|
|
Post by Infinity Blade on Oct 6, 2023 18:44:40 GMT 5
Infinity Blade Regarding the "nomen protectum/nomen oblitum" exception in the code, it seems that if we were to apply the same strict standards to T. rex as we do with everything else, it actually wouldn’t apply here: dinogoss.blogspot.com/2010/09/what-is-nomen-oblitum-not-what-you.htmlBut of course we don’t, so everything is just collectively fine with bending the rules a little if it means we can keep the name Tyrannosaurus rex. In pretty much every other case, it is a binding, non-negotiable rule that oldest valid name takes precedence, even if it has fallen out of use in the mean time and another name is much more popular (e.g. usage of the name Allosaurus was also pretty much discontinued in the early 20th century in favour of "Antrodemus", and only really started being used again after Madsen published his 1976 osteological monograph, still the valid genus name is Allosaurus). T. rex, of course, is above the rules (even rules like this one, that already look like they were custom-made in its favour, but that it still somehow isn’t required to follow). So Manospondylus gigas still has legitimate footing for being the "correct" name, but we just don't care? God damn... To be honest, though, my sentiments on that are pretty much just "it is what it is". Maybe I'm just biased because I'm not an ICZN member (and I won't lie that "tyrant lizard king" is a cool name, though that alone certainly wouldn't make me feel like retaining the name), but I do genuinely believe there are cases where it is, in practice, fair to be lenient. This isn't comparable to the T. rex situation, but there are two insects named in honor of Adolf f*cking Hitler that, under ICZN rules, "should" retain that name, but I wouldn't mind at all being rechristened (and this isn't even the only example like this). Moving away from the case of T. rex, I don't think the rule should be taken to literally every and all extremes (though, the vast majority of the time I don't bat an eye). |
|
|
|
Post by Exalt on Oct 6, 2023 18:44:52 GMT 5
Well, it might have been record breaking at the time, at least. But yes, part of why I asked was because as I thought about the high-end claims( I first heard them at an age where you question these things less), I became more skeptical, and even less sensational measures seem to have a sizable range. When you add on that theropods and sharks seem like the most likely things to themselves be exaggerated, it gets hard to figure out who to believe.
I didn't know that there are species that see more color than we do. Imagine what it's like to see the world that way.
Edit: funny how name subject discussion involves both "the king lizard" and "the tyrant lizard king". Neither are lizards, even if the latter case isn't as blatant.
Edit 2: is part of this because Basilosaurid was the first Basilosaurus To be discovered, where as the dire wolf was obviously not the first animal to be placed in Canis?
Edit 3: tfw autocorrect decides it knows what Basilosaurus is, and corrected "Basilosaurid" to it.
|
|
|
|
Post by theropod on Oct 6, 2023 19:44:42 GMT 5
Yes, that is part of it. Every genus has its type species (which is usually the species that genus is first erected for), just as every species has its type specimen, so whatever that species is placed in retains the original genus name, even if the rest are reclassified. E.g. if it was decided that Smilodon fatalis was actually a different genus than Smilodon populator, the latter would continue being called Smilodon, while the former would get a new/different genus name. That is exactly what happened with "Canis" dirus.
That, incidentally, is also why in dinosaur paleontology the norm is to name just one species per genus, except in very rare cases where it is abundantly clear two species are extremely closely related. It doesn’t really matter, because the genus concept has a lot of inherent subjectivity to it (it is often a matter of mere personal preference whether two similar species are within one genus or different genera), but what does matter is that is we kept naming multiple species per genus, the genus names would change around all the time due to the interrelationships of these species changing with new phylogenetic analyses.
Yes, that’s why it’s always best to go to the actual research papers (and check that they really exist). People on the internet will make up basically anything they feel like making up, and the giant extinct predator fandom is particularly bad in this regard because they are particularly prone to sensationalism. I could certainly find you some guy on the internet who claims that Dunkleosteus had the strongest bite force ever, but that doesn’t mean it is true. What it is is a good story that maybe people will be inclined to believe, because it looks so different from anything alive today that people are likely more ready to believe outlandish claims about it.
