[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
Re: Dinosaur Vocalization
Even if they didn't have avian vocalisation, crocodilian vocalisation
is most impressive. One way or another I'm sure the Mesozoic was a
bizarre and unique soundscape.
On Saturday, December 4, 2010, Sim Koning <email@example.com> wrote:
> I'm currently reading through Phil Senter's 2008 paper 'Voices of the
> past: a review of Paleozoic and Mesozoic animal sounds'. So far I'm finding
> it very interesting and informative, but I have some problems with some of
> his arguments for the lack of vocalization in dinosauria. I'm not a
> scientist, so I'm hoping that others on this list can help point out some key
> points that I may have missed. The argument seems to be as follows: there is
> lack of osteological indicators for pneumatization of the humerus in
> non-avian dinosaurs and since there are osteological indicators for other air
> sacs in dinosaurs, but not for the clavicular air sac, then it is unlikely
> that non-avian theropods possessed clavicular air sacs. I think there may be
> several logical flaws with this claim:
> 1. If ontogeny recapitulates phylogeny in bird embryos, then as the paper
> suggests, we may presume that clavicular air sacs evolved late in
> ornithodiran history. However, using the same reasoning, we may presume that
> air sacs evolved before they invaded the bones. Therefore, the lack of
> osteological indicators for a particular air sac is not strong evidence for
> its absence.
> 2. There may not have been sufficient selective pressure for theropods to
> evolve highly pneumatized humeri prior to the evolution of flight. The
> forelimbs of theropods were used primarily in the acquisition of prey, so it
> may have been more beneficial for (most) theropods to retain solid furculae
> and forelimb bones. The possibility that flying pterosaurs were the only
> other archosaurian group outside aves that evolved pneumatic humeri may be
> evidence of this.
> 3. Since air sacs of dinosaurs probably evolved before they invaded bone, the
> ancestors of Aerosteon may have had fully formed clavicular air sacs and
> therefore a syrinx. Considering this, I find it more parsimonious that the
> common ancestor of Aerosteon and aves possessed a clavicular air sac rather
> than evolving independently in allosauroids and aves. If this was the case,
> then we may use phylogenetic bracketing to presume that most taxa between
> Aerosteon and aves may have possessed a syrinx and so may have been capable
> of avian style vocalization.
> Those are a few things that came to mind while reading that section of the
> paper. I apologize if this subject has already been heavily addressed on the
> mailing list.
> Simeon Koning.