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RE: Alvarezsaur spurs (was Re: dino-lice)



Yes.  In Shuvuuia IGM 100/977 and 100/1001, both photographed in Chiappe et al. 
(2002).  They're ~37% of skull length, slender and bowed laterally with no 
expansions I can see.

Mickey Mortimer

----------------------------------------
> Date: Tue, 3 May 2011 06:38:25 +0800
> From: ron.orenstein@rogers.com
> To: augustoharo@gmail.com
> CC: d_ohmes@yahoo.com; dinosaur@usc.edu
> Subject: Re: Alvarezsaur spurs (was Re: dino-lice)
>
> Picid tongues are supported by an extremely elongate hyoid apparatus. I would 
> expect that if alvarezsaurids had a protrusible tongue the hyoid would show 
> specialization to that effect - are hyoid elements known for the group?
>
> Ronald Orenstein
> 1825 Shady Creek Court
> Mississauga, ON
> Canada L5L 3W2
>
> On 2011-05-03, at 2:09 AM, Augusto Haro  wrote:
>
> > Perhaps conservation of canines until developing powerful arms with
> > large claws is a way an anteater can protect itself. Phylogenetically,
> > conservation of canines makes sense, overall if descending from a
> > clade where the canines were much used. At least, there is an
> > intraspecific struggle selective force acting for their conservation,
> > in absence of other weapon. I once saw a video with an aardvark trying
> > to bite a cheetah which was trying to play with it. I suppose that
> > although biting will not be great thing against a larger hyena, lion
> > or leopard, it may at least diminish the list of predators, because
> > the similarly sized jackal and Cape badger would likely go for it if
> > this defense was not present (as far as I was able to observe, no
> > matter how courageous they are, mammalian carnivores do not prey on
> > other carnivores not smaller than they one-on-one, probably because
> > they have canines similar in effect to their own).
> >
> > Returning to the question of mymecophagy and cursoriality, I think
> > they are not exclusive, as shown by Proteles, and also the canid
> > Otocyon, but this is constrained because most myrmecophages today are
> > quadrupedal mammals, where you cannot specialize the forelimb for
> > myrmecophagy in the sense of anteaters or pholidotans while keeping
> > being a cursor. When termites go around without need to break their
> > nests, a cursor may perfectly feed upon them. The limbs of cursors are
> > energy-saving because of their longer stride and lesser weight
> > distally, requiring less force to be moved forwards, so can easily be
> > used for an energy-saving myrmecophage. It seems that the inactivity
> > of the specialized Proteles has more to do with the inactivity of the
> > termites themselves. Likely, if the termites were less seasonally
> > variable in activity, or active during a larger part of the day, the
> > aardwolf would be a similarly more active animal.
> >
> > Now, turning back to alvarezsaurs, they may have simply specialized
> > their forelimb without need to lose their hindlimb cursorial
> > adaptations (as many said). Thus, lack of cursoriality in most
> > myrmecophagous mammals can be explained because of the adaptation of
> > the forelimb, instead of metabolic rate constraints. Now, if
> > alvarezsaurids were capable of preying upon termites in their nests,
> > thanks to their forelimbs, they may have likely enjoyed this food
> > during a larger part of the year, overall accepting the calid
> > conditions loved by termites were more common in the Mesozoic.
> >
> > Other thing: there are birds, like picids, which have a long, sticky
> > tongue to grab insects. This seems to make them more similar to their
> > mammalian myrmecophagous counterparts. Tubular mouths are less common
> > outside mammals because there are no cheeks (oh, well, except for
> > seahorses and curculionids). We may say it was difficult for
> > alvarezsaurs to have had a tubular mouth because of phylogenetic
> > constraints.