There aren’t just species that see more color than we do, actually the standard condition for vertebrates is to see more color than we do. Of course we never know what we are missing; for us trichromats to try and envision what the world looks like to a tetrachromatic animal is similary difficult to us three-dimensional beings trying to envision what the universe would look like to a four-dimensional being. So our imagination is sort of limited by the ways we have to perceive the world, and anything beyond that is by its very nature quite abstract to us.
At least if what Martinuyk wrote in 2010 still holds true (I haven’t read anything to the contrary, but I suppose it’s possible that someone since then has formally petitioned the ICZN to have M. gigas declared a nomen oblitum and T. rex declared a nomen protectum without me being aware of it.
But if that hasn’t happened, which as far as I am aware is the case, then the usage of Tyrannosaurus rex is simply a collective unspoken agreement by everyone to use a junior synonym rather than the valid name (a bit like Otodus chubutensis, honestly, which everyone seems to prefer to its senior synonym O. subauriculatus).
|
|
|
|
Post by Exalt on Oct 6, 2023 20:31:57 GMT 5
This does remind me of when I was a kid, and I tried to imagine a new color. You can figure out well that went.
|
|
|
|
Post by Exalt on Oct 6, 2023 21:49:04 GMT 5
I have some more questions, this time a bit more Mesozoic-focused. 1. Is there any particular reason why the Archosaurs would not dominate the seas as they did the land and sky? My one guess is that some of the Pseudosuchians would have gone extinct at the end-Triassic extinction, which could have influenced this. 2. Why did the ratites all evolve flightlessness separately? I know thanks to PBS Eons of how the "Moa's Ark" hypothesis was disproven. 3. Why did birds evolve to be so vocal? We know that non-avian dinosaurs were not roaring and what not all the time, and just as mammals would have lived "in the shadow of the dinosaurs", wouldn't early birds (heh) have had to do the same with Pterasaurs around? 4. Following question 3, do we have any thread for discussing animal "language" capabilities? With other primates, the subject needs no introduction, and Meerkat sentinels have different calls for different threats. (Rauber and Manser, 2017.) Psitticaformes and Ravens are capable of mimicking human speech, though if they know what they're saying at any point is another matter. --- Rauber, R., Manser, M. Discrete call types referring to predation risk enhance the efficiency of the meerkat sentinel system. Sci Rep 7, 44436 (2017). doi.org/10.1038/srep44436 |
|
|
|
Post by theropod on Oct 6, 2023 22:12:55 GMT 5
I have some more questions, this time a bit more Mesozoic-focused. 1. Is there any particular reason why the Archosaurs would not dominate the seas as they did the land and sky? My one guess is that some of the Pseudosuchians would have gone extinct at the end-Triassic extinction, which could have influenced this. In the end this is just my own personal guess, but I wonder if there is some underlying constraint in archosauromorphs that makes it harder for them to evolve viviparity (which is only definitely proven to have evolved one single time among them, in some protorosaurs, though it is likely that at least derived Metriorhynchids were also viviparous). On the other hand, it is actually quite common among non-archosauromorph reptiles, and evolved among most of the major lineages of marine reptiles (Sauropterygians, Ichthyosaurs, likely also mosasaurs), due to its obvious advantage over oviparity for a fully aquatic tetrapod. If Archosauromorphs were more limited by their reproduction in terms of ability to exploit aquatic niches, that might explain why they are, overall, less likely to bring forth as many dominant aquatic tetrapod lineages as other reptiles, although it doesn’t really explain why those few archosaur lineages that did evolve viviparity didn’t manage to become dominant (that was likely just pure bad luck, but Thalattosuchians were actually quite successful, so I guess in a way they did). Well besides the obvious, that they all obviously live/lived on separate landmasses and hence a common, flightless ancestor couldn’t have actually dispersed to all of those places, I honestly do not know what exactly it is about ratites that seems to make them so prone to evolve into such similar flightless forms so often. We actually do not know how vocal non-neornithine birds were, as the oldest known syrinx is that of Vegavis, a Maastrichtian anseriform, and iirc was interpreted, based on its assymmetrical anatomy, to have produced swan- or goose-like honking sounds. However I think that the capacity to fly, coupled with pterosaurs already being on the decline since the mid-Cretaceous, makes this a somewhat different