Is Evolutionary History Rewritten with New Fossil Discoveries?

This week we discussed the following paper:

Tarver, J. E., P. C. J. Donoghue, and M. J. Benton. 2011. Is evolutionary history repeatedly rewritten in light of new fossil discoveries? Proceedings of the Royal Society B 278, 599–604.

Tarver et al. (2011) compared the catarrhine and non-avian dinosaur phylogenetic trees in terms of balance (do we know more about one part of the tree than the other?), completeness (how congruent the tree is with the stratigraphic context), and perception of macroevolutionary trends (do bursts of origination remain after new fossil discoveries?). They compared the trees through time to determine how new fossil discoveries changed these parameters. Tarver et al. (2011) conclude that the catarrhine tree is currently more complete and more robust to new fossil discoveries than the non-avian dinosaur tree. The non-avian tree is continually being altered by new, dramatic fossil discoveries.

We thought these results had important implications for those of us who want to use phylogenetic trees to study macroevolutionary trends. The paper provided us with three methods to analyze our trees before drawing grand conclusions from analyses of evolutionary rates or of correlation among traits. We, however, found that the comparison between catarrhines and non-avian dinosaurs was not appropriate. We felt that the two trees represent very different levels of diversity and that the non-avian dinosaur tree should have been compared to a larger group of mammals (one hopefully containing a similar level of morphological and ecological diversity). We also felt that analyzing two groups with living members may have improved the comparison. The phylogenetic relationships of catarrhines are likely better understood due to the extant forms. 

In general, the paper will be useful in shaping our future analyses. We felt that the title of the paper was misleading as it did not provide an answer to the question besides "in some groups and not others."

Thanks to everyone who showed up! See you next week.

Thomas Cullen will be presenting next week's paper.