Gactornis, Han, Robbins & Braun, 2010

Sigurðsson, Snorri & Cracraft, Joel, 2014, Deciphering the diversity and history of New World nightjars (Aves: Caprimulgidae) using molecular phylogenetics, Zoological Journal of the Linnean Society 170 (3), pp. 506-545 : 522-528

Gactornis (1 species)

South American Clade (~28 species)

Nighthawk Clade (~7 species)

Old World Clade (>36 species)

Poorwill Clade (~18 species)

Lyncornis (~3 species)

data (see supporting information), which is unsurprising as their allopatric ranges are roughly split by the Amazon River; however, the branches leading to these two subclades are extremely short ( Fig. 4 ). Morphological differences between the two are present, with males of the nominate form Podager nacunda nacunda Viellot, 1817 having a darker crown and breast with black feathers more prominent than Podager nacunda minor Cory, 1915 . A more detailed investigation of the genetic structure and morphological variation in this species is needed.

Only three of the six recognized subspecies ( Dickinson et al., 2003) of Chordeiles pusillus were sampled in this study. The overall range of C. pusillus in South America is not well defined and is fragmented, and mostly consists of relatively small areas each inhabited by a single subspecies. There is some evidence indicating that C. p. novaesi is taxonomically distinct from the other two subspecies ( Fig. 4 ), as it is genetically separated on the tree ( Fig. 4 ), but more sampling is needed to fully investigate intraspecific diversity within this species.

The remaining nighthawk species all belong to the genus Chordeiles , and they form a monophyletic clade ( Fig. 4 ). There are two well-supported species groups. One of these species groups contains the monotypic Chordeiles rupestris (Spix, 1825) (sand-coloured nighthawk) and Chordeiles acutipennis (Hermann, 1783) (the lesser nighthawk), which is polytypic with seven subspecies distributed throughout a large range extending from south-eastern USA and northern Mexico, south to coastal Peru, as well as Brazil south of the Amazon basin ( Holyoak, 2001; Dickinson et al., 2003). Both ND2 and ACO1 I9 sequences indicate that Chordeiles acutipennis should be split into two phylospecies. There is a particularly high degree of divergence in the ND2 sequences, with 14 homologous substitution events present in the sequences of the three individuals of the northernmost taxon Chordeiles acutipennis texensis Lawrence, 1856 . These character changes separate them from the individuals of the other subspecies of C. acutipennis ,

Eurostopodus tornis SOUTH AMERICAN CLADE Antillean Nighthawk Chordeiles gundlachii ( Chordeiles gundlachii ) Chordeiles gundlachii Chordeiles minor hesperis Chordeiles minor hesperis Chordeiles minor sennetti Chordeiles minor minor Chordeiles minor howellii Chordeiles Chordeiles minor minor minor minor Common Nighthawk Chordeiles minor panamensis ( Chordeiles minor ) Chordeiles minor minor Chordeiles minor minor Chordeiles minor minor Chordeiles minor minor Chordeiles minor minor Chordeiles minor chapmani Chordeiles minor chapmani Chordeiles minor asseriensis Chordeiles acutipennis texensis Texan Nighthawk Chordeiles acutipennis texensis Chordeiles acutipennis texensis ( Chordeiles texensis ) Chordeiles acutipennis aequatorialis Chordeiles acutipennis acutipennis Chordeiles acutipennis acutipennis Chordeiles acutipennis acutipennis Chordeiles acutipennis acutipennis Lesser Nighthawk Chordeiles acutipennis acutipennis ( Chordeiles acutipennis ) Chordeiles acutipennis acutipennis Chordeiles acutipennis exilis Chordeiles acutipennis littoralis Chordeiles acutipennis littoralis Chordeiles acutipennis micromeris Chordeiles rupestris Sand-coloured Nighthawk Chordeiles rupestris ( Chordeiles rupestris ) Chordeiles pusillus novaesi Chordeiles pusillus septentrionalis Least Nighthawk Chordeiles pusillus septentrionalis ( Podager pusillus ) Chordeiles pusillus esmeraldae Podager nacunda minor Podager nacunda minor Nacunda Nighthawk Podager nacunda nacunda ( Podager nacunda ) Podager nacunda nacunda OLD WORLD CLADE POORWILL CLADE cornis

resulting in a strongly supported clade on the concatenated tree ( Fig. 4 ). Individuals of C. a. texensis are noticeably larger in size and have a lighter plumage than most other subspecies of C. acutipennis . Thus, we suggest that C. a. texensis be elevated to full species status as Chordeiles texensis .