situation to the nocturnal bottleneck in mammals (which, in the terrestrial biome, likely had a much greater pressure to drive them to avoid competition with larger taxa). I don’t think small body size is as much of a competitive disadvantage for a flying animal; the vast majority of flying animals are small, and small flyers aren’t necessarily inconspicuous and go out of their way to avoid confrontation with larger ones, quite the opposite. It’s also not like all bird groups are equally vocal, in fact it is primarily the Passeriformes, so this is to an extent an innovation of that clade (that correlates with increased neuron density and cognitive capacity) similar to how improved color vision compared to other mammals is an innovation of primates. It just so happens that passeriforms, perhaps as a result of their vocal specializations, are the most diverse and arguably the most successful extant birds (that could be partly because using vocal signalling created many more opportunities for these birds to undergo sympatric speciation due to becoming reproductively isolated from former conspecifics that evolved a different "language", so to speak). So that makes it appear that birds are generally very vocal, but in fact that’s largely because passeriforms are so diverse and dominate bird biodiversity, rather than because birds in general were necessarily more vocal than non-avian dinosaurs. [/quote] I don’t think we have such a thread yet, someone correct me if I am wrong. You are very welcome to make one! |
|
|
|
Post by Exalt on Oct 6, 2023 22:24:47 GMT 5
I see, I had not considered the reproductive angle.
This does remind me of when I ended up looking at bird taxonomy. It began when I was informed that falcons are not that closely related to hawks and eagles, and then later when I ended up looking into phorusrhacids, I discovered that Australaves include falcons, seriemas, phorusrhacids, psittacaformes, and passerines...and then later on I learned that passerines are so diverse that I wonder how meaningful this cladogram is.
|
|
|
|
Post by Infinity Blade on Oct 6, 2023 22:25:47 GMT 5
The first aquatic reptiles were actually from the Permian (mesosaurs). Recently, the earliest known ichthyopterygian fossils turned out to be ~250 million years old; that's very, very early Triassic, to the point where ichthyosauromorphs are now thought to have probably originated in the Permian (which would, surprisingly, make them P-T survivors) ( Kear et al., 2023). Sauropterygians (the group that contains both plesiosaurs and placodonts) also originated in the early Triassic. So in short, other reptiles seem to have beat them to it (even though archosaurs did fill in some marine niches in the Mesozoic, like metriorhynchoids and later hesperornithean birds). Well, that doesn't mean they weren't particularly vocal compared to birds. Regardless of how much non-avian dinosaurs roared*, it still seems to be generally agreed that they did vocalize (and to my knowledge, the recent discovery of a larynx in an ankylosaur supports this; Yoshida et al., 2023). *I'd argue that if crocodiles can make sounds people regard as "roaring", there's no reason why some non-avian dinosaurs couldn't do the same. |
|
|
|
Post by Exalt on Oct 6, 2023 22:29:10 GMT 5
I see, I was not aware of that tidbit regarding crocodiles, and I guess I still made assumptions on dinosaur vocalization based on what I remember in Prehistoric Planet and such.
|
|
|
|
Post by Exalt on Oct 6, 2023 23:28:57 GMT 5
One more question that I just thought about:
Why did (the evolutionary factors that influenced) the Therians ditch laying eggs, to begin with?
|
|
|
|
Post by theropod on Oct 7, 2023 0:32:55 GMT 5
One more question that I just thought about: Why did (the evolutionary factors that influenced) the Therians ditch laying eggs, to begin with? Again I am limited to speculation, but there are several reasons I can think of for why viviparity might have been selected for in therian-line mammals. It removes the need to incubate eggs (which might be more difficult for a small, nocturnal mammal than it is for larger animals, such as dinosaurs, whose eggs are also larger and don’t lose heat as easily). It also means there is no nest that requires constant attention and care, meaning the animals and their future offspring are more mobile (which is advantageous if you cannot effectively defend a nest from predators, and don’t have the advantage of flight that allows you to nest in places inaccessible to most of them). At the same time, it potentially allows individual offspring to be born at a larger size, and thus (together with the mammalian characteristic of milk glands) plays into the whole higher parental investment-strategy, although I don’t know if that really played a role for early theriimorphs. |
|
|
|
Post by Exalt on Oct 7, 2023 0:59:20 GMT 5
Thanks.
