Class

Gastropoda Cuvier, 1797

Gastropods

Taxon overview

The Gastropoda or gastropods, more commonly known as snails and slugs, are a large taxonomic class within the phylum Mollusca.
Snails are distinguished by an anatomical process known as torsion, where the visceral mass of the animal rotates 180° to one side during development, such that the anus is situated more or less above the head. This process is unrelated to the coiling of the shell, which is a separate phenomenon. Torsion is present in all gastropods, but the opisthobranch gastropods are secondarily de-torted to various degrees.
Gastropods typically have a well-defined head with two or four sensory tentacles with eyes, and a ventral foot, which gives them their name (Greek gaster, stomach, and poda, feet). The larval shell of a gastropod is called a protoconch.
The class Gastropoda contains a vast total of named species, second only to the insects in overall number. The fossil history of this class goes back to the early Cambrian.

Selection of related publications
Vinn, O., Wilson, M. A., Isakar, M., Toom, U. 2025. Rare Arachnostega traces in brachiopod and gastropod molds from the Silurian of Gotland (Sweden) and Saaremaa (Estonia): was tropical climate unfavorable for the trace makers?. Neues Jahrbuch für Geologie und Paläontologie. Abhandlungen 313, 2, 153-159. DOI:10.1127/njgpa/2024/1226
Nützel, A., Ebbestad, J. O., Seuss, B., Munnecke, A., Mapes, R. H., Cook, A. G. 2023. On Paleozoic platycerate gastropods. Zitteliana 97, 29-51. DOI:10.3897/zitteliana.97.115688
Toom, U., Vinn, O., Isakar, M., Madison, A., Hints, O. 2020. Small faecal pellets in Ordovician shelly fossils from Estonia, Baltoscandia. Estonian Journal of Earth Sciences 69, 1, 1-19. DOI:10.3176/earth.2020.01
Vinn, O., Wilson, M. A. 2013. Silurian cornulitids of Estonia (Baltica). Carnets de Géologie A09, 357-367. DOI:10.4267/2042/53034
Ebbestad, J. O. R., Lindström, A., Peel, J. S. 2009. Predation on bellerophontiform molluscs in the Palaeozoic. Lethaia 42, 4, 469-485. DOI:10.1111/j.1502-3931.2009.00167.x
Ebbestad, J. O. R., Högström, A. E. S. 2007. Locality descriptions, the Siljan District. WOGOGOB 2007. 9th meeting of the Working Group on Ordovician Geology of Baltoscandia. Field guide and Abstracts, pp. 52-58. SGU.
Frisk, Ǻ. M., Ebbestad, J. O. R. 2007. Paragastropoda, Tergomya and Gastropoda (Mollusca) from the Upper Ordovician Dalby Limestone, Sweden. GFF 129, 2, 83-99. DOI:10.1080/11035890701292083
Isakar, M., Ebbestad, J. O. R. 2000. Bucania (Gastropoda) from the Ordovician of Estonia. Paläontologische Zeitschrift 74, 1-2, 51-68. DOI:10.1007/BF02987951
Isakar, M., Ebbestad, J. O. R., Peel, J. S. 1999. Homeomorphic gastropods from the Silurian of Norway, Estonia and Bohemia. Norsk Geologisk Tidsskrift 79, 4, 281-288. DOI:10.1080/002919699433717
Isakar, M. 1995. The platyceratacean gastropod Cyclonema (Cyclonema) hiiumaa Teichert, 1928 from the Llandovery (Silurian) of Estonia. Proceedings of the Estonian Academy of Sciences. Geology 44, 3, 184-187. DOI:10.3176/geol.1995.3.04
Isakar, M. 1991. Harjuan (Late Ordovician) new Bivalves and a new Gastropod from North Estonia. Acta et Commentationes Universitatis Tartuensis 934, 43-60.
Isakar, M. 1990. Bivalvia and Gastropoda. Field Meeting Estonia 1990. An Excursion Guidebook, pp. 64-65. Estonia Academy of Sciences.
Kiselev, G. N., Sinicyna, I. N., Isakar, M. A., Mironova, M. G., Saladzhius, V. Y. 1990. Atlas mollûskov verhnego ordovika i silura severo-zapada Vostočno-Evropejskoj platformy. pp. 1-80. Leningrad University.
Linsley, R. M., Peel, J. S. 1983. Gonad pouches in a new clam-like monoplacophoran from the Silurian of Sweden. Lethaia 16, 3, 273-280. DOI:10.1111/j.1502-3931.1983.tb02009.x
Peel, J. S., Yochelson, E. L. 1976. Two new gastropod genera from the Lower Silurian of the Oslo Region, Norway. Norsk Geologisk Tidsskrift 56, 1, 15-27.
Rõõmusoks, A. 1970. Stratigraphy of the Viruan Series (Middle Ordovician) in Northern Estonia, I. pp. 1-346. Valgus.
