The evolutionary clues hidden in the inner ear, subject of Alessandro Urciuoli doctoral thesis

Alessandro Urciuoli during his thesis defense Alessandro Urciuoli during his thesis defense Alessandro Urciuoli during his thesis defense

 Alessandro Urciuoli during his thesis defense

Alessandro Urciuoli, researcher at the Paleoprimatology and Paleoanthropology Research Group of the Institut Català de Paleontologia Miquel Crusafont (ICP), defended his doctoral thesis on the usefulness of the semicircular canals morphology in the inner ear as a tool to establish phylogenetic relationships between catarrhine primates. His work has been supervised by Salvador Moyà-Solà and David M. Alba (ICP).

The court has awarded the work "The Evolution of Semicircular Canals in Anthropoid Primates: Phylogenetic Implications for Miocene Catarhines" with the highest score and granted Urciuoli with the PhD degree in Biodiversity. Due to the current pandemic circumstances, the defense has been carried out in a blended way at the Universitat Autònoma de Barcelona (UAB).

Cover of Urciuoli's doctoral thesis 

Summary of the doctoral thesis:

Catarrhine primates originated in Africa by the Oligocene. Besides cercopithecoids and hominoids they include several lineages from the Miocene of Africa and Eurasia. Their phylogenetic relationships are controversial due to their incomplete fossil record, abundant homoplasy, and mosaic evolution. The identification of anatomical areas not very prone to homoplasy, such as the inner ear semicircular canals (SCs), is crucial for inferring the phylogeny of extinct catarrhines. The present dissertation explores the utility of SCs for phylogenetic inference among anthropoids, and particularly Miocene catarrhines.

Specific aims include: (1) testing the suitability of different three-dimensional geometric morphometric (3DGM) approaches; (2) quantifying the phylogenetic signal embedded in SC morphology and identifying characters amenable to cladistic analysis; and (3) testing competing phylogenetic hypotheses for European Miocene catarrhines (pliopithecoids and hominids). The methods rely on microcomputed tomography scans and landmark-based standard 3DGM, as well as an innovative deformation-based (landmark-free) alternative approach. Shape data were analyzed by means of bivariate (allometric) regressions and multivariate analyses (between-group principal component analysis), coupled with phylogenetically-informed methods (phylomorphospace with ancestral node reconstruction, cladistic indices), metrics of phylogenetic signal (Pagel’s λ and Blomberg’s K), and cluster analysis.

The results are provided in three published articles, which are subsequently discussed in relation to the literature and prospects for the future. The first article analyzes patterns of SC shape variation in extant catarrhines and tests its utility for making phylogenetic inferences in extinct hominoids. The remaining two articles test alternative phylogenetic hypotheses in the pliopithecoid Epipliopithecus and the dryopithecines Hispanopithecus and Rudapithecus.

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Last modified on Friday, 16 April 2021 13:04
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