(698) to South American Classification Committee
Zimmerius chicomendesi Whitney et al.
2013 as a species
Background: Zimmerius are small-bodied, frugivorous tyrannulets that are
widespread in wooded habitats from southern Mexico south to central Bolivia and
central Brazil (or to southeastern Brazil, if Phyllomyias griseocapilla Gray-capped Tyrannulet proves to be a Zimmerius, as suggested by Whitney et
al. 2013). The plumage of all Zimmerius
is drab. The seemingly dull and innocuous outward appearance of these
tyrannulets belies the complexities of their phylogenetics. SACC already has
grappled with several proposals dealing with this genus, some of which passed
and some of which did not. For a review, see
taxa of Zimmerius were described in
the 19th or early 20th century. It was something of a
surprise, then, when Jose "Pepe" Alvarez discovered a new species of Zimmerius, Z. villarejoi Mishana Tyrannulet, in 1997 (Alvarez Alonso and
Whitney 2001). The type locality of villarejoi
is very close to the major Amazonian port of Iquitos, in northern Peru. As
Alvarez and Whitney pointed out, even then there was evidence of yet another
previously unknown Zimmerius, in the
Rio Mayo Valley in the foothills of the Andes in San Martin, Peru, southwest of
the type locality of villarejoi. The first specimen of the Mayo Valley
population had been collected in 1912 (!), and seemed to be identical to villarejoi from near Iquitos; but at the
time of Alvarez and Whitney (2001), the Mayo Valley population was unknown in
life. Subsequently the Mayo Valley population has been collected again, by Dan
Lane and colleagues (LSU), and its vocalizations documented (see ,
and Whitney et al. 2013).
New information: The latest twist is
the discovery, in 2009, of yet another unknown Zimmerius, this time in central Amazonian Brazil. This population
currently is known from the east bank of the Rio Madeira east to the
Aripuana/Roosevelt/Maderinha drainage. This population was described by Whitney
et al. (2013) as a new species, Zimmerius
chicomendesi Chico's Tyrannulet.
plumage, chicomendesi appears to be
indistinguishable from both villarejoi
and from the villarejoi look-alike in
the Mayo Valley, which Whitney et al. refer to as aff. villarejoi. All three of these populations also inhabit somewhat
similar habitats: villarejoi in white
sand forests (locally known as varillales),
aff. villarejoi in semidry forests in
the Mayo Valley, and chicomendesi in campina woodland and scrub.
than having a highly disjunct range, chicomendesi
differs from villarejoi and aff. villarejoi in two ways: it is slightly
smaller than the two other populations (these differences being especially
apparent in body mass; see the Supporting Information); and it has slightly
different vocalizations, which are described as "notably lower in frequency"
than the otherwise similar vocalizations of villarejoi
and aff. villarejoi. Their summary is
based on a relatively small number of samples (especially of aff. villarejoi; see Supporting Information).
Sonograms of vocalizations of all three are presented, but I didn't notice any
quantitative comparisons of songs or calls across these taxa.
are only two proposed new taxa from the 2013 new species special volume for
which there is no associated phylogenetic analysis, and this Zimmerius is one of them (the other is Tolmomyias sucunduri, dealt with in
Recommendation: This case is somewhat
similar to that of Nystalus obamai
Alvarez Alonso, J., and B.M. Whitney.
2001. A new Zimmerius tyrannulet
(Aves: Tyrannidae) from white sand forests of northern Amazonian Peru. Wilson
Bulletin 113: 1-9.
E.C., and L. Christidis (editors). 2014. The Howard and Moore complete
checklist of the birds of the world. Fourth edition. Volume 2. Passerines. Aves
Press , Eastbourne, United Kingdom.
Piacentini, V. de Q., A. Aleixo, C.E. Agne,
G.N. Maurício, J.F. Pacheco, G.A. Bravo, G.R.R. Brito, L.N. Naka, F. Olmos, S.
Posso, L.F. Silveira, G.S. Betini, E. Carrano, I. Franz, A.C. Lees, L.M. Lima,
D. Pioli, F. Schunck, F. Raposo do Amaral, G.A. Bencke, M. Cohn-Haft, L.F.A.
Figueiredo, F.C. Straube, and E. Cesari. 2015. Annotated checklist of the birds
of Brazil by the Brazilian Ornithological Records Committee / Lista comentada
das aves do Brasil pelo Comitê Brasileiro de Registros Ornitológicos. Revista
Brasileira de Ornitologia 23: 91-298.
Lista comentada das aves do Brasil pelo Comitê
Brasileiro de Registros Ornitológicos. Revista Brasileira de Ornitologia 23:
Rheindt, F.E., J.A. Norman, and L.
