Proposal (677) to South American Classification Committee
Recognize Systellura longirostris ruficervix, Systellura longirostris roraimae, and Systellura longirostris decussata as species
Effect on SACC: Elevate 3 subspecies within Systellura longirostris to species rank.
Background: Band-winged Nightjar Systellura longirostris is a very widespread, polytypic species, distributed from northern and Andean Venezuela south to southern Chile and Argentina, and in eastern Brazil. Currently no fewer than nine taxa are recognized (Cleere 2010, Dickinson and Remsen 2013). These taxa generally have a similar plumage pattern, but differ in plumage saturation and size. A few subspecies, such as ruficervix (Cory 1918, Chapman 1923, 1926) and decussata (Cory 1918) previously were recognized, based solely on plumage variation, as separate species. Davis (1978) considered ruficervix to be a species, but it is unclear how many taxa he vocally examined. Cleere (1998) included all taxa within longirostris, but at the time the vocalizations of only a few taxa were known. Later Cleere (2010) recognized both roraimae and decussata as species, "based on distinct vocalizations and range"; he included ruficervix in longirostris, but also commented that "review of subspecies needed" across longirostris.
There is no comprehensive quantitative survey of vocalizations in longirostris; for that matter, the songs of some taxa may not be known (e.g. mochaensis, which is restricted to a small region in Chile). However, a nice summary of vocalizations of six taxa in this complex, with sonograms and audio recordings, was prepared by Andrew Spencer; the included taxa are longirostris, atripunctata, bifasciata, ruficervix, roraimae, and decussata": see xeno-canto.
More recently, the situation was summarized by Crestol (2015):
"Across much of its range, the song of Band-winged Nightjar is a series of thin, high-pitched whistles. This song variously is described as "a high thin seeeeerp or seeEEEeert (emphasis varies), squeezed out, rising then down slurred in pitch" (Hilty 2003; subspecies ruficervix); as "a very high-pitched psee-yeet or psee-ee-eeyt" (Ridgely and Greenfield 2001b; subspecies ruficervix); as "a series of high, thin slurred whistles: teeeEEEEuu" (Lane, in Schulenberg et al. 2010; subspecies ruficervix and atripunctata); as "a shrill but weak two-syllabled whistle, tse sweeet" (Jaramillo 2003; subspecies bifasciata); and as "a single, weak, very high-pitched plaintive whistle, repeated constantly: tseeooeet ... tseeooeet" (Belton 1984; subspecies longirostris).”
"The song of subspecies roraimae of the tepuis is very different, and is a series of short, unmodulated, slightly rising whistles.”
“The song of decussata, of the coastal lowlands of western Peru and northern Chile, also is distinct: "a loud series of cueeo notes, reminiscent of [the songs of Common] Pauraque [Nyctidromus albicollis] and Scrub Nightjar [Nyctidromus anthonyi], but more monosyllabic" (Lane, in Schulenberg et al. 2010)."
New Information: The current SACC taxonomy and nomenclature for Caprimulgidae is based on Han et al. (2010), a phylogenetic analysis of DNA sequence data (from cytochrome b, and nuclear c-myc and growth hormone genes). Han et al. included a single example of polytypic longirostris (the subspecific identification was not provided in the paper, but their sample represents ruficervix). More recently Sigurdsson and Cracraft (2014) conducted an independent phylogenetic analysis of New World caprimulgids, again based on DNA sequence data (NADH dehydrogenase subunit 2, cytochrome b, RAG-1, and nuclear intron 9 from the aconitase gene). Sigurdsson and Cracraft also presented the first genetic data for multiple Band-winged Nightjar taxa, with 18 samples that are identified as representing all but two of its subspecies: mochaensis of Chile and pedrolimai of northeastern Brazil.
As can be seen from their Figure 7, most taxa of longirostris form a clade, which in turn has two subunits, one composed of a group of taxa (atripunctatus, bifasciatus, longirostris, and patagonicus) representing a wide swath of the geographic range of the species, and another that pairs two taxa (ruficervix and roraimae) that occur in montane areas (Andes and tepuis) of northern South America; these two taxa are darkest in plumage.
A more surprising result is that the traditional species longirostris is highly polyphyletic, as decussata is distantly related to other taxa included in longirostris. Instead, it is basal to the clade that includes the following genera recognized by SACC: Setopagis, Hydropsalis, Macropsalis, Hydropsalis, Systellura, and Eleothreptus (!).
Based on the above, the following actions can be contemplated:
A) recognize decussata as a species
B) recognize both ruficervix and roraimae as separate species, based on the genetic distinctions from the clade atripunctatus, bifasciatus, longirostris, and patagonicus, and the vocal distinctions between ruficervix and roraimae
Recommendation: Separation of decussata as a species is mandatory, as the phylogeny presented by Sigurdsson and Cracraft makes clear that it is not conspecific with the rest of the longirostris group. Based on the above data sets, we also recommend a "yes" vote on Part B, for elevating both ruficervix and roraimae to species level.
