Information about Accipitridae

Accipitridae
Swallow-tailed Kite Elanoides forficatus Swallow-tailed Kite Elanoides forficatus
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Aves Order: Falconiformes Family: Accipitridae Vieillot, 1816
Subfamilies
Accipitrinae Aegypiinae Buteoninae Circaetinae Circinae Elaninae Milvinae Perninae but see text

The Accipitridae is one of the two major families within the order Falconiformes (the diurnal birds of prey). Many well-known birds like hawks, eagles, kites, harriers and Old World vultures are included in this group. Most, but not all, other raptors belong to the Falconidae, or falcon family, which is often considered a distinct order (e.g. in the Sibley-Ahlquist taxonomy), in which case the present group would belong to the order Accipitriformes.

The Osprey is usually placed in a separate family (Pandionidae), as is the Secretary bird (Sagittariidae), and the New World vultures are also usually now regarded as a separate family or order. Karyotype data^[1] indicated that the accipitrids hitherto analyzed are indeed a distinct monophyletic group, but whether this group should be considered a family of the Falconiformes or one or several order(s) on their own is a matter of taste.

Systematics

The accipitrids have been variously divided into some 5-10 subfamilies. Most of them share a very similar morphology, but many of these groups contain taxa which are more aberrant. These are placed in their respective position more for lack of better evidence than anything else. It is thus not very surprising that the phylogenetic layout of the accipitrids has always been a matter of dispute.

As mentioned above, the accipitrids are recognizable by a peculiar rearrangement of their chromosomes. Apart from this, morphology and mtDNA cytochrome b sequence data gives a confusing picture of these birds' interrelationships. What can be said is that the hawks, kites, eagles and Old World vultures as presently assigned in all likelihood do not form monophyletic groups:

According to the molecular data, the Buteoninae are most likely poly- or paraphyletic, with the true eagles, the sea eagles, and the buteonine hawks apparently representing distinct lineages. These appear to form a group with the Milvinae, Accipitrinae and Circinae but the exact relationships between the lineages are not at all robustly resolvable with the present data. The Perninae and possibly the Elaninae are older lineages, as are the Old World vultures. The latter are fairly likely also poly- or paraphyletic, with some aberrant species like the Bearded and Egyptian Vultures standing apart from the naked-necked "true" vultures.^[2]

• Subfamily Elaninae - elanid kites (8 species)
• Genus Elanus
• Genus Chelictinia
• Genus Machaerhamphus
• Genus Gampsonyx
• Genus Elanoides
• Subfamily Perninae - honey-buzzards (c.14 species)
• Genus Aviceda
• Genus Henicopernis
• Genus Pernis
• Genus Leptodon
• Genus Chondrohierax
• Subfamily Aegypiinae - Old World vultures (c.15 species, probably poly- or paraphyletic)
• Genus Sarcogyps
• Genus Aegypius
• Genus Torgos
• Genus Trigonoceps
• Genus Gyps
• Genus Neophron
• Genus Necrosyrtes
• Genus Gypohierax
• Genus Gypaetus
• Subfamily Buteoninae - buteonine hawks, true eagles and sea-eagles (c.100 living species, probably poly- or paraphyletic)
• Genus Geranoaetus
• Genus Buteo
• Genus Parabuteo
• Genus Buteogallus
• Genus Busarellus
• Genus Leucopternis
• Genus Kaupifalco
• Genus Butastur
• Genus Harpyhaliaetus
• Genus Morphnus
• Genus Harpia
• Genus Pithecophaga
• Genus Harpyopsis
• Genus Oroaetus
• Genus Spizastur
• Genus Spizaetus
• Genus Lophaetus (possibly junior synonym of Ictinaetus)
• Genus Stephanoaetus
• Genus Polemaetus
• Genus Hieraaetus
• Genus Aquila (paraphyletic)
• Genus Ictinaetus
• Genus Haliaeetus
• Genus Ichthyophaga
• Subfamily Circinae - harriers (some 16 living species)
• Genus Circus
• Genus Polyboroides
• Genus Geranospiza
• Subfamily Milvinae - milvine kites (some 14 species)
• Genus Harpagus
• Genus Ictinia
• Genus Rostrhamus
• Genus Helicolestes - formerly included in Rostrhamus
• Genus Haliastur
• Genus Milvus
• Genus Lophoictinia
• Genus Hamirostra
• Subfamily Accipitrinae - goshawks, sparrowhawks, and relatives (c.55 living species)
• Genus Accipiter
• Genus Micronisus
• Genus Melierax
• Genus Urotriorchis
• Genus Erythrotriorchis
• Genus Megatriorchis
• Subfamily Circaetinae - snake-eagles (about one dozen species)
• Genus Terathopius
• Genus Circaetus
• Genus Spilornis
• Genus Eutriorchis

Fossil record

Like with most other birds of prey, the fossil record of this group is fairly decent from the latter Eocene onwards (c.35 mya), with modern genera being well documented since the Early Oligocene, or around 30 mya.

