Proposal (755) to South American Classification Committee

Split Campylopterus largipennis into four species

Effect on South American CL: This proposal would recognize four species within the taxon that we currently treat as Campylopterus largipennis.

Two taxa from the interior of the eastern Brazil: the montane Campylopterus largipennis diamantinensis and another Campylopterus sp.n., recently described from dry forests (see Proposal 756), are isolated from the predominantly lowland Amazonian Campylopterus largipennis (including the nominate taxon) by more than 600 km of dry open intervening habitats, the “dry diagonal” formed by the Caatinga, Cerrado, Pantanal, and Chaco.

Preferred habitat of the populations of C. largipennis diamantinensis found in eastern Brazil (high altitude “campos rupestres” above 1,000 m a.s.l.), and Campylopterus sp.n., (tropical dry forests occurring below 900 m a.s.l.) contrasts sharply with the humid habitats of the three Amazonian subspecies (C. l. largipennis, C. l. obscurus and C. l. aequatorialis).

From the examination of 1012 specimens and detailed morphological analysis, Lopes et al. (2017) proposed that not only Campylopterus sp.n. from dry forests, but also C. l. largipennis, C. l. diamantinensis and C. l. obscurus (embedding C. l. aequatorialis), should be considered as independent species.

The following morphological, ecological and biogeographical evidences support this proposition: 1) the lack of hybridization between C. l. largipennis and C. l. aequatorialis, even though there is no absolute barrier separating them (and they may be parapatric); 2) the important chromatic differences in the tail patterns between members of the group showing broadly light tail tips and members of the group showing short and greyish light tail tips; and 3) the well-marked ecological differences between Amazonian taxa and eastern Brazilian taxa, which are fully diagnosable on morphological basis.

Parapatric distribution (only 25 km apart) without evidence of free gene flow between C. l. diamantinensis and Campylopterus sp.n. is adequate evidence for species rank also under the BSC (Remsen 2015).

Colombian bird specimens, revealed two records that suggest that C. l. largipennis and C. l. aequatorialis possibly come into contact somewhere in eastern Colombia, in the departments of Guaviare or Vaupés. The specimen of C. l. largipennis in the right bank of the Negro River (Papuri) and one specimen of C. l. aequatorialis collected in La Pedrera, rio Caquetá. Although these two records are separated by about 200 km, the intervening area is covered by continuous forests, harboring no large river or landmark barrier, which suggests that C. l. largipennis and C. l. aequatorialis might be parapatric taxa.

Recommendation: I recommend a "YES" on this one

Literature Cited:

Lopes, L. E., Vasconcelos, M. F., and Gonzaga, L. P. (2017) A cryptic new species of hummingbird of the Campylopterus largipennis complex (Aves: Trochilidae). Zootaxa 4268 (1): 001–033.

Remsen, J.V. Jr. (2015) Book review: HBW and BirdLife International Illustrated Checklist of the Birds of the World Volume 1: Non-passerines. Journal of Field Ornithology 86, 182–187.

José Fernando Pacheco, Sep. 2017

Note from Remsen: Let’s split into 2: (A) diamantinensis from largipennis, and (B) aequatorialis from nominate largipennis.

Comments from Stiles: "I am on the fence here. The morphological and ecological data look good, at least for separating diamantinensis+ calcirupicola from largipennis + aequatorialis; I am less sure regarding splitting the latter two because of the large gap with no records, hence the evidence for parapatry of these is largely conjectural, despite the lack of apparent barriers between them; it seems surprising that no specimens exist over such a wide region. For what it´s worth, I did not observe any largipennis-type birds during several sets of observations in 2 yrs. at San José del Guaviare, and was unable to collect the species when I observed it on the río Apaporis (where aequatorialis would presumably be expected). Genetic data might help to clarify this split, although specimens would be highly desirable. So I would vote YES for splitting the two Brazilian forms from the western group, and give a tentative NO for splitting the latter two."

Comments from Areta: "YES to separating C. diamantinensis from C. largipennis (I already voted yes to Proposal 756 to recognize C. calcirupicola). Like Gary, I am less sure about splitting obscurus (including aequatorialis) from C. largipennis. I would like to see more detailed analyses on this front, with specific comparisons in areas where obscurus and aequatorialis occur closer to largipennis."

Comments from Zimmer: “This proposal should be split into subproposals for operational purposes. I would vote YES on splitting diamantinensis and calcirupicola from one another on grounds of their parapatric distributions and ecological replacement of one another. I would also vote YES on separating each of these taxa from largipennis + aequatorialis, based upon morphology, biogeography and ecology. But, I would vote NO for splitting largipennis and aequatorialis from one another given the incomplete evidence for parapatry.”

Comments from Remsen: “A. NO. Range disjunction and differences in habitat are not in themselves criteria relevant to taxonomic rank. B. NO, until actual contact zone discovered; given the phenotypic similarity between the two and lack of known vocal differences between the two, I think we should be cautious.” [more detailed comments to be submitted soon]

Comments from Jaramillo: “A - YES on separating C. diamantinensis from C. largipennis. B – NO

Comments from Robbins: “YES. I agree with recognizing diamantinensis as a species (I voted Yes for recognizing calcirupicola as a species), but until more information becomes available not recognizing any further species division of largipennis (nominate, obscurus, aequatorialis).”

Comments from Claramunt: “YES. Mainly because it does not make sense to maintain a widespread largipennis after separation of calcirupicola (already decided in proposal 756). Both for morphological and biogeographic reasons, it is likely that diamantinensis and calcirupicola are closest relatives. Then it does not make sense to maintain diamantinensis as a subspecies of a different species. Regarding the Amazonian group, obscurus and largipennis show clear morphological differences in tail pattern. And I think that the patter of sexual dimorphism could be a sign of divergent preferences among females: differences among males in tail pattern are greater than differences among females (Lopes et al. page 7). This suggests that obscurus females are choosing males with dark tail tips whereas largipennis females are choosing males with broad white tips. I agree that data from the contact zone would be very informative for a decision, but obscurus and largipennis may be allopatric, as specimen records suggest. The proposed four-species solution may not be rock solid and further analyses of character variation and genetic data may not support it, but given that we already separated calcirupicola, separating diamantinensis and obscurus seems necessary for consistency (and monophyly).

Comments from Stotz:

“A. YES. This seems consistent with the already accepted split of calcirupicola.

“B. “NO. I just don’t find the current evidence compelling supporting a split compelling. I think we would need a better understanding of the distribution of the two forms in Eastern Colombia/NW Brazil. There is more ecological variation across this region than ‘continuous forest’ might imply. There are other species that appear to reach range boundaries in this region.”