Asthenosoma varium is a sea urchin (an echinoderm, a member of the phylum that also includes star fish). Growing up to 25 cm (10 in) in diameter, it lives on sand and rubble sea bottoms in the Indo-Pacific, from the Red Sea to Australia and Southern Japan. Its venom tipped spines, with distinctive globular swellings below the tip, can inflict a painful sting if handled; the pain lasts as long as several hours. This capacity, perhaps coupled with its reddish-brown colour, has given it the common name fire urchin; other commonly used names are Pacific fire urchin, elusive sea urchin, variable fire urchin, and electric sea urchin.
Close-up of Asthenosoma varium, showing distinctive spines
Asthenosoma varium is a large sea urchin, hemispherical in shape, and growing to a diameter of 25 cm (10 in). The plates from which the test is formed are not joined rigidly together, as is the case in most sea urchins.[2] Instead, the plates are fused in groups of three, each group consisting of a central primary plate with a half-size plate on each side. The edge of each group of plates overlaps the next group in the same manner as tiles do on a roof, and this means the test is flexible.[3] The test is divided into five interambulacral areas separated by five ambulacral grooves. There are two series of spines arranged in five radial bands, each spine articulating with the test in a ball-and-socket joint. The primary spines on the aboral (upper) surface are short, thick and sharply-pointed, grow in rectangular areas and are clumped together in dense bundles. Each spine has several hollow spherical capsules, separated by constrictions, which are filled with toxin; they function like hypodermic syringes.[2] On the oral (under) surface, the primary spines have a different structure and are trumpet-shaped, the shaft being divided into four zones with different microstructure, in a similar way to the spines of some Diadematidae (especially Echinothrix) and Toxopneustidae.[4] The secondary spines are long, flexible, slender and blunt, and mostly found near the base of the test; they are used in locomotion and righting, and have sensory cells at their tip. The general colour of this sea urchin is orangish, red, brown or purple, or occasionally beige or some shade of green. The primary spines are banded, usually with paler bases and darker tips, and the secondary spines are yellowish.[2]
Distribution and habitatedit
Asthenosoma varium is native to the Indo-Pacific region where its range extends from the eastern Indian Ocean to Japan, the Philippines and New Caledonia. Records of its presence in the Red Sea are likely to be from the closely related species, Asthenosoma marisrubri. It inhabits coral environments at depths down to about 167 m (550 ft).[2]
Asthenosoma varium is omnivorous, feeding on the algal film that covers the substrate, as well as on encrusting invertebrates such as sponges and tunicates, and also organic detritus. The sexes are separate in this species. The gametes are released into the water, where fertilisation takes place. The larvae are planktonic and drift for several months before settling on the seabed, undergoing metamorphosis and becoming juvenile sea urchins.[7]
The spines of this sea urchin are venomous, and its bright colouration warns other organisms of this fact. Divers should be wary and avoid handling the urchins.[8]
Referencesedit
^ abGosliner, T.; D. Behrens & G. Williams (1996). Coral Reef Animals of the Indo-Pacific. p. 271.
^ abcdeModrak, Gaël; Caro, Valérie; Drouet, Isabelle; Weinberg, Steven & Maran, Vincent (10 May 2021). "Asthenosoma varium (Grube, 1868)" (in French). DORIS. Retrieved 26 June 2021.
^Barnes, Robert D. (1982). Invertebrate Zoology. Philadelphia, PA: Holt-Saunders International. p. 980. ISBN0-03-056747-5.
^Régis, M.B. & Thomassin, B.A. (1985). "Macro- and microstructure of the primary spines in Asthenosoma varium Grube (Echinothuridae: Echinoidea): Affinities with the Diadematidae and Toxopneustidae". Echinodermata. CRC Press. p. 12. doi:10.1201/9781003079224-59. ISBN9781003079224.
^Guardini, Matteo & Boyer, Massimo. . World Database of Marine Species. Archived from the original on 19 November 2011. Retrieved 11 March 2012.
^Humann, Paul & DeLoach, Ned (2010). Reef Creature Identification: Tropical Pacific. p. 448.
^"Asthenosoma varium Grube, 1868". SeaLifeBase. Retrieved 30 June 2021.
^Mooi, Rich (6 May 2011). "There's just some sting about you..." 2011 Philippine Biodiversity Expedition. California Academy of Sciences. Retrieved 4 July 2021.
