|
If you buy some of the molecular clock estimates that have been published, a Turonian galliform makes perfect, uncontroversial sense, and the various Cretaceous fragments that were assigned by paleoornithologists to modern orders also really might be charadriiforms,
gruiforms, etc. - busting the ghost lineage. In what little I know about birds, though, they are prone to homoplasy. Especially with the fragmentary, mostly postcranial material from the late Cretaceous (Senonian), where one would want completely-preserved
fossils from lagerstaetten (e.g. the Jehol fauna), it seems amazing to me that anything concrete is know about these birds.
Thomas Yazbeck
From: dinosaur-l-request@mymaillists.usc.edu <dinosaur-l-request@mymaillists.usc.edu> on behalf of Mickey Mortimer <mickey_mortimer111@msn.com>
Sent: Wednesday, April 28, 2021 4:18 PM To: dinosaur-l@usc.edu <dinosaur-l@usc.edu> Subject: Re: [dinosaur] What is the earliest known bird
Based on the previous discussion here by Chen (http://dml.cmnh.org/2021Feb/msg00135.html)
on how labile the positions of basal Aves are just based on the inclusion or exclusion of various large flightless forms, I don't think we have a good enough analysis to answer what the earliest avian is. If something as complete as vegaviids can move in
and out of Aves, what chance do the usual fragments have of being placed with confidence? Also of note is that even if we have great evidence a taxon exhibits avian synapomorphies, it could still be on the stem unless we can also tie it to neognaths or palaeognaths.
That said, I think two pre-Campanian records than deserve more analysis are Turonian Tingmiatornis and Agnolin et al.'s Turonian-Coniacian galliform-like coracoid.
Reference- Agnolin, Novas and Lio, 2006. Neornithine bird coracoid from the Upper Cretaceous of Patagonia. Ameghiniana. 43(1), 245-248.
Mickey Mortimer
From: dinosaur-l-request@mymaillists.usc.edu <dinosaur-l-request@mymaillists.usc.edu> on behalf of David Marjanovic <david.marjanovic@gmx.at>
Sent: Tuesday, April 27, 2021 3:02 PM To: dinosaur-l@usc.edu <dinosaur-l@usc.edu> Subject: Re: [dinosaur] What is the earliest known bird The oldest member of what is, unfortunately, officially* called Aves is not the late Maastrichtian
Vegavis and not the end-Maastrichtian Asteriornis. Most likely it is the presbyornithid stem-anserimorph
Teviornis, which is from somewhere low in the Nemegt Formation. That seems to mean it's from the very beginning of the Maastrichtian or older. (For the meaning of "seems", watch
this space.) If you read the so-called supplementary information** of the
Asteriornis paper, you'll find the authors were aware of Teviornis and didn't even try to argue that it wasn't a member of Aves.
The latest phylogenetic analyses have found Vegaviidae outside Aves. But if it's inside after all, keep in mind that the oldest known vegaviid is probably not
Vegavis (or Polarornis or Neogaeornis, all late Maastrichtian) but
Maaqwi, which is end-Campanian (so about the same age as Teviornis).
*In Phylonyms, the starting point of regulated phylogenetic nomenclature; its registration number is 113. Go
here, click on the search result, then click on "Definition".
** Always read the supplementary information. That's
particularly important in Nature, Science and PNAS, where the "paper" is just an
extended abstract and the "supplementary information" is
the actual paper. Asteriornis deservedly came out in Nature.
Gesendet: Dienstag, 27. April 2021 um 21:41 Uhr
Von: "Meig Dickson" <mdickso2@uic.edu> Alternatively, we go the *fun* route and say all members of Pan-Aves are Birds (since they're more bird than anything else), and then, well, there was some sort of avemeta-thing in Poland in the Early Triassic...
Not that I know of. Are you thinking of the stem-archosauromorph Osmolskina?
|