Taxonomic structure and notes

Sometimes misspelt Talegallus.

Recent phylogenetic study suggests that genus is sister to a clade containing Eulipoa and Megapodius#R; earlier genetic study instead found that it belongs to a clade containing mound-building Alectura, Aepypodius, Talegalla and Leipoa#R. Alternatively used genus name, Megacephalon, is a nomen nudum#R.

Recent genetic studies#R#R#R suggest that this genus should be lumped with Aburria, a treatment supported by some morphological data. On the other hand, some clear morphological and, especially, vocal differences exist between the two, and it seems more appropriate to retain them as separate genera, pending further investigation#R. In the past, all members of Pipile were even included in Penelope.

Some recent studies suggest that Pipile should perhaps be subsumed within this genus (see above).

Genetic data support this genus as representing a monophyletic group#R. Members considered to form a superspecies#R.

Generic limits in the curassows are controversial. Some authors have subsumed Mitu, Pauxi and even Nothocrax within Crax. Others have given reasons for maintaining the four genera separate, and pointed out also that Nothocrax was a strong outlier in the group, a prediction subsequently verified by genetic data (revealing that Pauxi, Mitu and Nothocrax share the same clade and are sister to Crax#R); most authors since 1970s have followed this second course. Recent osteological data, however, provide evidence for subsuming Mitu into Pauxi#R, and another recent study produced morphological and genetic data to support this merger#R. Further investigation needed#R. The four members of genus Mitu are all closely related.

Generic limits in the curassows are controversial (see Mitu).

Recent genetic investigations indicate that this genus, previously included with the Old World members of Phasianidae, is close to the New World Odontophoridae#R#R#R.

Sometimes subsumed within Callipepla#R.

This genus incorporates Lophortyx Bonaparte, 1838.

Recent study found weak relationship between this genus and Polyplectron#R.

Genus considered incertae sedis#R. Included here tentatively, as a possible link between Rollulinae and Phasianinae, pending the required genetic study.

Recent molecular research suggests that Afropavo forms a weakly supported clade with Pavo, Argusianus, Rheinardia and Polyplectron#R.

Recent molecular research suggests that Pavo forms a weakly supported clade with Afropavo, Argusianus, Rheinardia and Polyplectron#R.

Recent molecular research suggests that Argusianus forms a weakly supported clade with Afropavo, Pavo, Rheinardia and Polyplectron#R. Citation of genus name replaces previous version “Argusianus Rafinesque, 1815”, which is a nomen nudum, as it was not associated with any particular taxon#R.

Recent molecular research suggests that Rheinardia forms a weakly supported clade with Afropavo, Pavo, Argusianus and Polyplectron#R. Genus name has frequently been misspelt Rheinartia, and in the past even as Rheinhardius, Rheinardius, Rheinartius or Rheinhardtius, among others#R.

Recent molecular research suggests that Polyplectron forms a weakly supported clade with Afropavo, Pavo, Argusianus and Rheinardia#R.

Broad molecular (mtDNA) study of Asian Phasianidae found that genera Coturnix, Gallus and Bambusicola form a subclade within a clade of pheasants, to the exclusion of the two partridge genera Alectoris and Perdix#R, although other studies have not supported this finding.

Broad molecular (mtDNA) study of Asian Phasianidae found that genera Alectoris and Perdix form a monophyletic grouping to the exclusion of all pheasants and such genera as Bambusicola and Coturnix#R. In a phylogenetic study of Alectoris#R, analyses of mtDNA sequences supported the existence of three main evolutionary events and accorded with relationships reconstructed on the basis of allozyme data. The first event separated N African A. barbara and Arabian A. melanocephala from the other Alectoris; following this, W taxa A. graeca and A. rufa separated from E species; recent speciation events gave rise to A. chukar, A. magna, and A. philbyi.

Formerly treated as a subgenus within a broad genus Francolinus, but latter as then constituted was found to be polyphyletic#R#R. Francolinus has therefore been restricted to the five Asiatic species; the African species are now generally divided among Pternistis, Peliperdix and Scleroptila (see below)#R.

Formerly treated as a much broader genus, including Pternistis and others, but when thus constituted was found to be polyphyletic#R#R. It has therefore been restricted to the five related Asiatic species; the African species are now mainly divided among Pternistis (see above), Peliperdix and Scleroptila (see below)#R.

Formerly treated as a subgenus within a greatly expanded Francolinus, but latter genus, when thus constituted, was found to be polyphyletic#R#R.

Formerly treated as a subgenus within a greatly expanded Francolinus, but latter genus, when thus constituted, was found to be polyphyletic#R#R. Francolinus has therefore been restricted to the five Asiatic species; the African species are now generally divided among Pternistis (see above), Peliperdix and Scleroptila (below)#R.

Formerly treated as a subgenus within a greatly expanded Francolinus, but latter genus, when thus constituted, was found to be polyphyletic#R#R. Francolinus has therefore been restricted to the five Asiatic species; the African species are now generally divided among Pternistis and Peliperdix (see above) and Scleroptila#R.

Broad molecular (mtDNA) study of Asian Phasianidae found that genera Coturnix, Gallus and Bambusicola form a subclade within a clade of pheasants, to the exclusion of two partridge genera (Alectoris, Perdix)#R.

Broad molecular (mtDNA) study of Asian Phasianidae found that genera Coturnix, Gallus and Bambusicola form a subclade within a clade of pheasants, to the exclusion of two partridge genera (Alectoris, Perdix)#R, although other studies have not supported this finding.

Broad molecular study of Phasianidae found that genera Tetraophasis, Lophophorus, Tragopan and Ithaginis form one of two major subclades, within which present genus is most closely related to Lophophorus#R. Recent molecular study found a sister relationship between Lophophorus and Tetraophasis#R, hence placement of Tetraophasis in tribe Lophophorini.

Broad molecular study of Phasianidae found that genera Tetraophasis, Lophophorus, Tragopan and Ithaginis form one of two major subclades, within which present genus is most closely related to Tetraophasis#R. Recent molecular study found a sister relationship between Lophophorus and Tetraophasis#R.

Broad molecular study of Phasianidae found that genera Tetraophasis, Lophophorus, Tragopan and Ithaginis form one of two major subclades, within which present genus is most closely related to Ithaginis#R.

Genus sometimes considered incertae sedis. Broad molecular study of Phasianidae, however, found that genera Tetraophasis, Lophophorus, Tragopan and Ithaginis form one of two major subclades, within which present genus is most closely related to Tragopan#R.

Genus previously considered incertae sedis. Broad molecular study of Phasianidae, however, found that Pucrasia forms a well-supported subclade which also comprises Syrmaticus, Chrysolophus, Phasianus and Lophura#R.

Recent broad molecular (mtDNA) study of Phasianidae found no evidence that Syrmaticus is polyphyletic; instead, the genus is part of a well-supported subclade that also contains Pucrasia, Chrysolophus, Phasianus and Lophura#R.

In recent broad molecular (mtDNA) study of Phasianidae, this genus found to be part of a well-supported subclade that also contains Pucrasia, Syrmaticus, Phasianus and Lophura#R.

In recent broad molecular (mtDNA) study of Phasianidae, this genus found to be part of a well-supported subclade that also contains Pucrasia, Syrmaticus, Chrysolophus and Lophura#R.

Broad molecular study of Phasianidae found that Crossoptilon forms, together with Lophura, one branch of a subclade that also comprises Pucrasia, Syrmaticus, Chrysolophus and Phasianus#R.

In a genetic study (cytochrome b) of relationships of Syrmaticus to Phasianus, Catreus and Lophura, it was found that Phasianus versicolor, Catreus wallichii and Lophura erythrophthalma formed a cluster. Catreus was considered more closely related to Phasianus than to Syrmaticus#R.

Broad molecular study of Phasianidae found that Lophura forms, together with Crossoptilon, one branch of a subclade that also comprises Pucrasia, Syrmaticus, Chrysolophus and Phasianus#R.

Position of genus uncertain. Recent genetic studies give contradicting results. One broad molecular (mtDNA) study of Asian Phasianidae found that the genera Alectoris and Perdix form a monophyletic grouping to the exclusion of all pheasants and such genera as Bambusicola and Coturnix#R. Another analysis found Perdix to be related either to typical pheasants (Phasianini) or to Ithaginis#R. Yet another study, however, places Perdix as sister to Meleagris in Tetraonini#R.

