Biodiv Sci ›› 2018, Vol. 26 ›› Issue (10): 1074-1082.DOI: 10.17520/biods.2018105

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Origin and evolution of earthworms belonging to the family Megascolecidae in China

Jibao Jiang1,2,3, Jiangping Qiu1,2,3,*()   

  1. 1 School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240
    2 Key Laboratory of Urban Agriculture, Ministry of Agriculture, Shanghai 200240
    3 Shanghai Urban Forest Research Station, State Forestry Administration, Shanghai 200240
  • Received:2018-04-10 Accepted:2018-10-02 Online:2018-10-20 Published:2019-01-06
  • Contact: Qiu Jiangping
  • About author:# Co-first authors

Abstract:

A total of 579 Megascolecidae species have been reported in China through 2017. Most belong to the genera Amynthas and Metaphire. The family’s rich diversity merits further investigation into its evolutionary history. The arc of research indicates that analysis based on taxonomical and molecular methods reveals the evolutionary history of the family Megascolecidae in China. This paper summarizes updated findings regarding origin, speciation and dispersal of Megascolecidae in China, and discusses the evolution of major familial characteristics (e. g. spermathecal pores, caeca). Several analyses suggest that the ancestors of Megascolecidae in China may have come from the Indo-China Peninsula. Speciation radiation likely occurred after the Cretaceous-Palaeogene mass extinction, and species richness increased rapidly during the Cenozoic period. Ancestral range reconstruction analysis shows that species-groups are polyphyletic and that evolutionary reversal often resulted in sharp evolution of caeca, so we suggest that the current taxonomic system of Megascolecidae, which is based on a few morphological characters, should be reconstructed. We also note that the specific mechanism of evolution in Megascolecidae has not been studied. Hence, future research to reveal the specific evolutionary mechanism of Megascolecidae earthworms requires more systematic sampling of this family, combined with morphological research, phylogeny construction and analysis of geographical patterns, geological history and environmental factors.

Key words: Megascolecidae, earthworm, origin, speciation, evolution of characteristics