Abelisauridae (Dinosauria: Theropoda) from the Late Jurassic of Portugal and dentition-based phylogeny as a contribution for the identification of isolated theropod teeth

Theropod dinosaurs form a highly diversified clade, and their teeth are some of the most common components of the Mesozoic dinosaur fossil record. This is the case in the Lourinhã Formation (Late Jurassic, Kimmeridgian-Tithonian) of Portugal, where theropod teeth are particularly abundant and diverse. Four isolated theropod teeth are here described and identified based on morphometric and anatomical data. They are included in a cladistic analysis performed on a data matrix of 141 dentition-based characters coded in 60 taxa, as well as a supermatrix combining our dataset with six recent datamatrices based on the whole theropod skeleton. The consensus tree resulting from the dentition-based data matrix reveals that theropod teeth provide reliable data for identification at approximately family level. Therefore, phylogenetic methods will help identifying theropod teeth with more confidence in the future. Although dental characters do not reliably indicate relationships among higher clades ...兽脚类恐龙（Theropod dinosaurs）属于高度多样化的演化支（clade），其牙齿是中生代（Mesozoic）恐龙化石记录中最为常见的组成部分之一。葡萄牙洛里尼扬组（Lourinhã Formation，晚侏罗世，基默里奇阶-提通阶）的化石记录亦符合这一规律，该地层产出的兽脚类牙齿尤为丰富且多样。本文对4枚孤立的兽脚类牙齿进行描述与鉴定，鉴定依据为形态测量学（morphometric）与解剖学（anatomical）数据。我们将这些牙齿纳入两项分支系统学分析（cladistic analysis）：其一基于包含60个分类单元（taxa）、141个基于牙齿特征的性状的数据矩阵（data matrix）；其二为将本数据集与6项近年基于完整兽脚类骨骼的数据矩阵整合得到的超级矩阵（supermatrix）。基于牙齿特征数据矩阵得到的合意树（consensus tree）显示，兽脚类牙齿可提供可靠的鉴定数据，其鉴定精度大致可达科级水平。因此，未来系统发育方法（phylogenetic methods）将有助于更可靠地鉴定兽脚类牙齿。尽管牙齿特征无法可靠反映高级演化支之间的系统发育关系……