Phorusrhacoid birds: comments and some references

[bh162@scn.org (Phillip Bigelow)]

Regarding paleoecology and competition, Brian Choo wrote:

>>On Fri, 13 Mar 1998, Phillip Bigelow wrote:
>>
>>Many hypotheses can be mounted for this extinction.  But birds are
>>incredibly evolutionarily maleable.  In light of the low diversity of
>>large bodied birds (roughly one type per southern hemisphere continent),
>>something more general must be going on.  Whatever this something is, it
>>is apparently relaxed on mammal-free islands, eg., elephant birds and moa.

>Huh?...then whats with Australasia with Emus, 3 Cassowary species and,
>until the Holocene, Mihirungs and giant megapodes?


Actually, someone got the addributions wrong;  I didn't write
the above.  And, I wouldn't agree with it, either.
Phorusrhacoid birds got along quite well with North American
mammalia for over 1 million years, thankyouverymuch.



John Jackson wrote (regarding big killer ground birds of N.A.):

> a similar sort of bird
> holding a horse up in the air in its beak and waving it around - a very
> early horse of course! - and that WAS a very early tertiary bird. Try as
> I might I can=92t find that picture now.


If I recall, the picture you remember was in an issue of _Discover_
magazine of a year or so ago, along with a profile of Chandler, the
principal investigator.  It was of _Titanis walleri_, a
phorusrhacid birdy.

Dr. Chandler scuba dives for the fossils (which are found
in the bottoms of deep river channels and sink holes in
Florida).


> (PS any Ph.s in the tar pits?)

None as yet.  The phoro's may have been climate sensitive.
They got into North America by the Pliocene, and stayed
into the Pleistocene.  The only occurrences I have read about
are in Florida and one occurrence of a phalanx found in
a Pleistocene gravel pit in south Texas (the thing looks
strongly like an ornithomimid toe bone).
There is the small chance that the Texas occurrence may
be a bone that was reworked from older Pliocene rocks,
and later redeposited in the Pleistocene gravels.


Here's a ref. on the phoro' toe bone from Texas:


Baskin, J.A. 1995. The giant flightless bird _Titanis walleri_
  (Aves: Phorusrhacidae) from the Pleistocene coastal plain
  of south Texas. Journal of Vertebrate Paleontology
  15(4):842-844



Here are two other "big killer ground birdy" refs:


Brodkorb, P. 1963. A giant flightless bird from the
   Pleistocene of Florida. Auk 80:111-115.


Chandler, R. 1994. The wing of _Titanis walleri_ (Aves:
   Phorusrhacidae) from the late Blancan of Florida.
   Bulletin of the Florida Museum of Natural History,
   Biological Sciences 36:175-180.


                 <pb>


--
                 Phil Bigelow
                 bh162@scn.org