[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: SVP 2004

David Marjanovic wrote:

grubs (forelimbs used to strip bark),

Not recommended for an animal that can climb... about as well as a horse.

I wasn't suggested that alvarezsaurs were arboreal! Eeek! However, if their ancestors were arboreal gliders or fliers, then the changes to the forelimb (such as the coossified carpometacarpus and manual digital reduction) may have originally been adaptations to aerial locomotion. I was suggesting that MAYBE the weird forelimbs of alvarezsaurids are a consequence of the forelimbs regaining grasping function after a period during which they were not used for grasping - analogous to _Titanis walleri_.

eggs (forelimbs used to carry and break open large eggs - and the
long legs were used to run away from angry mothers),

Unless the eggs had unrealistically thick shells, I'd rather suggest ordinary long maniraptoriform arms for that job. Several long fingers for grasping, long arms in general for fast snatching.

See above.

(BTW, I'm not at all hooked on this secondary-flightless ("2F") hypothesis for alvarezsaurids. I'm just putting the idea "out there".)

Oh yes. But then the Morrison Fm preserves termite mounds that are up to 30 m high.

Hasiotis, S.T. (1996). Termite (Insecta: Isoptera) nests from the Upper Jurassic Morrison Formation: Evolutionary, paleoecologic, and paleoclimatic implications. Geological Society of America, Abstracts With Programs. 28 (4) 10.