Re: Ceratopsian paraphernalia

[Ronald Orenstein <ornstn@inforamp.net>]

At 05:24 PM 12/10/97 -0500, you wrote:
>Why do birds have such a wide range of feather patterns/colors?  Because
those patterns help with species identification, especially during the
breeding season.  In the same way, ceratopian (note the missing "s")
headgear is a way for the different species to tell each other apart, and
prevents interspecies unions.
>Rob Meyerson

This is, I am afraid, a gross oversimplification.  There are many suggested
reasons for the colour patterns we see in birds, and species recognition is
only one of them.  Colour patterns may not be important in species
recognition at all in some birds (eg owls, perhaps) or far less important
than voice.  I recommend the following paper:

Savalli Udo M. 1995. The evolution of bird coloration and plumage
elaboration: a review of hypotheses. Current Ornithology 12: 141-190

Savalli reviews some thirty different hypotheses.

In short - it may well be true that the difference in frill size and shape
in ceratopians was for interspecific recognition but it is unjustifiable to
claim that this is an open-and-shut matter.  At least some of the
differences may have related to differing diet (involving differing muscle
attachment scenarios), antipredator or intraspecific combat behaviour, or
something else we haven't thought of yet.  Besides, although differences
between species may have evolved for species recognition, differences
between genera or higher taxa may reflect other functions.  The more
divergent taxonomic lines become the less critical is the need to maintain
specific mechanisms to avoid interbreeding.  For example - the basic
differentiation between long-frilled and short-frilled forms may reflect
fundamental differences in diet , feeding behaviour or social structure;
minor differences among species within each group may be isolating
mechanisms.
--
Ronald I. Orenstein                           Phone: (905) 820-7886
International Wildlife Coalition              Fax/Modem: (905) 569-0116
1825 Shady Creek Court                 
Mississauga, Ontario, Canada L5L 3W2          mailto:ornstn@inforamp.net