Solenogastres

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Solenogastres
Epimenia verrucosa.jpg
A preserved specimen of Epimenia verrucosa
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Mollusca
Class: Solenogastres
Orders

The Solenogastres (less often referred to as Neomeniomorpha), common name the solenogasters, are one class of small, worm-like, shell-less molluscs (Aplacophora), the other class being the Caudofoveata (Chaetodermomorpha). [1]

Contents

Some recent literature, and recent molecular evidence, indicates that the Aplacophora may be polyphyletic, and therefore these taxonomists divide Solenogastres and Caudofoveata into separate classes. [2]

Morphology

In contrast to all other molluscan classes, the Aplacophora have no shell, and are instead covered by aragonitic sclerites (calcareous spicules), which can be solid or hollow. These spicules can be arranged perpendicular to one another within the cuticle to form a skeleton, or can stick up to form a palisade, or can lie flat against the cuticle. [3]

80% of solenogaster species have a radula, while in others it is secondarily lost. The radula may bear one or more teeth per row; where there is more than one tooth, there is no central radular tooth. [3] The radula grows by dividing existing teeth in two, or by adding a new tooth at the centre of the radular row. [3] The salivary glands are very elaborate, and are an important character for taxonomy. Next to the mouth they have a unique sense organ, the vestibulum.

The solenogastres do not have true ctenidia, although their gill-like structures resemble them. [4]

Development

During development many Solenogastres are covered by a spiny scleritome comprising spines or scale-like plates; this has been likened to the halwaxiid scleritome. [5]

Sclerites of Epimenia start out solid before developing a hollow stem that subsequently solidifies. [6]

Solenogastres can be found in a diverse range of habitats across the world, from the coast to the deep ocean. [7]

Ecology

Diet

Solenogastres feed on cnidaria and ctenophores, either sucking their bodily fluids or eating their tissue. [8] They do not use their radulae to rasp prey, as other molluscs do. [9]

Phylogeny

There is some uncertainty regarding the phylogenetic position of the solenogastres. Traditionally considered to be the most basal molluscan group and the sister group to the Caudofoveata, alternatives to both of these statements have been proposed on various lines of evidence. [5] Indeed, some molecular datasets plot Solenogastres as an outgroup to Mollusca. [10]

However, there are cryptic species which are hard to delineate due to their being a lack of multiple morphological characteristics that are necessary. [11]


Families

Unassigned in Solenogastres
Synonyms

Related Research Articles

<span class="mw-page-title-main">Aplacophora</span> Class of molluscs

Aplacophora is a presumably paraphyletic taxon. This is a class of small, deep-water, exclusively benthic, marine molluscs found in all oceans of the world.

<span class="mw-page-title-main">Proneomeniidae</span> Family of molluscs

Proneomeniidae is a family of uncommon molluscs in the class Solenogastres.

<i>Wirenia argentea</i> Species of mollusc

Wirenia argentea is a species of marine mollusc of solenogastres in the family Gymnomeniidae.

Notomenia is a genus of solenogasters, shell-less, worm-like, marinemollusks. In this genus the animal bears non-mineralized sclerites. This genus is the sole representative of the family Notomeniidae, and has secondarily reduced its radula, which is vestigial.

<span class="mw-page-title-main">Cavibelonia</span> Order of molluscs

The Cavibelonia are one of the four orders of solenogaster, a kind of shell-less, worm-like mollusk.

Macellomenia is a genus of solenogaster, and the only genus in its family.

Spiomenia is a genus of solenogaster, shell-less, worm-like, marine mollusks.

Plawenia a genus of solenogasters, shell-less, worm-like, marine mollusks.

Kruppomenia is a genus of solenogaster, a kind of shell-less, worm-like, marine mollusk.

Helicoradomenia is a genus of solenogasters, shell-less, worm-like mollusks.

Cyclomenia is a genus of solenogaster, a kind of shell-less, worm-like mollusk.

<i>Rhopalomenia</i> Genus of molluscs

Rhopalomenia is a genus of solenogasters, shell-less, worm-like, marine mollusks.

<i>Epimenia</i> Genus of molluscs

Epimenia is a genus of cavibelonian solenogasters, a kind of shell-less, worm-like mollusks.

Epiherpia is a genus of solenogasters, shell-less, worm-like molluscs.

Alexandromenia is a genus of solenogaster, a kind of shell-less, worm-like mollusk.

Pruvotinidae is a diverse taxonomic family of cavibelonian solenogasters, shell-less, worm-like marine mollusks.

