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Re: Early birds



>Tom Holtz <tholtz@geochange.er.usgs.gov> says:
>> Maniraptora is a clade defined as "birds and all dinosaurs sharing a more
>> recent common ancestor with birds than with ornithomimosaurs".
>
>This prompts me to ask a question I have been wondering about.
>Birds apparently evolved in the Jurassic so they were around a long
>time before the other dinosaurs died off.  Were they a wide spread
>and conspicuous taxa like today or where they relegated to the
>backwaters of evolution until the K-T extinction like the mammals?

Recent evidence shows that birds were fairly diverse during the Cretaceous,
including perchers, flightless runners, toothed swimming loon-like forms,
and toothed flying tern-like forms.  One group of flying birds, the
Enantiornithes, are found on almost every continent.

>I realize that birds did not fossilize well and their ancestory is
>poorly known.  However, what is known?  Were there Cretaceous
>equivalents of oxpeckers eating the ticks off T. rex or cattle
>egrets following Triceratops around?

No forms like that have been found (although those aren't unreasonable from
an ecological point of view).  None of the really specialized modern groups
(woodpeckers, flamingos, owls, swifts, etc.) are known from the time.  In
fact Alan Feduccia presented data on Sunday (how's that for up-to-date!)
that none of the Mesozoic bird can be placed in any modern order.

                                
Thomas R. Holtz, Jr.                                   
tholtz@geochange.er.usgs.gov
Vertebrate Paleontologist in Exile                  Phone:      703-648-5280
U.S. Geological Survey                                FAX:      703-648-5420
Branch of Paleontology & Stratigraphy
MS 970 National Center
Reston, VA  22092
U.S.A.