Position of genus uncertain; in past, often awarded its own family, Meleagrididae. Recent phylogenetic study places Meleagris as sister to Perdix in Tetraonini#R.

Genetic analyses show that Bonasa is monophyletic and is basal to all grouse of the traditionally recognized family Tetraonidae (below, species 168–187)#R#R.

Often included in Dendragapus, but a molecular analysis validates generic separation of Falcipennis#R.

This genus is sometimes subsumed within Tetrao, and the two appear to be very close, to the extent that they are sister-taxa#R#R; however, given the striking homogeneity of each species-pair, generic separation seems appropriate#R.

One genetic study found that this genus forms a single well-differentiated clade#R, but subsequent molecular work suggested that it is closely related to Dendragapus obscurus#R and, more recently, that it comprises together with Dendragapus and Centrocercus an exclusively North American clade#R.

Genus resurrected on basis chiefly of phylogenetic and ecological study which showed Nomonyx to be sister to Oxyura#R.

Systematic position of this genus uncertain. Some studies suggest that it is not close to Oxyura, but represents an independent lineage of its own#R. It is retained here in its traditional position, pending further information.

Phylogenetic analyses indicate the branching of this genus prior to the divergence of geese and swans, and suggest a possible sister-group relationship between Coscoroba and Cygnus#R.

Sometimes isolated in its own tribe (Sarkidiornini).

Sometimes considered incertae sedis; one recent phylogenetic study found it to be sister to Cairina#R.

In recent phylogenetic analysis, this genus found to be close to Netta and Aythya#R.

Considered incertae sedis by many. Traditionally placed here in Anatini, but further research needed.

Recent study found this genus to form a monophyletic clade, distinct from Lophonetta, Speculanas and Amazonetta#R.

Separation from genus Anas appears to be warranted#R. In recent phylogenetic study, this genus found to be monophyletic but relationships unclear#R.

Separation from genus Anas appears to be warranted#R. In recent phylogenetic study, this genus and Amazonetta were supported as sister-groups in all analyses#R.

Separation from genus Anas appears to be warranted#R#R. In recent phylogenetic study, this genus and Speculanas were supported as sister-groups in all analyses#R.

Recognition of this genus supported by genetic findings#R.

Separation of this genus from Anas supported by genetic study#R.

A mtDNA study corroborated the monophyly of Mareca, but placed this clade among other dabbling ducks, thereby possibly making Anas paraphyletic#R. More recently, separation of this genus from Anas supported by another genetic study#R.

Genus occasionally merged into Podiceps.

In past, genus listed as Mesoenas Reichenbach, 1861, a name introduced to replace the preoccupied Mesites I. Geoffroy Saint-Hilaire, 1861. Present name is older and now well established in literature, but was not correctly introduced and so requires application to ICZN for formal conservation; Mesitornis meantime retained herein, as in most other works, in order to favour stability#R.

Phylogenetic study of species genera Columba and Streptopelia led to extensive reorganization; all New World species traditionally included within present genus were transferred to a separate genus, Patagioenas#R, a split supported by previously described differences in morphology, serology and behaviour#R.

Often merged into Columba but rather distinctive, with strong terrestrial habits.

Phylogenetic study of genera Columba and Streptopelia led to extensive reorganization#R; some species traditionally included within present genus are here transferred to reinstated genera Spilopelia and Nesoenas.

Genus recently split from Streptopelia on basis of genetic differences#R combined with long-recognized distinctiveness amidst Streptopelia species; sometimes listed as Stigmatopelia#R but Spilopelia, from same publication, was selected by First Revisers#R.

Genus as currently constituted sometimes merged “back” into Streptopelia, where may be treated as a subgenus#R; the two species form a distinctive, reasonably well-defined group, with shared similarities in plumage, morphology (e.g. bifurcated neck feathers) and voice#R, and they are genetically related#R, so separate generic treatment appears appropriate#R. Genus is masculine#R.

Genus generally regarded as being closely related to Macropygia, and indeed sometimes included within it; however, this has been questioned, and similarities in coloration noted with some members of Columba, e.g. C. vitiensis.

Genus probably closest to Macropygia, which it resembles in shape and colour pattern of outer rectrices.

Recently split from Columba on basis of genetic differences#R, supporting previously described differences in morphology, serology and behaviour#R.

Affinities not well known, and in the past placed in its own subfamily due to details of skeleton and tarsal scutellation#R; traditionally considered close to, and herein provisionally placed alongside, Geotrygon, pending genetic studies.

In past, present genus was restricted to G. versicolor, the type species, with Osculatia applied to purpurata/saphirina, and all other species of group (herein Leptotrygon, Zentrygon) placed in Oreopeleia#R#R. Subsequently all were normally lumped into Geotrygon#R#R, but recent genetic work has demonstrated that this arrangement is polyphyletic, recommending the arrangement adopted herein#R.

Previously included within Geotrygon, but genetic evidence backs up long-held belief that this taxon is highly distinct; genetically closest to Leptotila, though similar in aspect and habits to Geotrygon#R.

Hitherto included within Geotrygon, and previously in Oreopeleia, but genetic evidence indicates that this group of ground-doves is most closely related to Zenaida, despite marked differences in morphology and behaviour; present genus morphologically inseparable from Geotrygon#R.

Distinctive genus perhaps belonging to the large radiation of bronzewings, where may be most closely allied to Chalcophaps; however, genetic study suggests sister relationship to group consisting of Alopecoenas, Gallicolumba, Geopelia and others#R.

Formerly considered to include Alopecoenas, but molecular data reveal that arrangement to be polyphyletic#R.

Formerly included within Gallicolumba, but molecular data reveal that arrangement to be polyphyletic; present genus close to Leucosarcia, and also to Geophaps, Phaps, Ocyphaps and Geopelia#R.

Monotypic genus of uncertain affinities; considered by some to be derived from bronzewings (Phaps and allied genera), but other authors have suggested a relationship with Gallicolumba, or with the monotypic Trugon of New Guinea. A new phylogenetic hypothesis, however, indicates that Leucosarcia is part of an Australasian radiation (rather than sister to Alopecoenas) and distant from Gallicolumba#R.

Belongs to the large radiation of Australian bronzewings, which also includes the genera Geophaps, Phaps and Ocyphaps, and, more distantly, Henicophaps and Chalcophaps.

Belongs to the large radiation of Australian bronzewings, which also includes Petrophassa, Phaps and Ocyphaps, and, more distantly, Henicophaps and Chalcophaps; sometimes subsumed within Petrophassa.

Belongs to the large radiation of Australian bronzewings, which also includes Petrophassa, Geophaps and Ocyphaps, and, more distantly, Henicophaps and Chalcophaps.

Monospecific genus belonging to the large radiation of Australian bronzewings, which also includes Petrophassa, Geophaps and Phaps, and, more distantly, Henicophaps and Chalcophaps.

Despite superficial resemblances to Streptopelia, probably most closely related to bronzewing group (Phaps and allies) on basis of behaviour.

Unique among pigeons in having no gallbladder; also lacks oil-gland, has reticulate scaling on the strong, thick legs, and has 16 rectrices; no obvious close relatives.

Distinctive genus of uncertain affinities. Probably close to Goura#R; perhaps closest to Gallicolumba, with which it may share a common ancestral stock. Larger extinct form C. canacorum, known from New Caledonia and Tonga, extinct c. 2500 years ago.

Very distinctive genus of uncertain affinities, perhaps most closely allied to Gallicolumba. Some early workers placed it in its own family, Didunculidae, but recent molecular analyses indicate that it is basal to a clade containing Goura, Caloenas, Raphus and Pezophaps#R. Single species survives, although a larger, extinct member of the genus has been found in cave deposits on ‘Eua (S Tonga).

Shows affinities with both Australian bronzewings (Phaps and allies) and African spot-winged doves (Turtur).

Apparently has no close relatives; restricted to Philippines.

Until recently subsumed within Ptilinopus (which see); present genus is basal to all fruit-doves, and is characterized by bright yellow underwing-coverts#R.

Until recently subsumed within Ptilinopus (which see)#R; restricted to Philippines and Sulawesi, apart from one aberrant form from SE Asia, and characterized by relatively large size, and emarginated first primaries.

