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The newest _Nature_ has this in the letters pages...
FEDUCCIA, A. and MARTIN, L.D. 1998. Theropod-bird link reconsidered.
_Nature_ 391: 754
Feduccia and Martin assert that the furcula recently described by
Norell et al (_Nature_ 389: 447) is not homologous to bird furculae
because it is rounded in cross-section (therefore unlike the
caudodorsally grooved design in birds), articulates along the
entire margin of the coracoid, and cannot be a furcula because
_Velociraptor_ and kin did not fly. They also say that the furculae
of _Longisquama_ indicate how furculae-like structures have evolved
several times in archosauromorphs.
They also bring up that old chesnut: 'The earliest-known bird,
_Archaeopteryx_, occurred 75-80 million years ealier than the
_Velociraptor_ and other Cretaceous theropods that had 'wishbones''.
They go on to say how all supposed Jurassic furculae are from
carnosaurs.. 'a group generally thought to be distant from birds -
although the cladistic analysis of Thulborn (1984) places
_Tyrannosaurus_ closer to modern birds than to _Archaeopteryx_'.
Oooh, a controversial phylogenetic statement: _Tyrannosaurus_ is back
in the Carnosauria! Theropod cladists: your hard work has been
Of course, Feduccia and Martin cannot get away with all of this, and
the letter is followed by...
NORRELL, M.A., MAKOVIKCKY, P. and CLARK, J.A.
1998. Theropod-bird link reconsidered: Norell et al reply. _Nature_
All of the weak arguments put up by Feduccia and Martin are refuted.
Exact similarity is not a requirement for homology, the
_Velociraptor_ furcula does not articulate along its entire length
with the coracoid, and _Longisquama_ is too controversial to overturn
the maniraptoran evidence.
And, of course, 'We did not say.. that _Velociraptor_ was a direct
ancestor, only that dromaeosaurs are related to birds. How do
Feduccia and Martin explain the presence of primitive living mammals
such as monotremes and marsupials 100 million years after they split
from the line leading to ourselves?'.
"Off the record? We were abducted by aliens"