Christidis. 2008. DNA evidence shows vocalizations to be better indicator of
taxonomic limits than plumage patterns in Zimmerius
tyrant-flycatchers. Molecular Evolution and Phylogenetics 48:150-156.
Rheindt, F.E., A.M. Cuervo, and R.T.
Brumfield. 2013. Rampant polyphyly indicates cryptic diversity in a clade of
Neotropical flycatchers (Aves: Tyrannidae). Biological Journal of the Linnean
Society 108: 889–900.
Whitney, B.M., F. Schunck, M.A. Rego,
and L.F. Silveira, 2013. . Pages 286‐291 in J. del Hoyo, A. Elliott, J.
Sargatal, and D.A. Christie, editors, Handbook of the birds of the world.
Special volume: new species and global index. Lynx Edicions, Barcelona.
Schulenberg, January 2016
from Zimmer: “YES. Although Whitney et al. (2013) did not
present a quantitative vocal analysis comparing vocalizations of chicomendesi, villarejoi and what they refer to as aff. villarejoi, the various
vocalizations appear (based upon the sonograms presented) to differ
qualitatively between taxa beyond the noted differences in frequency. This is true of both songs and the homologous
two-note calls. The sonograms of aff. villarejoi sensu Whitney et al (2013)
appear more similar to those of chicomendesi
songs and calls than they do to the corresponding vocalizations of villarejoi. I would say this is true of the note shapes
of the two-note calls, and of the constituent notes making up the songs. Those note-shape similarities are reflected
in qualitative similarities (to my ears anyway) between the San Martin villarejoi and chicomendesi, at least based upon the various recordings that I
listened to on Xeno-Canto. Nonetheless,
I think that the 3 taxa, although indistinguishable in plumage characters, and
possessing similar vocal repertoires, are different enough vocally, and with
clearly disjunct distributions, as to warrant recognition as separate
species. As an aside, I think Whitney et
al. (2013) are also correct in their suggestion that Gray-capped Tyrannulet (Phyllomyias griseocapilla) will
ultimately prove to be a Zimmerius,
an assertion that I’ve been making for years, based upon plumage pattern, vocal
repertoire, and foraging behavior and posture.”
from Claramunt: “YES. Morphometric data suggests that chicomendesi
is smaller than the San Martín population (aff. villarejoi). Comparison
with true villarejoi (from Iquitos) is difficult given the low number of
specimens available; the few specimens of villarejoi tend to be
intermediate between chicomendesi and the San Martín birds and cause
most of the overlap in measurements. This is what you would expect if body size
changed gradually E to W, or if foothill birds are larger than lowland birds
for some ecogeographic reason. However, vocal data suggest that this is not a
case of intraspecific geographic variation. Regarding vocal data, there is no
quantitative analysis, but Whitney et al. stated that homologous vocalizations
are “immediately and primarily distinguishable”, implying that vocalizations
vary in a discrete way, whit no overlap or intermediates. One aspect that
caught my attention is the significant lower frequency of chicomendesi
vocalizations, against the expectation for a smaller bird. This aspect suggests
to me that this is not a case of intraspecific variation and something else is
going on, at least regarding allometry between body size and vocal tracts that
suggests a history of independent evolution and accumulation of phenotypic
differences. Therefore, the Brazilian birds do not seem to be just a new
population of villarejoi and I tentatively concur with Whitney et al.
and Tom in that they deserve species status.”
from Remsen: “YES.
I am persuaded by the points made by Tom, Kevin, and Santiago.”
from Stiles: “YES. I
too find the arguments of Tom, Kevin and Santiago persuasive.”
from Areta: “YES. The
diagnostic calls and songs of all three species in the complex support their
recognition as different species. I had to dig into sound archives (MLNS and
XC) to convince myself that differences in shape and pitch in calls and song
notes were consistent within each taxon. Despite some variation, the
spectrograms shown by Whitney et al. (2013) constitute good representations of
the vocal differences between these morphologically very similar taxa. I wonder
whether other to-be-found populations will sound intermediate between any of
the currently recognized vocally diagnosable units, especially given the vocal
similarities between aff. villarejoi and chicomendesi.”
from Pacheco: “YES. I also agree that the data presented so far
are sufficient to agree with Tom's proposal. Even though the population of San
Martín (aff. villarejoi) proves in the future be an isolated population
of the same type as the newly discovered Brazilian Amazonian scrub, the name
must be chicomendesi.”
from Jaramillo: “YES –
I am particularly persuaded by the comments by committee members with more
experience with this group, as well as their independent listen and analysis of
voice. Thanks for that help!”
Comments from Robbins: “YES, based on
comments by Tom et al. for recognizing Zimmerius
chicomendesi as a species.”