Dick Matthew H, Mawatari Shunsuke F, Sanner Joann, Grischenko Andrei V
Department of Natural History Sciences, Faculty of Science, Hokkaido University, N10 W8, Sapporo 060-0810, Japan.
Zoolog Sci. 2011 Feb;28(2):134-47. doi: 10.2108/ZSJ.28.134.
We provide original descriptions for nine new species in the cheilostome bryozoan genus Cauloramphus (C. gracilis, C. Ordinarius, C. amphidisjunctus, C. cheliferoides, C. oshurkovi, C. infensus, C. parvus, C. peltatus, and C. ascofer) and a redescription of C. disjunctus Canu and Bassler, 1929 . We delineate a group of eight species, here termed the 'C. disjunctus clade,' that have the opesial spine joints calcified to a greater or lesser extent in mature zooids; most also have paired, hypertrophied avicularia. This group includes C. amphidisjunctus, C. cheliferoides, C. infensus, C. parvus, C. peltatus, and C. ascofer in the Aleutian Islands, Alaska; C. oshurkovi in the Commander Islands; and C. disjunctus in Japan. High levels of apparent endemism in two unrelated bryozoan genera (Cauloramphus and Monoporella), and geographical population differentiation in C. ascofer indicating ongoing allopatric speciation, suggest high speciation rates for deep benthic bryozoans in the western Aleutians. A phylogenetic hypothesis for the C. disjunctus clade indicates that populations of Cauloramphus dispersed between the Aleutians and Asia on at least three separate occasions, and that the polarity of at least two of these dispersal events was from the Aleutians to Asia.
我们提供了唇口目苔藓虫类Cauloramphus属九个新物种（纤细Cauloramphus、普通Cauloramphus、间断双叉Cauloramphus、似螯Cauloramphus、奥舒尔科夫Cauloramphus、密集Cauloramphus、微小Cauloramphus、盾形Cauloramphus和囊腔Cauloramphus）的原始描述，并对1929年卡努和巴斯勒描述的间断Cauloramphus进行了重新描述。我们划定了一组八个物种，在此称为“间断Cauloramphus分支”，这些物种在成熟个虫中，开口脊关节或多或少都有钙化；大多数还具有成对的、肥大的鸟头体。该组包括阿拉斯加阿留申群岛的间断双叉Cauloramphus、似螯Cauloramphus、密集Cauloramphus、微小Cauloramphus、盾形Cauloramphus和囊腔Cauloramphus；指挥官群岛的奥舒尔科夫Cauloramphus；以及日本的间断Cauloramphus。两个不相关的苔藓虫属（Cauloramphus和单孔苔藓虫属）中明显的高特有性水平，以及囊腔Cauloramphus中的地理种群分化表明正在发生异域物种形成，这表明阿留申群岛西部深海底栖苔藓虫的物种形成率很高。间断Cauloramphus分支的系统发育假说表明，Cauloramphus种群至少在三个不同的时期在阿留申群岛和亚洲之间扩散，并且这些扩散事件中至少有两次的方向是从阿留申群岛到亚洲。
