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PhyloCode 2020: Naming the Tree of Life

Donoghue, Michael [1], Clement, Wendy [2], Cellinese, Nico [3], Edwards, Erika J [4].

Sensitivity of phylogenetic nomenclature to changes in tree topology: lessons from Viburnum.

One concern with the use of phylogenetic nomenclature is what happens to the application of names when tree topologies change. How can we presage possible changes and frame maximally robust phylogenetic definitions? Viburnum provides a test from which we derive some general lessons and best practices. In 2014 we provided names and phylogenetic definitions for 30 clades within Viburnum (Clement et al., 2014) based on a tree inferred from plastid and nrITS sequences. Since then we have developed a comprehensive Viburnumphylogeny (including all 163 species that we currently recognize) with a backbone based on RADseq data (Landis et al., 2020). There are six major topological differences between the earlier cpDNA tree and the newer RADseq tree that affect the names proposed by Clement et al. (2014). Of the 30 phylogenetic names proposed, 22 names apply to the same clade in the new tree, but in eight cases a name applies to a different clade. In two of these eight cases a name applies to a clade that already has a phylogenetic name, and we simply need to choose between the two (rendering one of the names a synonym). For the remaining six cases the original definitions refer to a clade that was not previously named, and in four of these six cases the previous name can be applied to the new clade without causing confusion. However, the remaining two cases (Valvatotinus and Pseudotinus) are problematical because the name would apply to a clade that would cause confusion with respect to usage in the literature. Of course, now that the PhyloCode has gone into effect, we can simply officially redefine these two clade names so as to avoid the problems. If the PhyloCode were in effect in 2014 when we first proposed these names we would have needed to petition for conservation using the mechanism described in the PhyloCode. However, because this is cumbersome, we suggest that the original authors be granted the ability to simply flag a change in the definition in the Regnum database. We have learned from our Viburnum experience that it is better to err on the side of including more specifiers, especially when definitions refer to species outside of the clade being named. Our new definitions of Valvatotinus and Pseudotinus switch from maximum crown-clade definitions to minimum clade definitions, and they include more specifiers. For comparison, a rank-based classification system for Viburnum would require a minimum of eight formal ranks, and changes in the underlying tree would have triggered a cascade of meaningless name changes.

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1 - Yale University, Department Of Ecology And Evolutionary Biology, 21 Sachem St., New Haven, CT, 06511, United States
2 - The College Of New Jersery, Dept. Of Biology, 2000 Pennington Road, Ewing, NJ, 08628, United States
3 - University Of Florida, FLORIDA MUSEUM OF NAT. HISTORY, 1659 Museum Rd, 354 Dickinson Hall, Gainesville, FL, 32611, United States
4 - Yale University, Ecology and Evolutionary Biology, New Haven, CT, USA

none specified

Presentation Type: Colloquium Presentations
Session: C07, PhyloCode 2020: Naming the Tree of Life
Location: /
Date: Thursday, July 22nd, 2021
Time: 11:15 AM(EDT)
Number: C07006
Abstract ID:807
Candidate for Awards:None

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