Alviniconcha Explained

Alviniconcha is a genus of deep water sea snails, marine gastropod mollusks in the family Provannidae.^[1] These snails are part of the fauna of the hydrothermal vents in the Indian and Western Pacific Ocean.^[2] These and another genus and species within the same family (Ifremeria nautilei) are the only known currently existing animals whose nutrition is derived from an endosymbiotic relationship with a member of bacteria from phylum Campylobacterota (formerly Epsilonproteobacteria) and Gammaproteobacteria, occurring as endosymbionts within the vacuoles of Alviniconcha ctenidia (or molluscan gills).^[3] All species of Alviniconcha are thought to be foundational species found near hydrothermal venting fluid supplying their bacterial endosymbionts with vent derived compounds such as hydrogen sulfide. These snails can withstand large variations in temperature (5 - 33 °C),^[4] pH, and chemical compositions.

Description

The size of the shell varies between 20 mm up to 60 mm in shell height. The surface of the shell is studded with hairs on the periostracum, which ranges from a yellow/green to brown coloring. However, this thin periostracum is often missing or degraded due to high temperatures and chemical reductants found in nearby venting fluid. While Alviniconcha has been considered cryptic for many years, morphoanatomy studies on A. boucheti, A. kojimai, and A. strummeri have found distinguishing characteristics of the shell and head-foot regions.^[5] These three species are the only ones known to cohabitate vent fields, all other species are found in isolated basins in the NW Pacific and Indian Oceans. Morphoanatomy has not been studied for A. adamants, A. hessleri, or A. marisindica, thus shell variation or morphology does not yet correspond to individual species.^[2]

Life History

Knowledge gaps remain in the life history of Alviniconcha, however adult shell anatomy resembles planktotrophic development. Unlike the sister genus Ifremeria whose development includes a novel "Waren's" larval form, held within a brood pouch (absent in Alviniconcha).^[6]

Species

Until 2014, Alviniconcha consisted solely of the species Alviniconcha hessleri, described in 1988. In 2014, increased recognition of genetic differences between populations resulted in the formal description of five cryptic species within the former A. hessleri that were believed to be morphologically indistinguishable from each other but that have consistent differences in mitochondrial DNA sequences.^[2] New research also suggests distributions of Alviniconcha in the SW Pacific are linked to geochemical gradients and endosymbiont chemical requirements.^[7]

Species within the genus Alviniconcha include:

• Alviniconcha adamantis - found in the relatively shallow seamounts (<1000m) of the Mariana's Arc and hypothesized to be the ancestor of all other extant Alviniconcha species. Hosts gammaproteobacterial endosymbionts.^[8] S.B. Johnson, Warén, Tunnicliffe, Van Dover, Wheat, Schultz & Vrijenhoek, 2014
• Alviniconcha boucheti - found in hydrothermal vents in the Manus, Fiji, and Lau basins ranging from 1300 to 2700 m in depth. Hosts epsilon-proteobacterial endosymbionts. Named after deep sea gastropod scientist Philippe Bouchet. S.B. Johnson, Warén, Tunnicliffe, Van Dover, Wheat, Schultz & Vrijenhoek, 2014
• Alviniconcha hessleri - first Alviniconcha species to be described. Found at hydrothermal vents in the Mariana Trough at depths greater than 1400 m. Hosts gamma-proteobacterial endosymbionts. Most closely related to A. kojimai. Okutani & Ohta, 1988
• Alviniconcha kojimai - found at hydrothermal vents of the Manus, Fiji, and Lau Basins ranging from 1480 to 2700 m in depth. Hosts both epsilon- and gamma-proteobacterial endosymbionts. S.B. Johnson, Warén, Tunnicliffe, Van Dover, Wheat, Schultz & Vrijenhoek, 2014
• Alviniconcha marisindica - only Alviniconcha species found in the Indian Ocean, named by T. Okutani for the latin name for Indian Sea. Found specifically at vent sites on the Central Indian Ridge ranging from 2400 to 330 m in depth. Hosts epsilon-proteobacterial endosymbionts. Okutani, 2014
• Alviniconcha strummeri - named after punk musician Joe Strummer of The Clash.^[9] Only found in the Southern Lau Basin, specifically at the Tui Mall vents sites at a depth of 1850 m. Hosts both gamma- and epsilon- proteobacterial endosymbionts. S.B. Johnson, Warén, Tunnicliffe, Van Dover, Wheat, Schultz & Vrijenhoek, 2014

