Who’s Who in the Sipuncula: Matching Larvae and Adults Using DNA

Abstract

Sipunculan pelagosphera larvae are represented by many distinct morphotypes that can be distinguished by size, color, ciliation pattern, texture of the body surface, and head morphology. Some larval types have been reared to adulthood in the lab, but for many of the morphotypes species identification has previously not been possible. We sequenced larvae of 14 different morphotypes for mitochondrial and nuclear markers and performed phylogenetic analyses including larval and adult sequences. The adult sequences covered 16 of the 17 currently recognized sipunculan genera and more than one-third of the 150 known sipunculan species. Analyses were conducted in two phases: the first phase involved the full data set of adult sequences and eight larval morphotypes; in the second phase, individual clades were analyzed separately on the basis of only one of the markers. Of the 14 larval morphotypes included in this study, 11 were identified to species, and 3 were identified only to genus level. We also reconciled the terminology for the larval types used in this study with that of previous studies.