Richard Klim
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Rush, Gaines, Eddleman & Conway 2012. Clapper Rail Rallus longirostris. BNA Online.
Taylor 1996 (HBW 3):
Maley 2012. Ecological Speciation of King Rails (Rallus elegans) and Clapper Rails (Rallus longirostris). [PhD dissertation]Related Species
It is clear that R. longirostris is sister to R. elegans, although even this statement assumes the two are good biological species (e.g., Dickerman 1971, Ripley 1977). Early studies of mitochrondrial DNA variation are inconclusive with regard to species limits (Avise and Zink 1988). If separate species are involved, these two taxa, with R. wetmorei, the Plain-flanked Rail of coastal n. Venezuela, form a superspecies (Sibley and Monroe 1990). But it is perhaps debatable whether R. wetmorei is itself a species, with some arguing it be treated as a distinctive subspecies of R. longirostris (e.g., Meyer de Schauensee 1966). Blake (1977) stated that R. wetmorei occurred sympatrically with R. longirostris in Carabobo, Venezuela, which would seem to settle the matter. . . yet Olson (1997) intriguingly posited that R. wetmorei may not be a taxon at all but is rather a well-marked color morph, one that simply lacks black-and-white barring on the flanks (it is structurally identical to adjacent subspecies of R. longirostris).
Putting R. wetmorei aside, and under the assumption that R. longirostris and R. elegans are biological species, there remains the question of which subspecies to allocate to which species. For example, although subspecies in the obsoletus group are nowadays typically classified with R. longirostris, they have been classified with R. elegans (e.g., Peters 1934, Hellmayr and Conover 1942). By contrast, R. elegans tenuirostris Ridgway, 1874, of central Mexico has been grouped with R. longirostris (e.g., Oberholser 1937, Williams 1989). Species limits may even exceed the traditional two taxa of R. longirostris and R. elegans. For example, Bent (1926) treated the obsoletus group as a separate species. And a recent comprehensive survey of mitochondrial DNA argues for breaking the complex into five separate species (Maley and Brumfield ms.): R. elegans of the e. United States and Cuba; R. crepitans of the Atlantic seaboard, Gulf Coast, Greater Antilles, and Yucatan peninsula; R. obsoletus of w. North America; R. tenuirostris of central Mexico; and R. longirostris of South America. Only time will tell if this taxonomy is found acceptable by the American Ornithologists' Union's checklist committees for North America and for South America.
Regardless, R. longirostris, as currently constituted, hybridizes with R. elegans in brackish marshes where geographic ranges overlap (Meanley and Wetherbee 1962, Meanley 1969, Bledsoe 1988, Olson 1997). Hybrids exhibit a variety of plumage intermediacy (Meanley 1969), and gene flow may partly explain the color morphs of some R. longirostris subspecies.
Proposes four species (tenuirostris is treated as a ssp of R obsoletus):
Pieplow 2012. King and Clapper Rails. Earbirding.com.- R longirostris (incl phelpsi, margaritae, pelodramus, cypereti, crassirostris)
- R obsoletus (incl levipes, beldingi, yumanensis, tenuirostris)
- R elegans (incl ramsdeni)
- R crepitans (incl waynei, scottii, insularum, saturatus, caribaeus, pallidus, grossi, belizensis, leucophaeus, coryi)
Taylor 1996 (HBW 3):
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