TY - JOUR T1 - Diversification of acorn worms (Hemichordata, Enteropneusta) revealed in the deep sea. JF - Proceedings. Biological sciences / The Royal Society Y1 - 2012 DO - 10.1098/rspb.2011.1916 A1 - Osborn, Karen J A1 - Kuhnz, Linda A A1 - Priede, Imants G A1 - Urata, Makoto A1 - Gebruk, Andrey V A1 - Holland, Nicholas D SP - 1646 EP - 54 AB - Enteropneusts (phylum Hemichordata), although studied extensively because of their close relationship to chordates, have long been considered shallow-water, burrowing animals. The present paper more than doubles the number of enteropneust species recorded in the deep sea based on high-resolution imaging and sampling with remotely operated vehicles. We provide direct evidence that some enteropneusts are highly mobile-using changes in posture and currents to drift between feeding sites-and are prominent members of deep, epibenthic communities. In addition, we provide ecological information for each species. We also show that despite their great morphological diversity, most deep-living enteropneusts form a single clade (the rediagnosed family Torquaratoridae) on the basis of rDNA sequences and morphology of the proboscis skeleton and stomochord. The phylogenetic position of the torquaratorids indicates that the group, after evolving from near-shore ancestors, radiated extensively in the deep sea. VL - 279 ER -