Saladžius, V. J. 1966. Mollusk fauna of the Silurian deposits of the south of the East Baltic territory. Palaeontology and stratigraphy of the Baltic and the Byelorussia. Number I (VI), pp. 31-73. Mintis.
Öpik, A. 1930. Beiträge zur Kenntnis der Kukruse-(C2-C3-)Stufe in Eesti. IV. Tartu Ülikooli Geoloogia Instituudi Toimetused 24, 1-34.
Koken, E., Perner, J. 1925. Die Gastropoden des baltischen Untersilurs. Zapiski Rossiiskoi Akademii Nauk 37, 1, 1-318.
Bekker, H. 1925. Lühike ülevaade Eesti geoloogiast (Eozoiline ja paleozoiline ladekond). Eesti Loodus. Äratrükk koguteosest "Eesti", pp. 31-61.
Bekker, H. 1924. Devon Irboska ümbruses: stratigraafia, fauna ja paleogeograafia. Eesti Loodusteaduse Arhiiv X, 1, 1-55. K. Mattiesen.
Schvets, F. P. 1912. Fauna Tšokrakskogo izvestnjaka Kertchenskogo poluostrova. Verhandlungen der Russisch-Kaiserlichen Mineralogischen Gesellschaft zu St. Petersburg XLIX, 2, 251-380. Tipo-litograafia K. Birkenfelda.
Koken, E. 1897. Die Gastropoden des baltischen Untersilurs. Bull. Sci. Acad. Imp. Sci. Saint-Petersbourg 7, 2, 97-214.
Koken, E. 1896. Die Leitfossilien. Ein Handbuch für den Unterricht und für das Bestimmen von Versteinerungen. pp. 1-848. Chr. Herm. Tauchnitz.
Lindström, G. 1884. On the Silurian Gastropoda and Pteropoda of Gotland. Kungliga Svenska Vetenskapsakademiens Handlingar 19, 6, 1-250. P. A. Norstedt.
Kjerulf, T. 1865. Veiviser ved geologiske excursioner i Christiania Omegn med et Farvetrykt Kart or Flere Traensit. Universitätsprogram for andet Halvaar 1865. pp. . Brøgger & Christie's Bogtrykkeri.
Eichwald, E. 1861. Paleontologiâ Rossii. Drevnij period. II. Fauna grauvakkovoj, gornoizvestkovoj i medistoslancevatoj formacij Rossii. pp. 1-521. R. Golike (former Ya. Ionsona).
Eichwald, E. 1860. Lethaea Rossica ou Paléontologie de la Russie. Premier volume. Ancienne Période en deux sections. pp. XIX+1–1657. E. Schweizerbart. DOI:10.5962/bhl.title.52391
Schmidt, Fr. 1858. Untersuchungen über die Silurische Formation von Ehstland, Nord-Livland und Oesel. Archiv für die Naturkunde Liv-, Ehst- und Kurlands 2, 1, 1-249. Heinrich Laakmann.
Eichwald, E. 1856. Beitrag zur geographischen Verbreitung der fossilen Thiere Russlands. Alte Periode. (Fortsetzung. S. Bulletin 1856. N 2. pag. 406.). Bulletin of the Moscow Society of Naturalists. Geological series 29, IV, 555-608.
Eichwald, E. 1854. Die Grauwackenschichten von Liv- und Estland. Bulletin de la Société Imperiale des Naturalistes de Moscou 27, 1, 1-111.
Pacht, R. 1849. Der devonische Kalk in Livland. Ein Beitrag zur Geognosie der Ostseeprovinzen. pp. 1-52. J. C. Schünmann's Wittwe und C. Mattiesen.
Eichwald, E. 1842. Neuer Beitrag zur Geognosie Estlands und Finlands. Die Urwelt Russlands, durch Abbildungen erlautert. Zweites Heft, pp. 1-138, plate I-III.
Eichwald, E. von 1840. Ueber das silurische Schichten-system in Esthland. Zeitschrift für Natur- und Heilkunde 1-2, 1-210. DOI:10.5962/bhl.title.150763
List of species
4. Boucotspira carinifer (Koken, 1896) | Vormsi Stage→Pirgu Stage
5. Brachytomaria baltica (Verneuil, 1845) | Jõhvi Substage→Rakvere Stage
6. Brachytomaria nodulosa (Schmidt, 1858) | Nabala Stage→Pirgu Stage
8. Brachytomaria plicifera (Eichwald, 1854) | Vormsi Stage→Pirgu Stage
11. Bucania cornu Koken, 1897 | Vormsi Stage→Pirgu Stage
17. Bucania radiata (Eichwald, 1856) | Rakvere Stage→Pirgu Stage
18. Bucania salpinx (Koken, 1897) | Middle Ordovician
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Classification
Organism groupBiota
KingdomAnimalia
PhylumMollusca
SubphylumConchifera
ClassBivalvia
Cephalopoda
Diplacophora
Gastropoda
SubclassArchaeobranchia
Archaeogastropoda
Eogastropoda
Neritimorpha
Orthogastropoda
Prosobranchia
Streptoneura
Vetigastropoda
OrderBellerophontida
Heterostropha
SuperfamilyPatelloidea
GenusSemizona
ClassHelcionelloida
Hyolitha
Paragastropoda
Polyplacophora
Rostroconchia
Tergomya
FamilyChelodina
GenusEesticonus
Eobucania
Jinonicella
See also