The second species group contains Chordeiles minor (J.R. Forster, 1771) (the common nighthawk) and Chordeiles gundlachii Lawrence, 1856 (the Antillean nighthawk). There are nine subspecies of C. minor , eight of which were sampled. There is little to no genetic structure within the species, and what there is does not follow subspecies lines or any geographic patterns. In the two markers that were best sampled for C. minor, ND 2 and ACO1 I9, there are 12 polymorphic sites: ten in ND2 and two in ACO1 I9. The way in which these polymorphisms are distributed among the sampled individuals does not follow any congruent pattern, however, and analysis results in a basal polytomy in the concatenated tree ( Fig. 4 ). This lack of structured genetic diversity suggests either a recent expansion of its range or that gene flow is high

VENEZUELA - VENEZUELA Nyctiprogne latifascia - Amazonas, BRAZIL - PARAGUAY - GUYANA Nyctiprogne leucopyga - BOLIVIA Nyctiprogne vielliardi - PARAGUAY - Rio Negro, BRAZIL - GUYANA Lurocalis semitorquatus - Amazonas, BRAZIL - GUYANA ECUADOR Lurocalis rufiventris vielliardi - Bahia, BRAZIL Nyctidromus hirundinaceus cearae - Ceara, BRAZIL Nyctidromus nigrescens , BRAZIL VENEZUELA - PANAMA MEXICO - PANAMA Nyctidromus merrilli Texas, USA - Maria Madre Island, MEXICO Texas, USA - Alagoas, BRAZIL - Sao Jeronimo, BRAZIL Nyctidromus derbyanus - BOLIVIA - GUYANA - PERU - PANAMA Nyctidromus albicollis - ECUADOR - VENEZUELA ECUADOR Nyctidromus anthonyi

Hydropsalis whitelyi Hydropsalis segmentata Hydropsalis lyra Hydropsalis segmentata *, PERU, PERU Hydropsalis decussatus PERU VENEZUELA Hydropsalis heterurus PARAGUAY URUGUAY Hydropsalis parvulus BOLIVIA Hydropsalis maculicaudus Hydropsalis forcipata GUYANA Hydropsalis cayennensis GUYANA ECUADOR COLOMBIA Hydropsalis albicauda PANAMA - Parra, BRAZIL - GUYANA - ECUADOR - BOLIVIA Hydropsalis climacocerca - VENEZUELA Rio Madeira, BRAZIL Tocantins, BRAZIL Hydropsalis torquata , ARGENTINA ARGENTINA Yumbel, CHILE URUGUAY Rios, ARGENTINA BOLIVIA Hydropsalis longirostris BOLIVIA Acomayo, PERU PERU Cuzco, PERU, VENEZUELA Amazonas, VENEZUELA Hydropsalis roraimae , VENEZUELA ECUADOR, VENEZUELA Hydropsalis ruficervix , COLOMBIA Hydropsalis candicans Hydropsalis anomalus

between populations. In this study, sampling was too sparse to test for the presence and directionality of gene flow in the species.

Two individuals of C. gundlachii were sampled, one from Florida and the other from the Bahamas, but the results from the two individuals are strikingly different. The nuclear data do not demonstrate that C. gundlachii is a distinct species, as it falls within C. minor . The ND2 data tell the same story about the Florida individual, thus suggesting it may be a wrongly identified Chordeiles minor chapmani Coues, 1888 (see supporting information, Fig. S1 ). But, the ND2 sequence of the individual from the Bahamas is different from the Florida individual (3.5% divergent) as well as all the other C. minor individuals, such that it is placed as their sister taxon. This is also the result on the concatenated tree ( Fig. 4 ).

Figures

Figure 1. A summary figure, showing the individual gene trees of the four markers: ND2 (1041 bp); CYTB (1143 bp); RAG-1 (2873 bp); and ACO1 I9 (871 bp). The trees show the relationships among the three basal nightjar genera and the four core radiations. Bootstrap values from maximum-likelihood (ML) analyses are displayed on the nodes (only values> 60 are displayed).

Figure 4. A phylogeny of the nighthawk clade based on a maximum-likelihood (ML) analysis of a concatenated 5298-bp molecular data set. ML bootstrap values higher than 60 and Bayesian posterior probability values higher than 0.95 are displayed on the nodes. Names on the tree represent current taxonomy; names on the right represent those resulting from this revision (see text).