Chironex yamaguchii
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Chironex yamaguchii , in the Enoshima Aquarium , Japan |
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| Scientific name | ||||||||||||
| Chironex yamaguchii | ||||||||||||
| Lewis & Bentlage , 2009 |
Chironex yamaguchii (Japanese "Habu-kurage") is a type ofbox jellyfish (Cubozoa) from the family of Chirodropidae . The species is very poisonous and can cause fatal poisoning in humans. The specific epithet honors Prof. Masashi Yamaguchi, who contributed a lot to the understanding of the Japanese box jellyfish and to the early ontogeny of Chironex fleckeri .
features
The medusa has a maximum shade height of about 110 mm; that's only about half to a third the size of Chironex fleckeri . On average, however, the animals are much smaller with an umbrella height of around 60 mm. The maximum interradial diameter of the screen is 95 mm. The exumbrella of the adult medusa is smooth, without warts. Juvenile medusas still have warts on their screen. The pedalia are claw-like; each pedal has up to nine tentacles, but on average only about seven tentacles (compared to up to 15 tentacles in Chironex fleckeri ). The nematocyst bands are lavender in color.
The kink of the pedal canal at the proximal end of the pedal is more rounded (like a volcanic cone) in Chironex yamaguchii , the downswing more straight, in contrast to the sharp kink and concave downswing in Chironex fleckeri .
The manubrium is cruciform with lanceolate lips. It only measures about 2/3 to 3/4 of the height of the umbrella. The gastric phacellae in the four "corners" are V-shaped. The gastric cirrus is unbranched and simple. The gastric sacs on the ceiling of the subumbrella are cock-comb or grape-like. In the adult animals they develop into the gonads. The perradial lobes are smooth, relatively broad, and triangular; they extend almost to the subumbrellar margin of the velarium. Four perradial muscle connections (frenulae) clamp the right-angled connection about 3/4 of the way from the tip of the rhopalial niche to the velarium envelope or its edge. Each frenula is made up of a single thick, gelatinous layer. The numerous velarial canals are heavily branched.
Each of the four Rhopalia has six eyes, the two median lens eyes and two slit and pit pigment eyes each. The statolith is oval and sits at the base of the rhopalium. The rhopalial niche sits in a triangular depression in the exumbrella.
Chironex yamaguchii has eight different types of nettle cells : microbasic mastigophores, microbasic euryteles, large and no trirhopaloids, holotric isorhizas, ellipsoidal isorhizas, ovoid isorhizas, and large ovoid isorhizas. Two types of nettle cells, the large ovoid isorhizas and the microbasic euryteles, were only observed in small medusa (> 10 mm screen height), the other types occur in all medusa stages. Umbrella, umbrella warts (in small individuals), manubrium, pedalia, gastric filaments, and tentacles are each occupied somewhat differently with the above types of nettle cells.
Geographical distribution and habitat
Chironex yamaguchii has been detected in the waters of southern Japan ( Ryūkyū Islands ) and the Philippines ( Masbate , Luzon , Mindanao , Mindoro and Palawan ). They live there in flat areas near the coast. Off the Ryukyu Islands, the medusas only occur between August and the end of September.
Chironex yamaguchii poisoning
Chironex yamaguchii , like Chironex fleckeri, appears to be extremely poisonous. Three confirmed deaths can be traced back to poisoning with the nettle poison of Chironex yamaguchii . The poison can cause cardiac arrest and pulmonary edema.
Systematics
The species had earlier been misidentified as Chiropsalmus quadrigatus Haeckel, 1880 (see also). This species was recently added to the genus Chiropsoides Southcott, 1967. Chiropsoides quadrigatus (Haeckel, 1880) from the waters off Myanmar has little in common with Chironex yamaguchii .
swell
Individual evidence
- ↑ a b c A. Oba, M. Hidaka and S. Iwanaga: Nematocyst composition of the cubomedusan Chiropsalmus quadrigatus changes with growth. Hydrobiologia, 530/531, 173-177, Dordrecht 2004 doi: 10.1007 / s10750-004-2692-2 .
- ↑ Lisa-Ann Gershwin: Comments on Chiropsalmus (Cnidaria: Cubozoa: Chirodropida): a preliminary revision of the Chiropsalmidae, with descriptions of two new genera and two new species. Zootaxa, 1231: 1-42, Auckland 2006 Abstract (PDF; 19 kB)