Proposal (684) to South American Classification Committee
Elevate Conopophaga lineata cearae to species rank
Effect on SACC: This proposal would add a species to the list by removing the subspecies cearae from C. lineata and elevating it to species rank.
Background: Our current footnote sums up the situation:
5. The subspecies cearae of northeastern Brazil was formerly (e.g., Cory & Hellmayr 1924, Pinto 1937, Peters 1951) considered a separate species from Conopophaga lineata, but most authors have followed Pinto & Camargo (1961) and Meyer de Schauensee (1966) in considering them conspecific. Vocal differences between cearae and other populations of C. lineata suggest that it deserves a return to species rank (Whitney 2003), and Batalha-Filho et al. (2014) found that cearae was the sister to C. peruviana, not C. lineata. SACC proposal badly needed.
New Information: The phylogeny of Batalha-Filho et al. (2014), based on DNA sequence data (3 mitochondrial genes, 2 nuclear introns, 3300 bp) yields the following tree (which is difficult to read here; I recommend looking at the original – let me know if you need pdf):
Fig. 1. (a) Phylogenetic relationships of Conopophagidae. The topology was obtained by Bayesian inference based on 3309 bp of mitochondrial and nuclear gene concatenated sequences. Node supports are posterior probabilities (PP) and bootstrap (BT) values for Bayesian inference and maximum likelihood, respectively. Asterisks indicate when both PP and BT were maximum (1.0 and 100, respectively).
As you can see, the subspecies cearae is not particularly close to Conopophaga lineata. Although the support for the sister relationship between C. ardesiaca and cearae is one of the weakest nodes in the tree, the sister relationship between C. lineata (minus cearae) and C. roberti is strongly supported; therefore, even if further data showed that cearae and ardesiaca were not sisters, there is still no support for any close relationship to nominate lineata. Wise inclusion of multiple individuals of all taxa eliminate essentially eliminate any possibility of errors in analyses, labeling, etc.
Concerning this finding, the authors noted:
“The form cearae has, until now, been recognized as a subspecies of C. lineata, based on plumage phenotypes (Whitney, 2003), but our results strongly suggests C. l. cearae as a separate species, and our Bayesian concatenated phylogeny recovered it as sister of C. peruviana, although with low support (0.93 of PP). Better genetic and geographical sampling of the disjunct geographical populations of C. l. cearae (in northern Chapada Diamantina, patches of forest amidst dry Caatinga locally known as Brejos de Altitude, and northern Sčo Francisco River) may help to reveal ancient connections between Amazonia and the Atlantic Forest. The similarities in plumage between C. lineata and C. (lineata) cearae could be the result of retention of ancient polymorphism or parallel evolution, as these species share very similar plumage phenotype.”
What the authors did not mention here is that Whitney (2003) had already noted that vocal differences suggested that cearae merited treatment as a separate species from C. lineata, although this is alluded to earlier in the paper.
Analysis and recommendation: The genetic data alone force treatment of cearae as a separate species. Add to this that Whitney (2003) already mentioned species-level differences in vocalizations between cearae and lineata, and I consider the evidence to be strong for ranking cearae as a separate species.
English name: Should the proposal pass, I recommend Ceara Gnateater as an English name to emphasize its tiny geographic range and the importance of the state of Ceará to this species’ survival.
BATALHA-FILHO, H., R. O. PESSOA, P.-H. FABRE, J. FJELDSĀ, M. IRESTEDT, P. G.P. ERICSON, L. F. SILVEIRA, & C. Y. MIYAKI. 2014. Phylogeny and historical biogeography of gnateaters (Passeriformes, Conopophagidae) in the South America forests. Molecular Phylogenetics and Evolution 79: 422–432.
WHITNEY, B. M. 2003. Family Conopophagidae (gnateaters). Pp. 732-747 in "Handbook of the Birds of the World, Vol. 8. Broadbills to tapaculos." (J. del Hoyo et al., eds.). Lynx Edicions, Barcelona.
Van Remsen, October 2015
Comments from Areta: “YES. Differences in vocalizations and genetic placement are convincing for species-level treatment of cearae.”
Comments from Stiles: “YES, genetic and vocal data show that cearae definitely merits species status.”
Comments from Jaramillo: “YES. Multiple lines of evidence clarify that cearae (Ceara Gnateater) deserves species rank.”
Comments from Zimmer: “YES. The vocal differences between cearae and other lineata have been known for some time, but now we have genetic data to confirm that these two are not closest relatives. I think there are still some odd things going on within lineata (minus cearae), as regards vocal differences between some populations not being congruent with understood distributions of the named subspecies lineata and vulgaris, but recognizing the distinctiveness of cearae is a good start to sorting out the relationships in this complex.”
Comments from Robbins: “YES, vocal and genetic data clearly indicate that cearae should be considered a species.”
Comments from Pacheco: “YES. This phylogeny supports the previous perception of Whitney (2003). I was standing beside Bret when he realized the distinctiveness of this taxon.”