Proposal (354) to South American Classification Committee

 

Move Heliangelus zusii (Bogota Sunangel) to hypothetical list

 

Effect on South American Checklist: This proposal would transfer a species from the Main List to the Hypothetical List.

 

Background: In Proposal 57, SACC decided not to transfer H. zusii from the main list to the "dubious taxa" list (5-4 in favour of doing so, but insufficient votes).

 

Proposal: The present proposal does not query the validity of H. zusii, which has been subject to a previous proposal (and no new information relevant to that proposal has been published). Rather, it is proposed that the species be moved to the hypothetical list on account of it not being confirmed to occur in the SACC region. The distribution section of Graves' (1993) description states "Origin and range unknown. See discussion." Graves (1993) hypothesised a likely distribution for the species in the Central or East Andes of Colombia. As most "Bogot‡" skins were apparently collected in the East and Central Andes of Colombia and the Magdalena Valley, and given the likely relations of the type specimen, this is a sensible hypothesis. However, it is merely a hypothesis. Some "Bogot‡" skins were apparently collected in Ecuador and Peru (possibly Panama, which used to be part of Colombia?); and old specimen label data, especially data with such cursory locality information, is in any event often unreliable. The occurrence of H. zusii in the SACC area has not been documented. Other species considered likely to occur in the SACC area, including a host of reliable sight records, are on the hypothetical list. That would also be a sensible home for this species - which is hypothesised but not confirmed to occur in the SACC region - until a confirmed locality is found for it. A rationale for a no vote on this would be that the likelihood of this specimen having been collected outside the SACC area is minute.

 

Thomas Donegan, May 2007

 

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Comments from Cadena: "NO, exactly for the reason that Thomas mentioned at the end of his proposal. Although we don't know the exact provenance of the specimen, I think it is beyond any reasonable doubt that it comes from the area of SACC coverage. I cannot help noticing that in a paper published yesterday Donegan used a different logic and argued for the inclusion of Chalcostigma stanleyi in Colombia's official bird list based on a specimen with similarly vague locality data."

 

Comments from Stiles: "YES, although not for the reasons stated by Thomas (at least in part). My reading of Graves's description is that he discounted a hybrid origin of H. zusii based upon the supposition that it was taken in central Colombia, where there is no combination of suitable putative parental species that would give the appropriate phenotype. However, the bird might well have come from southern Colombia or Ecuador, where Eriocnemis nigrivestis or isabellae occur along with some Heliangelus species, especially exortis - hence I wonder whether a wider consideration of possible progenitors might not support a hybrid origin after all ... added to the fact that considerable recent fieldwork in Colombia has failed to turn up any indication of a wild population. As I mentioned under that proposal, this case differs from that of Atlapetes blancae where three specimens exist, one or two with definite locality data and where the other Atlapetes species present in that region do not present the appropriate combination of characters for one to support a hybrid origin."

 

Comments from Stotz: "NO. I still need to think about this. How certain do we need to be of the provenance of specimens? Is it 100% that it was within the SACC area, beyond a reasonable doubt, or just the preponderance of evidence. I don't think that it is 100%. If we had to be 100% certain of the taxonomic status of something then we'd never do that. The situation is not equivalent in my mind to sight records. We place sight records on the hypothetical list because of a different set of concerns."

 

Comments from Nores: "NO. Aunque pienso que la propuesta est‡ bien fundamentada, me parece muy poco probable, casi imposible, que el ejemplar provenga de un lugar fuera de Sudamˇrica. Si hemos aceptado la validez de la especie, pienso que lo que corresponde es incluirla en la SACC list. Si se llegara a encontrar que la especie es de otra zona, de Panam‡, por ejemplo, habr’a que eliminarla de la lista, pero mientras tanto mejor no innovar."

 

Comments from Zimmer: "NO, for reasons summed up nicely by Daniel and Doug."

 

Comments from Schulenberg: "NO. I share Gary's reservations about this taxon: it's hard not to, when dealing with a unique type with an unknown locality. But that's not the subject of this proposal, which instead has to do with the provenance of the specimen. My default assumption - the "null hypothesis" - is that the specimen came from South America; and I don't seen any strong argument against the null hypothesis.

 

"We did consider earlier whether or not zusii was a hybrid, and on that point (which, again, is not really the subject of this proposal), to date no one has identified a likely combination of parent species. I think we need a specific pair or two of proposed parental species to consider, if we wish to revisit the question of hybrid origin."

 

Comments from Jaramillo: "NO - Nothing to add here that hasn't been said. Besides it is called the Bogota Sunangel, if we move it to the hypothetical list we probably need to change the English Name (smiley face needed here because I am joking)."

 

Comments from Pacheco: "NO. A origem geogr‡fica dos "Bogot‡ skins" atˇ aqui j‡ "traced" torna remota a possibilidade do t‡xon provir de alguma ‡rea fora do noroeste da Amˇrica do Sul."

 

Additional comments from T. Donegan:" "In relation to Carlos Daniel's point on our Colombia checklist, which is not strictly relevant to this proposal, Heliangelus zusii (and also Chalcostigma stanleyi among other species) have an annotation "Bog" in the checklist text, which denotes that they are known only in the country from "Bogota", "New Grenada" or "Colombia" specimens.  In the totals in the front of the list, these species are treated separately, as for "hypothetical" species and introduced species, allowing persons adopting particular standards to report species totals for the country in different ways."