If these pass, we need to think about English names. Cory (1918) and Cleere (2010) used the name "Tschudi's" for decussata; we have no objections to this name, and adopting it saves us the trouble of thinking further about the issue. Cleere (2010) adopted the name "Tepui Nightjar" for roraimae. which again is a good name. Davis (1978) made the logical suggestion of "Rufous-naped Nightjar" for ruficervix. Obviously ruficervix is not the only "rufous-naped" nightjar, but then, longirostris is not the only "band-winged" nightjar. So, we propose that a "yes" vote for Parts A or B also constitutes assent to our proposed English names, unless otherwise specified in comments with each vote. If a committee member doesn't like our proposed names, then suggest something else! If necessary, a separate vote can be held later on alternative English names.
Finally, note that decussata clearly cannot be classified in the genus Systellura. If SACC votes to recognize decussata as a separate species, then a second proposal will be submitted on a generic classification for decussata.
Belton, W. 1984. Birds of Rio Grande do Sul, Brazil. Part 1. Bulletin of the American Museum of Natural History 178: 369-636.
Chapman, F.M. 1923. Descriptions of proposed new birds from Panama, Venezuela, Ecuador, Peru and Bolivia. American Museum Novitates number 67.
Chapman, F.M. 1929. Descriptions of new birds from Mt. Roraima. American Museum Novitates number 341.
Cleere, N. 1998. Nightjars: a guide to the nightjars, nighthawks, and their relatives. Yale University Press, New Haven, Connecticut.
Cleere N. 2010. Nightjars, potoos, frogmouths, oilbirds and owlet-nightjars of the world. Old Basing, UK: WILDGuides Ltd., Parr House.
Cory, C. B. 1918. Catalogue of birds of the Americas. Part II, number 1. Field Museum of Natural History Zoological Series volume 13, part 2, number 1.
Crestol, S. 2015. Band-winged Nightjar (Systellura longirostris), Neotropical Birds Online (T. S. Schulenberg, editor). Cornell Lab of Ornithology, Ithaca, New York.
Davis, LI. 1978. Acoustic evidence of relationships in Caprimulginae. Pan American Studies 1: 22-57.
Dickinson, E.C., and J.V. Remsen, Jr. (editors). 2013. The Howard and Moore complete checklist of the birds of the world. Fourth edition. Volume 1. Non-passerines. Aves Press, Eastbourne, United Kingdom.
Han, K.-L., M.B. Robbins, and M.J. Braun. 2010. A multi-gene estimate of phylogeny in the nightjars and nighthawks (Caprimulgidae). Molecular Phylogenetics and Evolution 55: 443-453.
Hilty, S.L. 2003. Birds of Venezuela. Second edition. Princeton University Press, Princeton, New Jersey.
Jaramillo, A. 2003. Birds of Chile. Princeton University Press, Princeton, New Jersey.
Ridgely, R.S., and P.J. Greenfield. 2001b. The birds of Ecuador: field guide. Cornell University Press, Ithaca, New York.
Schulenberg, T.S., D.F. Stotz, D.F. Lane, J.P. O’Neill, and T.A. Parker III. 2010. Birds of Peru. Revised and updated edition. Princeton University Press, Princeton, New Jersey.
Sigurdsson, S. and J. Cracraft. 2014. Deciphering the diversity and history of New World nightjars (Aves: Caprimulgidae) using molecular phylogenetics. Zoological Journal of the Linnean Society. 170:506–545.
Tom Schulenberg and Mark Robbins, July 2015
Comments from Zimmer: “This proposal seems to be split into two parts. Part A) Recognize decussata as a species: YES. On this, the genetic data are clear. Part B) Recognize both ruficervix and roraimae as separate species: YES. Genetic differences support splitting these two from the main clade that includes nominate longirostris, and vocal and range considerations would support treating ruficervix and roraimae as separate from one another. It has long been suspected that “Band-winged Nightjar” encompassed multiple species. Adopting this proposal would be a good start toward resolving some of the confusion, and provide a framework for redirecting focus on the status of some of the remaining taxa under the longirostris-umbrella. The proposed English names seem reasonable.”
Comments from Stiles:
“A) YES. At the very least, decussatus is clearly not a member of the clade containing the rest of longirostris.
“B) YES. Vocalizations and genetics support splitting S. roraimae and ruficervix from longirostris, and this also implies that atripunctatus and the other southern races will also constitute at least one other species, assuming that the Argentina sample is not nominate longirostris (although here, I assume that vocal data plus more thorough genetic sampling are needed to clarify this group).”
Comments from Areta:
“A) YES. The situation with decussata is different, as it is not part of the PRESUMED longirostris complex, and it appears to have been sufficiently well sampled.
