Transfer Uropsalis, Eleothreptus, Nyctidromus, Macropsalis, Nyctiprogne, Lurocalis, and Caprimulgus spp. (cayennensis, maculicaudus, longirostris, whitelyi, parvulus, anthonyi, and nigrescens) to the genus Hydropsalis
Han et al. (2010) published a molecular based phylogeny of Caprimulgidae from more than 60% of caprimulgid species and 14 of 16 currently recognized genera. The taxon sampling was broad and included all morphologically divergent lineages. New World taxa were particularly well represented. DNA sequences were collected from the entire mitochondrial DNA cytochrome b gene and parts of two nuclear genes (myelocytomatosis viral oncogene homolog and growth hormone). All analyses of the 72 ingroup plus outgroup taxa were conducted on the 4179 characters. The Han et al. (2010) phylogeny was well resolved and in substantial agreement with all previous molecular work on the family (Sibley and Ahlquist, 1990; Mariaux and Braun, 1996; Barrowclough et al., 2006; Larsen et al., 2007; Braun and Huddleston, 2009).
In proposing a new classification, Han et al. (2010) used the following criteria: foremost, all named taxa represented monophyletic groups. Second, for stability of the named taxa, whenever possible, currently recognized taxa were retained, and when more than one partitioning scheme for a clade was plausible, they opted for the one that was more likely to remain viable in the face of new data.
Within core caprimulgids, four strongly supported major clades (3 New World, 1 Old World) provided a natural partitioning scheme, but numerous taxa needed to be reassigned to reflect the non-monophyly of the current genus Caprimulgus. Additionally, a number of small or monotypic genera should be subsumed. Caprimulgus Linnaeus 1758 should be restricted to the Old World clade, since the type specimen for the genus is C. europaeus.
This proposal deals with New World clade 3 of Han et al. (2010), which consisted of caprimulgine genera Hydropsalis, Uropsalis, Eleothreptus, Nyctidromus, and Caprimulgus (in part), and the chordeiline genera Nyctiprogne and Lurocalis. The following Caprimulgus spp. are interspersed with the above genera: cayennensis, maculicaudus, longirostris, whitelyi, parvulus, anthonyi, and nigrescens.
Below is the tree from Han et al.:
Based on genetic data, New World clade 3 (Han et al. 2010), that currently is subdivided into seven genera, should be subsumed into Hydropsalis Wagler 1832, as it has priority over the other names (Peters 1940). An unsampled eighth genus, Macropsalis, will presumably fall into this clade, and it was assigned to Hydropsalis as well. Although this course may seem drastic, the polytomy at the base of this clade makes any other course less palatable due to the difficulty of defining monophyletic groups. If this polytomy can be resolved, the taxa currently in Nyctiprogne and Lurocalis may deserve generic status, either separately or together. Caprimulgus candicans has been shown to be sister to Eleothreptus based on morphology (Cleere 2002) and genetics (Larsen et al. 2007), so it also belongs to Hydropsalis. Han et al. (2010) provisionally assigned Nyctiprogne (Chordeiles) vielliardi to Hydropsalis, based on the conclusions of Whitney et al. (2003), and Chordeiles maculosus and Chordeiles hirundinaceus to this genus based on their South American distributions.
Barrowclough, G.F., Groth, J.G., Mertz, L.A. 2006. The RAG-1 exon in the avian order Caprimulgiformes: phylogeny, heterozygosity, and base composition. Mol. Phylogenet. Evol. 41:238–248.
Braun, M.J., Huddleston, C.J. 2009. A molecular phylogenetic survey of caprimulgiform nightbirds illustrates the utility of non-coding sequences. Mol. Phylogenet. Evol. 53:948–960.
Cleere, N. 2002. A review of the taxonomy and systematics of the sickle-winged and white-winged nightjars (Caprimulgidae). Bull. Brit. Ornithol. Club 122:168–179.
Han, K.-L., Robbins, M.B., Braun, M.J. 2010. A multi-gene estimate of phylogeny in the nightjars and nighthawks (Caprimulgidae). Mol. Phylogenet. Evol. 55:443-453.
Larsen, C., Speed, M., Harvey, N., Noyes, H.A. 2007. A molecular phylogeny of the nightjars (Aves: Caprimulgidae) suggests extensive conservation of primitive morphological traits across multiple lineages. Mol. Phylogenet. Evol. 42:789– 796.
Mariaux, J., Braun, M.J. 1996. A molecular phylogenetic survey of the nightjars and allies (Caprimulgiformes) with special emphasis on the potoos (Nyctibiidae). Mol. Phylogenet. Evol. 6:228–244.
