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What annoys you about paleontology?; Rant on about moronic theories, complaints, or just animals that annoy you.
Topic Started: Sep 28 2013, 05:04 PM (256,244 Views)
Paleodude
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ex-Krampus

Well going away religion Jack Horner's latest claim on T.rex being purely scavenging is preposterous. Sure he was an opportunist and probobly scavenged from time to time but if he was a pure scavenger, who's doing all the killing?
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CyborgIguana
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Didn't he even reject the pure scavenger hypothesis himself recently?
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Acinonyx Jubatus
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I AM THE UNSHRINKWRAPPER!

David Peters.

I go to look for images of Drepanosaurs or something and all I find are his ridiculous skeletals, which have NO correction for post-fossilization deformation. At least his Vallesaurus isn't festooned with display structures...
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Similis
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Paleodude
Feb 23 2015, 12:09 AM
Well going away religion Jack Horner's latest claim on T.rex being purely scavenging is preposterous. Sure he was an opportunist and probobly scavenged from time to time but if he was a pure scavenger, who's doing all the killing?
This is few years old. As far as I recall, Horner agreed that pure scavenger hypothesis was bollocks.
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Jules
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Mihi est imperare orbi universo

Well, healed Tyrannosaurus bites on Edmontosaurus kinda destroys the scavenging argument...
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Furka
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But Crooky, that was actually a kissing attempt gone terribly wrong ...
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babehunter1324
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AFAIK Jack Horner mentioned in the "recent" documentary Dinosaurs Decoded that he tought that the the onthologic changes that Tyrannosaurus suffered throught is development resulted in it becoming almost an exclusive scavenger when they became old adults...

... As opposed to the logic conclussion that those were the result of adapting to deal with bigger and slower prey (Triceratops, Ankylosaurus...) when they became mature and which no other predator in their ecosystem (even if Nanotyrannus turns out to be a different genus) could handle.

Talking about Dinosaurs Decoded, not sure if it was Jack Horner or somebody else but one of the talking heads said that the new discoveries of onthological change could reduce the number of dinosaur genus from around 1,000 to 300.

Is that for real? Didn't we discover like 20 genus of new dinosaur last year? How about Iguanodon and other basket genus beign divided in atleast 10 new different genuses each? Dinosaurs lived for over 150 MYA after all so I doubt that they weren't at least several thousands if not tens of thousands of non-avian dinosaur genus.
Edited by babehunter1324, Feb 23 2015, 04:52 AM.
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Mathius Tyra
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Rat snake is love... Rat snake is life

Remember that different species can have very similar skeleton.....

Just look at tiger's and lion's skeleton....
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CyborgIguana
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Which means that we might actually know more species of dinosaur than we're even aware of ATM.
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Paleodude
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ex-Krampus

Yeah well the documentary did come from National Geographic who can and has made false claims in the past. Take everything they say with a grain of salt.
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babehunter1324
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Mathius Tyra
Feb 23 2015, 08:13 AM
Remember that different species can have very similar skeleton.....

Just look at tiger's and lion's skeleton....
That's a very good point specially when one considers than tigers and lions sit pretty far apart in the Panthera genus (tigers are more related with snow leopards and lions with leopards).

That brings me to another thing that annoys me and which is kinda related with paleontology, that the criteria used to classify animal genuses is extremely random, I'm pretty sure that some species in the genus Varanus diverged from each other long before for exemple the Loxodonta/Elephas split. And yeah I now that morphologically this Varanus species might be closer from each other than both extant elephant genus but I still found it odd.
Edited by babehunter1324, Feb 23 2015, 10:13 AM.
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Paleosaurus
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I've found that the entire genus/species distinction is entirely arbitrary and if you ever seriously sit and think about any of it you realize that it makes absolutely no sense at all.

Also, as for the total number of dinosaur genera, even if it turned out that we only knew a few hundred that wouldn't mean anything for total Mesozoic dinosaur biodiversity. I always see kids books saying things like "there may have been as many as 8,000 dinosaur species in the Mesozoic" which is absurd when you remember that there are close to 8,000 mammal species known to exist right now. There were likely hundreds of thousands, if not millions, of dinosaur species throughout the Mesozoic if the size of modern clades indicates anything.
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Incinerox
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Āeksiot Zaldrīzoti

Paleosaurus
Feb 23 2015, 02:21 PM
I've found that the entire genus/species distinction is entirely arbitrary and if you ever seriously sit and think about any of it you realize that it makes absolutely no sense at all.

