Proposal (349) to South American Classification Committee
Separar Pyrilia
coccinicollaris de Pyrilia haematotis
Antecedentes: Pyrilia coccinicollaris ha sido
generalmente considerada una subespecie de Pyrilia haematotis ya
que se consideraba que pesar de que ambas habitaban Panamá no había simpatría
entre ellas, porque haematotis ocupaba el este del país y coccinicollaris el
oeste. Cracraft y Prum (1988), usando caracteres externos del género,
codificados binariamente en primitivo o derivado, encuentran diferencias como
para separar las dos especies.
Nueva información: Análisis moleculares llevados a cabo por Ribas et al. (2005), mostraron
claramente que, a pesar de la similitud fenotípica entre ambos taxas, las
diferencias interespecíficas eran marcadamente más altas (2.6% in ND2, 4.6% in
cyt b) que la interespecíficas (0.1-1.2%), lo que indicaba que una efectiva
barrera existió en el pasado separando las dos especies. También estos autores
mencionan que parece haber una zona de simpatría en Panamá.
Recomendaciones: Teniendo en cuenta que ambos tipos de análisis evolutivos (morfológico y
molecular) indican que ambos taxas son especies diferentes y que aparentemente
habría una zona de simpatría en Panamá, yo voto SI a esta
propuesta.
Literatura
citada:
Cracraft, J.
& Prum, R.O. (1988) Patterns and processes of diversification: speciation
and historical congruence in some Neotropical birds. Evolution, 42,
603-620.
Ribas C.
C., Gaban-Lima, R., Miyaki, C. Y. y Cracraft, J. 2005. Historical biogeography
and diversification within the Neotropical parrot genus Pionopsitta (Aves:
Psittacidae). J. Biogeogr. 32:1409-1427.
Manuel
Nores, May 2008
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Comments from Remsen: "NO. Data published so far
are insufficient to elevate coccinicollaris to species rank.
If there is true sympatry, then this would be indisputable evidence for species
rank. I consider the published evidence for this inadequate until all the
details are published. First, the differences in plumage between these two taxa
are really very small. The illustration in HBW shows them to be essentially
identical except for an increase in reddish pigment in the neck area of coccinicollaris. Our
one specimen of this form (one of the three specimens used by Ribas et al.)
does not show nearly as much red as is indicated by the illustration in HBW,
and descriptions of coccinicollaris imply that the degree of
red is variable (although Wetmore [1968, birds of Panama book] suggested that
much of this is sex-based). Wetmore (1968), who probably had the world's
largest series of specimens from Panama to examine at USNM, did not note any
sympatry and in fact stated: 'Apparently
intergrades with the race coccinicollaris on the Caribbean
slope in northern Coclé and western Colón.'
"I am especially wary of any taxonomic decision in New World
parrots based only on distribution of red pigment. As those who have worked
with Aratinga, Pyrrhura, Pionus, and other genera
know, individual variation in expression of reddish pigmentation is
substantial; some of that variation may be due to gene flow from adjacent
populations or age/sex variation, but individual variation also appears
substantial. In fact, in Pyrilia haematotis, of our 20 LSUMZ
specimens from Costa Rica to Mexico, three show conspicuous red feathers in the
belly to varying degrees and a fourth has a hint of reddish coloration there.
None has any hint of reddish in the neck, as in coccinicollaris,
but the point is that in the sister taxon, red pigmentation shows apparent
individual variation. With the only known difference phenotypic between coccinicollaris
and haematotis a variable amount of splotchy red in the neck (note
that it is not a solid, discrete patch of color), we are on safe ground to
require a more detailed analysis of the geographic and individual distribution
of phenotypic traits in Panama. I cannot think of a single case of two parrot
taxa that are ranked as species by any definition because they are parapatric
or sympatric without gene flow that differ only by the presence/absence of a
variable extent of reddish feathering.
"Ribas et al.'s (2005) evidence is as follows:
'These
species occur in southern and northern Central America and there seems to exist
a region of sympatry in Panama. In the present study, one of the sampled G.
coccinicollaris individuals (number 27) is from a locality that is closer
to those of the two G. haematotis specimens from Veraguas than
it is to the other two G. coccinicollaris collected in Darien
Province (see Fig. 1). Despite the geographical proximity and phenotypic
similarity between these two species, interspecific distances were markedly
higher (2.6% in ND2, 4.6% in cyt b) than the intraspecific distances
(0.1-1.2%), indicating the existence of an effective barrier separating these
two species in the past. such as vicariance events, are limited.'
"That the two forms are that close but still show substantial
% sequence divergence is indeed of interest and points to the need for further research.
The within-genus comparative % sequence data are also of interest but I think
that many workers would not try to use them directly in taxonomic assessments.
Note that the authors claim a "region of sympatry" but that their
data show only allopatry, and not even parapatry.
"However, contrary to the statement of Ribas et al., these
data in themselves provide absolutely no evidence of sympatry. Veraguas and
Colón [where their #27 is from] are adjacent provinces, and the localities
sampled are on opposite sides of the very region proposed as a zone of
intergradation by Wetmore (1968). Worse, their locality for haematotis,
"Cascajilloso," is presumably El Cascajilloso, which is in extreme
southern Veraguas on the Azuero Peninsula on the Pacific slope, rather than on
the Atlantic slope from whence the coccinicollaris specimen came
from:
http://www.maplandia.com/panama/veraguas/montijo/el-cascajilloso/
Therefore, more than straight-line geography may be involved in
the separation of these localities. If a more comprehensive analysis of
specimen localities not included in their tissue sampling shows sympatry, this
in itself is worth publishing."
Comments from Stotz: "NO. In the absence of good
data indicating sympatry, I agree with Van that the morphological differences
are not typically those that suggest distinctive species. It may be that
eventually we would split these, but it seems premature at best
currently."
Comments from Jaramillo: "NO - This may be a good
cryptic species, and hopefully Ribas et al are continuing to obtain more
information on this question. If one taxon had a bright red head and the other
didn't, that would make me feel more at ease with separating these species.
However, given that the morphological difference is not there, something else -
voice, behavior, display - something would need to be there as evidence that we
have two biological species involved. It may be premature to make the
split."
Comments from Cadena: "NO. The argument seemed
sensible at first, but Van has now convinced me that definitive evidence for
sympatry is not all that clear, and that because the morphological differences
might not be as clear cut, it is best to wait for more detailed analyses."
Comments from Robbins: "NO. Van's comments
illustrate the shortcomings of current data."
Comments from Pacheco: "NO. A análise de Van acerca do caso demonstra com clareza
que as informações disponíveis não são congruentes com a proposta."