And one more:
I learned awhile back that it is estimated that bats make up around a quarter of all living mammal species. (I double-checked this beforehand, and every estimate I can find is either this or closer to a fifth.) Are there any ideas why they've had such success?
|
|
|
|
Post by theropod on Oct 7, 2023 2:12:06 GMT 5
Probably for a similar reason that birds make up over a quarter of all tetrapod species; the innovation of flight enables a group to radiate into a vast variety of available niches that are literally out of reach for anything on the ground. That true flight is so rare (evolving only four times in the history of life) makes it even more of a supercharger to diversification in a group. I’d argue that every single time flight has evolved, it has led to a massive radiation. Insects I guess require no explanation, two thirds of all animal species are insects. Birds are the most diverse extant clade of terrestrial vertebrates. Bats are the second-most diverse clade of mammals (after rodents, or, if you prefer, euarchontoglires, which include rodents). Pterosaurs may seem like the odd one out, as their diversity pales when compared to contemporaneous dinosaurs, but at least they deserve the distinction of being the only major radiation of ornithodirans other than dinosaurs, and likely the third-largest (and third-longest-lived) radiation of Archosauromorpha as a whole. And bats, as mammals, have certain predispositions that lend themselves to exploiting those volant niches that birds are usually less suitable for (and vice versa), namely nocturnal insectivorous ones (nocturnal insectivory just seems to be what mammals do best, and likely why both the mammalian middle ear and the original therian chewing apparatus evolved), especially due to their biosonar. But when it comes to insectivory in mammals you might want to have the benefit of creature386 ’s expertise. |
|
|
|
Post by Exalt on Oct 7, 2023 5:28:40 GMT 5
Why might dinosaurs have evolved feathers in the first place?
Also, how did scientists conclude that tetrachromacy (I looked it up just now) exists in the first place?
EDIT: One more thing that I finally remembered to ask: How did the "Allosaurus had never seen such bullshit before" meme come into being?
|
|
|
|
Post by theropod on Oct 7, 2023 17:20:22 GMT 5
Initially for insulation . That’s why small, hair-like or downy filaments initially evolved, trapping a layer of air around the body, which reduces heat loss. Same as fur in mammals, or clothing in humans. We know many dinosaurs lived in temperate or even cold climates, so this is a necessity for an endothermic animal to survive in such areas, and likely a prerequisite for endothermic dinosaurs to achieve the kind of global distribution that they had.
Secondarily for display (here’s what all that stuff I mentioned previously about color and color vision comes in). Display is likely the initial reason for the evolution of larger, more rigid, more complex feathers, i.e. pennaceous feathers (or feathers in the strict sense), although these were later also adapted for different purposes.
Finally for flight. This likely came last, adapting preexisting display feathers that already had many of the features (like a long, rigid rhachis and coherent vanes linked by barbs and barbules) into flight feathers by increasing the size of arm and leg feathers, evolving a more aerodynamic, asymmetrical feather shape, and later modifying the tail into a control surface.
This is also likely related to the evolution of contour feathers (which are the outer layer of pennaceous feathers that cover the body and the downy feathers underneath, giving it the kind of smooth, aerodynamic outline it has in birds, but also helping with waterproofing).
I suppose this could be determined in in vivo experiments by observing the behaviour of animals and testing which colors they can differentiate, and whether they can see a wider color spectrum than us (e.g. whether they see in UV). But the most straightforward is simply to do in vitro analysis of the receptor types on the retina and see how many different types of cones they are, as that is the basic feature to distinguish tetrachromacy.
|
|
