[Taxacom] another human-orangutan similarity

John Grehan jgrehan at sciencebuff.org
Wed Jan 12 09:34:29 CST 2011


Here's the latest result on another similarity between humans and
orangutans. This one is a little ambiguous with respect to character
polarity, although the similarity is definitive. Humans and orangutans
have about eight or more vallate papillae on the back of the tongue
arrange in a V formation. African apes have about eight or more arranged
in a Y formation. This difference seems pretty clear. Its polarity is a
little more problematic (i.e. which condition is derived). If only
gibbons were compared one would find the Y formation, although with less
papillae. If this were the end of the outgroup one would say that the V
form of humans and orangutans is the more specialized or restricted
condition. 

 

In Old World monkeys most have only three papillae arranged in a
'triangle' which may represent a 'V" with the minimum number of papillae
for that arrangement. In three baboons the number of papilla go up to
about five. In one case this is a Y shape, in others a V shape. But
there is also the complication of some smaller vallate papillae actually
being misidentified fungiform papillae.

 

In New World monkeys the usual number is three or less. A few species
may go to about five in a Y or V formation.

 

Tarsiers (only two illustrated) have none or three.

 

Prosimians have three or less, or in the case of Lemuridae and
Megaladapidae there are six or more (up to eight or nine) in a Y
formation.

 

So overall, the large bodied hominoids appear to uniquely share a larger
upper number of vallate papillae than in other primates (so this would
be another synapomorphy for large bodied hominoids).  Within the large
bodied hominoids humans and orangutans uniquely share a V with that
larger number compared to other primates whereas the Y shape of African
apes is not quite unique with respect to an overlap with some
prosimians. Either way, the pattern in each large bodied hominoid group
is consistent with current morphogenetic evidence of their respective
relationships, and certainly does not support humans being most closely
linked with chimpanzees.

 

Any comments that may lend clarity to the above will be of interest to
me.

 

John Grehan 

 

 

Dr. John R. Grehan
Director of Science and Research
Buffalo Museum of Science
1020 Humboldt Parkway
Buffalo, NY 14211-1193

email: jgrehan at sciencebuff.org
Phone: (716) 896-5200 ext 372
Fax: (716) 897-6723

Panbiogeography
http://www.sciencebuff.org/biogeography_and_evolutionary_biology.php

Ghost moth research
http://www.sciencebuff.org/systematics_and_evolution_of_hepialdiae.php

Human evolution and the great apes
http://www.sciencebuff.org/human_origin_and_the_great_apes.php

 




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