Moonshine worms are a popular bait species used for fishing. The taxon was not detected during surveys of the macrobenthos conducted in Knysna in the 1940s and 1990s, and was first reported as a harvested bait species in the mid-2000s, suggesting that it appeared for the first time in the estuary in the last three decades. A previous molecular analysis identified the worms asDiopatra aciculata, a species first described from Australia. This study provides an updated detailed morphological description ofD. aciculatain South Africa to facilitate future identifications and also investigates the species' distribution and population size in the Knysna Estuary. Specimens were examined by scanning electron, stereo- and compound microscopes.Diopatra aciculatahas tubes that protrude from the sediment in sandy areas, often decorated with algae and shell fragments; a large body size, up to 600 mm long and 11.5 mm wide. It has 10–18 rings on ceratophores; 5–10 teeth on pectinate chaetae; uni- and bidentate pseudo-compound falcigers and dorsal cirri approximately as long as branchiae.Diopatra aciculatawas detected up to 12 km from the mouth of the Knysna Estuary with densities measured at 18 sampled sites. Statistical analysis retrieved high and low density groups that were significantly different from one another (Kruskal-Wallis H(14, 800)= 376.55;P= 0.01), but distribution of high density sites was patchy. We estimate that the population comprises 20–24 million individuals. Given the size of individual worms and the population estimate, this species can be expected to have significant ecological impacts in the estuary.

中文翻译：

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南非克尼斯纳河口的月光虫 (Diopatra aciculata: Onuphidae, Annelida)；分类和分布

月光虫是一种流行的用于钓鱼的诱饵种类。在 1940 年代和 1990 年代在克尼斯纳进行的大型底栖动物调查中没有发现该分类单元，并在 2000 年代中期首次报道为捕捞的诱饵物种，这表明它在过去 30 年中首次出现在河口. 先前的分子分析将蠕虫确定为芍药，一种最早在澳大利亚被描述的物种。这项研究提供了更新的详细形态描述D. aciculata在南非，以促进未来的鉴定，并调查克尼斯纳河口的物种分布和种群规模。通过扫描电子、立体显微镜和复合显微镜检查样品。芍药在沙地的沉积物中有突出的管子，通常用藻类和贝壳碎片装饰；一个大的身体尺寸，长达 600 毫米和 11.5 毫米宽。角果上有 10-18 个环；栉毛纲上有 5-10 颗牙齿；单齿和双齿的假复合镰刀和背卷毛大约和鳃一样长。芍药在距克尼斯纳河口 12 公里处检测到，在 18 个采样点测量了密度。统计分析检索了彼此显着不同的高密度组和低密度组（Kruskal-Wallis H(14, 800)= 376.55；磷= 0.01），但高密度站点的分布不均匀。我们估计人口包括 20-2400 万人。鉴于个体蠕虫的大小和种群估计，预计该物种将对河口产生重大的生态影响。