Wednesday, August 27, 2014

"Non-avian dinosaurs"

What does "non-avian dinosaur" mean?

The phrase "non-avian dinosaurs" crops up in many articles. What does it mean? As we see below, it lumps in the basal paraves (the feathered primitive flying and secondarily flightless primitive birds) with the real dinosaurs such as Tyrannosaurus - all of them under the same label - "non-avian dinosaur". In other words, it lumps in basal paraves with actual dinosaurs. 

"Now consider the group consisting of the non-avian dinosaurs (which is what people usually mean by the informal term ``dinosaurs''). This is a paraphyletic group, because it can't be defined simply as ``this animal plus all its descendants'', but must be described as one clade minus another: in this case, Dinosauria minus AvesThe ``non-avian dinosaurs'' make up a singly paraphyletic group because only one clade need be omitted from its base definition."

"it was not until the early 1990s that clearly nonavian dinosaur fossils were discovered with preserved feathers. Today there are more than twenty genera of dinosaurs with fossil feathers, nearly all of which are theropods. "
"By the 1990s, most paleontologists considered birds to be surviving dinosaurs and referred to 'non-avian dinosaurs' (all extinct), to distinguish them from birds (aves)."

AND notice these variations:

"Recent studies by Varricchio et al. reveal that males cared for the eggs of troodontids and oviraptorids, so-called "non-avian theropods" of the Cretaceous".

"The smallest non-avialan theropod known from adult specimens is the troodontid Anchiornis huxleyi, at 110 grams in weight and 34 centimeters (1 ft) in length.[3] "

I will talk about why this is a problem in the next post. 

7 comments:

  1. When can we expect the next post? I'm on the edge of my seat.

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  2. I'm dying here. I've been refreshing this page all day, waiting for the next post and nothing. I've other stuff i could be doing if you're not going to post it anytime soon

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  3. Your enthusiasm is heartening. Any idea yourself, what the problem is with a phrase like "non-avian dinosaur?

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  4. I have no idea! That's why I'm so excited!

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  5. Tell you what. Why not think about it?
    The topic is actually quite interesting.
    Or you can keep up your charade and continue to waste your time.

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  6. So you're not going to post why it's a problem now? This was a waste of time.

    ReplyDelete
  7. You have certainly wasted your time with your silly pretense.

    ReplyDelete