Distinctive genus, shown by molecular data to be nested amidst traditional Ptilinopus (which see).

Distinctive monotypic genus characterized by notched primaries and short, very rounded wings. Perhaps most closely related to Chrysoena, but recent genetic study indicates sister relationship with Alectroenas#R.

Distinctive genus, comprising three small species, which are thought to represent an early colonization of Fiji by Ptilinopus stock; genus often merged into Ptilinopus (which see).

Recent molecular work#R indicates that morphologically distinctive genera Alectroenas and Drepanoptila nest within traditional, expanded version of present genus; the different lineages are accommodated here by the additional recognition of genera Megaloprepia, Ramphiculus and Chrysoena; further work required in order to confirm that present genus as defined here, in reduced form, is now monophyletic.

Distinctive genus of uncertain affinities, perhaps allied to Lopholaimus, which also has only 12 tail feathers, and cere feathered dorsally; more distantly allied to Ducula.

Affinities uncertain; apparently close to Gymnophaps and possibly also to Ducula; alternatively, may be related to the cuckoo-dove assemblage (Macropygia/Turacoena/Reinwardtoena).

Relationships uncertain; somewhat similar to some Ducula in coloration and colour patterns; recent molecular study suggests probable sister relationship with Lopholaimus#R.

Distinctive monotypic genus of uncertain affinities. Perhaps most closely related to Hemiphaga, as both of these genera have only 12 tail feathers, while cere is feathered dorsally; recent molecular study suggests probable sister relationship with Gymnophaps#R.

Recent genetic investigation#R suggested that this genus should also incorporate all species currently in Pterocles (see below), although that would mask relationships among the members of the family; alternatively, species could be grouped in three genera according to that study’s well-supported clades; or, more conservatively, a third treatment, involving two clades, may be more appropriate. Further study clearly required.

In recent genetic investigation#R, this genus as presently constituted was not recovered as monophyletic in any of the analyses, as it was rendered paraphyletic by Syrrhaptes. The placing of all species in Syrrhaptes (which pre-dates Pterocles), suggested as a possibility, would, however, mask relationships among the members of the family; alternatively, species could be grouped in three genera according to the well-supported clades found in the study; or, more conservatively, a third treatment, involving two clades, may be more appropriate. Further study clearly required.

In mtDNA study of this genus, sequence divergence among species was greater (11.1–16.2%) than is typical for congeneric birds, and there was little constant evidence for strong relationships among any of the species except N. griseus, N. maculosus and N. leucopterus#R. In a more recent study, interspecific variation in cranial morphology found to be so extensive that inclusion of all species in a single genus could be misleading#R.

Proposal that this genus be subsumed within Caprimulgus#R has received very little support; indeed now separated in different subfamilies.

Previously subsumed within Eurostopodus, but recently resurrected#R, a decision supported by a separate phylogenetic study#R. The two species included here appear not to be closely related to Eurostopodus.

A new genus created to accommodate G. enarratus, formerly placed in Caprimulgus. Phylogenetic analysis indicated this species’ wide genetic divergence in both nuclear DNA and mtDNA from all other genera and all other caprimulgid species studied: enarratus found to be sister to, and basal to, all caprimulgids apart from Eurostopodus#R. Plumage pattern distinct from that of all other nightjars, including pronounced facial discs, and unique narrow collar on side and rear of neck, and detailed investigation desirable; feeding behaviour apparently unusual, hunting perhaps confined to interior of forest#R; white eggs laid on low shrub (rather than on ground); voice and vocal behaviour almost unknown, but thought probably to be unusual.

Previously subsumed within Caprimulgus, but recent studies indicate that separate treatment is more appropriate#R#R. Some recent authors have subsumed Nyctipolus within Antrostomus#R.

Previously subsumed within Caprimulgus, but recent studies indicate that separate treatment is merited#R. Some recent authors have subsumed Systellura within Antrostomus#R.

Earlier genetic studies suggested that this genus was embedded in Caprimulgus#R, but more recent analyses found it to be basal to a group that included Uropsalis, Hydropsalis and some other New World groups#R. Present genus has been subsumed within Antrostomus by some authors#R.

Subsumed within Macropsalis by some authors#R#R, who maintain that distinguishing characters (primarily tail shape) are not appropriate for generic distinction.

Previously subsumed within Caprimulgus, and more recently#R within Antrostomus. Phylogenetic study, however, indicates that it merits separate treatment#R.

Previously subsumed within Caprimulgus, but recent phylogenetic study indicates that it merits separate treatment#R.

In the past sometimes subsumed within Chaetura or, occasionally, Rhaphidura.

Formerly merged into Chaetura.

Genus formerly merged with Chaetura or Mearnsia.

Formerly subsumed within Chaetura, but is morphologically and structurally distinct#R.

Perhaps closest to Aerodramus, and these two commonly merged into Collocalia.

Often subsumed within Collocalia.

Previously subsumed within Apus; affinities uncertain.

Has commonly been subsumed within Apus, but nowadays is increasingly separated; differs in feather lice, foot structure of nestling, large size, and tendency towards white underparts. Recent molecular phylogeny based on a taxon-complete sampling at species level of Tachymarptis and Apus revealed that the two genera were reciprocally monophyletic in all reconstructions#R.

Recent molecular#R phylogeny based on a taxon-complete sampling at species level of Tachymarptis and Apus revealed that the two genera were reciprocally monophyletic in all reconstructions#R.

Perhaps related to Eulampis and Anthracothorax through nest and display; in past placed close to Oreotrochilus.

It has been suggested that this genus should be subsumed within Glaucis#R.

Genus formerly placed in subfamily Phaethornithinae owing largely to confusion regarding its nest, but behavioural and molecular studies suggest that it is not related to that subfamily; on basis of external morphology, hindneck musculature and behaviour it has even been placed, together with genus Androdon, in a separate subfamily, Doryferinae. Recent molecular analysis, however, indicates that both Doryfera and Androdon are part of the mango assemblage#R. In many older works generic name Hemistephania was used.

Previously subsumed within Augastes.

Affinities of genus unknown; song and nest pattern indicate relationship with Colibri.

Genus formerly placed in subfamily Phaethornithinae, but behavioural and molecular studies suggest that the species is not related to that subfamily; on basis of external morphology, hindneck musculature and behaviour it has even been placed, together with genus Doryfera, in a separate subfamily, Doryferinae. Recent molecular analysis, however, indicates that both present genus and Doryfera are part of the mango assemblage#R.

Previously thought to be close to genera Leucochloris and Leucippus, having morphological and behavioural affinities with those. Recent molecular analysis, however, indicates that present genus is part of the large mango assemblage#R.

Genus previously thought to be very closely related to, or even congeneric with, Orthorhyncus, but recent molecular analysis indicates that the two are genetically well separated#R.

Previously subsumed within Anthracothorax, mainly on grounds of some details of morphology, together with behaviour and nest structure. Remarkable form of bill, however, unique within the family. On the other hand, recent phylogenetic study based on plumage colour spectra supports retention in Anthracothorax#R.

Recent phylogenetic study based on plumage colour spectra suggests this genus is closest to Eulampis#R.

Recent phylogenetic study based on plumage colour spectra suggests that this genus is closest to Anthracothorax#R. Has been considered closely related to continental Anthracothorax and Topaza.

Genus has been thought to be closely related to a high-Andean lineage that includes Oreotrochilus, Lesbia, Oreonympha and Metallura. Present generic name based on misspelling of species name.

Closely related to Lophornis. Includes genus Popelairia (formerly used for D. conversii, D. popelairii, D. langsdorffi and D. letitiae).

Occasionally subsumed within Adelomyia; more information needed in order to assess most appropriate generic placement of these two species.

Systematic position poorly understood. Genera Phlogophilus, Urosticte and Anthocephala have been suggested as close relatives, some authors even considering all four to be congeneric; because monophyly of these four is doubtful, however, monospecific Adelomyia is maintained.

In past, these species listed in genus Cyanolesbia, but the name is unidentifiable.

Genus sometimes merged into Lesbia; may be closely related to L. victoriae.

Systematic position uncertain; has been thought probably closest to Sappho and Polyonymus. Genetic data suggest that Taphrolesbia may be sister to Aglaiocercus#R.

Genus sometimes merged into Lesbia; affinities uncertain, but may be closely related to Taphrolesbia. Genetic data suggest that Polyonymus may be sister to Oreotrochilus#R.

