PNEUMASTATICS & FROGS

[darren.naish@port.ac.uk]

Quick responses to a few things...

The idea that sauropods may have used air sacs to maintain self-
carrying beam-like neck constructions owes itself to the theory of 
pneumastatics. This was developed by John Martin and Dino Frey in 
the mid 1990s and covered in talks here in the Uk: work which, so far 
as I know, predates more recent research unveiled at SVP. However, 
they never published (though the philosophy clearly forms part of the 
background to their 1999 _Oryctos_ paper on sauropod neck 
constructions). 

John's on-stage illustration of the concept was much as visualised by 
Jerry: a series of long cardboard tubes, connected to one another by 
string, and with a bicycle inner tube running through all the tubes. 
When the inner tube is inflated, the cardboard tubes form a stable self-
carrying system. They compared this model with dissections of 
ostriches and other birds and proposed a lateral air sac system (as per 
Matt Wedel et al. in the excellent _Acta Pal. Pol._ _Sauroposeidon_ 
paper) as well as a dorsal one, the latter connected (somehow) to the 
external nares. Dorsal interspinous ligaments were also involved, and I 
recall Dino showing a slide of a _Dicraeosaurus_ mount that preserves 
an ?ossified remnant of part of one of the ligaments. I'm doing this 
from distant memories of unpublished work and long-ago pers. comm. 
with Dino, so some of the facts may be off.

David Marjanovic recently said a few things I'd like to briefly respond 
to. First off...

> Hunting frogs is difficult. 

This is a fairly silly generalisation, seeing as frogs are as difficult to 
hunt as any other animal. As you'll no doubt know from wildlife 
documentaries, most kinds of predatory animals kill frogs - storks, 
herons, owls, big cats, small cats, fringe-lipped bats, crocodiles, 
alligators, frogs, wolf spiders, desmans, water shrews, hedgehogs, 
humans, grass snakes etc etc etc. Seeing as there are many small frogs 
(today and, apparently, in the Mesozoic), many small-bodied predators 
eat them.

> Considerably larger size, and maybe
> arboreality or an ability to swim, will help. Same except for
> arboreality for urodeles. 

Quick note: there is a radiation of arboreal plethodontid salamanders 
(_Bolitoglossa_ and co: they have prehensile tails and adhesive foot 
pads and are tiny). Molecular phylogenies indicate that they arose in the 
Miocene however.

Finally.. David mentioned mystery big cats in Australia which are 
'often seen' (or words to that effect). Reports of 'Queensland tigers' 
(widely hypothesised in the cryptozoological literature to be extant 
thylacoleonids) range only from the late 1800s to the 1930s or so, 
with one or two more recent supposed sightings (Gilroy 
notwithstanding). Only a handful of these actually match the 
_Thylacoleo_-like incarnation of this beast devised by Heuvelmans 
(1958). Most Australian researchers now think that 'tiger' sightings 
were actually of thylacines (P. Chapple pers. comm.). I could say more 
but, hey, two words: DINOSAUR LIST.

"Here and there the perches gave way with a crash under the weight, 
and fell to the ground, destroying hundreds of birds beneath ... The 
scene was one of uproar and confusion. I found it quite useless to 
speak, or even to shout. Even the gun reports were seldom heard, and I 
was made aware of the firing only by seeing the shooters reloading"
        -- Audubon, on passengers pigeons

DARREN NAISH 
PALAEOBIOLOGY RESEARCH GROUP
School of Earth & Environmental Sciences
UNIVERSITY OF PORTSMOUTH
Burnaby Building
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