Abstract
The Anseriformes is a well-known and widely distributed bird order, with more than 150 species in the world. This paper aims to revise the classification, determine the phylogenetic relationships and diversification patterns in Anseriformes by exploring the Cyt b, ND2, COI genes and the complete mitochondrial genomes (mito-genomes). Molecular phylogeny and genetic distance analyses suggest that the Dendrocygna species should be considered as an independent family, Dendrocygnidae, rather than a member of Anatidae. Molecular timescale analyses suggests that the ancestral diversification occurred during the Early Eocene Climatic Optimum (58 ~ 50 Ma). Furthermore, diversification analyses showed that, after a long period of constant diversification, the median initial speciation rate was accelerated three times, and finally increased to approximately 0.3 sp/My. In the present study, both molecular phylogeny and diversification analyses results support that Anseriformes birds underwent rapid and recent diversification in their evolutionary history, especially in modern ducks, which show extreme diversification during the Plio-Pleistocene (~ 5.3 Ma). Therefore, our study support that the Plio-Pleistocene climate fluctuations are likely to have played a significant role in promoting the recent diversification for Anseriformes.
Highlights
Adaptive radiation, the evolution of ecological and phenotypic diversity within a rapidly multiplying lineage, has fascinated biologists over the past century [1,2,3]
We suggest that the warmer climatic conditions during the Eocene Climatic Optimum (EECO) induced this ancestral diversification in Anseriformes, which reinforced their habit of exploiting different ecological niches
Based on the results of molecular phylogeny and genetic distances, we revised the classification of the Dendrocygna, Amazonetta, Speculanas, Tachyeres, Lophonetta and Alopochen
Summary
The evolution of ecological and phenotypic diversity within a rapidly multiplying lineage, has fascinated biologists over the past century [1,2,3]. Rapid and recent diversification patterns in Anseriformes birds can be used to detect changes in speciation through time [7]. This information can be used to detect speciation bursts and identify historical factors underlying the emergence of ecological and phenotypic divergence within a lineage [8]. Rapid radiation and burst speciation events have been examined in several taxonomic groups, such as fishes [8, 9] and mammalian [4, 10,11,12]. An ancient, rapid radiation event was observed in the evolutionary history of the Galliformes species [13]. Birds show relatively high levels of hybridization [15, 16], such as the high incidence of hybridization in Anseriformes birds (e.g. ducks, geese and swans) [17, 18]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
