Proposal (144) to South American
Classification Committee
Split Aglaiocercus
berlepschi from Aglaiocercus kingi
This
proposal would split an isolated representative of the genus Aglaiocercus
(in NE Venezuela) from the widespread A. kingi as a separate
species-level taxon, A. berlepschi (Venezuelan Sylph).
The
forms in the genus Aglaiocercus have a very checkered history
due mainly to the variations in the colors of the male rectrices and gorgets.
Cory (1918) recognized six species: emmae, mocoa,
caudata, kingi, berlepschi and coelestis. Hartert
(1922), the next reviewer, lumped all into kingii. Berlioz (1940)
kept emmae, caudata, and mocoa in
kingii but retained coelestis and berlepschi as
separate species. Peters (1945) lumped berlepschi into kingi but
separated emmae (including mocoa and caudata)
and coelestis, but suggested that further analysis might show all
to be conspecific. In a more detailed analysis, Zimmer (1952) noted
intergradation between kingi and caudata, and kingi and mocoa, as well as between kingi and margarethae (the form nearest to berlepschi
but separated by a rather wide gap in N Venezuela, and between margarethae and caudata. He noted
several points of resemblance between berlepschi and coelestis (at
the opposite extremes of the distribution of the group) and suggested that a
paler rufous shade in the underparts of some specimens in the kingi group
might suggest intergradation with these white-breasted forms. He therefore
returned to the arrangement of Hartert, considering all the forms as races of a
broad kingi.
Meyer
de Schauensee (1966) separated coelestis as a species because
of sympatry in SW Colombia (reflected in recently taken specimens of von Sneidern) and differences in female plumages, while
retaining the emmae group and berlepschi in kingi (although
he did not comment upon the latter). Hilty & Brown (1986) retained the
split between kingi and coelestis, providing further details on
the sympatry and habitat differences between these forms. Sibley & Monroe
(1990) followed suit, and also suggested that the emmae group and berlepschi might
also be distinct species.
A
further detailed analysis by Schuchmann & Duffner (1993)
concluded, with Zimmer, that the emmae group belonged
with kingi but that both coelestis and berlepschi were
entitled to specific status. Their reasons for separating berlepschi were
its very different female plumage, certain morphometric differences between it
and the closest form of kingi (margarethae)
including wing and tail length, a difference between it and all forms of kingi
in the breadth of the male outer rectrix (similar to but greater than that
between kingi and coelestis, and different tail
coloration (blue, vs. green in adjacent forms of kingi), and the
gap in distribution (which makes intergradation between these forms unlikely as
an explanation for the occasional paler-breasted females in kingi).
They noted resemblances between berlepschi and coelestis in
several points as well, interpreting these as indication that these two were
"relicts of an early dispersion" of the group. Their split of berlepschi was
followed by Schuchmann (1999), who illustrated the differences, and by Hilty
(2002).
Taking
all of these differences together, I feel that the evidence definitely does
support the split of berlepschi at the species level. The
range gap obviates any question of intergradation, but the differences between berlepschi
and adjacent forms of kingi equal or exceed those between coelestis
and kingii, whose local sympatry and species status seems proven.
Whether or not one accepts the evolutionary-biographic scenario of Schuchmann
& Duffner, the other differences strongly favor
the split, if only to maintain consistency in the species-level taxonomy of the
group. I therefore recommend a YES vote on this proposal.
Literature
Cited:
Cory 1918.
Hartert 1922. Novitates
Zool. 29:411.
Berlioz 1940. L'Oiseaux 10: 221-231.
Peters 1945.
Meyer de Schauensee
1966
Hilty & Brown 1986.
Sibley & Monroe
1990.
Schuchmann, K-L. &
K. Duffner. 1993. Mitt. Zool. Mus. Berlin 69
Suppl.: Ann. Orn. 17:75-92.
Schuchmann 1999:
HBW vol 5.
Hilty 2002, Guide to
the birds of Venezuela.
ZIMMER, J. 1952a.
Studies of Peruvian birds, No. 62. The hummingbird genera Patagona, Sappho,
Polyonymus, Ramphomicron, Metallura, Chalcostigma, Taphrolesbia and Aglaiocercus.
American Museum Novitates 1595: 1-29.
Gary Stiles, December
2004
_____________________________________________________________________________________
Comments
from Remsen:
"YES. If A. kingi and A. coelestis are
syntopic, then their degree of difference can be applied as a standard by which
to rank allopatric taxa."
Comments
from Pacheco:
"YES. O tratamento em duas espécies
encontra suporte nos dados agora disponíveis."
Comments
from Jaramillo:
"YES. The data sound good. I assume we are going with
Venezuelan Sylph as an English name? Or does this require a second proposal
pending the outcome of this one?"
Comments
from Nores:
"SI. La gran diferencia de color en la hembra y algunas
diferencias en el macho parecen ser suficientes para considerarlas especie
diferentes.
“NOTA: pienso que, en todas las propuestas sobre
colibríes, excepto la 144, las características de coloración y distribución
geográfica corresponden mejor a subespecies que a especies. Aunque tampoco
nosotros tenemos fundamento de peso para afirmar esto, considero que sería
importante no tener en cuenta los cambios introducidos en el HBW hasta tanto
haya estudios genéticos, de vocalizaciones u otros que justifiquen la
separación de las especies."