著者
久保田 信 西原 史晃
出版者
日本生物地理学会
雑誌
日本生物地理学会会報 = Bulletin of the Biogeographical Society of Japan (ISSN:00678716)
巻号頁・発行日
vol.71, pp.199-202, 2017-01-20

Many (25 individuals) immature medusae of a large form of Turritopsis medusae were collected from Enoshima, Kanagawa Prefecture in April, 2016, and cultured in the laboratory for about two months until their death (rejuvenated from a medusa to stolon, but no formation of zooids). They grew well-grown (maximally 8 mm in umbrella height) medusae with scarlet-coloured manubrium and c 80-100 tentacles. The present occurrence of a large form, though not an adult, is the second southernmost distributional record of this species after one century. However, the number of tentacles of the present medusae showed the minimum number, in contrast to having much more tentacles in wild medusae collected from various places in Japan (from Kanagawa Prefecture to Hokkaido).
著者
久保田 信 北田 博一 菅野 和彦
出版者
日本生物地理学会
雑誌
日本生物地理学会会報 = Bulletin of the Biogeographical Society of Japan (ISSN:00678716)
巻号頁・発行日
vol.72, pp.219-222, 2018-01-20

Aberrant female and male medusae of Turritopsis rubra and T. sp. (most frequently those with three oral lips and three gonads, but with normal four radial canals) were found (c 13% incidence in female of both species, n = 107, 85) in November, 2016 from Iwaki City, Fukushima Prefecture, Japan. In both species, parasitic trematoda was found; in T. sp. maximally eight individuals/normal medusa and five ones/aberrant medusa. Moreover, in the same place in Fukushima Prefecture and in the other place in Ibaragi Prefecture aberrant Turritopsis rubra mature medusae without oral lips or with 1, 2, 3, 5 oral lips, were also found (18.3 %, n = 142 in Otsu harbour in Ibaragi Prefecture) in October, 2017
著者
久保田 信
出版者
日本生物地理学会
雑誌
日本生物地理学会会報 = Bulletin of the Biogeographical Society of Japan (ISSN:00678716)
巻号頁・発行日
vol.69, pp.203-205, 2014-12-20

Stranded tetraclitid shells were collected and their number was counted according to the species at Shirahama town, Wakayama Prefecure, Japan during the period between June 1 and August 4, 2014. Tetraclita japonica Pilsbry was abundant due to broken into four pieces, while shells of T. squamosa Bruguière hardly broken into pieces (the former is 118 times than the latter). However, shells of T. formosana Utinomi was not found.2014年6月1日から8月4日までの期間中、和歌山県白浜町に所在する京都大学瀬戸臨海実験所"北浜"で、クロフジツボ類の打上について調査した。その結果、クロフジツボは殻が4断片に割れたものが多かったが、ミナミクロフジツボではそれが極めて少なかった(前者は後者の118倍)。また、クロフジツボでは穿孔されて食害を受けている殻も見られた。しかし、タイワンクロフジツボの殻は全く見つからなかった。