As presently constituted, genus is almost certainly polyphyletic#R#R. Chalcostigma and Metallura may be sister-genera#R#R. It has been proposed that Chalcostigma consists of two species-groups: (i) C. olivaceum + C. stanleyi, and (ii) C. ruficeps + (C. herrani + C. heteropogon)#R.

Genus thought to be closely related to Chalcostigma, Oreonympha and Metallura. Recent genetic study found that this genus and Oreonympha, although closely related, were nested within Chalcostigma#R.

A distinctive genus which may, on basis mainly of plumage coloration, be closest to Oxypogon. Recent genetic study found that this genus and Oxypogon, although closely related, were nested within Chalcostigma#R.

Genetic studies suggest that this genus and Chalcostigma may be sisters#R#R#R.

Sometimes merged into Eriocnemis; has also been considered to be close to Ocreatus and Urosticte.

Genus generally considered sister-taxon to Haplophaedia.

Preliminary genetic data suggest that this genus is close to, or even embedded within, Eriocnemis#R. In past, thought perhaps to be closely related to Heliactin and Heliothryx.

Recent molecular studies found this genus to represent a monophyletic group, with Heliodoxa as sister#R.

Has been thought possibly close to Oreotrochilus on basis of behaviour and external morphology.

Has been considered closely related to Coeligena, or even lumped with it#R, but this relationship is not supported by some studies#R.

Has been thought to be closely related to Coeligena, or even lumped with it#R#R, but this not supported by some studies#R.

On basis of display patterns, may be closely related to Haplophaedia, Eriocnemis and Urosticte.

Formerly considered a close relative of Oreotrochilus; behaviour and morphology suggest phylogenetic affinities with Boissonneaua.

On basis of behaviour, genus would belong to a clade including Haplophaedia, Eriocnemis and Ocreatus. Sometimes merged into Adelomyia.

Relationships uncertain. One study found this genus was not close to any other trochilid group#R. Previously thought perhaps to be closely related to Coeligena, even to the point that the two might be merged.

Recent molecular study suggested that this genus was almost certainly embedded within Chlorostilbon#R.

Recent molecular study suggested that this genus was almost certainly embedded within Chlorostilbon#R. Nest type indicates affinities with Chlorostilbon and Cynanthus; voice suggests affinities with Thalurania.

Sometimes merged into Abeillia; thought to be closely related to Stephanoxis.

Sometimes considered to incorporate Klais.

Previously thought to be very closely related to Chrysolampis, or even synonymous, but recent molecular analysis indicates that the two are genetically well separated#R.

Genus thought closely related to Klais.

Previously subsumed within Campylopterus, partly on grounds of external morphology and flattened and thickened shafts of outer primaries, but this treatment not supported by recent molecular study#R.

Systematic relationships uncertain; perhaps closely related to Microchera, but sometimes considered close to Adelomyia, and possibly even synonymous.

In one study, this genus was found to be monophyletic and the sister to Anthracothorax and Eulampis#R.

Previously subsumed within genus Campylopterus, largely on basis of song structure and enlarged shaft of primary of male, but such treatment has gained little support.

Genus sometimes merged into Eupherusa.

Genus sometimes merged with Leucippus.

Genus as currently constituted found not to be monophyletic#R. Further research required.

As currently constituted, this genus is not monophyletic#R; more thorough sampling of taxa required before a clearer picture can be presented. In HBW, species currently placed herein were spread out over six genera, with additional recognition of Agyrtria, Polyerata and Saucerottia, and relocation of some species in Leucippus and Hylocharis.

Genus previously thought to be closely related to Chlorostilbon. Recent study suggests much closer to Amazilia#R.

Monotypic genus, sometimes merged into Hylocharis because of similarity in plumage, but lacks swollen base of bill and enlarged nasal operculum of that genus. Recent study suggests that it is much closer to Amazilia#R.

Considered a close relative of Goldmania and perhaps of Hylocharis, sharing with former the long, stiffened central undertail-coverts; behaviour and external morphology show similarities to Eupherusa.

Genus linked with Goethalsia, with which it shares the long, stiffened central undertail-coverts; one proposal, based on external morphology, suggests placing of present species in Hylocharis; general behaviour, however, indicates possible affinities with Chlorostilbon. Study required.

This genus name replaces previously used Damophila, found to be preoccupied in Lepidoptera. Proposed replacement name Neodamophila#R not required, as Juliamyia already available. Affinities unclear; genus possibly close to Thalurania or Chlorostilbon.

Genus often merged into Hylocharis, though external morphology suggests closer relationship to Lampornis.

Genus sometimes merged into Eugenes or Heliodoxa.

Genus sometimes merged into Heliodoxa.

Genus sometimes merged into Heliodoxa.

Some authors merge Rhodopis into this genus.

Sometimes merged into an expanded version of Calliphlox; on basis of morphological characters, may be better placed within Chaetocercus.

Occasionally treated as a monospecific genus; at other extreme, considered to include all species of currently recognized genera Microstilbon, Doricha, Tilmatura, Calothorax and, sometimes, also Thaumastura, on grounds that females are very similar, males differing essentially in specialized details of plumage.

Genus sometimes merged into Calothorax, or incorporated in an expanded Calliphlox.

Genus sometimes merged into an expanded version of Calliphlox. Closely related to genus Doricha, which sometimes united with present genus on basis of similarity in morphological characters.

Sometimes expanded to include all species currently placed in Calypte, Archilochus and Stellula (the last now subsumed within Selasphorus).

Often merged into Archilochus, and both have sometimes been subsumed within Selasphorus; in morphology, vocalizations and displays, however, members of present genus stand apart from the Selasphorus–Archilochus assemblage. Alternatively, present genus sometimes merged into Mellisuga.

Sometimes merged into Mellisuga; alternatively linked with Selasphorus.

Probably closely related to Selasphorus, and sometimes subsumed within it.

Incorporates West Indian genera Saurothera and Hyetornis, which were found in a recent molecular analysis to be embedded within Coccyzus#R.

Name sometimes misspelt Eudynamis.

Sometimes incorrectly spelt Urodynamys.

Commonly lumped into Chrysococcyx, but mtDNA divides bronze-cuckoos into two well-defined clades#R, and these may appropriately be treated as separate genera#R.

Sometimes merged into Cuculus.

Sometimes subsumed within Cacomantis or Cuculus.

Sometimes subsumed within Cacomantis.

Often subsumed within Cuculus but shows notable morphological differences (e.g. in wing shape and tail-barring), and genetic data support this grouping#R.

Sometimes awarded a family of its own, Sarothruridae#R. In past, was subsumed within Coturnicops by some authors.

Sometimes subsumed within Canirallus, but differs in having imperforate (rather than perforate) nostrils.

Sometimes subsumed within Rallina, but differs in marked sexual dimorphism.

Name Anurolimnas previously used for this genus, but Rufirallus has precedence#R.

Sometimes subsumed within Rallus, but differs in bill shape and plumage.

Recent molecular phylogeny of Pacific rails advocated that almost all of the species should be lumped under a broadly defined genus Gallirallus#R.

Genus sometimes enlarged to include Aramides, Amaurolimnas and Gymnocrex.

Incorporates genera Habropteryx, Nesoclopeus and Tricholimnas; many forms previously placed in Gallirallus.

Sometimes merged into Eulabeornis.

Distinctiveness of genus from Neocrex merits elucidation.

Sometimes subsumed within Porzana, but molecular analysis suggests it is probably sister to Aramides#R.

Sometimes merged, with Aramides, in Eulabeornis; shows some similarities to Aramides, and may be derived from same stock.

Poliolimnas and Aenigmatolimnas are now subsumed within this genus. Differences in vocalizations among populations for which such data are available suggest that species diversity of bush-hens has probably been underestimated; further study required.

Incorporates genera Porphyrula and Notornis.

Usually included within Gallinula, but differs in structure of bill, skull and tarsus, and in plumage pattern.

Incorporates genus Porphyriornis.

Often subsumed within Gallinula, from which it differs in several morphological features.

Commonly merged into Grus.

Often included in Grus; ethological and DNA data imply closer to Anthropoides, but both sometimes merged into Grus; recent osteological and molecular studies support recognition of present genus#R#R.

Often merged with Grus, but recent osteological and molecular studies support its recognition#R#R.