April 13, 2024
asthenosoma, varium, urchin, echinoderm, member, phylum, that, also, includes, star, fish, growing, diameter, lives, sand, rubble, bottoms, indo, pacific, from, australia, southern, japan, venom, tipped, spines, with, distinctive, globular, swellings, below, i. Asthenosoma varium is a sea urchin an echinoderm a member of the phylum that also includes star fish Growing up to 25 cm 10 in in diameter it lives on sand and rubble sea bottoms in the Indo Pacific from the Red Sea to Australia and Southern Japan Its venom tipped spines with distinctive globular swellings below the tip can inflict a painful sting if handled the pain lasts as long as several hours This capacity perhaps coupled with its reddish brown colour has given it the common name fire urchin other commonly used names are Pacific fire urchin elusive sea urchin variable fire urchin and electric sea urchin Asthenosoma variumScientific classificationDomain EukaryotaKingdom AnimaliaPhylum EchinodermataClass EchinoideaOrder EchinothurioidaFamily EchinothuriidaeGenus AsthenosomaSpecies A variumBinomial nameAsthenosoma varium Grube 1868 It plays host to the commensal shrimps Periclimenes colemani and Allopontonia brockii and the zebra crab Zebrida adamsii 1 Contents 1 Description 2 Distribution and habitat 3 Ecology 4 ReferencesDescription edit nbsp Close up of Asthenosoma varium showing distinctive spinesAsthenosoma varium is a large sea urchin hemispherical in shape and growing to a diameter of 25 cm 10 in The plates from which the test is formed are not joined rigidly together as is the case in most sea urchins 2 Instead the plates are fused in groups of three each group consisting of a central primary plate with a half size plate on each side The edge of each group of plates overlaps the next group in the same manner as tiles do on a roof and this means the test is flexible 3 The test is divided into five interambulacral areas separated by five ambulacral grooves There are two series of spines arranged in five radial bands each spine articulating with the test in a ball and socket joint The primary spines on the aboral upper surface are short thick and sharply pointed grow in rectangular areas and are clumped together in dense bundles Each spine has several hollow spherical capsules separated by constrictions which are filled with toxin they function like hypodermic syringes 2 On the oral under surface the primary spines have a different structure and are trumpet shaped the shaft being divided into four zones with different microstructure in a similar way to the spines of some Diadematidae especially Echinothrix and Toxopneustidae 4 The secondary spines are long flexible slender and blunt and mostly found near the base of the test they are used in locomotion and righting and have sensory cells at their tip The general colour of this sea urchin is orangish red brown or purple or occasionally beige or some shade of green The primary spines are banded usually with paler bases and darker tips and the secondary spines are yellowish 2 Distribution and habitat editAsthenosoma varium is native to the Indo Pacific region where its range extends from the eastern Indian Ocean to Japan the Philippines and New Caledonia Records of its presence in the Red Sea are likely to be from the closely related species Asthenosoma marisrubri It inhabits coral environments at depths down to about 167 m 550 ft 2 Ecology editSeveral different organisms live in association with the Pacific fire urchin these include the commensal shrimps Periclimenes colemani and Allopontonia brockii and the parasitic snail Leutzenia asthenosomae as well as the zebra crab Zebrida adamsii 1 5 6 Siphamia tubifer is one of several small fish that make use of the protection provided by the urchin s toxic spines as do certain cephalopods 2 Asthenosoma varium is omnivorous feeding on the algal film that covers the substrate as well as on encrusting invertebrates such as sponges and tunicates and also organic detritus The sexes are separate in this species The gametes are released into the water where fertilisation takes place The larvae are planktonic and drift for several months before settling on the seabed undergoing metamorphosis and becoming juvenile sea urchins 7 The spines of this sea urchin are venomous and its bright colouration warns other organisms of this fact Divers should be wary and avoid handling the urchins 8 References edit a b Gosliner T D Behrens amp G Williams 1996 Coral Reef Animals of the Indo Pacific p 271 a b c d e Modrak Gael Caro Valerie Drouet Isabelle Weinberg Steven amp Maran Vincent 10 May 2021 Asthenosoma varium Grube 1868 in French DORIS Retrieved 26 June 2021 Barnes Robert D 1982 Invertebrate Zoology Philadelphia PA Holt Saunders International p 980 ISBN 0 03 056747 5 Regis M B amp Thomassin B A 1985 Macro and microstructure of the primary spines in Asthenosoma varium Grube Echinothuridae Echinoidea Affinities with the Diadematidae and Toxopneustidae Echinodermata CRC Press p 12 doi 10 1201 9781003079224 59 ISBN 9781003079224 Guardini Matteo amp Boyer Massimo Fire Urchin World Database of Marine Species Archived from the original on 19 November 2011 Retrieved 11 March 2012 Humann Paul amp DeLoach Ned 2010 Reef Creature Identification Tropical Pacific p 448 Asthenosoma varium Grube 1868 SeaLifeBase Retrieved 30 June 2021 Mooi Rich 6 May 2011 There s just some sting about you 2011 Philippine Biodiversity Expedition California Academy of Sciences Retrieved 4 July 2021 Retrieved from https en wikipedia org w index php title Asthenosoma varium amp oldid 1188237704, wikipedia, wiki, book, books, library,
