Proposal
(12) to South American
Classification Committee
Continue to recognize a broad Otus guatemalae (namely
to include O. vermiculatus, O. napensis, O roraimae)
RE Otus
guatemalae. In this very confusing genus this species complex may have the
most complicated taxonomic and nomenclatural problems. Nonetheless, there are a
couple of clear decisions that can be proposed. There is an Otus found
from at least central Panama (Canal Zone) south to the southern border of
Ecuador (west slope) that has a very distinct vocalization (listen to Hardy et
al.) from the rest of the guatemalae complex (includes guatemalae,
vermiculatus, napensis, roraimae; note that guatemalae has
priority). Hekstra's (1982) centralis (holotype from Cerro Mali, Darien,
Panama) appears to represent this distinctively vocal form, however, the
question that begs to be asked but may not be answered from examination of the
holotype, is whether the holotype unequivocally represents the Otus with
the distinct vocalization and not guatemalae (includes vermiculatus).
From recordings on the Hardy et al. tape, material in LNS, and recordings of
Paul Coopmans it appears that guatemalae does not occur in eastern
Panama. In fact, every vocalization that I have listened to from Panama is of centralis.
Is anyone aware of a guatemalae-type vocalization from anywhere in
Panama? I presume Bob and Brett can amplify on what occurs in Panama and Gary
perhaps can shed light on whether centralis occurs in Costa Rica. Guatemalae
is the screech-owl at La Selva, Costa Rica (recording by P. Coopmans). It would
be interesting to know whether the two species are sympatric. So, unless some
of the committee members are aware of any guatemalae vocalization from
the eastern half of Panama we can be confident that Hekstra's centralis
indeed represents the vocally distinct species.
See
Marshall et al.'s (1991) frontispiece for depictions of spectrographs and
distributions of selected Otus species relevant to the guatemalae
complex. Note in the text on page 315 that the Ecuador locality (Paramba) under
Otus atricapillus guatemalae is an error and should appear in their O.
vermiculatus species account. Finally, the vermiculatus species
account *now* refers to O. centralis.
The
other issue within this complex concerns the forms in northern South America
and along the east slope of the Andes. Individuals that I've recorded on the
north slope of Roraima (LNS # 42756-7; 85789) sound very similar to the
recording of napensis from prov. Huánuco, Peru on the Hardy et al. tape.
Also, my recording of a bird that we collected in the Acari Mtns. (LNS # 42755;
KU # 98695) in extreme southern Guyana sounds virtually indistinguishable from
the recording from the mountains just south of Caracas, Venezuela (Portachuelo
Pass, Aragua) on the Hardy tape. These data (as I conveyed to Terry Taylor in
the production of the Hardy tape) were the foundation for considering roraimae
and napensis conspecific. Note that König et al.'s range map for vermiculatus
is a composite of guatemalae, centralis, and the northern coastal
range of roraimae!
So, if
we consider roraimae and napensis conspecific (roraimae
has priority) the next question that needs to be dealt with is whether roraimae
and the Mexican and Central American bird, guatemalae (includes vermiculatus),
should be considered conspecific. Although they are widely disjunct (the gap
extends from at least central Panama to the Colombia/Venezuela border) and
there are morphological differences, they are vocally quite similar. In fact,
one could argue that guatemalae, roraimae, and atricapillus
(including hoyi) could all be considered conspecific based on vocal
similarities (Marshall et al. [1991]did just that, but note what I stated above
concerning molecular data). Without any additional information perhaps the
conservative thing to do is go with past taxonomic history and treat guatemalae,
roraimae, and napensis as conspecific, but for now consider atricapillus
as a distinct species.
If we
recognize roraimae (with napensis) as a distinct species from guatemalae,
then to be consistent, we should recognize colombianus (both have
allopatric distributions, some plumage differences, but relatively minor
differences in vocalizations).
Mark B.
Robbins, December 2001
________________________________________________________________________________________
Comments
from Schulenberg: "Re:
Proposal 12A (not yet presented on Van's web site as a formal proposal): To
recognize Otus centralis as a
species. "NO". This vote should not come as any surprise by now,
since I am being pedantic throughout, at least with respect to owl taxonomy.
The "whole world" seems to agree that there is an Otus with a "different" song
in Panama and northwestern South America, and that there is little or no
geographic overlap between this entity and other "Vermiculated" screech-owls.
But I'd still like to see this better documented than by reference to two
recordings on the Hardy et al. tape. Furthermore, someone ought to properly
document that Hekstra's name, centralis,
does apply to this bird, *and* that no earlier name does. Mark's proposal seems
to recognize this. Finally, this case overlaps in jurisdiction with the AOU
Check-list Committee for North America. I am not on the committee and I
shouldn't presume to speak for how they operate, but I'd be surprised if they
would act on this case simply because of the songs presented on the Hardy et
al. tape. Not to say that SACC should be the AOUCLC lapdog, but ... So, I think
I am going to hold off until someone (some combination of Mark Robbins, Gary
Stiles, Joe Marshall, Bob Behrstock???) writes something up for publication
that makes the full argument for recognizing this Otus as a species, and that
centralis is its name. If this case is as clear-cut as everyone makes it out to
be, then "it shouldn't be that complicated to do" (famous last
words).
Comments
from Jaramillo: "The proposal deals with two
questions, one is considering guatemalae to include roraimae and napensis.
I know little about this problem, but my understanding from reading the
argument and listening to the tapes is that these taxa sound pretty similar and
in terms of morphology are different, but only slightly. See my note regarding
similarity of song in allopatric owl populations under Proposal 11 for
something else to think about. Having said that, the available data does not
give much support for retaining all of these taxa as separate so I accept a
broad definition of guatemalae until further research is published. The
second question is the elevation of centralis, based on different song
from guatemalae mainly. On this topic, I have to agree with Tom's
comments. There is a need to publish something describing clearly what the song
differences are, distribution of song types, and tying the type of centralis
to this song type before I would feel comfortable elevating this form to a
species."