Also, as for the total number of dinosaur genera, even if it turned out that we only knew a few hundred that wouldn't mean anything for total Mesozoic dinosaur biodiversity. I always see kids books saying things like "there may have been as many as 8,000 dinosaur species in the Mesozoic" which is absurd when you remember that there are close to 8,000 mammal species known to exist right now. There were likely hundreds of thousands, if not millions, of dinosaur species throughout the Mesozoic if the size of modern clades indicates anything.
I totally agree with the second part of this post. Currently we're sitting at about 800 known dinosaur species (not including birds), I think. And that's over 145 MILLION YEARS worth of dinosaurs. There's two (perhaps 3 depending how you look at it) ways of thinking about this:

1) Mathematically, it's all completely bogus. I've said before in this topic, it is said that about 99% of all life on earth ever has already gone extinct. And that only 1% of those species will ever make it to the fossil record. And we'll probably ever find 1% of even THOSE. So lets say we stick specifically to dinosaurs (of which there are about 800, give or take). Now for the sake of argument, imagine that those 800 are ALL of them. That's how much we found. Taking the estimate that we've found 1% of all fossilised dinosaurs, that already brings fossilised representatives to about 80,000 species. Now, sticking with the estimated statistics, that 80,000 is the 1% that actually fossilised at all. The maths takes us to a staggering 8 MILLION species of dinosaur over the course of the Mesozoic.

And we'd know only 800 of them.

2) We haven't even fully understood our global ecosystems as they are right now. We have living, breathing animals and plants (not that plants "breathe", but you get the point) right in front of us, doing what they do. And we can't even figure out our own, current world. It's thought that we might be more or less half way there, depending on clade specifics. Now, given what was established in 1), how on earth are we supposed to even fathom what kind of creatures roamed the WHOLE planet in the final days of the Cretaceous? I mean, we have a fairly decent understanding of Hell Creek and its contemporary ecosystems up and down the east Laramidian coast. It's still by no means complete, but we sorta get VAGUELY what's going on. But beyond that? Off the top of my head: I think we have a part of India and Madagascar's ecosystem; Hateg Island in Romania with scattered remains across the rest of Europe; and tiny fragments of Russia. Everything else is scattered and/or dubious. We have almost nothing from Appalachia, ONE SPECIES from the north east continent that I'm not even sure has an actual name, nothing from East Asia, Africa, Australia or Antarctica. Nothing from Indonesia, and the list of "nothing" goes on. Most of our understanding of the very end of the Cretaceous is completely nonexistent.

And remember, those are the final DAYS of the Cretaceous. Many people would probably like to point out places like Horseshoe Canyon or Nemegt and would happily lump them in as contemporaneous with Hell Creek, even though places like those were in fact dated to more like 70Ma, a full 4 million years older.

And remember, 4 million years before this very post, Australopithecus was just leaving the trees and mammoths were only starting to appear. A lot can change in that kind of time. In terms of geological and evolutionary history, it's the blink of an eye. But it's still 4 MILLION YEARS. That's a very long time for things to happen anyway.

So with the bits we agree on out of the way, I have to say I sorta do agree with the first half of your post, but there are some distinct flaws in dismissing such distinctions as arbitrary.

If one were dealing with sister taxon (lets go with an easy and relatable genus today and go Panthera and other cats), your point would be totally valid. Whether I decide to call it a Tigris tigris as opposed to Panthera tigris makes no difference on where it goes on the family tree or how it relates to Panthera leo or whatever. At that point, it's just a name.

But then what if someone decides "Hmm, the Ocelot is a large, spotted cat that looks vaguely like a jaguar and lives in similar places as the jaguar, so I shall rename this animal to Panthera pardalis.

Suddenly it matters for obvious reasons.

But when you call into question the separation of two or more genera on the basis of ontogenetic growth phases, deciding what the line between individuals, species and genera MATTERS. A LOT. Imagine if some idiot goes "Hmmmmm the genus Leopardus doesn't exist because the Ocelot turns out to ACTUALLY be just a young jaguar, I don't even need to rename it to Panthera pardalis at all!"

Even though Leopardus contains 9 other species.

And this is exactly the sort of thing that happened when some tried to merge Alioramus and even Raptorex into Tarbosaurus (even though neither came even remotely CLOSE to coexisting with the giant Asian tyrannosaurine). Even though Alioramus has two confirmed species and a giant sister genus Qianzhousaurus.

Tl;dr, genus-species distinctions don't matter when nomenclature has no effect on a species' place in a cladogram. The moment stuff ends up being moved around, you need to be VERY sure you've got the name right.
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babehunter1324
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"even though neither came even remotely CLOSE to coexisting with the giant Asian tyrannosaurine"

Are you sure about that? The last info I read about Alioramus claimed that it was found in early Maastritichian strata just like Tarbosaurus (that said I think they were indeed different genuses).
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Paleosaurus
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There definitely are uses for genus and species, what I meant is more that the way it is currently defined is either directly contradictory or flawed. Prime example being the classic genus description "a species is of another genus when it cannot produce offspring at all with another species" and species meaning "can interbreed but do not produce fertile offspring with other species in the same genus."

At a glance that makes sense, but then you realize that intergeneric breeding with fertile offspring exist. Either the way we define the words genus and species are flawed, or we're splitting far too much. Genus and species are vitally important to classification, but you end up with the problem that neither term really has a satisfactory definition that is true in all circumstances.
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