In the past, frequently merged into Otis, and considered to be closely related to O. tarda mainly on grounds of similar bill shape and extensive sympatry; nowadays almost universally recognized as monotypic genus, and molecular phylogeny places it closer to Houbaropsis, Sypheotides and Lophotis#R. Recent detailed phylogenetic and biogeographical study, however, indicates that Tetrax is close to Otis and Chlamydotis#R.

Has frequently been considered to include Tetrax, and sometimes also Neotis and Ardeotis, but in structure, display and plumage highly distinctive and clearly meriting generic isolation from these forms.

Reported as apparently close to Neotis in HBW, but molecular evidence suggests it is closest to Otis#R.

Frequently merged into Eupodotis.

Sometimes merged into Otis; more recently, molecular evidence suggests that it belongs with Ardeotis#R#R, but situation still not fully resolved and for the present Neotis retained.

In past, frequently listed as Choriotis, but Ardeotis has priority. Sometimes merged with Otis (which see). One recent phylogeny based on mtDNA found that Ardeotis arabs and A. kori formed a clade with Heterotetrax rueppelii#R.

Sometimes merged into Eupodotis, but differs notably from all other bustards except Sypheotides in showing reversed sexual size dimorphism.

Occasionally merged with Eupodotis, but differs notably from all other bustards except Houbaropsis in showing reversed sexual size dimorphism.

Frequently merged into Eupodotis.

Sometimes subsumed within Eupodotis.

Frequently merged into Eupodotis. One study suggested that the two are sister taxa#R.

Relationships uncertain; further research required. One study suggested that this genus is sister to Afrotis#R.

Previously included in Corythaixoides, but appears sufficiently distinctive to warrant monotypic genus#R.

Recent cytochrome b work suggests this genus comprises specialized forms of typical turaco and should be merged into Tauraco#R; further study needed, as systematics of the entire group remain rather confused.

In the past, older genus name Colymbus was used for these species, but it has been suppressed#R.

Incorporates Oceanodroma, within which Hydrobates was found in recent studies to be embedded#R#R; since Hydrobates is the older name, it is used for this expanded genus.

Within the group of large albatrosses in this genus, significant confusion exists about the taxonomic rank of breeding populations on specific islands.

Previously subsumed within Diomedea.

This genus previously merged with Diomedea.

Earlier proposal that this genus is closer to Pachyptila than to any other genus#R is supported by recent genetic data#R.

Name Lugensa formerly used for this monotypic genus, but type species of that name is considered indeterminable; some authors, however, disagree and continue to use Lugensa#R#R#R.

Sometimes divided into several subgenera#R. Includes several species described in genus Aestrelata, which was erroneously emended by some authors to Oestrelata.

Previously included in Puffinus, but represents a lineage distinct from both Puffinus and Calonectris#R#R#R#R.

Until recently included all species currently placed in Ardenna, but these have now been shown to represent a distinct lineage#R#R#R#R. Taxonomy of the P. assimilis/P. lherminieri complex has long been debated. Recent molecular analysis by one group of researchers#R and further refinements by another#R have resulted in a major rearrangement of taxa and the promotion of many of them to species rank. Owing to the sheer number of taxa in the complex, the inaccessibility of much museum material for comparative purposes, the subtlety of many phenotypical characters and the expectation that nocturnal vocalizations, many unknown, will play a significant part in species limits, this is a particular case where the scoring system used herein is currently impractical. With the exception of N Atlantic taxa (see below under P. lherminieri) we therefore accept the taxonomy set out in one recent (2007) treatment#R as the most coherent reorganization of the complex based on the available evidence.

Considered somewhat intermediate between Pterodroma and Bulweria. Previously merged into Pterodroma, but appears sufficiently distinctive #R.

Separation from Pterodroma has been questioned, but supported by recent studies#R#R.

Sometimes subsumed within Pseudibis, and probably closely related to it, but greater size, absence of contrasting colour markings, calling behaviour and ecological specialization on wetter substrates#R all indicate phylogenetic distinctiveness.

Incorporates genera Lampribis and Hagedashia.

Sometimes subsumed within Tigrisoma#R.

Has been placed in a separate, monospecific family Cochleariidae. Traditionally linked with night-herons (especially Nycticorax), but DNA studies indicate possible relationship with Tigrisoma. Recent analysis of skeletal characters, however, suggested possibly closer relationship to Botaurus and Ixobrychus#R.

Phylogenetic study indicates that Zebrilus, despite resemblance to Tigrisoma in plumage and forest habitat, is closest to Botaurus#R.

Sometimes merged into Nycticorax.

Often merged into Gorsachius or Nycticorax.

Often merged into Nycticorax, but molecular study, as well as skeletal characters, indicates substantial divergence between the two#R.

Sometimes included in Ardeola.

Genus has been incorporated variously into Ardea, Ardeola and Egretta. DNA studies indicate closer genetic link with Ardea than with Egretta#R#R.

Relationships of this genus have long been uncertain; DNA studies indicate that it may be sister to Egretta#R.

Author of this genus has usually been given as Bonaparte, 1855, but the name Pilherodius was first used two years earlier, by Reichenbach#R.

Origins and relationships somewhat obscure. Some affinities with Ardeidae, Ciconiidae, Balaenicipitidae, Phoenicopteridae and Charadriidae suspected. A recent molecular study found this form to be sister to Balaeniceps#R.

Some morphological and behavioural affinities with Ardeidae, Scopidae and Pelecanidae; has previously been considered a member of Ciconiidae, and work on DNA suggested that it might belong within Pelecanidae. A recent molecular study found this form to be sister to Scopus#R.

Recent DNA work indicates that species in this genus fall into three well-supported clades: an Old World clade, a monospecific clade (Pelecanus onocrotalus, weakly grouped with the Old World clade), and a New World clade#R. These findings are reflected in the species sequence below.

Apparently sister to a clade formed by Morus and Sula#R.

Previously included in Sula, but recently found to represent a separate lineage#R.

Previously considered to include both Papasula and Morus, but recent study found that these taxa represent three monophyletic lineages#R.

Previously subsumed within Phalacrocorax, and some phylogenetic studies support lumping all species of this family into the single genus#R. Name Halietor is a junior objective synonym of Microcarbo.

Sequence of species below is based on findings of recent phylogenetic study#R.

Sometimes merged into Burhinus.

Genus Chionis described by diagnosis, but no species included; thus, description of genus pre-dates those of both species.

Species limits in this genus are complex, with varying degrees of hybridization where ranges of taxa overlap.

Recent extensive genetic study#R indicates that, contrary to some earlier suggestions, this genus belongs in Charadriidae, being sister to the other genera placed in this family.

Sometimes subsumed within Eudromias, but validity of this monospecific genus is supported by analysis of phenotypic characters#R. Recent genetic study indicates that Oreopholus is sister to a clade consisting of Vanellus and Charadrius#R.

Genetic data#R support placement of this genus in Charadriidae, rather than, as earlier suspected, in Scolopacidae.

Sometimes subsumed within Charadrius. Limits and validity of Thinornis perhaps still debatable.

Monotypic genus, often subsumed within Charadrius.

Often merged into Vanellus, although in several aspects, including plumage details and some physiological features, exhibits similarities to Charadrius. Recent analysis of phenotypic characters indicates that it is sister to Vanellus#R.

Often placed in Charadrius, and traditionally grouped with other Australasian aberrant Charadrius-like genera; however, recently grouped in Vanellinae on basis of allozymes, patterning of wing and presence of hind toe#R, and phylogenetic study supports its distinction from Charadrius#R.

Relationships uncertain, and somewhat controversial: formerly considered to belong to family Glareolidae, where listed closest to genus Rhinoptilus, and on occasion, also in past, placed in genus Eudromias; more recent biochemical studies suggested that genus might possibly be merged with Charadrius#R. Since then, correct placement still unclear: one study grouped it with Vanellinae#R and another with Charadriinae#R.

Has been considered very close to Charadrius, and perhaps even congeneric. However, recent study, based on multigene evidence, placed present genus along with Erythrogonys and Peltohyas as forming sister clade to Vanellus#R.

Sometimes merged into Rostratula, but shows marked differences in morphology and behaviour.

