Re: Dinosaur "baculae"

[pwillis@ozemail.com.au (Paul Willis)]

>
>        Oddly put, but true in some circumstances.  As for crocs', however,
>they do not possess a true penis.  Instead, they possess the corpora
>cavernosa penis, a pair of ridges that expand when filled w/ blood to form
>the lateral and ventral walls of the semenal passageway.  This does extend
>beyond the cloaca, and is inserted in the female.   Yes, the reduction in
>size of the genitalia in many birds could be an adaptation for load
>lightening, associated w/ flight.  The testicles of some species even
>atrophy when not in mating season.  You can't say that dinosaurs possessed
>true penises, because the penis has only been inherited through the lineage
>of one particular group:  for a real bunch of dicks, try mammals.
>
>


It all comes down to what you are prepared to accept as a penis. Call the
croc todger a penis, an intromitent organ, willy, eric, harold or whatever;
the structure ends up as an analogue of the mammalian John Thomas even if
not technically a homologous structure. And whatever the crocs have, the
birds haven't. So between crocs and birds, the nob has dropped off. I would
still stick by this genital protusion being lost in birds as a responce to
flight leaving the clear possibility that dinosaurs possessed a willyoid.

Bringing it back to baculae, is this a synapomorphic character of mammals?

Cheers, Paul

pwillis@ozemail.com.au