Peters, J.L. 1940. Checklist of Birds of the World. Harvard University Press, Cambridge.
Sibley, C.G., Ahlquist, J.E. 1990. Phylogeny and Classification of Birds: A Study in Molecular Evolution. Yale University Press, New Haven, London.
Whitney, W.M., Pacheco, J.F., da Fonseca, P.S.M., Webster, R.E., Kirwan, G.M., Barnett, J.M. 2003. Reassignment of Chordeiles vielliardi Lencioni-Neto, 1994, to Nyctiprogne Bonaparte, 1857, with comments on the latter genus and some presumably related chordeilines (Caprimulgidae). Bull. Brit. Ornithol. Club 123: 103–112.
Mark Robbins, December 2010
Comments from Stiles: “YES, with the minor “tweak” that I would not object to recognizing Lurocalis as a genus (and including Nyctiprogne therein if the genetic data were to indicate that they form a clade, which is not certain at present – both are aerial foragers like Chordeiles over water or clearings, unlike the remaining species in the broad Hydropsalis which are predominantly salliers from the ground or a perch. I can’t see any reasonable basis for more subdivision of the “NW3” clade, since the differences between the subsumed genera all reflect male ornaments of the tails or wings, and the often extreme divergences in such feature that can result from sexual selection frequently obscure relationships.”
Comments from Nores: “NO. Aunque los análisis moleculares muestran que varias de estas especies podrían ser transferidas al género Hydropsalis, considero que es exagerado transferirlas a todas juntas. Pienso, por ejemplo, que Lurocalis y Nyctiprogne deberías ser mantenidas como géneros apartes. Me parece que Mark debería subdividir la propuesta.”
Comments from Remsen: “NO. The group is monophyletic, yes, but violates badly my subjective notion of what a genus should be in terms of morphological integrity, especially when compared to the other nightjar clades. Even ignoring the secondary sex characters, the ornamental plumes of some males, the plumage and morphological heterogeneity combined with vocal heterogeneity leaves such a broad Hydropsalis totally undiagnosable by any but genetic criteria. That said, I understand completely Mark et al.’s rationale for one big genus because if the branching pattern is correct, there is no pleasing alternative. Recognizing a bunch of monotypic genera in order to also maintain Nyctiprogne and Lurocalis is very clumsy, but to merge them into Hydropsalis is worse, in my opinion. I would favor a proposal that broadens Hydropsalis to an extent (i.e. to include all taxa united by the strongly supported node that includes “C.” parvulus (support value 93), but not farther.”
Comments from Zimmer: “NO. I could roll with most of this, but I have real problems with merging Lurocalis and Nyctiprogne with the rest of this group. As Gary points out, the ecological differences between the aerial, above-the-canopy or above-the-water foraging Lurocalis/Nyctiprogne, and the remaining species, most of which basically sally from the ground or from low perches, are substantial. I would also note that Lurocalis and Nyctiprogne are much more arboreal in their roosting habits than are the vast majority of the other species proposed for inclusion in a broad Hydropsalis. I’m ambivalent about the inclusion of Macropsalis with the others. Even setting aside the sexually selected extremes in tail ornamentation (which could be argued as just one end of the spectrum, with species such as H. torquata and H. climacocerca as being in the middle, and most other Caprimulgus as being at the other end…), the members of Macropsalis are also pretty different ecologically (display flights above the canopy, selection of vertical perches, preference for steep banks and cliffs) and vocally from the others. I have no problem with the merger of Eleothreptus and Nyctidromus with the relevant New World Caprimulgus, and the subsequent reassignment of all of those to an expanded Hydropsalis. So, I would favor some compromise position, in which we would, at minimum, retain Lurocalis and Nyctiprogne (merging the two if the molecular data indicates they form a clade), possibly retain Macropsalis, and definitely move the others to Hydropsalis.”
Comments from Jaramillo: “NO. This creates an unwieldy and uninformative genus, particularly if it includes Lurocalis and Nyctiprogne. Although this may be a monophyletic group, I think there is room here to use vocalizations and other data to subdivide the genus into packages that are more informative, even with the unresolved polytomy.”
Comments from Pérez: “NO, I think this is a proposal that would benefit from inclusion of alternative characters that allow for a more informative decision. As pointed by others, Lurocalis and Nyctiprogne are very different morphologically and ecologically, and the rest of the group is not even well supported by the molecular data. In the present situation, I could even consider to recognize some monotypic genera providing more information than a big inclusive genus.”