Talk:Mahakala omnogovae

Tertials

Can someone explain how this species can be Late Appearing and more basal at the same time? —Preceding unsigned comment added by 96.57.23.82 (talk) 01:35, 6 April 2010 (UTC)

Sure. It's comparatively late in the fossil record, and its characteristics are not as derived ("advanced") as might be expected at that point in time. It's like a guy who's running Windows 98 in 2010. J. Spencer (talk) 02:04, 6 April 2010 (UTC)

Good analogy! Also think of modern animals, like kiwi and platypus, much more basal than their contemporaries. (Or monkeys and humans, for that matter). Evolution is a tree, not a line. MMartyniuk (talk) 02:32, 6 April 2010 (UTC)

This image[1] has been removed due to the presence of tertial feathers, but do we really know they were not present (if that simply means feathers on the humerus)? FunkMonk (talk) 18:29, 24 March 2009 (UTC)

Well, out of all the Microraptor, Archaeopteryx, etc. specimens that preserve feathers, tertials have never been found. It's likely they only appeared in more advanced pygostylians. That said, they may have had long shoulder coverts in this region, but they'd be more like long/shaggy body feathers, not remiges.

Anyway, the image in question gets a lot wrong besides the tertials. The limb lengths are off. Legs should be longer and arms much shorter. Dinoguy2 (talk) 20:05, 24 March 2009 (UTC)

Ah, ok. So just to make sure that I know what you mean by tertials, are pretty much all of these restorations of Microraptor wrong? http://images.google.com/images?hl=en&q=microraptor&um=1&ie=UTF-8&sa=N&tab=wi FunkMonk (talk) 20:19, 24 March 2009 (UTC)

Not really (though most of them are wrong for other reasons). The secondaries usually do nicely to form the wing without tertials. It only looks like the feathers go all the way up the arm because most of the time, the humerus is held close to the body, not extended. Here's a diagram: [2] This [3] is a very accurate model. You can see the humerus is not extended, all the regimes are anchored to the ulna (remember that the inboard feathers will extend from the elbow and round out towards the body, sort of overlapping the humerus). If it had tertials, the wing would continue in a smooth grade into the torso, rather than forming a V between the torso and the wing.

Man, this is tough to try and explain in writing, maybe I'll try to photoshop something :) Dinoguy2 (talk) 20:34, 24 March 2009 (UTC)

Hre ya go, maybe this will help... [4] Dinoguy2 (talk) 20:46, 24 March 2009 (UTC)

Wow thanks! So this drawing is alright too? [5] Though the feathers appear to come out from way beyond the elbow. FunkMonk (talk) 20:56, 24 March 2009 (UTC)

Yeah, I think that one is too minor to notice. It's just the one little sliver of a laterally-viewed feather that looks like its coming off the humerus. Although... it does look like the elbow is sort of projecting above the plane of the wing, which would be an unusual configuration. But those are kind of nitpicky details. My philosophy is if it's close enough that people who aren't scrutinizing the anatomy under a fine toothed comb won't be misled, it's ok. It's hard to tell anatomy from a folded wing, but the Mahakala extended wing is the kind of thing you can see people copying or using for reference and perpetuating the incorrect arrangement. Dinoguy2 (talk) 21:43, 24 March 2009 (UTC)

Well, most Archaeopteryx specimens don't show whether any tertials are present or not. However, the "Thermopolis" clearly shows that at least long coverts were present on the humerus (as long as the length of the humerus itself). Perhaps the longest of these feathers were in fact the tertials or the coverts covered the bases of even longer tertials. In any case, reconstructions showing an empty gap between the elbow and the torso, seem to be incorrect.--MWAK (talk) 07:01, 18 June 2011 (UTC)

IIRC the humerus is usually abducted against the body to some extent during flight in most modern birds at least, making tertials unnecessary. Looking through the paper on the Thermopolis specimen, the text describes feathers near the elbow that may be tertials, but the diagram in figure 3 makes it looks like they're almost certainly the scapulars, and the longest ones arching around the proximal side of the elbow on the right look like the expected position of the proximal secondaries to me (the distal secondaries are normally oriented distally while the proximal ones point proximally in all birds i'm aware of, forming a 'semicircle' and also partly filling the gap left by the humerus). MMartyniuk (talk) 12:03, 18 June 2011 (UTC)

In fact, at least one of the authors of the monograph on the Thermopolis specimen is not convinced that tertials are present on that specimen. Albertonykus (talk) 12:45, 18 June 2011 (UTC)