Recent multigene phylogeny indicates that this genus and Hydrophasianus are closely related and form one of two groups within the family, the other containing all remaining currently recognized genera#R. Earlier proposals that Hydrophasianus be included in Jacana, or that Actophilornis, Metopidius and Irediparra be synonymized with Jacana, now out of favour.

Recent multigene phylogeny indicates that this genus and Jacana are closely related#R (see Genus Jacana).

Occasionally lumped with Irediparra and Microparra in Metopidius, or alternatively with Metopidius and Irediparra in Jacana, but neither proposal widely accepted (see Genus Jacana).

Occasionally considered to include Actophilornis, Irediparra and Microparra, or alternatively lumped with Actophilornis and Irediparra in Jacana, but neither proposal widely accepted (see Genus Jacana).

Occasionally lumped with Actophilornis and Microparra in Metopidius, or alternatively with Actophilornis and Metopidius in Jacana, but neither proposal widely accepted (see Genus Jacana).

Occasionally lumped with Actophilornis and Irediparra in Metopidius, but this proposal not widely accepted (see Genus Jacana).

Name Erolia, often used in the past in North America, is a synonym of Calidris.

Formerly referred to as Capella, because this name was erroneously thought to pre-date Gallinago.

Sometimes subsumed within Phalaropus, but genetically distinct, and with several ecological and morphological differences; possibly quite close to Tringa.

Often subsumed within Tringa; molecular evidence, however, places it basal to that clade and closest to Phalaropus#R.

Sometimes included in Tringa, but recent molecular study indicated that the two are almost certainly sister-genera#R.

Sometimes considered to include Actitis, but recent molecular study indicated that the two are almost certainly sister-genera#R. Also incorporates previously recognized genera Heteroscelus and Catoptrophorus#R.

Differs from Turnix in morphology, ecology and behaviour; shape and structure, especially of wing and tail, and colour pattern of upperwing quite different.

Often subsumed within Rhinoptilus, or sometimes Cursorius, but shows significant differences in behaviour and syringeal morphology#R.

Forms an apparent link between genera Cursorius and Glareola.

Previously included within Larus (which see), but differs in its compressed bill, its long, slender tarsi, and its incised webs between the long toes; recently resurrected on basis of genetic data#R#R.

Previously included within Larus (which see); recently resurrected on basis of genetic data#R#R. Apparently sister to Rhodostethia#R.

Apparently sister to Hydrocoloeus#R, and sometimes merged into it, but, although there are many phenotypic and behavioural similarities between them, they show significant differences in adult plumage.

Recent study found this genus to be sister to Pagophila#R, despite entirely different plumages.

Osteologically quite distinct from Larus; considered by some intermediate between the gulls and the skuas (Stercorariidae). Recent study found this genus to be sister to Xema#R, despite entirely different plumages.

Incorporates Chroicocephalus, Leucophaeus and Ichthyaetus; several other genera, including Saundersilarus and Hydrocoloeus, have often been included in Larus, as occasionally have Xema and even Rissa, but all of these appear distinct. Recent genetic studies found that Larus as previously constituted was polyphyletic#R#R; some workers propose solving this by the removal of many species to other genera#R; a subsequent study, with much larger sample analysed, concluded that, in order to retain the monophyly of Larus, only two species (saundersi and minutus) would need to be moved to different genera#R, an arrangement followed here.

Previously included in Sterna. Genetic data indicate that the four species now placed in this genus form a monophyletic group, which is the outgroup to all other terns#R, prompting the resurrection of Onychoprion.

Previously included in Sterna.

Along with Onychoprion, Sternula, Hydroprogne, Chlidonias and Thalasseus, often merged into Sterna; behaviour intermediate between typical terns and crested terns, and unique combination of characters supports separate generic treatment. Recent genetic analysis also supports the retention of Gelochelidon#R.

Along with Onychoprion, Sternula, Gelochelidon, Chlidonias and Thalasseus, often merged into Sterna on basis primarily of ethological evidence; differs from all other terns, however, in massive, heavy bill. Recognition of monotypic Hydroprogne supported also by molecular evidence#R.

Sometimes subsumed within Sterna, but genetic study supports its retention#R.

Sometimes treated as including one or more of the genera Onychoprion, Sternula, Gelochelidon, Hydroprogne, Chlidonias and Thalasseus.

Often subsumed within Sterna, but recent genetic data support its recognition#R. Species placed herein share certain common features of morphology which set them apart from other terns.

Often subsumed within Stercorarius#R#R, but recent phylogenetic study based on skeletal morphology#R indicates that these four species represent a monophyletic genus, sister of which is Stercorarius pomarinus. All skua taxa of S oceans are very closely related, with at least some gene flow among several populations#R.

Incorporates Endomychura, which has occasionally been used for a few of the murrelet species.

In the past, listed as monospecific genus Plautus, but this name is unavailable.

Affinities of many species in this genus are uncertain; research required in order to clarify relationships.

Closely allied to Ninox, and sometimes merged with it, but wings more rounded.

Relationships uncertain; placed near Glaucidium on the basis of osteology and DNA.

Recent study of genetic data indicated that, while this genus is monophyletic, a major division exists between New World species and most of the Old World taxa#R, with proposal that latter be separated in genus Taenioglaux. As a consequence, Old World species, with exception of first four below (G. passerinum, G. brodiei, G. perlatum and G. tephronotum), have been placed in Taenioglaux by some recent authors#R; here considered more appropriate at present time to await further research and more extensive sampling of taxa.

Incorporates genus Speotyto.

Sequence of species in this genus is adopted in an attempt to conform to the findings of several recent molecular-phylogenetic studies#R#R, notwithstanding difficulty that a considerable number of taxa have not yet been sampled. Relationships of many species remain uncertain. Includes genus Mimizuku. Previously incorporated genus Megascops.

Genus until recently merged with Otus, but shown by molecular-biological studies to be very different, and eyes also much bigger.

Genus formerly merged with Asio; believed to be possibly closest to Asio, with similar contact calls, but often considered particularly close to Otus, while some authorities think that it is linked with Athene and Aegolius.

Previously subsumed within Otus, but differs in several respects#R.

Previously subsumed within Otus, but differs in several respects, including voice. Genetic analyses reveal clear division between New World species and Old World Otus#R, and indicate a sister relationship between Megascops and Psiloscops#R.

A replacement genus name for Gymnoglaux; latter shown to be an objective synonym of Gymnasio, both names currently being treated as synonyms of Megascops#R#R.

Genus considered by some to be related to Otus, and by others to Bubo. Recent studies, however, also suggest that it may have some link with Pulsatrix.

Includes Nyctea.

Sometimes subsumed within Bubo, or treated as a subgenus; separated on basis of slight differences in skull morphology. Molecular evidence suggests that Ketupa forms a robust clade within Bubo and therefore merits subgeneric ranking#R.

Relationships of genus uncertain, but appears closely related to Bubo; in recent monograph, given the rank of a subgenus within Bubo#R.

Frequently subsumed within Strix, to which it is genetically close, but differs in external ear structure.

Most morphological, behavioural and molecular affinities with other Accipitriformes, especially Accipitridae; some behavioural affinities with Ciconiidae. Proposed relationships to Cariamidae and other Gruiformes unsubstantiated.

Sometimes included within family Accipitridae, usually in its own subfamily, Pandioninae.

Recent phylogenetic study of family found that this genus and Gampsonyx were sister-taxa and were basal to all other accipitrid genera#R. Chelictinia commonly thought to be closely related to Elanus and sometimes subsumed within it.

Recent phylogenetic study found this genus and Elanus to be sister-taxa and basal to all other accipitrid genera#R. Formerly thought to be a falconid related to Polihierax and Spiziapteryx, but osteological evidence, scutellation and moult pattern, in addition to DNA data, place it near Elanus.

Commonly thought to be closely related to Elanus and sometimes subsumed within it, but differs in morphology.

Recent phylogenetic study found some evidence of relationship with Chondrohierax#R. Apparent affinity with Old World honey-buzzards (Pernis) and bazas (Aviceda) requires corroboration through molecular analyses.

Recent phylogenetic study found some evidence of fairly close relationship to Leptodon#R.

Not clearly or closely related to any other genus, but some similarities to Elanus and the Pernis group.

Recent study indicated that this genus is sister to Aviceda, with Australasian Henicopernis and Old World vultures Gypaetus and Neophron rather distant relatives#R.

