Adaptive radiation in extremophilic Dorvilleidae (Annelida): diversification of a single colonizer or multiple independent lineages?

Ecology and Evolution

Daniel J. Thornhill⁴  Torsten H. Struck⁴  Brigitte Ebbe³  Raymond W. Lee¹  Guillermo F. Mendoza²  Lisa A. Levin² 

[1] School of Biological Sciences, Washington State University, Pullman, Washington, USA;Center for Marine Biodiversity and Conservation, Integrative Oceanography Division, Scripps Institution of Oceanography, La Jolla, California, USA;Alfred-Wegener-Institute for Polar and Marine Research, Bremerhaven, Germany;Department of Biological Sciences, Auburn University, Auburn, Alabama, USA

关键词: Adaptive radiation;    cold seep;    deep sea;    Extremophile;    methane seep;    polychaete;   

DOI  :  10.1002/ece3.314

来源: Wiley

【 摘 要 】

Abstract

Metazoan inhabitants of extreme environments typically evolved from forms found in less extreme habitats. Understanding the prevalence with which animals move into and ultimately thrive in extreme environments is critical to elucidating how complex life adapts to extreme conditions. Methane seep sediments along the Oregon and California margins have low oxygen and very high hydrogen sulfide levels, rendering them inhospitable to many life forms. Nonetheless, several closely related lineages of dorvilleid annelids, including members of Ophryotrocha, Parougia, and Exallopus, thrive at these sites in association with bacterial mats and vesicomyid clam beds. These organisms are ideal for examining adaptive radiations in extreme environments. Did dorvilleid annelids invade these extreme environments once and then diversify? Alternatively, did multiple independent lineages adapt to seep conditions? To address these questions, we examined the evolutionary history of methane-seep dorvilleids using 16S and Cyt b genes in an ecological context. Our results indicate that dorvilleids invaded these extreme habitats at least four times, implying preadaptation to life at seeps. Additionally, we recovered considerably more dorvilleid diversity than is currently recognized. A total of 3 major clades (designated “ Ophryotrocha,” “Mixed Genera” and “ Parougia”) and 12 terminal lineages or species were encountered. Two of these lineages represented a known species, Parougia oregonensis, whereas the remaining 10 lineages were newly discovered species. Certain lineages exhibited affinity to geography, habitat, sediment depth, and/or diet, suggesting that dorvilleids at methane seeps radiated via specialization and resource partitioning.

【 授权许可】

CC BY-NC   
© 2012 The Authors. Ecology and Evolution published by Blackwell Publishing Ltd.

Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.