Proposal (323) to South American Classification Committee
Recognize the genus Tarphonomus for two "Upucerthia"
Effect on SACC: This would transfer two species from their current placement in Upucerthia to Tarphonomus, the genus newly described for them.
Background: SACC classification currently classifies all the earthcreepers in their traditional genus, Upucerthia. Multiple lines of evidence indicate that this genus is polyphyletic, with two of the major "offenders" being harterti and certhioides. Our current Note is as follows:
"7. The genus Ochetorhynchus was used for U. harterti and U. certhioides by Ridgely & Tudor (1994) to recognize the distinctiveness of these two species from other Upucerthia (especially with respect to nest type); however, the type species of Ochetorhynchus is ruficaudus, making that name unavailable for harterti + certhioides unless ruficaudus is also included (Remsen 2003). Peters (1951) treated those three species in Ochetorhynchus. The genus Upucerthia is highly polyphyletic (Chesser et al. 2007, FjeldsĆ et al. 2007), with (a) harterti and certhioides in a group with Pseudocolaptes and Premnornis, (b) andaecola and ruficaudus in a group with Eremobius and Chilia, (c) serrana basal to a group that includes Cinclodes and the remaining Upucerthia (dumetaria, albigula, jelskii, and validirostris). Chesser and Brumfield (2007) named a new genus Tarphonomus for certhioides + harterti."
New information: As noted above, two independent genetic data sets appeared in 2007, using different genes and samples, with the same results, namely that Upucerthia consists of 4 different groups of birds, and to keep that genus monophyletic would require merger of virtually every furnariine genus into one. For example, Chesser et al. (2007) found that the two Upucerthia that group with Eremobius and Chilia are basal to all other furnariine genera sampled, including, for example, Synallaxis, Philydor, Furnarius, and Cinclodes. With respect to this proposal, harterti and certhioides formed a group (96% ML bootstrap) with Pseudocolaptes, and true Upucerthia (dumetaria, albigula, validirostris, jelskii) form a group (100% ML bootstrap) with Cinclodes. Their sample was based on both nuclear and mitochondrial genes (total 1927 bp), and separate analyses of mtDNA and nDNA produced similar results, as did all methods of data analysis. Therefore, as suspected for decades (including even by master-lumper Peters), harterti and certhioides (clearly sisters) do not belong in Upucerthia.
Chesser and Brumfield (2007) named a new genus for these two species after establishing that there was no other name available and concluding correctly that no one in their right mind would merge these two into the sister genus Pseudocolaptes.
If anyone needs pdfs of these papers, let me know (or download them from Robb Brumfield's web page).
Analysis and Recommendation: In my opinion, there is no reason to hesitate on this one. Anyone familiar with these birds knows that the only thing that they shared with true Upucerthia was terrestrial foraging and a relatively long bill. The genetic data leave beyond a doubt that the genus Upucerthia grouped species that shared a morphotype, and pruning in needed to make this genus monophyletic. This proposal is a first step, and I recommend a YES, to recognize them under the new genus name Tarphonomus and to transfer them to follow Pseudocolaptes in our linear sequence.
Chesser, R. T., F. K. Barker, & R. T. Brumfield. 2007. Four-fold polyphyly of the genus formerly known as Upucerthia, with notes on the systematics and evolution of the avian subfamily Furnariinae, Molecular Phylogenetics and Evolution 44:1320-1332.
Chesser, R. T., & R.
T. Brumfield. 2007. Tarphonomus, a new genus of
ovenbird (Aves: Passeriformes: Furnariidae) from South America. PROCEEDINGS OF
THE BIOLOGICAL SOCIETY OF WASHINGTON
[See SACC Literature Cited for others]
Van Remsen (in consultation with Robb Brumfield and Terry Chesser), December 2007
Comments from Stiles: "YES. Again, the genetic data clearly mandate this change, and the morphological data favoring placement in Upucerthia were not particularly strong in the first place."
Comments from Zimmer: "YES for reasons stated by Van in the proposal."
Comments from Robbins: "YES. The Chesser et al. genetic data support erecting a new genus, Tarphonomus for certhioides and harterti."
Comments from Pacheco: "YES. A sugestčo me parece plenamente convincente. Voto sim pelo uso imediato do gźnero recém proposto."
Comments from Nores: "YES. Siempre consideré que certhioides y harterti tenían poco parecido con las verdaderas Upucerthia, pero tampoco me gustaba la idea de ponerlas junto con ruficauda y andaecola para sepáralas de Upucerthia. La creación del nuevo género para estas dos especies, apoyado por análisis genético, resuelve perfectamente este problema."