|
Absolutely losing my mind at the cockatoo in every drawing, it's so cute
|
#
¿
Apr 14, 2024 20:52
|
|
|
|
| # ¿ May 19, 2024 05:44 |
|
|
Goatse James Bond posted:I read that book a ton as a kid Me too! I checked it from the library so often an entire checkout card was stamped just from me. Met Bakker once after a talk in the geology department, real cool guy. Feathered theropods were just starting to gain some traction in the community around that time, he really lit up when I asked him about it.
|
|
#
¿
Apr 16, 2024 03:59
|
|
|
Another fine and informative megapost that I am happy to silently approve... almost.khwarezm posted:Sails like this are always controversial structures, whether they are on Synapsids like Dimetrodon, Dinosaurs like Spinosaurus, or Poposaurs as we see here, there's a range of uses they could have had from thermoregulation to display, but I tend to think that a display function is most likely because things like sexual selection always seem to be the best explanation for weird stuff like this and there's no living animals that use sails as part of their thermoregulation. Here's a possibly analogous structure that, if we found it on a distantly extinct creature with no living examples to draw a direct parallel with, would almost certainly get the same arguments:  "There's nothing like it around today so, eh, must've been a sex thing" is a tempting default position to take, but it's kind of like when archaeologists default to assuming anything they don't understand must've been a religious thing. And the absence of an adaptive form in geologically modern times isn't any kind of proof in and of itself, evolution simply takes whatever works best at the time and runs with it. McSpanky fucked around with this message at 09:36 on Apr 29, 2024 |
|
#
¿
Apr 29, 2024 09:16
|
|
|
khwarezm posted:That's a good point, but when it comes to sail functionality there's very little written about Ctenosaurs compared to more familiar cases like Spinosaurs and early Synapsids. If I can talk about those other animals, I know there's a lot of work that's been done on the thermoregulatory properties of them for Dimetrodon and its controversial because you get smaller sail like structures on related genera like Sphenacodon where my understanding is that research points towards them being of little use for gaining or losing heat. You also have the sails on much smaller species within the Dimetrodon genus, even though structures like this would be more useful for larger animals (like the elephant here) who may have bigger issues with getting too hot. Finally I think recent research has shown that the sails go through distinct growth spurts that would match sexual maturity more than anything, just generally most times I've seen this discussed I get the impression that thermoregulation is not a favoured idea at the moment. I didn't want to get extremely into the weeds on particulars, I was mostly just cautioning against the tendency to throw up our hands and go "I dunno, a sex display?" at anatomical features that don't have an immediately apparent function. Although I would mention that computer modeling of Dimetrodon's sail shows that it would be quite effective at gaining heat, though not nearly as much at losing it, so kind of the opposite of an elephant's ears in that regard. But that could well have been its function anyway; there's a whole spectrum of thermoregulatory schemes besides the commonly understood "cold-blooded" and "warm-blooded", maybe they needed more help getting revved up than coming down, and it became adapted to that purpose from an ancestor's smaller crest which was maybe a sex display (or fat hump, or whatever). quote:I do agree with the tendency for it to feel like Scientists go 'gently caress it, its sex related' to any bizarre feature lol. I've also noticed that meme about 'Ritual Object' when it comes to archaeology too. I suppose I'm not one to second guess but you do wonder if people are just doing that to have an explanation, I've sometimes wondered about things like the tail of a Thresher Shark and how we know it actually does have practical functionality of whipping fish, but if scientist 50 million years in the future with no Thresher sharks around found a fossil preserving this feature, wouldn't the automatic assumption be that it was for sexual display and any other reason is too ridiculous to explain such a weird tail? I think part of it too is just that, you know, scientists are people like anybody else, and people don't like to be put on the spot and not have a good answer for a pressing question. When you're an ostensible expert in your field and you're writing up a new discovery, or publishing another research review for our delightful "publish or perish" paradigm, "I don't know" isn't good enough -- even though that's supposed to be the germination of all discovery, the beginning of wisdom. It should be okay to admit that sometimes we just don't know, but pride and ego are as old as the rocks and the fossils.
|
|
#
¿
May 2, 2024 09:39
|
|