Zosimus aeneus explained

Zosimus aeneus, also known as the devil crab, toxic reef crab, and devil reef crab is a species of crab that lives on coral reefs in the Indo-Pacific from East Africa to Hawaii. It grows to a size of 60mm90mm and has distinctive patterns of brownish blotches on a paler background. It is potentially lethal due to the presence of the neurotoxins tetrodotoxin and saxitoxin in its flesh and shell.

Description

Zosimus aeneus reaches a size of 60x. It is "a well known brightly coloured and strikingly patterned species":[1] its carapace and legs (including the claws) are marked with a characteristic pattern of red or brown patches on a pale brown or cream background. The carapace is deeply grooved, and the walking legs have prominent crests.[2]

Distribution and ecology

Zosimus aeneus is found across a large part of the Indo-Pacific, from South Africa to the Red Sea, and as far east as Japan, Australia and Hawaii. It lives on reef flats in the intertidal zone.[2]

Taxonomy

Zosimus aeneus was first described by Carl Linnaeus in his 1758 10th edition of Systema Naturae. It was transferred to the genus "Zozymus" by James Dwight Dana in 1852, which was replaced with Zosimus by Mary J. Rathbun in 1907.[3] It is the type species of the genus Zosimus.[3]

Toxicity

Both the shell and the meat of Zosimus aeneus contain significant concentrations of neurotoxins including tetrodotoxin and saxitoxin.[4] Tetrodotoxin (TTX) is the compound responsible for the toxicity of puffer fish, while saxitoxin (SXN) is the best known of several related neurotoxins that cause paralytic shellfish poisoning (PSP).[5] Both are absorbed through the gastrointestinal tract and interfere with sodium channels in the membranes of nerve cells.[5]

Poisoning with Z. aeneus can be fatal; one man in Timor-Leste died hours after consuming the crab, having received a dose equivalent to 1–2 μg saxitoxin per kilogram body mass.[6] The flesh of Z. aeneus is reported to be ingested by inhabitants of the Pacific Islands with the intention of committing suicide.[7]

Z. aeneus is considered the most poisonous crab in the Philippines, with 50% of intoxication cases being fatal.[8] Studies determined that individual specimens contained in excess of 3000 MU/g of saxitoxin, a lethal amount for humans that resulted in 12 fatalities in Negros Island in the 1980s.[9] In February 2021, two children in Cagayan died after eating Z. aeneus caught by their father.[10]

External links

Notes and References

  1. Raffles Bulletin of Zoology. 2008. 17. 1–286. Systema Brachyurorum: Part I. An annotated checklist of extant Brachyuran crabs of the world. Peter K. L. Ng. Danièle Guinot. Peter J. F. Davie.
  2. Book: Marine Life of the Pacific and Indian Oceans. Periplus Nature Guides. Gerald Allen. Tuttle Publishing. 2000. 978-962-593-948-3. Crustaceans. One of the reef's most dominant groups. 31–40. https://books.google.com/books?id=7eg2mgVcMCcC&pg=PA40.
  3. Book: Raoul Serène . Alain Crosnier . amp . 1984 . Crustacés Décapodes Brachyoures de l'Océan Indien Occidental et de la Mer Rouge. Xanthoidea: Xanthidae et Trapeziidae . fr . Crabs (Crustacea: Decapoda: Brachyura) of the Western Indian Ocean and Red Sea. Xanthoidea: Xanthidae and Trapeziidae . Volume 24 of Faune Tropicale . . 978-2-7099-0701-9 . Sous-famille des Zosiminae Alcock, 1898 . 137–172. https://books.google.com/books?id=d7MK0yeEl6cC&pg=PA165.
  4. Book: D. S. Bhakuni. Diwan S. Rawat. amp. 2005. Bioactive Marine Natural Products. Gulf Professional Publishing. 978-1-4020-3472-5. Bioactive metabolites of marine invertebrates. 26–63. https://books.google.com/books?id=gR7gTwBc94MC&pg=PA36.
  5. Book: Shirley D. Tuorinsky. 2009. Medical Aspects of Chemical Warfare. Government Printing Office. Patrick Williams. Scott Willens. Jamie Anderson. Michael Adler. Corey J. Hilmas. amp. Toxins: established and emergent threats. 613–644. https://books.google.com/books?id=KZy_gRT1qu4C&pg=PA622.
  6. Book: Hans P. Egmond. M. E. van Apeldoorn. G. J. A. Speijers. amp. 2004. Marine Biotoxins . FAO Food and Nutrition Paper 80. Food and Agriculture Organization of the United Nations. 978-92-5-105129-0. Paralytic Shellfish Poisoning (PSP). 5–52. https://books.google.com/books?id=9fEfCzh5DXwC&pg=PA46.
  7. Web site: Creature Feature – Toxic Crabs. 23 January 2017. Western Australian Museum.
  8. Web site: Fresco . Mary Charlotte O. . Not all crabs are safe to eat . "Known in Zamboanga as Kagang-bugton, this is the most poisonous crab in our country and largely distributed in Ilocos, La Union, Batangas, Quezon, Albay, Sorsogon, Mindoro, Marinduque, Panay Island, Palawan, and Zamboanga. ...mortality rate is at 50%." . 24 February 2021.
  9. Web site: Daisuke Yasumura, Yasukatsu Oshima, Takeshi Yasumoto, Angel C. Alcala and Lawton C. Alcala . Tetrodotoxin and Paralytic Shellfish Toxins in Philippine Crabs . . "Occasional outbreaks of crab poisoning resulting in 12 fatalities on Negros Island, Philippines. The toxin content in the whole body exceeded 3000 MU, a PST level considered lethal for humans when taken orally." . 23 July 1985 . . 24 February 2021.
  10. News: Visaya Jr. . Villamor . 2 kids die, father in critical condition after eating 'kuret' crab in Cagayan . . "Two children died on Friday (Feb. 12), while their father is in critical condition after allegedly consuming "kuret", a type of coral reef crab, in the Cagayan town of Santa Ana, local authorities said on Saturday (Feb. 13). . 13 February 2021 . 24 February 2021.

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