Biogeography on the early distribution of cuckoos (Aves: Cuculiformes)

Abstract

Cuckoos are widely distributed, but are concentrated in the tropics, where they occupy a wide range of habitats. Both terrestrial and arboreal behaviors can be found in this group, but there is no consensus on as to whether these behaviors have arisen more than once. Moreover, the historical distribution of cuckoos is poorly understood. This paper presents a biogeographyc analysis of the early history of the distribution of these birds. The analysis was performed by using the Principle of Parsimony based on primary and secondary Brooks Parsimony Analysis (BPA). Despite some exceptions, the primary BPA corroborated events of vicariance (general pattern) in the early distribution of cuckoos and a terrestrial ancestor widespread in the Gondwana. The most parsimonious hypothesis suggests that the distribution of terrestrial cuckoos (basal group) is associated with the break-up of the Gondwana (Early to Mid Cretaceous), consistent with molecular data for other living birds. on the other hand, the fossil records indicate a more recent origin (Paleocene to Upper Tertiary) in the Laurasia. Nevertheless, to corroborate the fossil records, the early distribution of cuckoos would not be explained by parsimony, since additional steps on dispersion and local extinctions should be added. In addition, according to the secondary BPA, most exceptions can be explained by dispersion as the origin of the arboreal cuckoos (derived group) in South America, where they dispersed to other continents.