Karyotype of the Sea Anemone Aiptasiomorpha sp. (Anthozoa, Actiniaria) From Japan

In the Anthozoa, only one karyological study has been performed, namely, a study of the coral Goniopora lobata (2n = 28) by a "squash" method (1), and no information about the chromosomes of a sea anemone has been presented apart from a recent preliminary report of the diploid chromosome number and the complement of chromosomes of Haliplanella lineata (= H. luciae) (2n = 32), which were examined by an air-drying method (2). Morphological details of the chromosomes were not provided. The present study is the first attempt at karyotypic analysis in Actiniaria, a poorly studied order of Coelenterata (3-6). The karyotype of Aiptasionmorpha sp. was determined by conventional Giemsa-stained preparations of early embryos. This species has 2n = 32 chromosomes, consisting of 14 pairs of biarmed chromosomes and 2 pairs of chromosomes having one arm or with the second arm extremely small. The presence of two large metacentric pairs characterizes the karyotype of Aiptasiomorpha species.