Transitional evolutionary forms in chasmosaurine ceratopsid dinosaurs: evidence from the Campanian of New Mexico

PeerJ

article

Denver W. Fowler¹  Elizabeth A. Freedman Fowler¹ 

[1] Badlands Dinosaur Museum, Dickinson Museum Center;Museum of the Rockies, Montana State University;Department of Natural Sciences, Dickinson State University

关键词: Dinosaur;    Cretaceous;    Pentaceratops;    Anchiceratops;    Ceratopsidae;    Chasmosaurinae;    Anagenesis;    Diversity;   

DOI  :  10.7717/peerj.9251

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

Three new chasmosaurines from the Kirtland Formation (~75.0–73.4 Ma), New Mexico, form morphological and stratigraphic intermediates between Pentaceratops (~74.7–75 Ma, Fruitland Formation, New Mexico) and Anchiceratops (~72–71 Ma, Horseshoe Canyon Formation, Alberta). The new specimens exhibit gradual enclosure of the parietal embayment that characterizes Pentaceratops, providing support for the phylogenetic hypothesis that Pentaceratops and Anchiceratops are closely related. This stepwise change of morphologic characters observed in chasmosaurine taxa that do not overlap stratigraphically is supportive of evolution by anagenesis. Recently published hypotheses that place Pentaceratops and Anchiceratops into separate clades are not supported. This phylogenetic relationship demonstrates unrestricted movement of large-bodied taxa between hitherto purported northern and southern provinces in the late Campanian, weakening support for the hypothesis of extreme faunal provincialism in the Late Cretaceous Western Interior.

【 授权许可】

CC BY