CASSOWARY CRESTS

[darren.naish@port.ac.uk]

David Marjanovic and others have been writing about cassowary 
crests. This is something we have covered at length before, so excuse 
me for being repetitous. On the internal structure of cassowary 
casques, David wrote....

> Solid bone. Cassowaries have even been seen digging with it. (Well, 
> it could be hollow inside, but it is not fenestrated like in
> _Oviraptor_.)

Cassowary crests are tough because of their thick keratinous outer 
sheaths BUT the actual bony crest is very weak and certainly not solid. 
It is composed internally of hundreds of thin strut-like trabeculae 
which form a honeycomb-like arrangement: the external surface is a 
thin (approx. 1 mm) bony wall covered with foramina. On handling a 
skull once, I accidentally put my finger through the outer wall. The 
keratin sheath, which increases the crest height up to 100%, is the 
tough bit.

BTW, cassowaries have not really been seen 'digging' with the crest: 
instead they overturn soil or scrape leaf litter and soil aside.

For further discussion see the following, and the follow-ups...

http://www.cmnh.org/fun/dinosaur-archive/1998Jun/msg00222.html
http://www.cmnh.org/fun/dinosaur-archive/1998Jun/msg00075.html
http://www.cmnh.org/fun/dinosaur-archive/2000Mar/msg00024.html

"All jungles were their jungles, and no living thing could stand before 
them" (dholes, not cassowaries)

DARREN NAISH 
PALAEOBIOLOGY RESEARCH GROUP
School of Earth, Environmental & Physical Sciences
UNIVERSITY OF PORTSMOUTH
Burnaby Building
Burnaby Road                           email: darren.naish@port.ac.uk
Portsmouth UK                          tel: 01703 446718
P01 3QL