<span class="mw-page-title-main">Rhopalomeniidae</span> Family of molluscs

Rhopalomeniidae is a family of solenogaster,, a kind of shell-less, worm-like, marine mollusk.

<span class="mw-page-title-main">Epimeniidae</span> Family of molluscs

Epimeniidae is a family of solenogaster, a shell-less worm-like mollusk.

Acanthomeniidae is a family of solenogaster, a shell-less worm-like mollusk.

Amphimeniidae is a family of solenogaster, a shell-less worm-like mollusk.

References

  1. ↑ MolluscaBase eds. (2021). MolluscaBase. Solenogastres. Accessed through: World Register of Marine Species at: http://www.marinespecies.org/aphia.php?p=taxdetails&id=2094 on 2021-04-14
  2. ↑ e.g. Todt, C.; Okusu, A.; Schander, C. & Schwabe, E. (2008). "Solenogastres, Caudofoveata and Polyplacophora.". In Ponder, W. & Lindberg D. (eds.). Phylogeny and Evolution of the Mollusca. University of California Press. ISBN   978-0-520-25092-5.
  3. 1 2 3 Scheltema, A. H. (1999). "Two solenogaster molluscs, Ocheyoherpia trachia n.sp. From Macquarie Island and Tegulaherpia tasmanica Salvini-Plawen from Bass Strait (Aplacophora: Neomeniomorpha)". Records of the Australian Museum. 51: 23–31. doi: 10.3853/j.0067-1975.51.1999.1266 .
  4. ↑ Wilbur, Karl M.; Trueman, E.R.; Clarke, M.R., eds. (1985), "2. Early evolution and the Primitive Groups", The Mollusca, vol. 10. Evolution, New York: Academic Press, ISBN   0-12-728702-7
  5. 1 2 Todt, C.; Wanninger, A. (2010). "Of tests, trochs, shells, and spicules: Development of the basal mollusk Wirenia argentea (Solenogastres) and its bearing on the evolution of trochozoan larval key features". Frontiers in Zoology. 7 (1): 6. doi: 10.1186/1742-9994-7-6 . PMC   2828982 . PMID   20181015.
  6. ↑ Okusu, A. (2002). "Embryogenesis and development of Epimenia babai (Mollusca: Neomeniomorpha)". The Biological Bulletin. 203 (1): 87–103. doi:10.2307/1543461. JSTOR   1543461. PMID   12200259. S2CID   39411465.
  7. ↑ Vortsepneva, Elena; Chevaldonné, Pierre; Klyukina, Alexandra; Naduvaeva, Elizaveta; Todt, Christiane; Zhadan, Anna; Tzetlin, Alexander; Kublanov, Ilya (2021-12-15). "Microbial associations of shallow-water Mediterranean marine cave Solenogastres (Mollusca)". PeerJ. 9: e12655. doi: 10.7717/peerj.12655 . ISSN   2167-8359. PMC   8684320 . PMID   35003936.
  8. ↑ Guralnick, R.; Smith, K. (1999). "Historical and biomechanical analysis of integration and dissociation in molluscan feeding, with special emphasis on the true limpets (Patellogastropoda: Gastropoda)". Journal of Morphology. 241 (2): 175–195. doi:10.1002/(SICI)1097-4687(199908)241:2<175::AID-JMOR7>3.0.CO;2-0. PMID   10420163. S2CID   14497120.
  9. ↑ Scheltema, A. H.; Jebb, M. (1994). "Natural history of a solenogaster mollusc from Papua New Guinea,Epimenia australis(Thiele) (Aplacophora: Neomeniomorpha)". Journal of Natural History. 28 (6): 1297. doi:10.1080/00222939400770661.
  10. ↑ Wilson, N.; Rouse, G.; Giribet, G. (2010). "Assessing the molluscan hypothesis Serialia (Monoplacophora+Polyplacophora) using novel molecular data". Molecular Phylogenetics & Evolution. 54 (1): 187–193. doi:10.1016/j.ympev.2009.07.028. PMID   19647088.
  11. ↑ Bergmeier, Franziska S.; Haszprunar, Gerhard; Todt, Christiane; Jörger, Katharina M. (September 2016). "Lost in a taxonomic Bermuda Triangle: comparative 3D-microanatomy of cryptic mesopsammic Solenogastres (Mollusca)". Organisms Diversity & Evolution. 16 (3): 613–639. doi:10.1007/s13127-016-0266-6. ISSN   1439-6092. S2CID   256005322.

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