Re: vampire ptero toe

["Tim Williams" <twilliams_alpha@hotmail.com>]

Silvio Renesto wrote:

> Chris suggested that its life style might be compared to that of nightjars 
> and other big mouthed birds who chase insects on wing, in dim light or even 
> during night. Maybe not a vampire, but nocturnal however... ;-)

A wider mouth or beak tends to be associated with aerial hawking for both 
birds and bats.  I know there have been morphometric studies in bats on this 
very topic.  A broader beak also occurs in birds that catch insects on the 
wing, irrespective of whether the bird is diurnal or nocturnal.

Catching aerial insects is not an easy thing to do.  Many members of the 
Caprimulgiformes (mostly nocturnal or crepuscular) have rictal bristles 
around the mouth, which serve as insect-detection devices, as well as a sort 
of insect net (or funnel).  I believe certain insect-catching passerines 
have rictal bristles, such as flycatchers (Tyrannidae) and the redstart 
(Parulidae).

All this undercuts the hypothesis that the ancestors of birds developed 
wings in order to catch aerial insects.  Non-avian theropods have narrow 
snouts (with the possible exception of _Epidendrosaurus_/_Scansoriopteryx_, 
which is described as having a wide mouth).  Insect-catching theropods would 
presumably have to compete with insect-catching pterosaurs, which had a 
headstart on them of about 70 million years.



Tim

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