Sea pens are benthic marine organisms, which have important roles as three-dimensional structures and habitats on sandy and muddy seafloors. Although the behavior of a few species of sea pens has been sporadically reported since the seventeenth century, and despite their presence across a wide range of habitats, the behavior of most sea pen taxa has not been well studied or documented. In this study, via video images of an Echinoptilum sp. specimen in an aquarium (shown in this study at 128-times speed), we observed unreported aspects of behavior, namely mole-like movement within the seafloor sand, and bending of the colony when emerging from the sand. Such mole-like behavior may be advantageous to avoid dangerous and other unfavorable situations, such as predation and competition for space. Aspects of Echinoptilum sp.’s morphology, such as a digitiform colony shape, lack of an axis, and the presence of retractable autozooids and three-flanged sclerites may assist in this behavior. Finally, it appears that peristalsis and active movements are common features for anthozoans in sandy bottom environments, and have so far been reported from sea pens, zoantharians, and scleractinian corals.

中文翻译：

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首次观察到在海笔中观察到的痣状穴居行为

海圈是底栖海洋生物，在沙质和泥泞海底作为三维结构和栖息地具有重要作用。尽管自17世纪以来偶而报告了几种海笔的行为，尽管它们存在于广泛的生境中，但大多数海笔类群的行为尚未得到充分研究或记录。在这项研究中，通过Echinoptilum sp。的视频图像。在一个水族馆的标本中（本研究以128倍的速度显示），我们观察到了未报告的行为方面，即海底沙子内的痣状运动，以及从沙子中出来时菌落的弯曲。这种类似摩尔的行为对于避免危险和其他不利情况（例如掠夺和争夺太空）可能是有利的。的方面Echinoptilum sp。的形态，例如指状菌落形状，缺乏轴，以及可伸缩的类动物和三凸缘巩膜的存在，可能有助于这种行为。最后，蠕动和活跃的运动似乎是沙质底部环境中的拟蝇类动物的共同特征，迄今为止，从海笔，动物黄足动物和巩膜珊瑚中已有报道。