Proposal (228) to South American Classification Committee
Merge Asturina into Buteo
The Gray Hawk species nitidus was in the genus Buteo in AOU 5th and 6th editions but was placed in the monotypic genus Asturina in the 7th, 1998, with a reference to Amadon (1982), which was a revision of the sub-buteonine hawks. The merger was accepted by the AOU CLC in the 19th Supplement, 1944.
Now, Riesing et al. (2003) have done a mitochondrial DNA study of 61 taxa of that group. In that study, the species nitidus falls well within the species normally considered Buteo, near those often called the "woodland buteos" --approximately where it was in the earlier editions.
I propose following Riesing et al. (2003) by merging Asturina into Buteo and placing the species nitidus in a position just before platypterus.
Riesing, M. J., L Kruckenhauser, A. Gamauf, and E. Haring. 2003. Molecular phylogeny of the genus Buteo (Aves: Accipitridae) based on mitochondrial marker sequences. Molecular Phylogenetics and Evolution 27:328-342.
Richard C. Banks, August 2006
Note: This proposal was solicited by Remsen from Banks and is a slight modification of the one submitted by Banks to AOU/NACC. It was accepted by NACC - see Banks et al. (2006).
Addendum by Bill Clark, 3 August 2006:
Quote below from Dr. Rob Fleischer was taken from his email to me with his permission:
"I get Buteo nitidus falling as sister to B. lineatus (and platypterus in some trees), basal to all the normal buteos (swainsoni, regalis, lagopus, jamaicensis, etc.). I get that clade falling within a clade that includes Leucopternis and the SA Buteos (albicaudatus, polyosoma, leucorrhous). So, it looks like a Buteo to me."
My personal experience is that Gray Hawk is closest to Red-shouldered Hawk in plumage and behavior. Putting one is another genus (in this case, Gray in Asturina) without including the other didn't seem to make much sense.
Gray Hawk is, from all aspects, a Buteo.
Comments from Remsen: "YES. A lingering concern, as noted in our Notes, is that Amadon's point was that nitida shares some characters with Leucopternis, and yet Leucopternis was not included in the taxa studied by Riesing et al. Comments from Rob Fleischer relayed by Bill Clark (above) indicate that Amadon's concerns about a connection to Leucopternis may not be far off, and that Leucopternis may have to be merged (when data published) into Buteo to maintain the latter's monophyly."
Comments from Stiles: "YES. I never found the Asturina split convincing - in voice, flight, habits nitidus always seemed like a perfectly normal Buteo to me (more so than magnirostris, for that matter). As for merging Leucopternis, it will be interesting to see what genetic analysis shows - this genus seems pretty heterogeneous (heterogenus?) to me and I wouldn´t be totally amazed if it were found to be not monophyletic."
Comments from Cadena: "YES. The genetic data are solid. Regarding Leucopternis, note that in agreement with Van's and Gary's remarks, the polyphyly of this genus with respect to Buteo has already been shown by Amaral et al. 2006 (BMC Evolutionary Biology 6:10), so this is something we will need to act upon soon. However, it would probably be best to wait until the study by Fleischer, which I assume has dense taxon sampling, is published."
Comments from Pacheco: "YES. O trabalho de Riesing et al. 2006 é um "retrato apropriado (embora, transitório) da informação disponível. Até que mais estudos abrangendo táxons dos gêneros próximos sejam apresentados, voto pela subordinação de nitidus em Buteo."
Comments from Zimmer: "YES. I never agreed with the separation of nitidus from Buteo. As others have mentioned, the complication will come with the whole question of relationships within Leucopternis and between Leucopternis and Buteo, but that is another battle."
Comments from Jaramillo: "YES. This is clearly the preferable arrangement, like others I never understood why Asturina existed. It is good to get an independent data set that confirms the placement of this species."