Proposal (32) to South American Classification Committee
Recognize Glaucidium
mooreorum
Effect on South American CL: This proposal would
add a newly described species to the list
Background: Silva et al. (Ararajuba
10:123-130, 2002) presented evidence for recognizing a new pygmy-owl (Glaucidium
mooreorum) that is restricted to the Pernambuco region of the northern
Atlantic Forest of Brazil.
Although the evidence presented consisted of
only two specimens and a single sound recording, I believe they have
convincingly established, based on the very distinct song, that the Pernambuco
Pygmy-owl is indeed different from the morphologically very similar Amazonian
Pygmy-owl (G. hardyi) and Least Pygmy-Owl (G. minutissimum).
Plumage color and pattern is extremely similar
among the presumed Least Pygmy-Owl (G. minutissimum) species complex
(sensu Howell and Robbins 1995). Because of this extreme interspecific
similarity coupled with variability in plumage within each taxon (varying in
brown and dull red pigmentation and wear), I don't put any weight in the
described color differences that they present. Because there were only two
specimens available (no surprise given how difficult these subcanopy-dwelling
owls are to obtain) the relevance of the tail/ring ratio in separating these
taxa is hard to determine, especially given that one could argue that the two
Pernambuco specimen ratios fall within the range of minutissimum.
However, the primary vocalization that they
present is very distinct from that of minutissimum and hardyi.
They accurately describe this in paragraph 2, left hand column of page 127.
Although this is based on only a single recording (under natural conditions),
my experience with this complex suggests that there is little intraspecific
variation in natural song. Thus, I suspect that the vocal material that they
present is an accurate representation of this taxon. Because this is truly the
key (until we have genetic data) for separating these cryptically plumaged
owls, I believe, despite the very limited material, that the authors have
demonstrated that mooreorum deserves species rank.
Mark Robbins, June 2003
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Comments
from Zimmer: "I
vote "yes" to add Glaucidium mooreorum as a new species to the
list. I would like to see a bigger sample size here, but I agree with Mark that
there doesn't seem to be much individual variation in this group (other than
perhaps slight variation in number of notes, e.g. 2 versus 3 or 4, within an
individual), so that the one tape recording is likely to reflect a very real
distinction. It also fits a biogeographical pattern. I'm not very impressed
with slight morphological distinctions (particularly color saturation) in this
genus -- I think voice is the key."
Comments
from Silva: "Voice
is different as well as plumage colouration. Based on the specimens that I
examined of minutissimum and hardyi I did not see a so large
intraspecific variation in plumage colour that seems to be common in other
species of the genus."
Comments
from Jaramillo:
"YES I am a bit concerned regarding the small sample sizes looked at,
both skins and vocalizations. But I know a lot less than Mark about variation
in natural songs, thus the fact that he is comfortable with the small number of
voice samples is enough to make me comfortable with it."
Comments from Nores: "Si estoy de acuerdo, aunque uno esperaría una mayor cantidad de ejemplares y de registros vocales para dar una opinión definitiva."