Geranoaetus

Abstract: Karyotypic descriptions are given of 16 species of Accipitridae new to cytology, viz. Accipiter novaehollandiae, Aegypius monachus, Aquila rapax, Circaetus gallicus, Circus aeruginosus, C. cyaneus, C. pygargus, Geranoaetus melanoleucos, Gyps bengalensis, G. rueppellii, Haliaeetus leucogaster, H. leucorhyphus, Lophoaetus occipitalis, Necrosyrtes monachus, Stephanoaetus and Torgos tracheliotus. For reasons of comparison the karyotypes are included of 5 species that have been previously studied. viz. Gypaetus barbatus, Haliaeetus albicilla, H. leucocephalus, H. vocifer and Pernis apivorus. All these species share the typical characteristics of the accipitrid karyotype, a moderate diploid number (66–72), the absence of large macrochromosomes, the presence of only 6–12 microchromosomes and a high number of mediumsized to small macrochromosomes. Differences exist in the numbers of biarmed and acrocentric autosomes and in the size and shape of a pair of typical satellited marker chromosomes. The karyological relationships in the Accipitridae are briefly discussed. On the basis of the morphology of the pair of satellited chromosomes (acrocentrics, subtelocentrics or microchromosomes) and the numbers of acrocentric elements nine possible phylogenies are constructed. When compared to conventional phylogenetic trees for the Accipitridae, the following points are remarkable in all possible karyological phylogenies: (1) the position of Pithecophaga is uncertain, it either represents an independent ancient lineage or is related to the Old World vultures; (2) Gypaetus probably is not related to the Old World vultures, it rather evolved from an ancester in common with the booted eagles; (3) genera like Buteo, Geranoaetus and Accipiter may have evolved independently from the booted eagles; and (4) the kites probably do not constitute a natural group.

Abstract: Geranoaetus polyosoma (Quoy & Gaimard, 1824) is a diurnal raptor widely distributed in South America. Although the trophic ecology of this bird has been more studied in the southern extreme of its range, little information is available on its dietary response to prey supply in desert environments. In the present study, we report on the trophic ecology of G. polyosoma in a sub-urban desert zone in northern Chile, with the following objectives: (1) to quantitatively describe its diet and (2) to determine its dietary selectivity in response to prey supply in the study area. The diet of G. polyosoma consisted mainly of rodents (97.2%). A greater preference (p 19.5 g): two native rodent species, Phyllotis xanthopygus (Waterhouse, 1837) and Eligmodontia puerulus (Philippi, 1896); and two introduced rodent species: Rattus rattus (Linnaeus, 1769) and R. norvegicus (Berkenhout, 1769).

Abstract: The generic name Geranoaetus Kaup, 1844 (type species: Falco aguia Temminck = Spizaetus melanoleucus Vieillot) generally has been applied only to its type species, G. melanoleucus , although inclusion of fossil species in the genus has been suggested (Wetmore 1933; Amadon 1963). Although Geranoaetus is still recognized by some authors (e.g., Thiollay 1994; Remsen et al. 2010), others consider it a junior synonym of the genus Buteo Lacepede, 1799, because of similarities to some species in that genus (e.g., Wetmore 1933; Hellmayr & Conover 1949; Clark 2006). Recent studies of the molecular phylogenetics of buteonine hawks (Riesing et al. 2003; Lerner et al. 2008; Amaral et al. 2006, 2009) unanimously agree on the lack of monophyly of three buteonine genera, namely Buteo , Leucopternis Kaup, 1847 and Buteogallus Lesson, 1830, as currently recognized (Remsen et al. 2010).

Abstract: We report late Quaternary fossils of the hind limb (tibiotarsus, tarsometatarsus, hallux, pedal phalanges) of an extinct species of eagle (Accipitridae) from Hispaniola (Haiti, Dominican Republic). We are unable to refer these 24 fossils with confidence to any Accipitrid genus, living or extinct. Among living genera, the Hispaniolan fossils are most similar in nonquantitative characters to leg elements in Geranoaetus Kaup 1844, as represented in our comparisons by the South American species Black-chested Buzzard-Eagle (G. melanoleucus Vieillot 1819). Although it may be that Geranoaetus eventually will be found to accommodate the Hispaniolan eagle and perhaps other large, extinct species of West Indian eagles (from Cuba and Bahamas), the fossil material available at this time is inadequate. Generic assignment is complicated further by uncertain generic limits among surviving New World buteonine/buteogalline hawks and eagles, which themselves also are not well represented in scientific collections. Measures of the tibiotarsus suggest the Hispaniolan eagle was 15–30% larger than the extant Golden Eagle (Aquila chrysaetos). It is likely that the large Hispaniolan eagle went extinct along with, and potentially as a consequence of, the extinction of most endemic species of large- and medium-sized mammals (primates, rodents, and sloths) that once served as prey.