Description and evolutionary significance of the sauropodomorph dinosaurs from the early Jurassic (Hettangian) McCoy Brook Formation.
Date
2007
Authors
Fedak, Timothy J.
Journal Title
Journal ISSN
Volume Title
Publisher
Dalhousie University
Abstract
Description
A rich bone bed of prosauropod dinosaurs was discovered in the Lower Jurassic (Hettangian) McCoy Brook Formation of Nova Scotia. At least five individuals are present within the bone bed, based on unique femora and coracoids, therefore the new bone bed is now the richest site in North America for prosauropod dinosaurs. Based on the morphology of the ilium and sacral vertebrae from these new specimens, the McCoy Brook prosauropods are not referable to cf. Ammosaurus, but rather represent a new taxon, Fendusaurus eldoni. A phylogenetic analysis of the holotype, which includes the first cranial material from the McCoy Brook Formation, and three other articulated specimens referred to Fendusaurus, place this new taxon within the terminal branches of Massospondylidae. Fendusaurus is unique among Massospondylidae, for the extreme elongation of the cervical vertebrae, a four vertebrae sacrum that includes a dorsosacral and caudosacral, the elongate postacetabular process of the ilium, and an expanded anterior distal process of the tibia. Morphological variation within the bone bed is attributed to intra-specific variation; although additional specimens remaining to be collected from the bone bed may provide further information to identify at least one other taxon. The two skulls of Anchisaurus (= Ammosaurus) have been misinterpreted for over one hundred years, and the new preparation and description of these skulls further clarifies the morphology of the cranial and braincase elements. The absence of Anchisaurus and the presence of a the new massospondylid Fendusaurus, further strengthens the similarities between the McCoy Brook Formation and the Lower Jurassic deposits of the western USA, China, and South Africa.
Thesis (Ph.D.)--Dalhousie University (Canada), 2007.
Thesis (Ph.D.)--Dalhousie University (Canada), 2007.
Keywords
Paleontology.