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CASSOWARY DIMORPHISM



Hey folks. I have the _Sinosauropteryx_ paper in hand: much 
interesting stuff on compsognathid digits (relevant to recent 
discussions) as well info on eggs, stomach contents and much more. 
I'll post about it later. 

Anyway, Jim Farlow wrote..

> I noticed that the big ungual on digit II of a  male cassowary, 
>_Casuarius unappendiculatus_, was something like 20%  longer
> than on a similarly sized foot of a female of the same species.     
> The horny claw on digit II on a study skin of a male of _C. bennetti_,    
>  and also a male of _C. unappendiculatus_, looked positively 
> enormous.  I don't remember seeing anything in the published 
> literature about possible sexual dimorphism in the nasty digit 
> II claw of cassowaries.  Does anybody out there know if such 
>sexual dimorphism has in fact been  documented in these birds?  

I consider myself well read on ratites (and modest too),  and, what 
can I say: wow! While there are _numerous_ allusions to sexual 
dimorphism in cassowaries, these refer only to a size difference: 
females are bigger. Female emus are bigger than males too, 
incidentally. From my notes (so, sorry, no complete refs) it also 
seems that females are more brightly coloured than males: Pizzey 
(1991) states 'female averages slightly larger, heavier than males... 
wattles and skin of neck brighter', Simpson and Day (1994) [best 
field guide on extant dinosaurs ever published] says 'females 
slightly larger, brighter coloured'. 

In fact, one is hard pressed to find any mention of the 
hyperenlarged sickle-claw of cassowaries in the literature 
(though there are frequent mentions of the horrific disemboweling 
kicks the birds can wield), and to my knowledge no-one has ever 
observed sexual dimorphism in the claw. Want to co-write a paper 
Jim?;)

"They don't see it. None of them see it. But I see it"

DARREN NAISH
darren.naish@port.ac.uk