References

• Healy, J.M. 1992, Dimorphic spermatozoa of the hydrothermal vent prosobranch Alviniconcha hessleri: systematic importance and comparison with other caenogastropods; Bull. Mus. Natl. His. Nat. Paris 4 sér A 14: 273-291
• Desbruyères, D., M. Segonzac & M. Bright (eds.). 2006. Handbook of Deep-sea Hydrothermal Vent Fauna. Second Edition Denisia 18:1-544. (Copepods 316-355)(Polychaeta 183-296)

Notes and References

1. Bouchet, P. (2013). Alviniconcha Okutani & Ohta, 1988. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=449922 on 2013-06-25
2. Johnson. Shannon B.. Warén. Anders. Tunnicliffe. Verena. Dover. Cindy Van. Wheat. C. Geoffrey. Schultz. Thomas F.. Vrijenhoek. Robert C.. Molecular taxonomy and naming of five cryptic species of Alviniconcha snails (Gastropoda: Abyssochrysoidea) from hydrothermal vents. Systematics and Biodiversity. 13. 3. 2014. 278–295. 10.1080/14772000.2014.970673. 85253352 . free.
3. Yohey Suzuki, Takenori Sasaki, Masae Suzuki, Yuichi Nogi, Tetsuya Miwa, Ken Takai, Kenneth H. Nealson & Koki Horikoshi (September 2005) "Novel Chemoautotrophic Endosymbiosis between a Member of the Epsilonproteobacteria and the Hydrothermal-Vent Gastropod Alviniconcha aff. hessleri (Gastropoda: Provannidae) from the Indian Ocean". Applied and Environmental Microbiology, 71(9): 5440-5450.
4. Waren . Anders . Bouchet . Philippe . New records, species, genera, and a new family of gastropods from hydrothermal vents and hydrocarbon seeps . Zoologica Scripta . January 1993 . 22 . 1 . 1–90 . 10.1111/j.1463-6409.1993.tb00342.x . 83548576 .
5. Laming . Sven R. . Stephane . Hourdez . Cambon-Bonavita . Marie-Anne . Pradillon . Florence . Classical and computed tomographic anatomical analyses in a not-so-cryptic Alviniconcha species complex from hydrothermal vents in the SW Pacific . Frontiers in Zoology . May 2020 . 17 . 12 . 12 . 10.1186/s12983-020-00357-x . 32391066 . 7203863 . free .
6. Reynolds . Kyle C . Watanabe . Hiromi Kayama . Strong . Ellen . Sasaki . Takenori . Uematsu . Katsyuki . Miyake . Hiroshi . Kojima . Shigeaki . Suzuki . Yohey . Fujikura . Katsunori . Kim . Stacy . Young . Craig M . New Molluscan Larval Form: Brooding and Development in a Hydrothermal Vent Gastropod, Ifremeria nautili (Provannidae) . Biological Bulletin . August 2010 . 219 . 1 . 7–11 . 10.1086/BBLv219n1p7 . 20813984 . 34778665 .
7. Beinart . Roxanne A. . Sanders . Jon G. . Faure . Baptiste . Sylva . Sean P. . Lee . Raymond W. . Becker . Erin L. . Gartman . Amy . Luther III . George W. . Seewald . Jeffrey S. . Fisher . Charles R. . Girguis . Peter R. . Evidence for the role of endosymbionts in regional-scale habitat partitioning by hydrothermal vent symbioses . Proceedings of the National Academy of Sciences of the USA . November 2012 . 109 . 47 . E3241-50 . 10.1073/pnas.1202690109 . 23091033 . 3511114 . free .
8. Breusing . Corinna . Hagen Klobsunik . Nathan . Hauer . Michelle A . Beinart . Roxanne A . Genome assembly of the chemosynthetic endosymbiont of the hydrothermal vent snail Alviniconcha adamantis from the Mariana Arc . G3: Genes, Genomes, Genetics . October 2022 . 12 . 10 . 10.1093/g3journal/jkac220 . 35997584 . 9526052 .
9. https://www.npr.org/2014/12/20/372052995/a-snail-so-hardcore-its-named-after-a-punk-rocker A Snail So Hardcore It's Named After A Punk Rocker