Proposal (26) to South American Classification Committee
Elevate Automolus paraensis to
species rank
Effect
on South American CL: this proposal would split Automolus
infuscatus (Olive-backed Foliage-gleaner) into two species: A. infuscatus
and A. paraensis.
Background: To my knowledge, paraensis has never been
considered a full species. It is found in eastern Amazonian Brazil, south of
the Amazon, from R. Madeira east to Maranhão. In terms of plumage and
morphology, this form does not stand out, however, from other subspecies
currently included in A. infuscatus.
New
information: Zimmer (2002) concluded that paraensis
warranted recognition as a separate species from A. infuscatus
based primarily on vocal characters. He analyzed recordings of about 95
individuals from across the range of A. infuscatus, including all
four described subspecies and including about 30 individual paraensis,
from near-extremes of its distribution. The only weak-point in the sampling is
that only 3 individuals from 1 locality were available for the subspecies badius.
He also examined about 300 specimens from throughout the range of infuscatus,
including good samples from all five component taxa.
The taxon
paraensis is diagnosable based on plumage characters, but it is really
no more distinctive than the other taxa in question. In terms of measurements,
the five taxa generally differ significantly from one another in one or more
characters, but none can be diagnosed by any single measurement.
In
vocalizations, however, paraensis differs substantially from the other
four in each of the four characters considered (general loud-song type, note
structure, note length, and calls): "paraensis differed strikingly
and consistently in all aspects of its vocal repertoire from all other
subspecies in the complex." In contrast, differences among the other four
were nonexistent or minor, although some consistent but slight call note
differences among some of them. Zimmer noted that that paraensis was
more similar vocally to A. leucophthalmus lammi of NE
Brazil than to any subspecies of A. infuscatus (but that is
another project ).
Recommendation: I recommend a YES on this proposal. Although sampling
could always be improved and playback trials would be great, in my opinion the
vocal differences between paraensis and infuscatus are greater or
better documented than those between roughly 25 other pairs of ovenbirds
currently treated as separate species. It seems to me that the burden of proof
after Zimmer's analysis would fall on those who would continue to treat paraensis
as a subspecies of A. infuscatus.
English
name: Zimmer recommended "Para
Foliage-gleaner" for A. paraensis; in the absence of
distinguishing plumage features, this seems fine to me ad appropriate. Zimmer
recommended leaving the English name of infuscatus unchanged
(Olive-backed Foliage-gleaner) rather than concocting a new one to distinguish
it from the older, broader infuscatus; I agree with this, given that
even with paraensis split out, A. infuscatus still
occupies the vast majority of Amazonia.
Lit Cit:
Zimmer,
K. J. 2002. Species limits in Olive-backed Foliage-gleaners. Wilson Bull.
114: 20-37.
Van Remsen, 19 May 2003
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Comments
from Zimmer: "Obviously a "YES"
vote on this one. Sample sizes even larger after my most recent Brazil trip to
Carajas; all vocalizations of that population consistent with recordings of paraensis
from elsewhere in the range, and completely different from other populations of
infuscatus."
Comments
from Stotz: "If we could only get everybody
to publish such evidence to support splits."