Marty Michener quoted Doug as writing:
>>
>> Plesiomorphic traits are traits that have been passed down through earli=
er
>> taxa. They arose in animals which evolved prior to the animal in questio=
n,
>> and they continue to manifest themselves, usually because they are
>> effective. In the sense of bird (and other animal) communication, we oft=
en
>> find certain calls that several different, but related, species use - th=
is
>> is a plesiomorphic call - it came from a common ancestor.
>
And in discussing that statement, Marty added a note of caution:
> So, although what Doug says sounds fair enough for my purposes, he is
> assuming the plesiomorphologicality of sound traits, and it is going to g=
et
> trickier and tricker before AOU is done. Taxonomists got where we are no=
w
> by always assuming certain characteristics are non-adaptive (conservative
> characteristics). I think we sound-people should now be more and more
> suspicious of convergence, especially in evolving communication
> systems.=20
Now there are two species of lyrebirds (and two only, apart from a fossil),
clearly closely related. They both use the same intense alarm call - an
extremely loud, ear-piercing shriek. On rare occasions I have walked aroun=
d
some obstacle blocking the view and come face to face with a lyrebird.
Believe me, that shriek gives one a hell of a shock. I can well imagine it
causing a predator to pause for just that fraction of a second the lyrebird
needs to escape.
I wonder if Menura tyawanoides (the fossil species) was their plesiomorphi=
c
ancestor? Bit hard to tell from one petrofied leg bone, what its alarm cal=
l
sounded like.
Anyway, the situation seems to fit what Doug and Marty are on about ... or
am I assuming plesiomorphologicality (what a lovely word!) where none
exists?
Cheers
Syd :-)
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