“B) “NO. The taxonomy of Systellura longirostris has long been known to be problematic and inaccurate. However, I see several problems in adopting the proposed taxonomy in Sigurdsson & Cracraft (2014).
“1) Nominate longirostris, atripunctatus, and bifasciatus/patagonicus have distinctive vocalizations (as diagnostic as those of other taxa afforded species rank in their proposed taxonomy). Lumping them under a single species is not recommended if we are to split the others, as it would mean having an internally inconsistent Systellura.
“2) Their single sample of nominate longirostris from Entre Rios (Argentina) is very likely a migratory bifasciatus/patagonicus and not a true longirostris. I speculate this based on known winter migration of bifasciatus/patagonicus, and the lack of confirmed records of nominate longirostris in Argentina. Thus, strictly speaking, we do not know what longirostris is in terms of phylogenetic placement. This being said, since I fear that nominate longirostris was not sampled, we do not know if longirostris indeed deserves to be in the genus Systellura (type species Stenopsis ruficervix).
“3) Subspecific distinctions of patagonicus and bifasciatus are contentious, and they might not even be diagnosable (but more work is needed on this). So it is surprising to find subspecific identification attached to the bird in Uruguay, which must also be a winter visitor.
“4) We (Thomas Valqui, Chris Witt and I) have been working for some time on a paper on this complex, analyzing more recordings of all taxa, and with a better genetic sampling. At present, even when there is disperse data clearly indicating that current species limits are wrong, there is not a careful and thorough characterization of variation and discreteness of vocalizations of the involved taxa. Thus, I'd rather postpone a decision until such a work is published.
“5) I must stress that if we make a decision on this proposal based on xeno-canto recordings, then a cascade of other proposals without critical proper review must pass too. We all know of several groups with erroneous taxonomy and could put 'quick' proposals together compiling disperse data to support a different taxonomic treatment. I am of the view that solid taxonomic works require careful scrutiny and attention to detail. I thus do not feel comfortable with deep taxonomic changes in nightjars when the goal of a paper was not to evaluate species limits, when the rationale for subspecific identification of taxa is not made clear, and when relevant natural history information is not included in the arguments. The work by Sigurdsson & Cracraft (2014) is a great contribution to our understanding of phylogenetic relationships in nightjars. But I do not think it contains enough information to solve this puzzle.
Comments from Remsen: “A) YES, for reasons outlined by others. B) NO – I am strongly persuaded by Nacho’s reasoning.”
Comments from Pacheco: “A) YES, in accordance with what has been presented.
B) NO. After the careful arguments provided by Nacho, I prefer to wait for more evidence to decide about the specific limits within that complex.”
Comments from Nores: “A: YES. B: YES, especially with the vocal difference between ruficervix and roraimae, which are together in a separate clade.”
Comments from Jaramillo: “A. YES. The form decussata/decussatus is clearly not part of this group, based on molecular data. It is also the most vocally divergent. If this proposal does go through, I would NOT be happy with Tschudi’s Nightjar. I would rather choose an ecological/habitat name. Is Desert Nightjar taken in the Old World?.
“B. YES. Although this may be piecemeal and incomplete based on Nacho’s comments, I think that it would be best to make a decision on these two (ruficervix and roraimae) now. We have the data, and it looks good. I doubt that Nacho’s work will not agree in the separation of these two forms. I am guessing that their work may consider more splits in the longirostris/bifasciatus/atripunctatus etc. groups. But that can happen later, and I don’t see that it impacts the current decision. I agree with Nacho that the Sigurdsson & Cracraft paper does not “contain enough information to solve this puzzle” but it does contain enough to solve some of the puzzle. So I think a YES on part B of this proposal is defensible. By the way, I am unsure of where exactly mochaensis is found, but assume that Chiloe Island is part of the distribution. These birds sound, to my ears at least, just like birds from Central Chile. They also respond to recordings of birds from Central Chile.”
Comments from Stotz: “
A. decussatus YES
B. split ruficervix and roraimae YES
“I understand that this is not the final story on this complex, but it seems like recognizing these is not really affected by the fact that there may still be further splits to do within longirostris. There are other taxa where we have recognized splits, while still having complexes that have not been fully worked out within the unit. An example of that would be the recognition of Tolmomyias traylori, despite the fact that are almost certainly multiple species within T. sulphurescens.”
Comments from Cadena: “677A. YES. 677B. NO. These sonograms do look different and songs sound rather distinct, but are they representative of variation existing within each of the groups and consistent across geography? I think we cannot tell until data are properly (i.e. quantitatively) analyzed with careful geographic sampling and such analyses are published. Also, although this does not matter much given the proposal, the proposal states that the longirostris clade has two “subunits” with one corresponding to the montane taxa ruficervix and roraimae, but I note there is no support for these two taxa forming a clade.”