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ORNITHOCHEIRIDS 'RESOLVED' etc
I'm combining responses to several recent DML threads in this one
email, ostensibly to save valuable time.
_Ornithocheirus_ has been described as the most tangled taxonomic
mess of all archosaur taxa. Remarkably, within the space of a few
weeks, it looks like most of the mess is going to be resolved - I've seen
Dave Unwin's in press MS on the Cambridge Greensand pterosaurs and
this sorts out a lot of the problems concerning the type material.
Furthermore, Dave Martill and Dino Frey now have their new crested
ornithocherid in press - again I have seen the MS and this provides
some new intriguing resolution of the _Ornithocheirus_ problem. No
doubt if Dave Unwin is reading this he will take umbridge...:) Also,
Michael Fastnacht has just published...
2001. First record of _Coloborhynchus_ (Pterosauria) from the
Santana Formation (Lower Cretaceous) of the Chapada do Araripe,
Brazil. _Palaontologische Zeitschrift_ 75, 23-36.
This describes a new large specimen which has a particularly vicious
array of rostral teeth (we have a cast of it here at UOP - great fun to
play with) which helps to sort out the _Criorhynchus_-
_Coloborhynchus_-_Tropeognathus_ situation. Some of this will be
further resolved when the papers alluded to above come out.
SERIEMAS AND SICKLE CLAWS
Seriemas do have an enlarged and strongly curved claw on the second
digit and it is sometimes (but not always) 'held up' relative to the other
digits (though not hyperextended). I have photos that demonstrate this.
This claw is not just used in tussles with other seriemas - according to
HBOW it's also employed in climbing.
Jaime - since when are caprimulgiforms s.l. raptorial? I used the sensu
lato because of recent suggestions that caprimulgiforms are
paraphyletic, or that steatornithids are not allied to other
caprimulgiforms - they have fallen out in a few recent super-trees with
herons and other ciconiiforms.. but then I did say 'super-tree':)
PAMPRODACTYLY IN BIRDS
'Trunk-clinging' scansorial birds, which include the campephilin
woodpeckers, pygmy parrots and coliiforms, are generally
pamprodactyl, thus pamprodactyly is reasonably interpreted (IMHO) as
advantageous for trunk-climbing behaviour in birds. The alternative
option seems to be to have hyper-curved pedal claws (e.g.
rhabdornithids, sittids, certhiids) but this can only work if the bird is
very small (Naish 2000 paper in _Archaeopteryx_). For animals which
have manual claws as well the pedal ones the rules may be different.
Dave Peters has suggested that the presence of a sternal keel may also
be something to do with trunk-clinging behaviour.
FURTHER ON WARBLERS
Nick Pharris noted that some of the parulids (_Dendroica_ and kin)
might be very difficult/impossible to separate osteologically. I don't
know, but of relevance to this is the recent finding that the parulid
radiation is apparently younger than that of the OW sylviid warblers
with which it is often compared (Price et al. 1998 - Different timing of
the adaptive radiations of North America and Asian warblers - _Proc.
R. Soc. London B_ 265, 1969-1975). For comments on osteology of
leaf warblers see Boev's recent stuff on Pleistocene Bulgarian records
of this genus.
Also, WRT to the comment that generic boundaries among sylviids are
still pretty fuzzy, I neglected to mention one recent development that is
more or less evidence of this: Leisler et al. (1997) found that
_Hippolais caligata_ (Booted warbler) and _H. pallida_ (Olivaceous
warbler) are actually members of _Acrocephalus_. Haven't yet seen
this reflected in any field guide.
WALKING WITH BEASTS THING LAST NIGHT
Last night BBC screened part 2 of their 'making of' thing for WWB.
All about primate evolution, and by and large rather dull without much
new stuff. IMHO they simplified hominid phylogeny too much by
implying that the australopithecine-modern human lineage involved
incremental steps in 'improving' the upright posture and in enlarging
the brain. In fact the recent work of McHenry, Pickford and others
seems to show that hominid evolution is more mosaic than this - e.g.
some of the 'more primitive' australopithecines are proportionally
more human-like than certain of the 'more derived' taxa, and there is an
indication from _Orrorin_ and other fossils that bipedality might be
primitive for hominids or hominines.
Finally, the programme ended by stating that the end-Pleistocene
megafaunal extinctions were caused by climate change, and were not
anthropogenic. Bletch! This indicates that they did not consult with
John Alroy, Martin Klein, Jared Diamond and others who can present
good arguments to the contrary: there is no consistency in the pattern
of climate change and megafaunal extinction, whereas human invasion
and megafaunal extinction are _always_ correlated. Coincidence?
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