Proposal (536) to South American Classification Committee

 

Elevate Laterallus jamaicensis tuerosi to species status

 

The Black Rail (Laterallus jamaicensis) is represented within South America by three taxa: two endemic to Peru (coastal murivagans, and Andean tuerosi, the latter restricted to the marshes around Lago Junín), and Chilean endemic salinasi. The Junín population, tuerosi, described by Fjeldså (1983), is found strictly in the Scirpus marsh around the margins of Lago Junín, at 4200 m elevation in the central Andes of Peru. The subspecies was described based on only two specimens. This lake is highly subject to manipulation by the nearby mining industry, and has suffered water contamination and water level fluctuation as a result. There is concern that waterbird populations on Lago Junín are at risk; indeed, the lake’s endemic Junin Grebe (Podiceps taczanowskii) is critically endangered.

 

On the SACC webpage under Laterallus jamaicensis, is the following footnote:

“Fjeldså (1983a) proposed that the South American form tuerosi, and usually treated as, and described by Fjeldså (1983b) as, a subspecies of Laterallus jamaicensis, should be recognized as a separate species; this was followed by Collar et al. (1992). Jaramillo (2003) also suggested that the southern subspecies salinasi might also warrant recognition as a separate subspecies from L. jamaicensis.”

Some authors (e.g., Collar et al. 1992, Clements and Shany 2001, the IOC checklist committee [http://www.worldbirdnames.org/n-bustards.html]) have adopted the measure of elevating tuerosi to species status apart from L. jamaicensis; however, others have not (Fjeldså and Krabbe 1990, Taylor 1996, Taylor 1998, Dickinson 2003, Schulenberg et al. 2010). Because at the time virtually nothing was known about the natural history or voice of tuerosi, I suspect that this taxonomic change was entirely based on plumage, but there is no published support for this move other than the two publications by Fjeldså.

 

In the past few years, recordings of the voices of the three South American taxa within L. jamaicensis have been deposited online at Xeno-canto.com [http://www.xeno-canto.org/species/Laterallus-jamaicensis] and Macaulay Library [http://macaulaylibrary.org/search?taxon=Laterallus%20jamaicensis&taxon_id=12006947&taxon_rank_id=67&tab=audio]. These recordings provide the first evidence of geographic variation in vocalizations among the populations of the species, and as such, are very important data for any study of the systematics of the species. I suspect that Al Jaramillo’s comment in the footnote quoted above is due to salinasi being the first of the South American taxa to be voice-recorded and shared. Now, however, with the songs and many calls of all three South American taxa known, the distinctiveness of salinasi is far less obvious. Indeed, the three are (allowing for small sample sizes) remarkably alike in their vocalizations, although all three are similarly unlike North American taxa in having a much more rapid ‘kee-kee-der’ song with more introductory notes.  Differences from the Galapagos L. spilonotus are less clear, because few recordings of its voice (particularly its song) are available—however, the description in Taylor (1998) suggests that it sounds very similar to South American populations. The conclusion that salinasi, murivagans, and tuerosi are very similar vocally flies in the face of elevating any of the three to species level without including the other two.  A molecular phylogeny to determine whether the three South American taxa do, in fact, form a monophyletic clade would be helpful, particularly if L. spilonotus was included, in separating them from the North American populations (including jamaicensis, stoddardi, and coturniculus), but the rarity of specimens may preclude such a study.

 

Thus, in the face of present information, it would appear that, despite tuerosi representing the most heavily spotted extreme within the Laterallus jamaicensis complex, and its isolation at uniquely high elevation, there is little to support its separation at the species level from other populations within the complex. I predict that a more detailed study into the systematics of this complex will reveal a deep node separating North and South American clades, and that these two clades may be best considered species-level taxa with respect to one another. As an aside, I also predict that the entire L. jamaicensis complex will be found not to be closely related to the remaining members of the genus Laterallus, because they do not share particularly similar vocalizations or preferred habitats, and true Laterallus (the type is melanophaius) are not nocturnal.

 

Recommendation: I recommend that the committee vote NO to the recognition of Laterallus tuerosi as a separate species.

 

Literature cited:

 

CLEMENTS, J. F., and N. SHANY. 2001. A field guide to the birds of Peru. Ibis, Temecula, California.

COLLAR, N., L. P. GONZAGA, N. KRABBE, A. MADROÑO NIETO, L. G. NARANJO, T. A. PARKER III, AND D. G. WEGE. 1992. Threatened birds of the Americas. The ICBP/IUCN red data book. Third edition, part 2. International Council Bird Preservation, Cambridge, United Kingdom.

DICKINSON, E. C. (ed.). 2003. The Howard and Moore complete checklist of the birds of the World, Revised and enlarged 3rd Edition. Christopher Helm, London, 1040 pp.

FJELDSÅ, J. 1983.  A Black Rail from Junin, central Peru: Laterallus jamaicensis tuerosi ssp. n. (Aves, Rallidae).  Steenstrupia 8: 277-282.

FJELDSÅ, J., AND N. KRABBE. 1990. Birds of the High Andes. Zoological Museum, University Copenhagen, Copenhagen, Denmark.

SCHULENBERG, T. S., D. F. STOTZ, D. F. LANE, J. P. O’NEILL, and T. A. PARKER, III. 2010. Birds of Peru (revised ed.). Princeton University Press, Princeton.

TAYLOR, P. B. 1996. Family Rallidae. In Handbook of birds of the world, volume 3 (J. del Hoyo, A. Elliott, J. Sargatal, eds.). Lynx Edicions, Barcelona.

TAYLOR, B. 1998. Rails. Yale University Press, New Haven.

 

 

Comments from Stiles: “NO. After reading Dan’s proposal, I tend to agree: the available evidence for splitting L. jamaicensis is suggestive, but too limited. It should be possible to extract DNA, as the techniques for doing so from old specimens have improved greatly, and a good statistical analysis of sonograms (comparing all the subspecies, hopefully with playback experiments between at least one NA and one SA race) will also be needed in order to take this step.  Like Dan, if any splitting were to be done, this should probably be between South and North American subspecies groups (would the S. Am. species then be called salinasi?), but the evidence simply isn’t sufficient at this point.”

Comments from Remsen: “NO.  Fjeldså & Krabbe (1990) themselves didn’t take this step, so why should we?  We need some sort of published paper on this before splitting, and as Dan noted, the entire complex must be included.  I wouldn’t be surprised if salinasi, murivagans, and tuerosi each turned out to be independent colonizations from migratory jamaicensis stock, and that they are more recent and thus less divergent phenotypically than is spilonotus.  I think this is as plausible as one of the tiny South American resident populations giving rise to the others. The vocal similarities, if thoroughly documented, would argue otherwise, but perhaps there is convergence associated with year-round residency.”

Comments from Zimmer:  “NO.  It sounds as if the three South American forms may be divergent enough to split from jamaicensis (although not from one another; at least not on vocal evidence), but this will clearly require a vocal and molecular analysis of the entire group.  Lacking that, I see no impetus for doing anything now.”

Comments from Robbins:  “NO.  It seems premature to elevate the South American taxa of Laterallus jamaicensis to species level.  Clearly, more data are needed.”

Comments from Pacheco: “NO.  Após ler o arrazoado, eu considero frágil considerar tuerosi ao nível de espécie.”

Comments from Pérez-Emán: “NO. No data are available to make this change.”