Bare-bones Paleontology: An Examination of the Systematic Methods Used in Vertebrate Paleontology and their Congruence with Avian Ichnotaxonomy

• Author / Creator

  Buckley, Lisa G

• Data used in the systematic paleontology of extinct vertebrates is limited to what can be collected from detailed comparisons of preserved anatomy. This restricts vertebrate paleontologists to those characters preserved on osteological specimens. Furthermore, parataxonomies such as ichnotaxonomy use different morphologic criteria for assigning tracks and trackways to ichnogeneric and ichnospecific levels. For taxa with no extant representatives, it is difficult to ascertain whether the osteologic characters used are consistent in their ability to discern among closely-related or morphologically-similar vertebrates. It is also difficult to determine the strength of congruence between osteology-based systematics and those taxonomic methods using criteria other than osteology data. Phylogenetic relationships of higher-level taxonomic groupings using morphologic data on appendicular skeletal elements do not necessarily correlate with those relationships recovered using molecular data; while the genus-level groupings are (in the case of Accipiter, Charadrius, Ciconiidae, Falco, Grus, Parapavo, Tringa) retained by appendicular skeletal synapomorphies, similar groupings recovered by other morphologic phylogenetic analyses conflict with evolutionary hypotheses recovered by molecular phylogenies. Regardless of the lack of congruence between molecular and morphologic phylogenies, there is increased osteologic information from the morphology of the distal tarsometatarus of Aves that can be used to increase the accuracy of avian ichnotaxonomy. Specifically, the plantar displacement of the trochlear surfaces of metarsals II and IV is greater in Aves than in non-avian theropods, even in avian taxa whose distal tarsometatarsal morphology shares convergent features with non-avian theropods, such as size. Multivariate statistical analyses are demonstrated to be an additional tool to successfully test the relationships between avian osteomorphology and avian ichnotaxonomy. The statistically significant difference in the degree of plantar rotation in distal tarsometatarsals II and IV between Charadriidae and Scolopacidae, correlating with the significantly different digit splay in the footprints of these two families of shorebirds, demonstrates that osteomorphology and ichnomorphology can be used to increase the ichnotaxonomic resolution of Cretaceous-age avian footprints. It is likely that the differences in plantar displacement and torsion of metatarsals II and IV between avian and non-avian theropods, and its effects on the footprints of the respective trackmakers, will prove to be reliable synapomorphy-based characters that can be utilited in ichnotaxonomy to distinguish between the traces of large avian and small non-avian theropods.

• Subjects / Keywords

  • Footprints
  • Cladistics
  • Systematics
  • Statistics
  • Ichnotaxonomy
  • Avian
  • Paleontology
  • Vertebrates
  • Osteology

• Graduation date

  Spring 2016

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3QR4NW2Z

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.