In the past, commonly regarded as a primitive kite with milvine affinities. In recent decades, suggested to be part of an old endemic Australasian clade which also includes Lophoictinia and Henicopernis; the close relationship of these three genera was strongly supported by a recent phylogenetic study using DNA sequences#R, which concluded that the three belong together in Pernini, and indeed might perhaps be considered congeneric; the same study firmly rejected a suggested relationship of these three with three other species-poor Australo-Papuan genera, namely Harpyopsis, Erythrotriorchis and Megatriorchis.

Has been regarded as related to Milvus, but resemblance superficial and convergent. Now considered part of an endemic Australasian clade which also includes Hamirostra and Henicopernis (see above, Hamirostra).

Traditionally considered close to Pernis, although one molecular study suggested that it is rather distantly related to that genus#R. Now considered part of an endemic Australasian clade which also includes Hamirostra and Lophoictinia (see above, Hamirostra).

Recent genetic study indicated that this genus is sister to Pernis#R.

Affinities uncertain; previously thought to be most similar to likewise monotypic African Dryotriorchis. Placement with Pernis and relatives suggested in recent DNA study#R.

Relationships far from clear; has been associated variously with Spilornis, Dryotriorchis, Circus and Geranospiza, but also thought possibly closest to Melierax. Recent phylogenetic study indicated that apparent morphological and behavioural similarity to much smaller Neotropical Geranospiza due to convergence, rather than to genetic relatedness#R.

Has been considered intermediate between fish-eagles and vultures.

Doubtful affinities; usually considered closest to Neophron.

Possibly closest to Gypaetus; has been combined with Necrosyrtes, but differs in morphology and some aspects of behaviour.

Taxonomy extremely confused and tentative; complete revision and extensive study of relationships and species limits required. Research priorities include field studies of biology, especially with regard to prey and vocalizations, and laboratory analyses of DNA; extent of sympatry of various taxa requires full investigation.

May be most closely related to Asian Spilornis; previously thought to be most similar to Madagascan Eutriorchis. Recent molecular phylogeny, however, found that it falls within the clade of typical African snake-eating eagles of genus Circaetus#R.

Several features of morphology, in addition to juvenile plumage and feeding habits, indicate links with Circaetus.

Affinities uncertain. Recent molecular study suggested that it may be sister to Circaetus#R.

In the past, often subsumed within Aegypius.

In the past, often subsumed within Aegypius.

Sometimes combined with Neophron, but differs markedly in morphology and e.g. nesting behaviour.

Sequence of species in following list is based on that suggested in recent phylogenetic and phylogeographical study#R.

Sometimes considered to incorporate genera Sarcogyps, Trigonoceps and Torgos.

Formerly subsumed within Aegypius.

Affinities uncertain; formerly placed in Falconidae. Recent DNA study indicated that this genus is closest to Harpyopsis, Morphnus and Harpia#R. Name often spelt Machaerhamphus, but present spelling has priority.

Traditionally considered related to Harpia and Pithecophaga. Recent phylogenetic study found that present genus, Morphnus and Harpia formed a well-defined clade, but were not close to Pithecophaga#R. Another recent phylogenetic study using DNA sequences#R reconfirmed relationship with Morphnus and Harpia and suggested that all three might be lumped into a single genus, perhaps also including even Macheiramphus; the same study firmly rejected a proposed clade of species-poor endemic Australo-Papuan genera comprising the pernine Hamirostra, Lophoictinia and Henicopernis, the hawks Erythrotriorchis and Megatriorchis (both close to Accipiter), and present genus.

One recent phylogenetic study found that this genus, Harpyopsis and Harpia formed a well-defined clade#R. Another molecular study suggested that Morphnus was hardly separable from Harpia and that the two should perhaps be merged#R.

One recent phylogenetic study found that this genus, Harpyopsis and Morphnus formed a well-defined clade#R. Another molecular study suggested that it was so similar to Morphnus as to be hardly separable from it, and that the two should perhaps be merged#R.

Sometimes merged with Spizaetus (sensu lato), but skeletal anatomy recalls Harpia. In study of Spizaetus and its presumed close relatives, present genus suggested as being part of a clade of American and African hawk-eagles that included several members of Spizaetus (sensu lato), as well as some species traditionally placed in Lophaetus, Aquila and Hieraaetus#R.

Asian genus previously included within Spizaetus, but recent studies support its recognition as separate from American taxa#R#R.

Molecular studies indicate that this taxon occupies a phylogenetic position isolated from other hawk-eagles#R#R.

One recent phylogeny considered present genus to be sister to a clade formed by Lophaetus, Aquila and Hieraaetus#R.

Following several independent phylogenetic studies#R#R#R, former monotypic genera Oroaetus and Spizastur now incorporated in this genus, and Asian hawk-eagles, previously placed in Spizaetus, are not close to latter and are transferred to resurrected genus Nisaetus#R.

Affinities uncertain. Some molecular studies indicate that this genus is member of a clade that includes also Afrotropical Lophaetus and the Eurasian spotted eagles now placed in Clanga (see below)#R; other molecular studies, however, suggest that it is a rather distantly related sister of Asian Nisaetus#R. Further research required.

Recent molecular study indicated that this monotypic genus is sister to Clanga#R. Has previously been thought to be closest to Spizaetus (sensu lato).

Previously included within Aquila, but recent phylogenetic study found it to fall outside that clade, as sister to Lophaetus or perhaps even congeneric#R. Recently proposed Aquiloides is a junior synonym#R.

Several recent phylogenetic studies have led to extensive reorganization of this genus, most notably in removal of species now placed in Clanga, and in redefining of limits with Hieraaetus (which see)#R#R#R#R.

Some systematists favour merging this genus into Aquila#R. Recent molecular study, however, indicated that two distinct lineages are involved, the smaller species forming a separate clade; the five species currently placed in this genus are closely related#R. Composition of these two genera has recently been reassessed and modified on the basis of several phylogenetic studies#R#R#R#R.

Recent molecular appraisal of all buteonine genera indicated that Kaupifalco is sister to the goshawks in genera Melierax, Micronisus and Urotriorchis#R. Already linked with Melierax on basis of plumage, behaviour and egg-yolk colour.

Sometimes treated as incorporating Micronisus. The two may be closely related to Urotriorchis, with Kaupifalco as sister to the three#R.

In the past, thought perhaps closely related to Accipiter. Recent study, however, indicates that it is closest to Melierax, and sometimes subsumed within latter; these two genera may be closely related to Urotriorchis, with Kaupifalco as sister to the three#R.

Distinctive, with no very close allies. May be closest to Circus, Accipiter and perhaps Buteo#R. Some similarities to Aviceda. Formerly thought to belong in same subgroup as Elanus.

Recent molecular analyses indicate that this genus may be embedded in Accipiter#R#R.

Traditionally linked with Accipiter, and has sometimes been merged into it; a close relationship of these genera was strongly supported by a recent phylogenetic study using DNA sequences#R, which also placed Megatriorchis with Accipiter but in a different clade from present genus; the same study firmly rejected a proposed old endemic Australasian clade consisting of Erythrotriorchis and Megatriorchis with four other species-poor Australo-Papuan genera, namely Hamirostra, Lophoictinia, Henicopernis and Harpyopsis.

Traditionally linked with Accipiter, and has sometimes been merged into it; a close relationship of these genera was strongly supported by a recent phylogenetic study using DNA sequences#R, which also placed Erythrotriorchis with Accipiter but in a different clade from present genus (see also Erythrotriorchis, above).

Traditionally placed close to Accipiter, or even merged therein; recent molecular appraisal indicates that Urotriorchis forms a clade with Melierax and Micronisus, with Kaupifalco as sister to these three#R.

Alternative spelling Ichthyophaga often used, but present spelling selected by First Reviser#R.

Subsumed within Milvus by some authors, but differs in plumage, voice and behaviour.

Traditionally considered to be allied to Buteogallus and Parabuteo, but morphological evidence#R suggests closer relationship to a group of largely Old World genera (Milvus, Haliastur, Icthyophaga, Haliaeetus) than to the New World genera; this relationship supported by recent genetic studies#R#R.

Probably allied to Neotropical “sub-buteonines”, rather than Afrotropical Polyboroides, but found in recent study to be convergent with latter#R. Name Ischnosceles used in past, but, although described a few years earlier than Geranospiza, it is best regarded as a forgotten name.