• Milvoides (Late Eocene of England)
• Aquilavus (Late Eocene/Early Oligocene - Early Miocene of France)
• Palaeocircus (Late Eocene/Early Oligocene of France)
• Palaeastur (Agate Fossil Beds Early Miocene of Sioux County, USA)
• Pengana (Early Miocene of Riversleigh, Australia)
• Promilio (Agate Fossil Beds Early Miocene of Sioux County, USA)
• Proictinia (Early - Late Miocene/Early Pliocene of C and SE USA)
• Neophrontops (Early/Middle Miocene - Late Pleistocene) - formerly in Neophron
• Palaeoborus (Miocene)
• Thegornis (Miocene of Argentina)
• Garganoaetus (Early Pliocene of Gargano Peninsula, Italy)
• Amplibuteo (Late Pliocene of Peru - Late Pleistocene of S North America and Cuba) - may belong to extant genus Harpyhaliaetus
• Neogyps
• Palaeohierax - includes "Aquila" gervaisii
• Wetmoregyps - formerly Morphnus daggetti

Accipitrids are known since Early Eocene times, or about from 50 mya onwards, in fact, but these early remains are too fragmentary and/or basal to properly assign a place in the phylogeny. Likewise, as remarked above, molecular methods are of limited value in determining evolutionary relationships of and within the accipitrids. What can be determined is that in all probability, the group originated on either side of the Atlantic, which during that time was only 60-80% its present width. On the other hand, as evidenced by fossils like Pengana, some 25 mya, accipitrids in all likelihood rapidly acquired a global distribution - initially probably even extending to Antarctica.

• Accipitridae gen. et sp. indet. AMNH 7434 (Huerfano Early Eocene of Huerfano County, USA)^[3]
• Accipitridae gen. et sp. indet. (Borgloon Early Oligocene of Hoogbutsel, Belgium)^[4]
• "Aquila" danana (Snake Creek Late Miocene/Early Pliocene of Loup Fork, USA) - formerly also Geranoaetus or Buteo
• Accipitridae gen. et sp. indet. (Late Pliocene/Early Pleistocene of Ibiza, Mediterranean) - Buteo?^[5]
• Accipitridae gen. et sp. indet. (Egypt)

Footnotes

References

• Alcover, Josep Antoni (1989): Les Aus fòssils de la Cova de Ca Na Reia ["The fossil birds of Ca Na Reia cave"]. Endins 14-15: 95-100. [Catalan with English abstract]
• Amaral, Karina Felipe & Jorge, Wilham (2003): The chromosomes of the Order Falconiformes: a review. rarajuba 11(1): 65-73. PDF fulltext
• Cracraft, Joel (1969): Notes on fossil hawks (Accipitridae). Auk 86(2): 353-354. PDF fulltext
• de Boer, L.E.M. (1975): Karyological heterogeneity in the Falconiformes (Aves). Cellular and Molecular Life Sciences 31(10): 1138-1139. doi:10.1007/BF02326755 (HTML abstract)
• Federico, Concetta; Cantarella, Catia Daniela; Scavo, Cinzia; Saccone, Salvatore; Bed'Hom, Bertrand & Bernardi, Giorgio (2005): Avian genomes: different karyotypes but a similar distribution of the GC-richest chromosome regions at interphase. Chromosome Research 13(8): 785-793. doi:10.1007/s10577-005-1012-7 (HTML abstract)
• Smith, Richard (2003): Les vertébrés terrestres de l'Oligocène inférieur de Belgique (Formation de Borgloon, MP 21): inventaire et interprétation des données actuelles. [Early Oligocene terrestrial vertebrates from Belgium (Borgloon Formation, MP 21): catalog and interpretation of recent data.] Coloquios de Paleontología E1: 647-657. [French with English abstract] PDF fulltext
• Wink, M.; Heidrich, P. & Fentzloff, C. (1996): A mtDNA phylogeny of sea eagles (genus Haliaeetus) based on nucleotide sequences of the cytochrome b gene. Biochemical Systematics and Ecology 24: 783-791. doi:10.1016/S0305-1978(96)00049-X PDF fulltext

External links

• American Museum of Natural History: Accipitridae AMNH 7434 Specimen Data. Retrieved 2007-FEB-10.
• Internet Bird Collection: Accipitridae videos. Retrieved 2006-DEC-01.
• xeno-canto.org: Accipitridae sounds. Retrieved 2006-DEC-01.