tag theropod to see what he thinks. Hopefully we won't be wasting too much of his time.

[creature386]

The parallel was mainly about similarities to the LCA.

To make this analogy work, maybe we can take Panderichthys, Tiktaalik and Homo as our three taxa and take this tree as 100% accurate:
en.wikipedia.org/wiki/Stegocephalia#Phylogeny
According to it, Tiktaalik and Homo are phylogenetically equidistant to Panderichthys, but if we counted base pairs I would expect a greater match between Panderichthys and Tiktaalik than Panderichthys and Homo (admittedly, I cheated by taking unequal divergence times, but unequal selective pressures can have a similar effect, at least on coding DNA; that's one reason why molecular clocks typically avoid coding DNA). Right now, I'm struggling to find data on the genetic differences between humans and gorillas and chimps and gorillas to see if they are anyhow different (IIRC, they were not exactly the same on a biology worksheet I once had, but I'm not gonna dig that one up),

[Infinity Blade]

Perhaps I should probably wait for you to see if you find the data you're looking for. I might edit my post accordingly with both genetic info and the last point I made in my last post, or I might just let viewers look at this (not very long) conversation and that would be that.

[creature386]

Don't hold your breath, I gave up searching.
If such data exists, it is buried under all the data about human-chimp or human-gorilla similarities.

[thalassophoneus]

Dec 8, 2015 8:47:49 GMT 5 Infinity Blade said:

There was a thread on Carnivora that Mantrid created about Spinosaurus and whatnot. In that thread, some user made some claims, I went on to try and refute them, then I went in for a second shot, as I felt my first replies weren't really that in depth. The only thing I changed were the emoticons and replaced them with similar ones on here (as Carnivora's emoticons obviously don't work here).

Let me take another shot at this rubbish.

I should have mentioned. I love how you just assumed that Spinosaurus "had way sharper teeth than tyrannosaurus or whatever else did" without any reference whatsoever. I've seen nothing to suggest a fresh-from-the-oven Tyrannosaurus tooth would be any less pointed at the tip than a similarly new Spinosaurus tooth and if anything, the latter lacks the former's tooth serrations (although Tyrannosaurus' teeth weren't of the optimal design for cutting due to their laterally-thickened shape, I think the serrated carinae could still cut with sufficient force). If "whatever else" refers to other predatory theropods, you couldn't be any farther from the truth, as a conical tooth with no carinae whatsoever simply isn't sharper (let alone to a far greater degree) than a labiolingually-flattened, serrated, and pointed tooth. It's actually like saying ice is way hotter than fire!

They certainly won't be causing "horendous [sic] lacerations"


Although the "teeth" were powered by a human (which would be light years weaker than a giant theropod's jaw and neck muscles), it puts into perspective the functional morphology of the teeth of Spinosaurus (which you seem to be ignorant of). The teeth DID NOT CUT WHATSOEVER, as they're not morphologically designed for it.

And although it looks as if Spinosaurus had a bit of a long neck for a theropod, it's still not to a *really large* degree, thus it doesn't look long enough to really give it so huge of a reach advantage over other large theropods.



Lastly, swan-necked, physics-defying-toothed Spinosaurus or not, how is that outside of "normal theropod rules"? In the predatory non-avian theropod world, the jaws and neck tend to form the central weapon and all you basically did was give a (BS) interpretation of the formidability of Spinosaurus' jaws in conjunction with the matter of its neck's reach. That's within "normal theropod rules"!

Indeed? Then why the hell do animals evolve lateromedially compressed, recurved, and carinated teeth in the first place when they can supposedly just cut through things with teeth that lacked all of the aforementioned characteristics?

Conical-toothed animals that manage to create extensive soft tissue damage also do not cut through things "like butter". They actually take some time and effort.

Finally, your moray eel analogy fails, as the two animals have radically different skull morphologies.

*sigh, the ignorance. I can't see how people can possibly think this



could produce a particularly forceful bite, especially relatively speaking.

Man, you'd think everyone here understands the well-established facts regarding these animals ...

I'm Mantrid and this brings back memories.

[Infinity Blade]

I forgot who made that thread until now. I remember my rebuttal above but I haven’t looked at it in a while.

I feel a bit a bit bad about that rebuttal now, though. It was one thing that I clearly wasn’t at my nicest there, it’s another that I’ve since learned at least some longirostrine, conical-toothed animals can cause some rather nasty injuries with them (botos). Of course, nothing will ever change the fact that they’re absolutely not ideal for the job and that such a jaw is not an ideal weapon against another large animal, but yeah.

