On Thursday, May 21, 2020 at 8:46:43 PM UTC-4, DD'eDeN aka note/nickname/alas_my_loves wrote:due to climate drying giving advantage to those which could swiftly transit increasingly open land between swamp forests, evading large land predators.
On Thursday, May 21, 2020 at 10:34:19 AM UTC-4, nyik...@gmail.com wrote:
On Wednesday, May 20, 2020 at 10:45:10 PM UTC-4, DD'eDeN aka note/nickname/alas_my_loves wrote:
On Wednesday, May 20, 2020 at 9:30:22 PM UTC-4, nyik...@gmail.com wrote:
On Wednesday, May 20, 2020 at 8:30:07 PM UTC-4, DD'eDeN aka note/nickname/alas_my_loves wrote:
Laryngeal airsacs & quadrupedalism in great apes.
One occurred due to adopting swamp forest dwelling where loud repeated hoot vocalizations (aural battles kept them from crocs), larger (inflated) upper body size, and possibly flotation (falls into water) gave advantage; the other occurred
slowly crossing wide open spaces carrying roundshields, thrusting spears and throwing stones.Great apes are still swamp forest hominoids, even savanna chimps and mountain gorillas retain these traits, which humans and gibbons never had, due to living primarily along small shallow crystalline streams without big crocs; and groups
Here in Columbia, our award-winning Riverbanks zoo has had siamangs ever since
I came here in 1979, and probably several years before. They have two troops on
two separate big rocks separated by water, and one of the high points of our visits
is usually a "concert" by them that comes every few hours. It a long series of vocalizations that include loud hooting and highly conspicuous inflating of
laryngeal air sacs.
So it came as a surprise to me that the closely related gibbons have none of this.
Are you really sure about your data? If so, the large inflated air sacs of great
apes are probably a nice example of evolutionary convergence, and their lack
among gibbons and ourselves is a no-brainer example.
Peter Nyikos
Professor, Dept. of Mathematics -- standard disclaimer--
University of South Carolina
http://people.math.sc.edu/nyikos
The Eureka zoo (CA) had a pair of siamangs and next door about 6 spider monkeys, so I was able to compare their brachiating, climbing, carrying and walking habits.
I refer only to obvious, visible, balloon-like LAS in primates (and reindeer/caribou).
Several of the siamangs here exhibited them; in at least one case, the "balloon"
was about as big as the whole head.
This was at the height of their chorus.
A vast number of mammals have modifications to the simple larynx of either rigid or inflatable soft tissue. Humans (glass-blowers) can pathologically develop laryngocoeles undoubtedly analogous to ape LAS, but it is rare with no benefits.
Our South Carolina State Museum had a hologram of Dizzy Gillespie with cheeks
balooning while blowing the trumpet, but the two "balloons" together still didn't
equal the size of the rest of his head. Do glass blowers come close to even one-third
of the size of their heads with their laryngocoeles?
blistering that just appears similar to airsacs externally. I don't know.Peter Nyikos
I haven't seen an example, can't say for sure, but I think they are typically far smaller. I read a book on glass blowing, no mention of it at all. Perhaps it is due to errant methods, possibly due to accidental inhaling of heated air, a sort of
A little request: might you be able to contribute something to the thread I began
on postorbital bars in Hominidae? Do all known members have the postorbital bars
solidly fused to the rest of the skull? If so, what about the members of Hominoidea,
including the fossil members of "stem Hominoidea"?
By the way, I retract "no-brainer example" because over in t.o, you are hypothesizing
the non-parsimonious claim that there have been at least three separate examples
of evolutionary convergence just in Hominoidea. Possibly 5, if it arose separately
in gorillas and chimps, or australopiths and all others
You try to argue that your argument is the most parsimonious that takes all the
data into account, but the only datum I recall is movement towards swamps. You
contrast that with non-LAS being associated with shallow crystalline streams,
but what's the connection? Do you disagree with Mario about Hominina being dwellers of the grasslands?
Peter Nyikos
Professor, Dept. of Mathematics -- standard disclaimer--
University of South Carolina
http://www.math.sc.edu/~nyikos/
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