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The phylogenetic signal in the skull of New World monkeys

Many phylogenetic relationships based on morphology were rejected following the molecular revolution, yet there is a need for phylogenetic analysis of morphology that reliably infers phylogenetic relationships so that we can understand the evolutionary relationships of extant and fossil taxa. I use geometric morphometric and distance-based phylogenetic methods to study the phylogenetic signal in the skull of a clade of primates, the platyrrhines or New World monkeys, and re-examine congruence between molecular and morphological analyses. I collected digital anatomical landmark data from around 1400 specimens belonging to 16 genera and 50 species of New World monkeys, and nine primate outgroup taxa. I take a modular approach, inferring phylogenies based on the whole skull, face and cranial base, with a range of outgroups and outgroups combinations, and repeat analyses for male, female, pooled sex and separate sex data. Inferred relationships are compared to the most recent platyrrhine molecular phylogeny and past morphology-based analyses. Strepsirrhine outgroups performed slightly better as outgroups, as platyrrhines and Old World monkey or ape outgroups often shared homoplasy that interfered with accurate phylogenetic analysis. Phylogenetic analysis of all platyrrhines recovers a weak phylogenetic signal, but phylogenetic analysis of each of the three major molecular clades, atelids, pitheciids and cebids, finds greater congruence between molecular and morphological analyses. The atelids have a strong phylogenetic signal in the face, the pitheciids in all regions of the skull, and the cebid skull and face support three molecular lineages for callitrichines, cebines and owl monkeys, but infer molecular incongruent relationships within the callitrichines. Phylogenetic analysis of the face holds a stronger phylogenetic signal than expected, whereas the cranial base was more plastic and had a weak phylogenetic signal. In platyrrhines, phylogeny, diet, allometry and encephalization all have an important role in shaping craniodental morphology.
Date January 2012
CreatorsBjarnason, A.
PublisherUniversity College London (University of London)
Source SetsEthos UK
Detected LanguageEnglish
TypeElectronic Thesis or Dissertation

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