title: Feeding biomechanics in Acanthostega and across the fish-tetrapod transition.
abstract: Acanthostega is one of the earliest and most primitive limbed vertebrates. Its numerous fish-like features indicate a primarily aquatic lifestyle, yet cranial suture morphology suggests that its skull is more similar to those of terrestrial taxa. Here, we apply geometric morphometrics and two-dimensional finite-element analysis to the lower jaws of Acanthostega and 22 other tetrapodomorph taxa in order to quantify morphological and functional changes across the fish-tetrapod transition. The jaw of Acanthostega is similar to that of certain tetrapodomorph fish and transitional Devonian taxa both morphologically (as indicated by its proximity to those taxa in morphospace) and functionally (as indicated by the distribution of stress values and relative magnitude of bite force). Our results suggest a slow tempo of morphological and biomechanical changes in the transition from Devonian tetrapod jaws to aquatic/semi-aquatic Carboniferous tetrapod jaws. We conclude that Acanthostega retained a primitively aquatic lifestyle and did not possess cranial adaptations for terrestrial feeding.
authors.affiliation: Palaeontological Institute and Museum, University of Zurich, , 8006 Zurich, Switzerland, School of Life Sciences, University of Lincoln, , Lincoln LN2 2LG, UK, University Museum of Zoology, University of Cambridge, , Cambridge CB2 3EJ, UK, School of Earth Sciences, University of Bristol, , Bristol BS8 1RJ, UK.
authors.forename: James M
authors.initials: JM
authors.lastname: Neenan
authors.forename: Marcello
authors.initials: M
authors.lastname: Ruta
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Clack
authors.forename: Emily J
authors.initials: EJ
authors.lastname: Rayfield
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D001837:Body Weights and Measures; D017753:Ecosystem; D005247:Feeding Behavior / Q000502:physiology*; D020342:Finite Element Analysis; D005580:Fossils; D007568:Jaw / Q000033:anatomy & histology* / Q000502:physiology; D010802:Phylogeny; D013045:Species Specificity; D014714:Vertebrates / Q000033:anatomy & histology* / Q000145:classification / Q000502:physiology
keywords: Acanthostega; feeding; finite-element analysis; fin–limb transition; geometric morphometrics; phylogeny