As far as I’m concerned, “bird” starts with Avialae rather than Aves, in which case critters like those you mentioned would / should be considered birds.
Depends on which definition of Avialae Most common is the stem-based version (closer to modern birds than to Deinonychus), which would include the scansoriopterygids under most current cladograms, but not Pedopenna, which is usually recovered as a basal paravian/eumaniraptoran.
Either way, yes, if “birds” start with Avialae, Epidendrosaurus and Epidexipteryx (and Scansoriopteryx, if it’s distinct from the others) are currently the earliest known birds, not Archaeopteryx. Of course the common ancestor of all three must have lived even earlier.
To get back on track slightly, I don’t know what colors they were but the body feathers of Epidexipteryx preserve a darker hue than the tail feathers, which based on the link I posted a few posts back may indicate the color pattern in life. But somebody would have to examine it for evidence of melanosomes to confirm this.
Right, but dinosaurs come in all sizes. The existence of a 30-ton sauropod makes it a damn good idea for smaller dinos to come have some commensurate stealth technology.
Also, for 30-ton animals that don’t need to be any color or pattern in particular, that leaves a lot of room for sexual selection to work its exotic magic.
I didn’t see if anyone responded to this, but it’s not true…at least if I’m reading your post correctly. They have found actual fossilized skin, not just impressions in a cast.
Of course, no idea what the color was or may have been. Also, there isn’t enough DNA to do anything with this (responding to another poster up thread), from what I understand. Even in more modern mummified specimens there usually isn’t enough DNA to get more than fragments…in this I don’t think even fragments are available. The best things I’ve seen for attempting to reconstruct a dinosaur is to sort of reverse engineer it from existing species…like a chicken.
My guess is that dinosaurs were pink with purple spots…
-XT
That article is fairly poorly worded and it looks like the reporter may have been confused about some of the quotes by the paleos. See this thread from the Dinosaur Mailing List for example:
http://dml.cmnh.org/1994Jul/msg00144.html
http://dml.cmnh.org/1994Jul/msg00147.html
Granted the Dakota and Leonardo mummies were likely discovered after those posts but I haven’t seen any indication that actual, unmineralized soft tissue has been found. In another case of a dinosaur specimen preserving possible internal organs, Willow the Thescelosaurus (supposedly preserved a 4-chambered heart), the organ in question was found by examining irregularities in the rock–it is essentially a cast or impression. Nothing there but fossil, albeit fantastically preserved/detailed fossil.
Missed edit window:
I think I may have misread your post xtisme. Yes, they found actual fossilized skin–fossilized being the key word. That is, replaced by mineral. No actual tissue left, but a detailed mold formed by the same process as fossil bone. Might just be crossing terms here.
I’ll bet they were barbeque colored. Mmmmm. A nice big, tasty, raptor drumstick.
In Jurrassic Park, raptors eat you!
In Soviet Union, you eat raptors!
Yeah. But comparatively, reptiles are more distant than birds, or rather, within reptiles you find the subgroup “birds and dinosaurs” being more related than, for example, “dinosaurs and crocodiles.” Which is what I was talking about.
No, it’s:
In Jurrassic Park, raptors eat you!
In Soviet Union, the governement eats you!
That doesn’t make sense, though. It’s not a distance thing, it’s a hierarchical thing: ALL birds are dinosaurs, and ALL dinosaurs are reptiles. Non-avian dinosaurs may be more distant from basal reptiles than they are from birds, but none of them can be said to have any phylogenetic distance from reptiles in general. It’s like saying we’re more closely related to chimps than to mammals.
And all mammals are reptiles. Hierarchical ranking helps us understand origins and relatedness, but don’t lose sight of the fact there are reasons why “mammals” are distinct from “reptiles”, and there are reasons “birds” are distinct from “dinosaurs”.
No, chimps are mammals, but chimps are not reptiles except in the sense that all mammals came from reptiles. Birds are not reptiles, nor are they dinosaurs, but they came from reptiles through dinosaurs.
Which doesn’t negate your point that dinosaurs are reptiles. That distinction is not like mammals to reptiles, it is like crocodilians to reptiles.
Except that mammals did not evolve from reptiles–the two groups shared a common ancestor that was neither mammal nor reptile (in fact in layman’s terms it would have appeared more “amphibian.” Mammal skin in smooth, moist and glandular like the ancestral amphibians, not dry and scaly like the more “advanced” skin of reptiles). You seem to be treating ranks like Class and Order as if they denote something real, when in fact they’re simple bookkeeping tools. Modern classification does away with these distinctions in favor of a Russian nesting doll model. Chimps are primates are mammals are tetrapods are sarcopterygians. Birds are dinosaurs are reptiles are tetrapods are sarcopterygians.
See Phylogenetic nomenclature - Wikipedia
The reason for the change is that many people would disagree with you that there are any “good” (i.e., objective) reasons why mammals are separate from reptiles.
In addition to what Grendel’s Father said, note that such distinctions tend to fade away the closer you get to a common ancestor. Modern birds may “look” different than your typical dinosaur, but when you go back to the origins of birds, you can barely tell the two apart. The closer to the common ancestor of reptiles and mammals you get, the more similar the two groups get. “Distinctiveness” is relative.
Aren’t dinosaurs purple? I heard a song once that strongly suggests it, apparently based on actual video footage of a living dinosaur:
I hate you
You hate me
We’re a dysfunctional family
A shot rings out
Barney hits the floor
No more purple dinosaur
Note that mammals are not reptiles only if you specifically define “reptile” to exclude the ancestral amniotes and synapsids, which is not in accordance with either traditional paleontological use or the common-sense definition.
This is an artifact of trying to blend traditional Linnaean classifications with cladistics. It don’t work nohow.
Traditional reptiles comprise the clade Sauropsida (the sister clade being Synapsida, which eventually leads to us). Those two groups, along with early, pre-Sauropsida/Synapsida tetrapods & amniotes, further comprise the group Reptilomorpha.
The modern Linnaean version uses the Sauropsida / Synapsida names and assigns them the rank of Class (under Series Amniota). Aves retains the rank of Class, but is recognized to be within Sauropsida.
Now, while non-cladistis probably don’t care too much, the problem with the traditional definition of “reptile” is that it was paraphyletic (with a dose of polyphyly, with the inclusion of Synapsida, thrown in for good measure) because it didn’t include Aves. Really, it was too much of a jumble to be useful for establishing phylogenies between or amongst those groups. Sauropsida has thus become the “new Reptilia” (indeed, in some cases, Reptilia is used as the clade name), in that it includes pretty much everything that was traditionally classified as a reptile, while including birds and excluding synapsids.
Well, admittedly I’m going by what I remember about something I read on Talk Origins over 5 years ago. But okay, so the ancestor of mammals is no longer considered a reptile, and instead is an amphibian. Does that make all mammals amphibians? That seems a bit weird.
I’m confused. You just said mammals aren’t descended from reptiles. Now you’re saying that there’s no difference between mammals and reptiles?
How about the “objective” reasons that (1) mammals have live birth rather than eggs, (2) mammals have mammaries, (3) mammals tend to be hairy rather than scaly, (4) mammals have a different brain structure including the hippocampus and forebrain?
I understand that. Fact is, even something as simple as a modern species may be different enough across time that the earliest forms can’t interbreed with the current forms, sort of like ring species. That’s a problem of our need to define clear distinctions and classifications on something that is a blurry spectrum.
But the distinctions are relevant to at least some degree, or they wouldn’t exist. Otherwise, just call everything an amphibian* and leave it at that.
*Amphibian, reptile, bacteria - how far back on the evolutionary tree do you want to go?
Maybe the distinction isn’t over cladistics, but the definition of the word “are”?
Actually, I think it’s more a distinction over “old taxonomy” vs “new taxonomy”. As we learn more about various groups, we redefine them, both in terms of who ought to be included in the group, and who they are related to. For example, “amphibian” is one of those “old groups”. It is more descriptive of a lifestyle than it is representative of actual phylogenies. Mammals (and reptiles for that matter) were never actually amphibians (in the taxonomic sense; though, as Grendel’s Father alluded, the layman’s definition of “kinda newty-looking and wet” tends to overshadow the technical definitions); we just shared some ancestors among the early amniotes and tetrapods that looked kinda newty and spent a lot of time in the water. But we are unrelated to actual newts and frogs and salamanders, unless we go all the way back to those early tetrapods (at which point no-one was a strict, taxonomic “amphibian” yet…).
So, in a lot of ways, the distinctions being made today are the result of refining the way we think about relationships. Linnaeus was a creationist, so he grouped organisms together based largely on appearance, or modes of life, rather than any actual relationships. Today, we try to group organisms based on relationships, and the result is that a lot of older definitions for things like “bird”, “reptile”, “amphibian”, “dinosaur”, etc. wind up getting re-worked in the process. As we find older and older fossils for specific groups, we begin to get clearer pictures of just who is related to whom, and therefore into which groups one ought to be classified (with the caveat that all such classifications are inherently artificial).
That’s exactly the problem, and the new phylogenetic definitions propose to actually define these sorts of things. Recognizing that you need a cutoff point somewhere, hard and fast cutoff points are now being proposed, and the result is that in some cases, it’s impossible to keep recognized groups (like reptile, amphibian) in tact.
In your example, one of the criterion you list for “mammal” is that mammals give live birth. Well, monotremes have traditionally been included as mammals rather than reptiles or amphibians, and they lay eggs. So under your proposed definition, you’re already chopping up a traditional group. Under the most widely accepted phylogenetic definition, a mammal is the most recent common ancestor of placentals, marsupials, and monotremes, and all its descendants. This has the benefit of being defined explicitly to include all traditional mammals. However, it is based on relationships, not appearance or physical characteristics, and from what we know about mammal evolution, this means there are extinct non-mammals with hair and milk that would probably have been considered mammals if they were alive today (Castorocauda, for example).
Same goes for birds. If you define “bird” based on a suite of characters roughly corresponding to the quintessential bird (egg-laying, feathers, toothless beak) you exclude things like Archaeopteryx and Ichthyornis which had teeth. A looser definition based on one key character, say feathers, will include things like Velociraptor that have not traditionally been considered birds. Then you have to go further and define what you mean by feather (or hair, or mammary) since there will doubtless be intermediate stages where things have near-feathers or sorta-milk.
Strict phylogenetic definitions throw all this ambiguity out the window for better or worse.