Gigantopelta chessoia | |
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Gigantopelta chessoia The scale bar is 1 cm. | |
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View of a number of Gigantopelta chessoia (the brown snails) partially covered by limpets Lepetodrilus sp. (the small yellow-greenish oval shapes) at the East Scotia Ridge E2 hydrothermal vent site in the Scotia Sea. The scale bar is 10 cm. | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Mollusca |
Class: | Gastropoda |
Subclass: | Neomphaliones |
Order: | Neomphalida |
Family: | Peltospiridae |
Genus: | Gigantopelta |
Species: | G. chessoia |
Binomial name | |
Gigantopelta chessoia Chen, Linse, Roterman, Copley & Rogers, 2015 [1] | |
Gigantopelta chessoia is a species of deep sea snail from hydrothermal vents, a marine gastropod mollusk in the family Peltospiridae. [1]
The first information about this species, under the name "Peltospiroidea n. sp." or "peltospiroid gastropod", was published on 3 January 2012. [2] Peltospiroidea is the name of a superfamily of gastropods that was used in the taxonomy of the Gastropoda (Ponder & Lindberg, 1997). It contained only the extant family Peltospiridae and some prehistoric gastropod families. However, the taxonomy of the Gastropoda (Bouchet & Rocroi, 2005) does not use the name Peltospiroidea (in that system, Peltospiridae is placed within the superfamily Neomphaloidea).
It was described as a new species within the new genus Gigantopelta in 2015, in the family Peltospiridae. [1]
This species is known from two sites near hydrothermal vents in the East Scotia Ridge of the south Atlantic Ocean: from 2,394 m depth at the E9 vent site and from the 2,608 m depth at the E2 site. [2]
The color of the shell is dark olive. [1] The shell has three to four whorls. [1] The width of the shell is from 4.21–45.7 mm. [1] Body size of the juvenile snail is 2 mm, [3] while body size of the adult is 50 mm. [3]
It has non-papillate tentacles. [3]
The digestive system: there is one pair of radula cartilages. [3] The digestive tract is short and consist of a single loop. [3] The rectum does not penetrate the heart. [3] The radula consist of 1.4% of body volume in juveniles and radula cartilages consist of 2.6% of body volume in juveniles. [3]
The respiratory system consist of single left bipectinate ctenidium (gill). [3]
The circulatory system is hypertrophied: heart is greatly enlarged. [3] The ventricle is 0.42 mm in juvenile animal length of 2.0 mm. [3] The ventricle grows to the size 6 mm in adults. [3] There is a single left auricle. [3] Gigantopelta chessoia has symbiotic bacteria in its enlarged oesophageal gland. [4] The body of Gigantopelta chessoia has low values of carbon isotope δ13C. [5] This indicates that carbon fixation in Gigantopelta chessoia can occur via Calvin-Benson-Bassham cycle by endosymbiotic Gammaproteobacteria. [5] The occurrence of endosymbiont bacteria in the oesophageal gland was confirmed by transmission electron microscopy in 2017. [3]
The oesophageal gland is fused and enlarged to fill the entire ventral side of mantle cavity. [3] It is occupying 0.6% of visceral mass volume in juveniles, while it is increasing allometrically up to 9% visceral mass volume in adults. [3] Blood sinuses are large, but few and fixed in position. [3]
The nervous system has ganglia. [3]
The sensory organs of Gigantopelta chessoia include statocysts with statolith. [3]
The reproductive system has fully developed gonads in juveniles at body size 2.0 mm. [3]
This gastropod is generally found in dense aggregations up to ~1,000 m−2. [2]
Small limpets Lepetodrilus sp. East Scotia Ridge are sometimes found on the shells of Gigantopelta chessoia. [2] Other marine fauna, such as actinostolid sea anemones (family Actinostolidae), crabs in the genus Kiwa , and the pycnogonid arthropod or "sea spider" cf. Sericosura , can be found living together with this species. [2]
Gigantopelta chessoia may be a mixotroph in juvenile life and shifting to obligate symbiotrophy as an adult. [3]
Gigantopelta chessoia is gonochoristic (they have distinct males and females). [3]
This article incorporates Creative Commons (CC-BY-2.5) text from the reference [2] and CC-BY-4.0 text from the reference [3]