[thalassophoneus]

I remember continuing this Spinosaurus debate and some poor guy, Spinodontosaurus, was trying to reason with me. Eventually I made him sick until he left Carnivora to never be seen again. Does anyone know what happened to him?


My attitude towards Spinosaurus and dinosaurs in general has changed a lot in 4 years. I appreciate all of them for different reasons.

[Infinity Blade]

He just posted less and less frequently until he stopped altogether. No one seems to know why, maybe he just lost interest or had other things to do.

[dinosauria101]

This claim is very widespread across the internet and REALLY stinks.
You would not believe the amount of people who take Franoys' works and mass estimations (ie: super-hyped Tyrannosaurus and crazy-conservative carnosaurs). Much higher carnosaurian mass estimates are very well on the table and Tyrannosaurus, for obvious reasons, is not as big as it is often hyped to be, yet these people either do not even acknowledge the possibility for differing masses or brush them off as fanboy'hater claims. 

Perhaps to counter it, we shall go the OTHER way, with an MUCPv-95 that is more than 8 percent bigger than the holotype with a small head and jaw*, a 13.6 meter MCF-PVPH-108.145*2, a 13 meter MPEF-PV 1157*3, a 9 tonne SGM DIN-1*4, and Bucky, B-rex, or USNM 6183 to represent Tyrannosaurus

Kinda kidding, but these people probably need a taste of their own medicine, and/or a viewpoint of the other side

*1: Individual variation is not a one way street. Just as a smaller animal can have a bigger jaw than a larger one, so can a larger one have a smaller jaw than a bigger one. In fact, should you use that argument you are supporting both sides.
*2: It's a large pubic shaft and individual variation goes both ways, plus some authors give up to 13.6 meters (link, link)
*3: Princeton Field Guide to Dinosaurs, 2016 edition
*4: Link

EDIT: thalassophoneus, I don't know where he went or what happened to him either, but Spinodontosaurus may be back soon. He made a comment on DA on Nov 15, 2019, and I messaged him on Discord.

[creature386]

I know I'm not making the rules for this thread, but could you please make it a habit to show your sources/methodology in refutation posts?

[dinosauria101]

Sure - I can link to other estimates or reference them

[Infinity Blade]

"Two mammoth specimens with their tusks locked show one mammoth with its eye socket gouged by the other's tusk."

For those who do not know, in 1962, two Columbian mammoth specimens were discovered with their tusks locked together in Nebraska. It is believed that these mammoths died when they locked tusks during combat, but proved unable to free themselves. One claim I have read on the Internet is that one mammoth had its eye socket gouged by the tip of the other mammoth's tusk.

Photographs and detailed drawings of the specimens can be viewed by anyone online. Below is a modern day photograph of the fighting mammoths.


Photograph taken by Aly Baumgartner->

As you can see, there is no clear evidence of any tusk tip penetrating into the orbital cavity of either mammoth. Each mammoth had one broken tusk, and for both this was the tusk that is lying on the ground. Obviously neither of them show any signs of penetrating any eye sockets. It is sometimes claimed that the eye-gouging tusk was a broken one, but this is not the case. This was merely the original impression of one of the excavators (the idea that a tusk had gouged an eye at all was one of those first impressions too).

Inch by inch we excavated farther into the bank, hoping to discover the tusks, but were disappointed to find the tip of one tusk pointed the wrong way—pointing into the eye socket of the mammoth. How could this happen? Had the animal broken its tusk by falling headfirst?

As we continued to brush the silt away from the skull it finally dawned on us what we had: the "broken" tusk was the intact weapon of another elephant coming from the other direction.

history.nebraska.gov/sites/history.nebraska.gov/files/doc/publications/NH1994Time3_Hooves.pdf

That leaves one of the two intact tusks, each from one mammoth, as the alleged "eye-gouger". One of those tusks is running across the base of its opponent's tusks, far below the actual eye socket. The other unbroken tusk has a tip that is sitting above the nasal cavity (where its opponent's trunk would have started), but it is clearly visible, and clearly not embedded inside the orbital cavity.

This can be confirmed in bird's eye view of the specimens.


Photograph taken by Phil Hore->

We can again clearly see where the unbroken tusk tips ended up. The mammoth on the left (from this photograph) obviously did not have its unbroken tusk penetrate its foe's eye socket. We can confirm that the mammoth on the right (from this photograph) did not have its tusk actually penetrate its opponent's eye socket; the left mammoth's right eye socket is plainly visible with nothing invading it.