Saito Yasunori, Nagasawa Naoko
Shimoda Marine Research Center, University of Tsukuba, Japan.
Zoolog Sci. 2003 Jun;20(6):765-71. doi: 10.2108/zsj.20.765.
The morphology and life history of a new species of the genus Botryllus belonging to the family Botryllidae are described in detail. This ascidian was collected from the stony shore in the cove near Shimoda Marine Research Center, University of Tsukuba (Shimoda, Shizuoka Prefecture, Japan). The ascidian colony was easily distinguished from colonies of other botryllids because it was very thin and bright pink in color. The arrangement of ovary and testis in this ascidian was the same as that in other species of the genus Botryllus. This ascidian was prolific, with 1-5 embryos on each side of a zooid, and the embryos of this ascidian developed in the peribranchial cavity without any brooding organs as in Botryllus scalaris. We observed the processes and features of the allorecognition reaction in colony specificity and found that allorejection occurred after fusion of the vascular system between two incompatible colonies. This manner of allorejection is also shown in B. scalaris and Botryllus delicatus; however, the reaction speed of allorejection is faster than that of B. delicatus and similar to that of B. scalaris. These results indicate that this ascidian might be closely related to B. scalaris.
详细描述了玻璃海鞘科（Botryllidae）玻璃海鞘属（Botryllus）一个新物种的形态和生活史。这种海鞘是从筑波大学下田海洋研究中心附近海湾的石质海岸采集的（日本静冈县下田）。该海鞘群体很容易与其他玻璃海鞘科群体区分开来，因为它非常薄且颜色呈亮粉色。这种海鞘中卵巢和精巢的排列与玻璃海鞘属其他物种相同。这种海鞘繁殖力强，每个游动孢子体两侧有1 - 5个胚胎，并且这种海鞘的胚胎像标枪玻璃海鞘（Botryllus scalaris）一样在鳃腔中发育，没有任何育幼器官。我们观察了群体特异性中异体识别反应的过程和特征，发现异体排斥发生在两个不相容群体的血管系统融合之后。这种异体排斥方式在标枪玻璃海鞘和优美玻璃海鞘（Botryllus delicatus）中也有体现；然而，异体排斥的反应速度比优美玻璃海鞘快，与标枪玻璃海鞘相似。这些结果表明这种海鞘可能与标枪玻璃海鞘密切相关。
