The feather duster worm Schizobranchia insignis is an abundant marine annelid found subtidally and in the low intertidal of the northeastern Pacific Ocean. As in other sabellids, the anterior appendages, used for feeding and respiration, can be damaged by physical or biological means. Limited information is available on the regeneration of radioles leading us to study this process on a worm with radioles that dichotomously branch. First, we documented the occurrence of natural radiole damage in two populations of S. insignis found at environmentally distinct sites: a subtidal marina and an intertidal, rocky bench. All 21 worms collected from the exposed intertidal bench had branchial crown damage, whereas 15 of 22 worms (68%) sampled in the marina exhibited natural radiole damage. In the laboratory, we observed radiole regeneration on individuals of S. insignis from the marina by removing a single radiole. Radiole regrowth was a continuous process in which functionality was restored through radiole bifurcation, elongation, and the development of internal support structures. The regrowth of a single radiole of S. insignis took more than 35 days. However, in one of our studies, after 21 days, although not all individuals recovered, four of 12 worms (33%) had completed bifurcation. Pointed tips on the distal‐most branches signified the end of bifurcation. During recovery, individuals of S. insignis did not consistently regenerate the same number of branches observed prior to damage. In addition, a majority of the radiole elongation during recovery occurred after branching. The radiole regeneration in Eudistylia vancouveri, a closely related species found in the marina, was observed to compare regeneration in co‐occurring species. We found that the radiole regeneration in E. vancouveri was less complex because of the absence of branching. Since Schizobranchia is the only genus in which radioles are branched, our study of S. insignis provides a unique examination of natural radiole damage and regrowth.

中文翻译：

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鸡毛dust虫Schizobranchia insignis的自然放射性破坏和再生

鸡毛dust虫（Schizobranchia insignis）是一种丰富的海洋类网纹动物，在东北太平洋的潮间带低层潮间带精巧地发现。像在其他猿类中一样，用于进食和呼吸的前附肢可能会通过物理或生物手段受损。关于放射性核的再生的信息有限，因此我们需要研究一种具有分裂性的放射性核的蠕虫。首先，我们记录了两个S. insignis种群中自然放射性破坏的发生。在不同环境的地点发现：潮间带码头和潮间带岩石台阶。从潮间带裸露的长凳上收集的所有21种蠕虫均具有分支冠损伤，而在码头采样的22种蠕虫中有15种（68％）表现出天然的放射性破坏。在实验室中，我们观察到对个体radiole再生S.荚通过去除单个radiole从码头。放射性基团的再生是一个连续的过程，其中功能性通过放射性基团的分支，伸长和内部支持结构的发展得以恢复。的单个radiole的再生长S.荚花了超过35天的时间。然而，在我们的一项研究中，尽管不是所有的人都能康复，但在21天后，12个蠕虫中有4个（33％）完成了分叉。最远端分支上的尖头标志着分叉的结束。在恢复过程中，S。insignis的个体不能始终如一地再生出损伤之前观察到的相同数量的分支。此外，恢复过程中的大部分放射性伸长发生在分支后。观察到在滨海发现的紧密相关物种Eudistylia vancouveri的放射性再生，可以比较共生物种的再生。我们发现E. vancouveri的放射性再生较不复杂，因为没有分支。自精神分裂症以来是唯一的分支分支，在此，我们对S. insignis的研究提供了独特的自然放射性损伤和再生的方法。