For this assignment, you will read the following paper (found in the discussion readings folder):
Carr, T. D., Napoli, J. G., Brusatte, S. L., Holtz, T. R., Hone, D. W., Williamson, T. E., & Zanno,
L. E. (2022). Insufficient Evidence for Multiple Species of
Tyrannosaurus
in the Latest
Cretaceous of North America: A Comment on “The Tyrant Lizard King, Queen and Emperor:
Multiple Lines of Morphological and Stratigraphic Evidence Support Subtle Evolution and
Probable Speciation Within the North American Genus
Tyrannosaurus
”.
Evolutionary
Biology
,
49
(3), 327-341.
For some context on this paper, check out the NY Times coverage here:
https://www.nytimes.com/2022/02/28/science/tyrannosaurus-rex-species.html
https://www.nytimes.com/2022/07/25/science/tyrannosaurus-rex-dinosaurs.html
Based on this paper, answer the following questions and bring them to class with you.
1.
How did Paul et al. split
Tyrannosaurus rex
into three species?
-
Paul et al. claimed the species to be stratigraphically separate.
2.
Paul et al. define two chronospecies and one morphospecies. What are these and what
lines of evidence do they give to justify these species?
-
Two chronospecies being
T. imperator
–
>
T. rex
) and one morphological species (
T. regina
)
-
There were three main lines of evidence given: 1) The skeletal robusticity was consistent with
the specimen in question. 2)
“
Tyrannosaurus
femoral proportions do show unusual variation,
(Paul
et al, 2022). 3)the incisor teeth arrangement had a close correlation with femoral robusticity,
(Paul et al, 2022).
3.
How did Paul et al. diagnose the three species? Do you think these are sufficient
diagnoses?
-
There was a procedure formed to be able to test the hypothesis that a fossil species
may be several. First there needs to be a null and alternative hypotheses, from here a
there needs to complete a quantitative cladistic analysis in order for it to be tested and
observed if there are more than one species present. It is also mentioned for a
agglomerative hierarchical test to be done so that the statistical analysis can show any
differences in the data. The following approach from here is to obtain precise
stratigraphic data which would distinguish chronospeices form morphological
species.
4.
What was the basis of Carr et al.’s rebuttal?
