Proposal (141) to South American Classification Committee
Split Urosticte ruficrissa from U. benjamini (and not recognize U. "intermedia")
This is a messy one as the critical evidence has not been published per se, but the published arguments for lumping these two are based upon secondhand evidence that is far from satisfactory either.
Urosticte benjamini and ruficrissa were described as separate species by Bourcier (1851) and Lawrence (1854), respectively, the former from the Pacific slope and the latter from the Amazonian slope of Ecuador. They differ in plumage and somewhat in size, and were recognized as species by Cory (1918). The complications are due to the description of U. intermedia by Taczanowski in 1882, from the Amazonian slope of NE Peru, also recognized as a separate species by Cory and by Peters (1945). Two specimens were evidently involved, and from his interpretation of Taczanowski's description Zimmer (1951) considered them intermediate between benjamini and ruficrissa and therefore lumped ruficrissa into benjamini without having examined these specimens firsthand. In most features including size, these specimens were said to resemble ruficrissa, the main point of intermediacy being a violet patch on the lower throat similar to that of benjamini. Meyer de Schauensee (1966) followed Zimmer in lumping ruficrissa into benjamini.
Hilty & Brown (1986) separated them again based upon differences in plumage and distribution, but did not address the question of intermedia, and Sibley & Monroe (1990) essentially followed Hilty & Brown. Schuchmann (1999) recognized ruficrissa and benjamini as species, considering intermedia to tentatively represent a cis-Andean race of the latter. Ridgely & Greenfield (2001) also split these two species.
Apparently the intermedia specimens themselves were next examined and photographed by Krabbe (in litt.). Tom Schulenberg sent me the photos and I consulted with Niels as well. It turns out that only one of the specimens really has a well-developed patch that is bluish, not violet as in benjamini; the other has a dusky spot in this area; the placement of this spot in both is not entirely typical of benjamini either. The range of benjamini on the Pacific slope terminates well N of the point at which the "intermedia" specimens were taken, and Tom informs me that perfectly typical specimens of ruficrissa are known both N and S of this point in Peru, thus it seems most unlikely that the characters of intermedia could have resulted from introgression with benjamini, as was apparently assumed by Zimmer. In fact, given the distribution and the fact that no other such specimens have been collected, the status of intermedia as a recognizable taxon is decidedly doubtful. Krabbe (pers. comm.) considered them to represent "a mutation, possibly a reversion to an ancestral type" and while I'm not sure whether this interpretation is entirely correct, I think that the basic idea is likely sound: these specimens represent an individual variant of ruficrissa rather than a distinct taxon. I realize that this conclusion is based upon unpublished evidence, although it seems solider than the second-hand conclusions supporting lumping of ruficrissa into benjamini, and recommend a YES vote on this proposal.
Bourcier 1851, Compt. Rend. 32
Lawrence 1864, Ann. Lyc. Hist. Nat. NY
Taczanowski 1882, PZSL
Cory 1918, Catalogue of Birds of the Americas, Part II no. 1.
Peters 1945, Checklist of birds of the world, vol. 5
ZIMMER, J. 1951. Studies of Peruvian birds, No. 60. The genera Heliodoxa, Phlogophilus, Urosticte, Polyplancta, Adelomyia, Coeligena, Ensifera, Oreotrochilus, and Topaza. American Museum Novitates 1513: 1-45.
Meyer de Schauensee 1966, The Species of Birds of South America
Hilty & Brown 1986, Guide to the Birds of Colombia
Sibley & Monroe 1990, Distribution and Taxonomy of Birds of the World
Schuchmann 1999, Handbook of Birds of the World, vol. 5
Ridgely & Greenfield 2001, Birds of Ecuador
Gary Stiles, November 2004
Comments from Remsen: "NO, but strictly on the basis a 'technicality' namely that the non-intermediate nature of 'intermedia' needs to be published first, in my opinion. Yes, Zimmer was wrong, and current taxonomy is thus currently based on faulty reasoning, but on principle, I will wait to vote yes until Niels or Gary publishes this -- it wouldn't take much -- Gary's proposal as written as a half-page BBOC note would do it for me."
Comments from Robbins: "I vote "YES"; recognizing Urosticte ruficrissa as a species based on information supplied by Krabbe and Schulenberg regarding the validity of "intermedia".
Comments from Pacheco: "YES. O tratamento em duas espécies me parece mais apropriado. Ainda que, a reinterpretaćčo do que pode representar os únicos espécimes de "intermedia" nčo esteja publicada."
Comments from Jaramillo: "YES. But would encourage publication of the dubious nature of intermedia."
Comments from Nores: "NO; sin conocer a estos colibríes, me parece que las diferencias de plumaje son sólo subespecíficas. El hecho de que a pesar de que geográficamente ocupan una misma área estén separados altitudinalmente (benjamíni 700-1600m y ruficrissa 1600-2400) indica para mi subespecies y no especies."
Comments from Zimmer: "YES. J. Zimmer seems clearly to have gotten this wrong. I would reiterate Van's call to publish Gary's rationale, but I'm willing to not wait on it."