Larvae of many phyllodocidan annelids are planktotrophic, but the feeding mechanisms of larvae in this diverse clade are poorly known. Many larvae belonging to one large clade of phyllodocidans, Aphroditiformia, bear a bundle of long cilia attached to the left side of the prototroch, the oral brush, which they use in feeding. In 1936, D.P. Wilson observed that trochophore larvae of Nephtys hombergi, a member of the phyllodocidan family Nephtyidae, bore a strikingly similar bundle of long cilia on the left side of the body. Since Wilson's observation, numerous descriptions of nephtyid larvae have been published, but none remark on the presence of an oral brush. Here I show that metatrochophore I and II larvae of Micronephtys cornuta bear an oral brush, but that it is lost in the transition to the nectochaete stage, during which the larval mouth and foregut are also being remodeled to function in benthic feeding by juveniles. That an oral brush is clearly present in at least some larval stages of two genera suggests that oral brushes may be widespread in the feeding larvae of nephtyids, but have simply been overlooked for more than 80 years. Additional work is needed to make inferences on the evolutionary history of the oral brush in phyllodocidan annelids, and to distinguish among several hypotheses on the function of this peculiar group of cilia in larval feeding.

中文翻译：

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纤毛角鲨（Annelida，Nephtyidae）喂养幼虫的纤毛口腔刷

许多叶螨类幼虫的幼虫都是浮游性的，但在这种多样的进化枝中幼虫的摄食机制却鲜为人知。许多幼虫属于一个大的叶蝉科动物，壮阳药，带有一束长纤毛，附着在原生动物的左侧（口腔刷）上，用于喂养。1936年，DP威尔逊（DP Wilson）观察到，叶蝉科Nephtyidae的成员Nephtys hombergi的次生幼虫在其左侧长着一束非常长的纤毛。自从Wilson的观察以来，已经发表了许多关于夜蛾幼虫的描述，但是都没有提及存在口腔刷。在这里，我显示了微nephtys cornuta的metatrochophore I和II幼虫带有口腔刷，但在向油桃阶段过渡时会丢失，在此期间，幼虫的嘴巴和前肠也被重塑，以在幼鱼的底栖动物饲养中发挥作用。至少在两个属的某些幼虫阶段中明显存在口腔刷，这表明口腔刷可能广泛存在于肾上腺的食性幼虫中，但是已经被忽略了80多年。还需要进行额外的工作来推断出口腔刷毛虫在口腔刷毛中的进化史，并区分几种关于这种独特的纤毛在幼虫摄食中的功能的假说。