Proposal (902) to South American Classification Committee

Recognize Ortalis remota Pinto, 1960 (Silveira et al. 2017) as a species

Background: From SACC notes: “Ortalis guttata remota Pinto, 1960, was treated by Vaurie (1965a) as a synonym of Ortalis [guttata] squamosa (sic), and this was followed by all subsequent classifications.”

New Information: Silveira et al. (2017) studied the subspecies of Ortalis guttata (Spix, 1825), including the frequently neglected O. g. remota Pinto, 1960, a taxon described based on a single specimen from SE Mato Grosso do Sul state, Brazil.

In total, Silveira et al. (2017) examined the single known skin (the holotype) and 24 photos of O. g. remota, 20 skins and 1402 photos of O. squamata, 18 skins and 562 photos of O. araucuan and 242 skins and 168 photos of O. guttata (including O. g. subaffinis).

Among the specimens analyzed were also some topotypes of O. g. subaffinis Todd, and the holotypes of Penelope guttata Spix (= O. g. guttata) and Ortalida squamata Lesson, the latter one being relocated at MNHN, Paris.

The distribution of Ortalis remota occupies a geographically intermediate position between its related taxa, i.e. the Amazonian O. guttata, the Atlantic O. squamata and O. araucuan, and perhaps another one, the peripheral Chaco representative O. canicollis. It is probably an endemic of the central region of the “Bosque Paranaense” Province, an area severely modified even before adequate biological inventories could be taken (Silveira et al. 2017). Despite on its taxonomic status, O. remota was recently declared as a Critically Endangered taxon in the Official Red Lists of Brazil and São Paulo State.

Through the analysis of museum specimens and photos of all members of this complex, the authors performed a plumage analysis and showed that O. g. remota differ consistently from all other members of the genus currently treated as distinct, valid species, and O. remota must be recognized as a distinct taxon with a very restricted range on the upper Paraná River, SE. Brazil.

Recommendation: Based on the morphological and distributional information, we recommend a "YES" vote to accepting this chachalaca as a new biological species to the South American list.

References:

Pinto, O.M.O. (1960) Algumas adendas a avifauna brasileira. Papéis Avulsos de Zoologia, 14, 11–15.

Silveira, L. F., B. M. Tomotani, C. Cestari, F. C. Straube, and V. Q. Piacentini. (2017) Ortalis remota: a forgotten and critically endangered species of chachalaca (Galliformes: Cracidae) from eastern Brazil. Zootaxa 4306: 524-536.

Vaurie, C. (1965a) Systematic notes on the bird family Cracidae. No. 3. Ortalis guttata, Ortalis superciliaris, and Ortalis motmot. American Museum Novitates 2232: 1-21.

Luis Fabio Silveira & Fernando Pacheco, January 2021

Comments from Lane: “YES, simply to remain consistent with the various recently split Ortalis.”

Comments from Stiles: “A tentative YES, if only to bring this taxon into line with the general pattern of allopatric replacements in this genus. However, I’d like to consult the Silveira et al. paper to get a better feeling for the data, especially as regards plumage etc. Is it true that the holotype of remota is still the only specimen known?”

Comments from Bonaccorso: “NO. I do not see enough plumage difference between Ortalis guttata guttata and O. g. remota to call for species status (at least from the skins shown in the paper). There are no morphometric data, no genetic data, and no song data to support this split. Also, as discussed here many times, allopatry does not guarantee species status. I understand the pressing need (from the conservation point of view) to call this taxon a species, but I am hesitant to support this elevation to species based on so little data.”

Comments from Remsen: “NO. I echo everything Elisa said and also point out that conservation status should never be used as a criterion --- otherwise, this undermines the credibility of taxonomic decisions. Silveira et al. provided solid evidence that remota is a valid taxon, but insufficient evidence that its rank should be higher than subspecies.”

Comments from Claramunt: “YES. The mosaic of characters that make this taxon distinctive suggest treatment as a specie-level taxon.”

Comments from Areta: “NO. I agree with Lisa. I am rather uncomfortable with this split based on a few photographs and a single specimen. Although the population looks diagnosable, it could well be a paler (drier habitat?) relict population of guttata, but there are not enough good data to convincingly clinch the case. Some photographs portray darker birds, which sometimes show an indistinct pale eyebrow.”

Comments from Robbins: “Considering both Elisa and Nacho’s comments, for now, I vote NO until there is more evidence.”

Comments from Pacheco: “YES. As a co-author, please consider my vote as YES in proposal 902 at Proposal Tracking Chart.”

Comments from Zimmer: “NO. I would agree that Silva et al. have provided enough evidence of the validity of remota as a valid taxon, but with only a single specimen and 24 photographs, I’m not convinced that a strong enough case has been made for recognition as a distinct species as opposed to a subspecies. Normally, I would point to the prevailing trend toward recognizing allopatric taxa within the genus as distinct species and suggest that as an appropriate yardstick for evaluating the status of remota. However, I remain unconvinced that the sample size is large enough to hang our hats on, given the nature of the plumage differences between remota and guttata.”