2010 Vol 101.pdf (1.63mb) - Primate Society of Great Britain

for large brains. However, those groups characterized by strong
encephalisation signals were also likely to show bonded, stable sociality
amongst extant species. Some non-social groups, particularly amongst the
carnivores, also showed strong evidence of encephalisation. These results
finally are put into the context of conventional ecological and social
explanations of brain size increase. I will also discuss encephalisation in
primates versus other mammals.
Clinal patterns of craniofacial morphology in baboons (Papio spp.): a
geometric morphometric approach
J. Dunn 1 , A.Cardini 2 and S. Elton 1
1. Hull York Medical School, The University of Hull, 2. Museo di
Paleobiologia e dell’Orto Botanico, Universitá di Modena e Reggio Emilia,
Italy
Clinal variation in morphology is found in several primate species, yet the
ecological underpinning of these trends is unknown. Recent research on
African monkeys has discovered a trend common to three disparate taxa.
Blue monkeys, vervets and red colobus monkeys all exhibit a decreasing
size cline from Central to East Africa. This raises the question which other
species exhibit similarities in this clinal pattern and what can be learnt by
comparing these patterns? The baboon has an extensive geographical range
and exhibits subspecific diversity lending itself well to the exploration of
clinal variation. This study uses a trend surface analysis to visualise and
quantify the clinal trend. Environmental factors of known significance in
baboon ecology are included in a partial regression along with spatial terms
allowing the effects of the two factors to be quantified. The morphological
cline is separated into its allometric and nonallometric components. Size is
found to decrease from Central to East Africa in baboons as with red
colobus, vervets, and blue monkeys. Comparing allometrically and
nonallometrically controlled clines reveals that most of the observed
morphological diversity in baboons is the result of size only. Taxa
considered outliers in size, such as the Kinda baboon, cease to be such when
allometry is controlled for. However, some clinal patterning remains but
along a north-south axis and is perhaps indicative of a more ancient
diversification in morphology. These observations should aid further
research on determining the mechanisms underpinning clinal variation.
Ecological and life history considerations related size are discussed.
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