Proposal (560) to South American Classification Committee
Add “Tribes” to classification where
warranted
Effect on SACC list: If
this proposal passes, the “tribe” level of classification would be adopted in
those cases in which well-sampled subfamilies show major, deep lineages within
them.
Rationale: I personally
find it increasingly useful to have formal taxon names to label strongly
supported nodes in a densely sampled subfamily. The tribe level of classification is used in many
classifications, including by our sister committee, NACC, for North American
birds, and by the Handbook of the Birds
of the World series. The
forthcoming revision of Dickinson (2003) will use them to a much greater
degree.
A laborious discussion of the pros and cons of
the Linnaean categorical scheme is beyond the scope of this proposal. The glaring absence of objective
definitions of the higher-level categories that are already in widespread use
(order, family, subfamily) handicaps any real discussion of what a tribe would
be other than two or more monophyletic groups within a subfamily for which
strongly supported nodes identify divergent lineages. Best to use an example. In the Trochilidae, we currently recognize three
subfamilies. However, the McGuire
et al. data show that the subfamily Trochilinae consists of multiple, strongly
divergent lineages that might/could/should be recognized taxonomically. Certainly, the categorical minds of us
humans find these labels useful for discussions, as we did in those McGuire et
al. phylogenies.
Clearly, taken to the extreme, every strongly
supported node in a phylogeny could be given a name, and so we have to be
careful how far we go. However, in
this case, the tribe level is in widespread use in ornithology,
so we’re not breaking any new ground.
Recommendation: YES – the minimal “cost” of adding an additional
hierarchical level to our classification, on a careful case-by-case basis, is
offset by the benefit of upgrading the information content of a classification
and linear sequence, in my opinion.
Van Remsen, October 2012
Comments from Zimmer: “YES, for
reasons stated by Van in the proposal.
The fact that this category is already used by the NACC and by HBW adds
some additional impetus as far as I’m concerned. Better that we are all on the same page with this.”
Comments from Stiles:
“A qualified YES., as above, only if the
evidence from multiple genes notably nuclear ones)is consistent - otherwise,
going overboard with tribes now might only make more work for the future as new
studies add possibly conflicting information.”
Comments from Nores: “NO, definitely. After 15 years
of SAAC and when it should end, we cannot
start now with tribes,
superfamilies, subspecies or other
categories. This is already defined.”
Comments from Robbins: “NO, consistent with my comments made concerning
the utility of subfamilies. When examining a tree, tribe/subfamilies are
totally superfluous for understanding and communicating relationships. Why
interject yet two additional layers of nomenclatural subjectivity?”
Comments from
Stotz: “YES. I hope we won’t overdo it, but tribes
are useful in big intrafamilial units, think Ducks and Sandpipers, and
probably Hummingbirds and maybe Flycatchers, Tanagers, Furnariids etc.”
Comments from Pacheco: “YES.
I see advantages in using Tribes, but only in certain well-sampled
subfamilies.”