Morphological Variation in the Sacred Ibis Threskironis aethiopicus Superspecies Complex

Abstract

Skins of ibises attributed to forms within the Sacred Ibis Threskiornis aethiopicus complex, sensu Holyoak (1970) were examined for variation in 12 morphological characters and measured for four other characters. This investigation revealed significant variation within these characters and that several forms of the ibis showed distinct and diagnostic suites of characters. The study concludes that three species should be recognised viz. T. aethiopicus, T. melanocephalus and T. moluccus comprising a superspecies complex. It was also concluded that T. strictipennis is synonymous with T. moluccus and that T. pygmaeus is a distinct and dwarfed form of T. moluccus. The forms T. abbotti and T. bernieri are very similar to one another and are most closely related to T. aethiopicus. T. melanocephalus is distinct from other members of the complex.