Proposal (80) to South American Classification Committee
Lump Phrygilus punensis and P.
atriceps
Effect on South American CL: This proposal would lump two
species currently recognized as separate species on our baseline list.
Background: Species limits in the hooded sierra-finch
group in the genus Phrygilus have been historically fluid, with little
real data available to support any particular treatment, of which there are at
least three flavors.
Four "units" are involved: (1) P. patagonicus,
with largely austral distribution, and its status as a species never seems to
have been questioned; (2) nominate gayi (with minor and caniceps)
of Chile and Andean Argentina; (3) atriceps of southwestern Peru and
most of the Bolivian Andes; and (4) punensis (with chloronotus)
of the Peruvian Andes and northern depto. La Paz, Bolivia. They all share a
similar color pattern, with blackish or gray hood, wings, and tail contrasting
with yellowish green to yellowish rufescent underparts and back. Patagonicus
is evidently broadly sympatric with gayi. Nonbreeding movements
complicate assessment of true overlap. Although degree of actual syntopy is not
clear; it is clear (from what I can tell) that gayi and patagonicus
have to be considered separate species.
Treatment of the other three is where the problems arise. Hellmayr
(1938) treated them all as subspecies of a single species. However, atriceps
and gayi breed syntopically in n. Chile, according to Johnson (1967):
"However,
our field observations have shown conclusively that from Atacama to Coquimbo
the present form [atriceps] and Ph. gayi gayi live and nest
in the same territory and therefore cannot be conspecific."
(The original discovery of syntopy was published in a paper by
Philippi (1942) that I do not have.)
This led Meyer de Schauensee (1966, 1970) and Paynter (1970) to
treat atriceps as a separate species from gayi, with
inclusion of the northern, gray-headed punensis group as subspecies of
black-headed atriceps.
Ridgely & Tudor (1989), following François Vuilleumier's
unpublished 1967 dissertation (relevant parts of which have, I think, been
published, but I can't find where), further elevated punensis (with
chloronotus) to species rank. They wrote, in part:
"As these 2 taxa [atriceps and gayi]
appear to be reproductively isolated, we conclude that these latter 2 [atriceps and punensis]
should be considered separate species (though they were lumped in [Paynter
1970]). Note further, that adult females of punensis and gayi differ
quite markedly."
This split was followed by Fjeldså & Krabbe (1990), Sibley
& Monroe (1990), Dickinson (2003), and thus SACC.
Analysis: Real data on contact between atriceps and punensis,
or on comparative vocalizations, are ... surprise, surprise .... absent. So, we
have the usual frustrating task of working from assumptions and weak,
qualitative information. The above split of punensis from atriceps was
based on the assumption that if gray-headed gayi and black-headed atriceps do
not interbreed, then gray-headed punensis is unlikely to interbreed
with atriceps as well. The problem is that gayi differs in more
ways from atriceps than punensis does from atriceps --
the comparison isn't really analogous. The overall color tones of gayi are
much more greenish than those of punensis/chloronotus, which
ventrally shares the rufescent tones of atriceps. Also, punensis/chloronotus
have darker gray heads, closer in shade to atriceps (intermediate
between head color of gayi and atriceps). Despite the similarity
in head and back color between gayi and punensis, whose ranges
are separated from each other by atriceps, fiddling with skins
would lead most of you, I suspect, to predict that atriceps and punensis
are sisters relative to gayi. In fact, gayi might be the sister
to patagonicus -- they are so similar in plumage (differing mainly in
size) that Johnson (1967) explicitly stated that there was no point in making
plates of both of them, and he urged extreme caution in the field.
Recommendation: I will vote "NO" on this proposal
because in the absence of real data, I see no reason to change our current
classification. Although it would be easy to shoot down the evidence for the atriceps-punensis
split, I think Bob did the right thing with the split, given available data,
and I lean towards following it until real data are forthcoming for the
following reasons: (1) head color may indeed make all the difference in species
recognition -- for all we know, that indeed may be the sole basis for mate
selection between atriceps and gayi in n. Chile; (2) patagonicus
and gayi have virtually identical head colors yet as far is known behave
as two separate gene pools despite plenty of opportunity to do otherwise; and
(3) the fluidity in species limits in this group does not give any particular
treatment any sort of claim to long-standing tradition for which more
convincing data are required to overturn it.
Literature Cited:
DICKINSON,
E. C. (ed.). 2003. The Howard and Moore complete checklist of the birds of the
World, Revised and enlarged 3rd Edition. Christopher Helm, London, 1040 pp.
FJELDSÅ,
J., AND N. KRABBE. 1990. Birds of the High Andes. Zoological Museum, Univ.
Copenhagen, Copenhagen, Denmark.
HELLMAYR,
C. E. 1938. Catalogue of birds of the Americas. Field Mus. Nat. Hist. Publ.,
Zool. Ser., vol. 13., pt. 11.
MEYER DE
SCHAUENSEE, R. 1966. The species of birds of South America and their
distribution. Livingston Publishing Co., Narberth, Pennsylvania.
MEYER DE
SCHAUENSEE, R. 1970. A guide to the birds of South America. Livingston
Publishing Co., Wynnewood, Pennsylvania.
PAYNTER, R.
A., JR. 1970a. Subfamily Emberizinae. Pp. 3-214 in "Check-list of birds of
the World, Vol. 8" (Paynter R. A., Jr., ed.). Museum of Comparative
Zoology, Cambridge, Massachusetts.
RIDGELY, R.
S., AND G. TUDOR. 1989. The birds of South America, vol. 1. Univ. Texas Press,
Austin.
SIBLEY, C.
G., AND B. L. MONROE, JR. 1990. Distribution and taxonomy of birds of the
World. Yale University Press, New Haven, Connecticut.
Van Remsen, December 2003
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Comments from Robbins: "I vote "NO" for
this proposal for reasons outlined by Van."
Comments from Stiles: "NO - case is similar to no.
78, maintain the status quo until convincing evidence for change is
published."
Comments from Jaramillo: "NO. There are complexities
in this genus that make it even more of a mess than the proposal implies. The
taxa patagonicus and gayi are indeed
reproductively isolated for the most part. In many parts of the Chilean Andes
the two species breed within kilometers of each other, patagonicus in
forest, and gayi higher up in Andean scrub. However in the far south, particularly
in the region of Punta Arenas where the forest blends in to the open steppe
there is a narrow hybrid zone. This zone has been studied by Vuilleumier, but I
could not find the reference here. The southern gayi are a different
subspecies than the Andean gayi. In addition, there is a third
subspecies of gayi (minor) in the coast range of Chile that is in
many ways more similar to patagonicus than to gayi; it
may be best classified under that taxon? I will agree that overall gayi and
patagonicus behave as two good biological species. Now, there are a
couple of supposed hybrid specimens between gayi and atriceps known
from the Andes of Chile (Baños del Toro) but that is it -- otherwise the two
maintain their integrity. Finally, in Bolivia I have observed atriceps and
punensis in the same sites on several occasions; these observations have
been in August and October. I don't know when these species breed, but I had
assumed they were sympatric so was surprised to see this proposal. My guess is
that they are sympatric in many areas in the highlands of Bolivia, and given
that they do not appear to hybridize we are safe in keeping them
separate."
Comments from Nores: "Yo voto NO a juntar Phrygilus punensis con atriceps. De
hacer esto, habría también que juntar patagonicus con gayi.
Aunque estas dos formas son mayormente simpátricas en el sudoeste de
Sudamérica, ellas tienen muy diferente hábitat. P. gayi habita en
la estepa y P. patagonicus habita en el bosque de Nothophagus."