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Pterosaurs as basal archosauriforms



From: Ben Creisler
bcreisler@gmail.com

A new online paper:


S. Christopher Bennett (2012)
The phylogenetic position of the Pterosauria within the
Archosauromorpha re-examined.
Historical Biology (advance online publication)
DOI:10.1080/08912963.2012.725727
http://www.tandfonline.com/doi/full/10.1080/08912963.2012.725727


A previous analysis of the phylogenetic position of the Pterosauria
argued that pterosaurs were not closely related to dinosaurs as is
generally accepted, but rather were outside the crown group
Archosauria. However, that study was dismissed for the use of
inappropriate methods. Here, the data set from that analysis was
divided into five partitions: one with characters associated with
cursorial digitigrade bipedal locomotion and the other four with
characters from the skull and mandible, postcranial axial skeleton,
forelimb and hindlimb, respectively. The partitions were subjected to
homogeneity testing, and the Cursorial partition was found to be
incongruent with other partitions and all other characters at the α =
0.01 probability level. Deletion of the Pterosauria removed all
significant incongruence, demonstrating that the incongruence results
from the coding of pterosaurs for the cursorial characters. The cause
of the incongruence was interpreted as homoplasy in hindlimb
morphology, and after re-evaluating and reformulating the characters
of the Cursorial partition, the revised data set was tested for
homogeneity and no significant incongruence was found. Lastly, the
data set was updated with additional characters and taxa from recent
analyses, tested as before, and when analysed suggested that the
Pterosauria were basal archosauriforms well outside the crown group
Archosauria.