Climate change and species introductions strongly changed macrobenthic community composition in the North Sea during past decades. To find out whether there was a similar change in meiofauna, I re-examined a semi-exposed sandy beach of the Island of Sylt that had been intensively studied between 1965 and 1975. These previous studies provide the baseline for temporal change. As before, the analysis of species composition focused on Platyhelminthes. Minor change in the physical properties of the beach during the past decades was compensated for by including two adjoining beaches, one slightly more sheltered and the other slightly more exposed. In due consideration of somewhat differing sample size, platyhelminth species richness barely changed over the past 50 years, and the numerical dominant species were still the same. However, roughly 10% of the 220 species found during this study were not previously recorded from the Island of Sylt. Thirteen are new to science though unpublished records indicate that half of them already occurred previously. Seven species described from elsewhere were recorded for the first time in the Sylt area. Based on their known geographical range, none of these can be unambiguously assigned an immigrant or introduced species. I conclude that (1) the platyhelminth fauna displayed high temporal stability over the past 50 years, and (2) though this beach is among the best studied in the world, a rate of 10% new species indicates our knowledge on the diverse meiofauna is still relatively poor. Seven new species of Platyhelminthes are described and three re-described: Coelogynopora multispina n. sp., Pseudostomum gracilis Westblad 1955, Nesite ptychoperoides n. gen. n. sp., Haplovejdovskya scilliensis Faubel & Warwick 2005, Haloplanella magnarhabdita n. sp., Haloplanella spiralis n. sp., Moevenbergia oculifagi n. sp., Coronhelmis inaequalis n. sp., Proxenetes inflatus den Hartog 1966, and Diascorhynchus falconis n. sp.

中文翻译：

---

沙滩上动植物物种组成的长期变化，并描述了7种新的侧柏

在过去的几十年中，气候变化和物种引进极大地改变了北海大型底栖动物群落的组成。为了找出动物群落中是否存在类似的变化，我重新检查了半裸的叙尔特岛沙滩，该海滩在1965年至1975年之间进行了深入研究。这些先前的研究为时间变化提供了基线。如前所述，物种组成的分析主要集中在侧柏。在过去的几十年中，海滩的物理性质的微小变化通过包括两个相邻的海滩得到了补偿，其中一个靠近海滩，另一个靠近海滩，另一个稍微暴露。由于样本量略有不同，在过去的50年中，蠕虫的物种丰富度几乎没有变化，而优势种的数量仍保持不变。然而，在这项研究中发现的220个物种中，大约有10％以前从未在叙尔特岛上记录过。尽管尚未出版的记录表明其中有一半以前已经发生过，但有13项是科学新知识。在叙尔特州地区首次记录了从其他地方描述的七个物种。根据其已知的地理范围，不能明确地为这些物种分配移民或引进的物种。我得出的结论是：（1）在过去的50年中，蠕虫动物具有较高的时间稳定性；（2）尽管该海滩是世界上研究得最好的海滩之一，但有10％的新物种的出现表明我们对各种鱼类的认识还是比较差的。描述了7种新的侧柏，并重新描述了3种：Coelogynopora multispina n。sp。，Pseudostomum gracilis Westblad 1955，尼氏小孢子虫 gen。。等，Haplovejdovskya scilliensis Faubel＆Warwick 2005，Haloplanella magnarhabdita等。螺旋藻 sp。，Moevenbergia oculifagi n。sp。，Coronhelmis inaequalis。，Proxenetes inflatus den Hartog 1966和Diascorhynchus falconis n.。sp。