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| Telmatactis profundigigantica Izumi & Higashiji, 2023 many shrimps of Plesionika sp. are observed around the anemones (arrows). |
Abstract
Although the members of the genus Telmatactis Gravier, 1916 have been reported from broad area of the world including Japanese waters, the localities of the species have been limited to shallow areas. In this study, we report a new species in this genus, Telmatactis profundigigantica sp. nov., collected from the deeper area than 200 m of the East China Sea off Okinawa Island, discovered by ROV, and taken care of in Okinawa Churaumi Aquarium. This new species is chiefly characterized by its comparatively huge size of its body, over 10 cm in diameter and height, far larger than the other known species of this genus. Moreover, this species has characteristic multiple-headed tentacles and large cnidae in its acrospheres. In the present article, we also discuss the severe toxicity of this species and touch on the ecology of deep-sea anemones.
Keywords: sea anemone, Andvakiidae, Okinawa Churaumi Aquarium, deep sea, capitate, multiple-headed, hemolytic toxin, sting, taxonomy
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| External morphology of the holotype (NSMT-Co 1820) of Telmatactis profundigigantica sp. nov. A, Living polyp of T. profundigigantica sp. nov.; B, oral view of the specimen; C, aboral view (basal disc is damaged); D, enlarged view of a double-headed tentacle. Bold scale bars indicate 5 cm and a narrow bar 1 cm. Abbreviations: Acr, acrosphere; Bd, basal disc; Mo, mouth; Te, tentacle. |
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| Living images of Telmatactis profundigigantica sp. nov. in situ. A, A polyp adhering to a rock; B, a polyp buried in sponge. In both pictures, many shrimps of Plesionika sp. are observed around the anemones (arrows). Dates and Localities: A, [polyp no. 1], 19 September 2017, northeast off Ie island, Okinawa Pref.; B, [polyp no. 2], 7 January 2019, off Motobu-cho Town, Okinawa Island. |
Taxonomy
Order Actiniaria Hertwig, 1882
Suborder Enthemonae Rodríguez and Daly in Rodríguez et al., 2014
Superfamily Metridioidea Carlgren, 1893
Family Andvakiidae Danielssen, 1890
Genus Telmatactis Gravier, 1916
[Japanese common name: Mamire-isoginchaku-zoku]
Telmatactis profundigigantica sp. nov.
Taxonomic remarks. The morphological features of this anemone are corresponded to the latest diagnosis of Telmatactis in den Hartog (1995) as below: body wall without any structures; clavate 96 tentacles; mesogleal sphincter; two siphonoglyphs on actinopharynx; and presence of acontia. In this genus, Telmatactis profundigigantica sp. nov. is characterized by three characters: (1) enormously large body sizes (Fig. 2A–C); (2) numerous tentacles (Fig. 2A) with some peculiar multiple-headed ones (Fig. 2D); and (3) large tentacle basitrichs (Fig. 3C). As mentioned below, Telmatactis is distributed across a broad area of the world, and thus in this study we have mainly compared with the species of Telmatactis living in the western Pacific.
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Etymology. This new species is characterized by its comparatively far larger size and its deep-sea habitat. Thus, the species epithet is an adjective, composed of “profund-” (Latin profundus = deep) + “gigantica” [latinized Ancient Greek giganticus (gigantikos) = huge].
Japanese name: Ryugu-no-goten
Derivation of Japanese name. Ryugu (= castle under
the deep sea) + no (= of) + goten (= palace). Associated the
reddish color to the palaces of Okinawa covered with red
roof tiles.
Takato Izumi and Takuo Higashiji. 2023. Gigantic Anemone Species in the Deep ‘Churaumi’—Description of A New Species of the Genus Telmatactis (Cnidaria: Anthozoa: Actiniaria: Metridioidea), Telmatactis profundigigantica sp. nov. Species Diversity. 28(1); 99-106. DOI 10.12782/specdiv.28.99
