• Animal Systematics, Evolution and Diversity
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• v.37 no.4
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• pp.335-339
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• 2021

In 2020, during a survey of cnidarian fauna around Chuja-do locating in the northern part of Jeju-do, Korea, several hydroids were collected from the subtidal zone by SCUBA diving. Through taxonomic examination, one unrecorded species, Hydrodendron stechowi Hirohito, 1995, was found in Korea. It was newly added to the list of Korean hydrozoan fauna. This species was discovered for the first time since its first report as a new species in Japan. Their vivid orange-colored colonies were attached to the sponge on rocky substrate between depths of 15 and 20 m. Thus, a total of five species belonging to genus Hydrodendron, including the species reported in this study, have been reported in Korean waters so far.

• Animal Systematics, Evolution and Diversity
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• v.38 no.4
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• pp.242-247
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• 2022

In 2021, during a survey of cnidarian fauna around Geomundo located in the Dadohaehaesang National Park in the South Sea, complete pinnated hydroid colonies attaching on vertical rocky surface at depth of 45 m were collected by SCUBA diving. Through taxonomic examination, unrecorded species, Sertularella acutidentata Billard, 1919, is newly added to the hydrozoan fauna of Korea. Recently, taxonomic position of the genus Sertularella has been relocated into the new family Sertularellidae Maronna et al., 2016 and six species from Korean waters have been synonymized or transferred to new genera. Thus, a total of 17 species belonging to genus Sertularella, including the species reported in this study, have been reported in Korean waters so far.

• Animal Systematics, Evolution and Diversity
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• v.40 no.2
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• pp.140-146
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• 2024

A taxonomic examination of Zygophylax species collected from the subtidal zone of Seongsan Ilchulbong in the east of Jeju Island and a reexamination of the voucher specimens previously described as Z. biarmata were conducted. Through this study, the species previously reported as Z. biarmata in Korea was redescribed as Z. pacifica, and the specimens from Seongsan Ilchulbong were confirmed to be Z. biarmata. Zygophylax biarmata has two nematothecae on the apophysis of the hydrotheca, a clear distinction between the apophysis and the pedicel of the hydrotheca, and much smaller hydrothecae, whereas Z. pacifica has a single nematotheca on the apophysis of the hydrotheca, no distinction between the apophysis and the pedicel of the hydrotheca, and much larger hydrothecae. As a result of this study, a total of two species belonging to genus Zygophylax have been reported in the hydrozoan fauna of Korea to date.

• Animal Systematics, Evolution and Diversity
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• v.40 no.1
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• pp.79-87
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• 2024

A taxonomic examination of hydroids collected from the subtidal zones of Ulleungdo and Dokdo located in the East Sea of Korea from 2017 to 2023 was conducted. Through this study, Antennella aurantia n. sp., a new species belonging to the family Halopterididae, was newly added to the hydrozoan fauna of Korea. This new species is clearly distinguished from similar species by the different morphology and size of the hydrothecae, lateral nematothecae, and gonothecae. By comparing the 16S rRNA sequence with 7 recorded species within the Antennella, the interspecific genetic distance to the new species was 8.2-28.9%, which is very high compared to the intraspecific variation of 0.0%, showing that it was clearly distinguished from other species. As a result of this study, a total of 4 Antennella species are reported in the hydrozoan fauna of Korea.