Evidence for the independent acquisition of aquatic specializations in pinnipeds (seals, sea lions, and walruses): insights from the study of the phylogenetic position, locomotor behaviour, and description of the stem pinniped, Puijila darwini

Public Deposited
Resource Type
  • Monophyly of pinnipeds (seals, sea lions, and walruses) is well-established. However, it is difficult to reconcile a monophyletic origin of pinnipeds with the disparate locomotory modes and associated skeletal morphologies observed between the extant families. In this study, the skeletal anatomy of Puijila darwini, a key putative stem pinniped from Canada’s High Arctic, is fully described. A biomechanical analysis, using functional limb indices of extant carnivorans to predict locomotory modes in extinct taxa, confirms the aquatic adaptations of Puijila, and identifies it as a forelimb-dominated swimmer. Phylogenetic analyses of molecular and morphological data in isolation recover Puijila as a stem pinniped, and provide strong support for pinniped monophyly. However, a phylogenetic analysis combining molecular and morphological data together recovers an unconventional topology, suggesting the molecular and morphological data are incongruent. Closer scrutiny of previously-proposed pinniped synapomorphies suggests many features shared between seals, sea lions, and walruses arose in parallel.

Thesis Degree Level
Thesis Degree Name
Thesis Degree Discipline
Rights Notes
  • Copyright © 2017 the author(s). Theses may be used for non-commercial research, educational, or related academic purposes only. Such uses include personal study, research, scholarship, and teaching. Theses may only be shared by linking to Carleton University Institutional Repository and no part may be used without proper attribution to the author. No part may be used for commercial purposes directly or indirectly via a for-profit platform; no adaptation or derivative works are permitted without consent from the copyright owner.
Date Created
  • 2017


In Collection: