Proposal (574) to South
American Classification Committee
Elevate Knipolegus franciscanus to species rank
Effect on SACC: This would split Knipolegus franciscanus from K.
aterrimus.
Background: The current SACC
footnote summarizes the situation:
99. Silva & Oren
(1992) considered the subspecies franciscanus
to be a separate species from aterrimus;
see also Ridgely & Tudor (1994). Proposal needed.
New information:
Hosner and Moyle (2012) published a species-level phylogeny of Knipolegus, including three of the four Knipolegus aterrimus subspecies (Marañon heterogyna
was not available). Knipolegus aterrimus
aterrimus and K. a. anthracinus
formed a clade sister to K. hudsoni; K.
a. franciscanus was recovered sister to K.
lophotes + K. nigerrimus. Silva and Oren (1992), Ridgely and Tudor
(2009), and van Perlo (2009) already treat K.
franciscanus as a species-level taxon based on female plumage differences. Caatinga Black-Tyrant and Sao Francisco Black
Tyrant have been used recently for K.
franciscanus. Hosner and Moyle recommended Caatinga Black-Tyrant because it
is more commonly used (based on Google Searches). However, IOC prefers Sao
Francisco Black Tyrant. I do not feel strongly about any English name.
Recommendation: Yes. Maintaining the
status quo results in a paraphyletic K.
aterrimus; female plumages are distinctive.
Literature cited:
Hosner, P. A.
and R. G. Moyle. 2012. A molecular phylogeny of black-tyrants (Tyrannidae: Knipolegus) reveals strong geographic
patterns and homoplasy in plumage and display behavior. Auk 129: 156-167.
Ridgely,
R. S., and G. Tudor. 1994. The Birds of South America, vol. . University of Texas Press, Austin.
Ridgely,
R. S., and G. Tudor. 2009. Field Guide to the Songbirds of South America: The
Passerines. University of Texas Press, Austin.
Silva,
J. M. C., and D. C. Oren. 1992. Notes on Knipolegus franciscanus Snethlage,
(Aves: Tyrannidae), and endemism of central Brazilian dry forests. Goeldiana
Zoology.
Van
Perlo, B. 2009. A Field Guide to the Birds of Brazil. Oxford University Press,
New York.
Peter A. Hosner, March 2013
Comments
by Remsen:
“YES. The genetic data leave no doubt
that treatment of franciscanus as a
separate species is required.”
Comments
from Stiles:
“YES. Both to avoid paraphyly and to recognize plumage differences between
species in females in a genus in which male plumages are notoriously
conservative/similar (as in Cercomacra,
for example).”
Comments
from Zimmer: YES.
The genetic data place franciscanus
as sister to two other predominantly Brazilian taxa (lophotes and nigerrimus),
which makes a lot more sense biogeographically.
Female plumage differences between franciscanus
and other members of aterrimus are
pronounced. As Gary notes, male plumage
in this entire group is very evolutionarily conservative. I would probably cast my vote for São
Francisco Black-Tyrant as an English name, although I am used to referring to franciscanus as “Caatinga
Black-Tyrant”. “São Francisco” more
accurately describes the species’ range, and it fits nicely with the recently
described Arremon franciscanus (São
Francisco Sparrow). Much of the real caatinga region lies to the north of the
range of K. franciscanus.
Comments
from Pacheco: “YES. The
phylogeny of Hosner and Moyle confirms objectively the long-suspected taxonomic
independence of this inhabitant of dry forests from heart of Brazil. This
species is not exactly a Caatinga dweller nor is it representative of São
Francisco Basin. It is also in the headwaters of the Tocantins River. Perhaps
"Snethlage's Black Tyrant" is appropriate.”
Comments
from Robbins:
“YES. The Hosner and Moyle genetic data
clearly demonstrate that franciscanus
should be treated as a species.”
Comments
from Nores:
“YES. Strong genetic data evidence that franciscanus should be treated as a
species. Moreover, female plumage differences between franciscanus and other members of aterrimus are distinctive.”