EVOLUTION OF THE GENUS CHRYSOCOCCYX

• Published in: Ibis
• Main Author: Marchant, S.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1972
• Subjects: Antarc*; Antarctica
• Online Access: http://dx.doi.org/10.1111/j.1474-919x.1972.tb02604.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1474-919X.1972.tb02604.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1474-919X.1972.tb02604.x

Summary Modern geological ideas on ocean‐floor spreading are briefly reviewed. Pangea began to break up at the end of the Trias, but Africa, Antarctica and Australia remained together or close to each other till the end of the Cretaceous. The position of western New Guinea at the start of the Miocene could have been approximately where Arnhem Land is now, and at the start of the Pliocene somewhat north of the present‐day Aru Islands. Its size until the end of the Pliocene was much smaller than it is today. Friedmann's proposal for the evolutionary spread of Chrysococcyx therefore demands that the whole process occurred since about the start of the Pliocene. There may not have been enough time in these seven million years for the evolutionary dispersal of a genus of parasitic cuckoos halfway round the world. His proposal also regards C. osculans as an awkward throw‐back, and leaves a gap between species in New Guinea and southeastern Asia that is not bridged by intermediates. If a stock of cuckoos had been in Gondwanaland before it broke up, that stock could have given rise to the genus Cacomantis and the forerunners of C. osculans. The lineage of osculans would have quickly given rise to a lineage of glossy cuckoos that then divided into two branches. One could have penetrated Africa, south of where Madagascar then was, produced the species klaas, cupreus, caprius and flavigularis (an aberrant end‐product), and much later, after Madagascar had drifted south from India (having been separate from Africa since the Cretaceous), colonised Asia where maculatus and xanthorhynchus would have differentiated. The other line could have differentiated, perhaps more slowly, in Australia into basalts, lucidus, ruficollis and malayanut (minutillus). When Australia had drifted near enough to the Malay Archipelago and as New Guinea grew, ruficollis and minutillus could have moved forward to colonise the islands, where minutillus would have produced the many races oimalayanus and meyerii differentiated as an aberrant end‐product. ...