著者

Michael Ford Nicholas Bezio Allen Collins

出版者

The Plankton Society of Japan, The Japanese Association of Benthology

雑誌

Plankton and Benthos Research (ISSN:18808247)

巻号頁・発行日

vol.15, no.4, pp.296-305, 2020-11-18 (Released:2020-11-12)

参考文献数

36

被引用文献数

2 8

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On April 10, 2015, three individuals of an undescribed species of ctenophore were observed moving just above the seafloor in the Arecibo Amphitheater inside the Guajataca Canyon, north-northwest of Puerto Rico at a depth of approximately 3,900 m. The ctenophore is distinctive; having two prominent tentacle arms, a body that is rectangular when observed laterally along the tentacular plane, and rounded when observed laterally along the stomodeal plane. The tentacle arms each give rise to an extensible tentacle bearing short tentilla of uniform length and distribution. One ctenophore appeared to be anchored to the seafloor by its two long flexible tentacles, as well as by two filaments exiting its oral end. The overall form of the ctenophore suggests classification within the problematic, non-monophyletic order Cydippida, but the robust tentacle arms are more reminiscent of benthic species of Platyctenida, particularly those of families Lyroctenidae and Ctenoplanidae. Whereas most platyctenid ctenophores do not possess ctene rows in their adult forms, features that are possessed by the new species described herein, species of Ctenoplanidae retain comb rows as adults and are capable of limited swimming. The species described herein is easily distinguishable from all other known species of Ctenophora and may trace its origin to a lineage diverging near the origin of Platyctenida.

著者

Miles I Peterson Kei Chloe Tan Allen Collins Satoshi Kitano Yasushi Kusuoka Takahito G Suzuki Masao Migita Iffah Iesa Stacy Pirro Dhugal Lindsay Cheryl Lewis Ames

出版者

The Plankton Society of Japan, The Japanese Association of Benthology

雑誌

Plankton and Benthos Research (ISSN:18808247)

巻号頁・発行日

vol.17, no.2, pp.231-248, 2022-05-30 (Released:2022-05-31)

参考文献数

39

被引用文献数

1

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Freshwater jellyfish comprising the genus Craspedacusta are thought to have originated in the Yangtze River, China and have since spread to all continents except Antarctica. In this study, jellyfish were collected from Haruta-ike, an artificial pond in Chikuma City, Nagano (Japan). Medusae were identified as Craspedacusta sowerbii using morphological and molecular techniques. Despite the existence of Haruta-ike since prior to the Edo era (ca. 1603), this work represents the first published record of freshwater jellyfish in this pond. Herein, we report on the novel swimming behavior documented in this population, which includes both male and female C. sowerbii medusae. Additionally, we discuss the life cycle of polyps reared in culture from Machikane-ike, a pond in Osaka for which we have published the first complete mitochondrial genome of C. sowerbii from Japan. Finally, we report on the morphology and life cycle of the rare Japanese freshwater jellyfish Astrohydra japonica in Lake Biwa (Shiga), documented only a few times in the 40 years since its original discovery in Japan. The results of our robust phylogenetic analysis using the 16S rRNA gene and COI markers of C. sowerbii and A. japonica in this study and for C. sowerbii material from Singapore, together with all publicly available sequences for these markers for the two species worldwide, revealed two major C. sowerbii clades suggesting the Nagano and Osaka populations originated from two distinct introduction events. This collaborative research was made possible through international collaborations among multiple research facilities, museums and one wildlife reserve.