Molecular phylogeny of the hawk-eagles (genus Spizaetus)
A. Gamauf, J.O. Gjershaug, K. Kvaløy, N. Røv & E. Haring

Gamauf, A, J.O. Gjershaug, K. Kvaløy, N. Røv & E. Haring, Molecular phylogeny of the hawk-eagles(genus Spizaetus).
Zool. Med. Leiden 79-3 (21), 30-ix-2005, 179-180.— ISSN 0024-0672.
A. Gamauf & E. Haring, Museum of Natural History Vienna, Department of Vertebrate Zoology, Burgring
7, A-1014 Vienna, Austria. (e-mail: anita.gamauf@nhm-wien.ac.at, elisabeth.haring@nhm-wien.ac.at).
J.O. Gjershaug, K. Kvaløy & N. Røv, NINA, Norwegian Institute for Nature Research, Trondheim, Norway(e-mail: jan.o.gjershaug@nina.no).

The systematic relationships between genera of Accipitridae are only incompletely
known, especially between tropical taxa such as the Spizaetus hawk-eagles. This genus
includes, besides the genus Aquila, the greatest number of taxa within the “booted eagles”(eagles with feathered tarsi). Current taxonomy is based on morphology and plumage
patterns, but the cladogenesis of the currently distinguished 11 pantropical hawk-eagles
is still unclear. Common characters shared by all taxa are similar proportions and slenderappearance, especially short rounded wings, a long tail, and long feathered legs. Although variation in plumage coloration is high, some characters of adult plumage suchas barring on belly, tights and under tail coverts are found in all species. Moreover, thejuvenile plumage is strikingly different from that of adults. Most representatives of thisagile raptor genus are medium-sized but some species are small or rather large. Twospecies, S. ornatus (Daudin, 1800) and S. tyrannus (Wied, 1820) occur in Central and SouthAmerica, one, S. africanus (Cassin, 1865) inhabits West and Central Africa and eight species live in South-east Asia (S. nipalensis (Hodgson, 1836), S. alboniger (Blyth, 1845), S.
bartelsi Stresemann, 1924, S. nanus Wallace, 1868, S. lanceolatus Temminck & Schlegel,1844, S. philippensis Gould, 1863, S. pinskeri Preleuthner & Gamauf, 1998, S. cirrhatus(Gmelin, 1788).
To clarify the phylogeny within the genus Spizaetus and the relationships to othertropical “eagles” we sequenced two mitochondrial marker genes: sections of the control
region (CR) and the cytochrome b gene (cyt b). Samples of all valid species and subspecies of the genus Spizaetus were investigated, together with members of 12 other“booted” and “non-booted” Neotropical, Eurasian, Afrotropical and Australasiatic
genera (Oroaetus, Spizastur, Harpia, Morphnus, Lophaetus, Stephanoaetus, Hieraaetus, Aquila, Ictinaetus, Pithecophaga, Spilornis and Harpyopsis). The trees based on these two mitochondrial sequences show that the hawk eagles fall into three clearly distinct clades
and that this genus represents a paraphyletic group.
1.	The South American species S. ornatus forms a cluster with Oroaetus isidori (DesMurs, 1845) in both the CR and the cyt b tree. The other South American species S.
tyrannus belongs to this clade only in the CR tree. It should be emphasized that inboth markers the genetic distance between the two subspecies of S. ornatus (ornatus,vicarius Friedmann, 1935) is considerably high and lies in the range usually foundamong valid species.
2.	S. africanus belongs to another clade, which also includes various species of thegenera Hieraaetus (fasciatus (Vieillot, 1822), ayresii (Gurney, 1862), pennatus (Gmelin,180 Gamauf et al. Molecular phylogeny of hawk-eagles (genus Spizaetus). Zool. Med. Leiden 79 (2005)

1788)) and Aquila. However, low bootstrap values indicate that the relationships
among these taxa are not clearly resolved.
3.	The remaining species of the genus Spizaetus represent a third monophyletic group
comprising all taxa from South-east Asia. This clade is divided into two subgroups:(I) S. nipalensis (four subspecies), S. alboniger, S. bartelsi and S. nanus; (II) S. lanceolatus,
S. philippensis, S. pinskeri and S. cirrhatus (six subspecies). The position of S. nanus,
the smallest of the South-east Asian hawk-eagles, remains unclear. In the cyt b tree it
is found at the base of the two subgroups, whereas in the CR tree and in the combinedtree it belongs to the nipalensis-cluster.
The basal branches of our trees are not resolved unambiguously, especially in thecyt b tree branch support is rather low. Nevertheless, the data clearly show that the genus Spizaetus as defined so far represents a paraphyletic assemblage of more or lesssimilar species.
Based on the molecular data a taxonomic revision of the genus Spizaetus and someother taxa appears appropriate. Therefore, we suggest a new assignment of the taxa to
the following genera: Spizaetus (S. ornatus), Oroaetus (O. isidori), Ptenura (P. tyrannus) for
Central and South America, and Nisaetus (N. nipalensis, alboniger, bartelsi, nanus, lanceolatus, pinskeri, philippensis and cirrhatus) for the South-east to East Asian clade. The Africantaxon may be included into the genus Hieraaetus (H. africanus), but further studies haveto clarify first the relationships between Hieraaetus and Aquila.

Received: 1.iv.2004
Accepted: 1.iv.2005
Edited: R.W.R.J. Dekker & C. van Achterberg