No clear affinities to other genera.

Highly specialized, with no clear taxonomic affinities to other genera. Recent studies suggested that it may be sister to Geranospiza, but with poor support#R; one study indicated that it belonged to a clade also containing Busarellus#R.

Subsumed within Rostrhamus by most recent authors, but hamatus shows marked differences in proportions and shape (especially in flight), style of flight, calls, display and habitat.

Normally included within Buteo (which see), or alternatively in Asturina, but recently resurrected for magnirostris, which was found to be basal to all buteos#R#R#R.

Genetic data#R#R#R#R suggest that Parabuteo may be sister to Buteo and that it lies outside main group of true buteos.

Recently erected#R in order to recognize plumage combination unique among buteonine hawks: overall dark grey plumage, black tail with single white medial band, and white underwings-coverts.

Incorporates Harpyhaliaetus, Heterospizias and Urubitinga.

Name Tachytriorchis sometimes used, but Geranoaetus has priority#R.

Previously subsumed within Leucopternis, but recent analysis indicates that it merits recognition for the three species listed below#R. Both genera, however, sometimes merged into Buteo.

Has sometimes been incorporated within Buteo. Recent phylogenetic analyses suggested that only the three species listed below belong in Leucopternis#R#R.

Previously incorporated several other genera, including e.g. Rupornis, Morphnarchus, Pseudastur, as well as Leucopternis and Buteogallus. Present arrangement based largely on recent molecular studies#R#R#R, but further modification likely.

Often merged into Colius.

No known close relatives. In the past, considered to belong within Coraciidae, where typically awarded its own separate subfamily, or placed in its own family close to Coraciidae and Brachypteraciidae. Recent molecular studies suggest that Leptosomus is sister to a large clade which contains Coraciiformes, Trogoniformes and Piciformes, but within which it is distant from Coraciidae and Brachypteraciidae#R; or that it may be sister to Strigidae, Falconidae or Trogoniformes#R#R#R.

Incorporates monospecific genus Heterotrogon.

Name sometimes erroneously emended to Hapalarpactes. Previously subsumed within Harpactes; both species differ, however, in plumage coloration and in having a red bill, as well as being the only Asian trogons with metallic tones in plumage, and at least one (A. mackloti) has song quite unlike that of any other trogonid; recent molecular study indicated that Apalharpactes is a relictual lineage only distantly related to other trogons#R.

Includes Duvaucelius.

Sometimes incorporates Euptilotis.

Sometimes merged into Pharomachrus. Probably most closely related to Priotelus and Temnotrogon.

Often included within Priotelus, but differs significantly in bill pattern, plumage coloration and some morphological features.

Incorporates Chrysotrogon.

Usually merged into Tockus, within which often treated as a subgenus. Incorporates Rhynchaceros.

Often subsumed within Aceros, but closer to Horizocerus (formerly Tropicranus)#R.

Replacement for Tropicranus, having date priority over latter#R. Often merged into Tockus, or occasionally Berenicornis, but appears to be sufficiently distinct in behaviour and voice, as well as in some aspects of morphology, to merit separate treatment.

Previously subsumed within Ceratogymna, but genetic evidence supports separate generic treatment for the following smaller species.

Often subsumed within Buceros, but differs clearly in morphology, and in unique hooting call ending in loud cackle. Recent molecular study found Rhinoplax to be sister to Buceros#R, but it is retained owing to its extreme vocal and morphological divergence#R.

Includes Ptilolaemus.

Previously synonymized with African Tockus, but differs in feeding behaviour at nest. In recent comprehensive molecular phylogeny#R, mtDNA tree indicated that two taxa presently placed in Ocyceros (griseus, gingalensis) form a clade with Anthracoceros malayanus, with O. birostris divergent; as birostris is type species of Ocyceros, griseus and gingalensis would have to be moved to Anthracoceros or placed with malayanus in separate genus. Here, genera Ocyceros and Anthracoceros are maintained in traditional format, but further molecular study is needed in order to resolve their evolutionary relationships.

See under genus Ocyceros (above).

Has sometimes been considered to incorporate Rhyticeros. Authorship previously attributed to J. E. Gray#R.

Until recently included within Rhyticeros or Aceros.

Sometimes merged into Aceros.

Often merged into Phoeniculus.

Recent molecular study found this genus to be sister to all other bee-eaters#R.

Incorporates Melittophagus, Bombylonax, Aerops, Dicrocercus and Meropiscus.

Previously subsumed within Brachypteracias, but differs genetically#R, as well as in morphology and behaviour. Sister to Uratelornis#R.

Sister to Geobiastes#R.

Appears to be closest to momotid genera Hylomanes and Baryphthengus, all perhaps having a common ancestor#R#R #R.

Appears to be close to Baryphthengus and also to tody genus Todus, all perhaps having a common ancestor#R#R #R.

Appears to be close to Hylomanes and to tody genus Todus, all perhaps having a common ancestor#R#R #R.

Sometimes merged into Ceyx or Corythornis; incorporates Myioceyx. Relationships to other kingfisher clades uncertain#R.

Sometimes subsumed within Ceryle, but both phylogenetic analysis#R and osteological evidence#R support recognition of separate genera.

Distinctive, with no close relatives; some authors have placed some or all members of Megaceryle in present genus, but both phylogenetic data#R and osteological evidence#R support recognition of separate genera.

Has been thought perhaps an early offshoot of Dacelo lineage, with some resemblance to Tanysiptera.

Sometimes merged into Halcyon; in the past, genus name given as Ramphalcyon, but Pelargopsis has priority.

Includes Entomothera and Chelicutia.

Sometimes subsumed within Halcyon.

Sometimes merged into Halcyon; incorporates Dacelalcyon and Monachalcyon.

Sometimes merged into Halcyon, or occasionally even into Todiramphus.

Often merged into Halcyon.

Distinctive, with no close relatives.

Incorporates Uralcyon.

Includes Capricia and Sauromarptis, and sometimes Clytoceyx.

Very close to Dacelo and sometimes subsumed within it#R. Possibly related also to Melidora.

Close to Brachygalba, particularly B. lugubris, but segregated by foot morphology, elongated head feathers and gregarious behaviour.

Includes Urogalba.

Formerly considered sufficiently distinct to be placed in monotypic subfamily Jacameropinae, but this no longer considered warranted.

In the past was sometimes synonymized with Bucco.

Usually merged into Bucco. Generic name previously listed as Argicus, but Cyphos has priority (and is not excluded by homonymy, as previously thought)#R.

Usually merged into Bucco.

Genetic data indicate that Ramphastos is basal to all other genera in this family#R#R.

Molecular analyses suggest that this genus is sister to Andigena and Selenidera#R#R.

Several studies found this genus and Selenidera to be sister-genera#R#R#R, with Aulacorhynchus sister to the two#R#R.

Several studies found this genus and Andigena to be sister-genera#R#R#R, with Aulacorhynchus sister to the two#R#R.

Incorporates Baillonius and Beauharnaisius.

Relationships unclear. Has been considered close to African Gymnobucco on basis of plumage, voice and colonial nesting, but genetic evidence indicates that these similarites are convergent, and that the two genera are not closely related#R. Original spelling has often been erroneously emended to Calorhamphus.

Replaces Megalaima; recent study found Psilopogon to be nested within Megalaima#R and former has priority. Incorporates Xantholaema and Mesobucco.

Genetic data place this as basal to all other African barbets#R. Previous studies suggested it was: basal to all barbets, on morphological grounds#R; or, using cytochrome b, basal to New World Capitonidae and Ramphastidae#R.

Has been thought to be related both to Pogoniulus and to Tricholaema; larger than former, similar in size to latter but lacks bill “teeth”, and vocally distinct from both; genetic data suggest not closely related to either#R.

Very similar to Stactolaema, but some minor differences in morphology, plumage and some vocalizations.

Has been considered close to Asian Caloramphus on basis of plumage, voice and colonial nesting, but genetic evidence indicates that these similarites are convergent, and that the two genera are not closely related#R.

Includes Smilorhis.

Includes Viridibucco.

Has commonly been included within Lybius, but such treatment renders latter genus paraphyletic#R.

Sometimes included within Trachyphonus; genetic data support its placement there#R, although plumage, behaviour and vocalizations suggest it is distinct#R.