Not to be confused with the bivalve order Protobranchia.
Prosobranchia was a large taxonomicsubclass of sea snails, land snails and freshwater snails. This taxon of gastropods dates back to the 1920s. It has however been proven to be polyphyletic (consisting of more than one lineage of descent). Generally speaking in biology taxonomy is required to reflect phylogeny, in other words the classification of a group must reflect its evolutionary descent, as far as that is known, so the taxon Prosobranchia is no longer considered suitable to be used.
One can still encounter this subclass used as if it is still valid in many texts and websites. Although Prosobranchia is no longer generally accepted as a taxon by people who study living Mollusca, still the term prosobranch is legitimately used as an anatomically descriptive adjective or noun, and the taxon Prosobranchia is still sometimes used by paleontologists.
Prosobranch means gills in front (of the heart). In contrast opisthobranch means gills behind (and to the right of the heart). Prosobranchs have their gills, mantle cavity and anus situated in front of their heart. Most prosobranchs have separate sexes.
The majority of marinegastropods are prosobranch, as are a few land snails and freshwater snails. The prosobranch gastropods include the majority of marine snails, among them conches, cones, cowries, limpets, murexes, periwinkles, volutes and whelks, as well as numerous freshwater groups, and some land snails with an operculum.
Descriptionedit
Three views of a shell of a Harpa species, a prosobranch gastropod.Chicoreus ramosus, a prosobranch gastropod.
The majority of prosobranchs have an operculum, a corneous or calcareous plate situated on the dorsal surface of the foot. In many prosobranchs, the animal can completely close the aperture with the operculum.
The nervous system of prosobranchs is twisted into a figure 8 due to a developmental process known as torsion. The eyes are situated at the base of the tentacles.
Bieler, R. & P. M. Mikkelsen (eds.), 1992. Handbook of Systematic Malacology, Part 1 (Loricata [Polyplacophora]; Gastropoda: Prosobranchia). Smithsonian Institution and National Science Foundation, xviii + 625 pp., 470+1 text-fig. (Annotated English-language edition of: Thiele, J., Handbuch der systematischen Weichtierkunde, Teil 1). Also published, in 1993, by Gustav Fischer Verlag, Stuttgart/Jena/New York.
Bieler, R. (1992). "Gastropod phylogeny and systematics". Annual Review of Ecology and Systematics. 23: 311–338. doi:10.1146/annurev.es.23.110192.001523.
Haszprunar, G. (1988). "On the origin and evolution of major gastropod groups, with special reference to the Streptoneura". Journal of Molluscan Studies. 54 (4): 367–441. doi:10.1093/mollus/54.4.367.
Bieler, R. (1990). "Haszprunar's "clado-evolutionary" classification of the Gastropoda - a critique". Malacologia. 31 (2): 371–380.
December 08, 2023
prosobranchia, confused, with, bivalve, order, protobranchia, large, taxonomic, subclass, snails, land, snails, freshwater, snails, this, taxon, gastropods, dates, back, 1920s, however, been, proven, polyphyletic, consisting, more, than, lineage, descent, gene. Not to be confused with the bivalve order Protobranchia Prosobranchia was a large taxonomic subclass of sea snails land snails and freshwater snails This taxon of gastropods dates back to the 1920s It has however been proven to be polyphyletic consisting of more than one lineage of descent Generally speaking in biology taxonomy is required to reflect phylogeny in other words the classification of a group must reflect its evolutionary descent as far as that is known so the taxon Prosobranchia is no longer considered suitable to be used Shells from a variety of prosobranch gastropods from Ernst Haeckel s Artforms of Nature 1904 One can still encounter this subclass used as if it is still valid in many texts and websites Although Prosobranchia is no longer generally accepted as a taxon by people who study living Mollusca still the term prosobranch is legitimately used as an anatomically descriptive adjective or noun and the taxon Prosobranchia is still sometimes used by paleontologists Prosobranch means gills in front of the heart In contrast opisthobranch means gills behind and to the right of the heart Prosobranchs have their gills mantle cavity and anus situated in front of their heart Most prosobranchs have separate sexes The majority of marine gastropods are prosobranch as are a few land snails and freshwater snails The prosobranch gastropods include the majority of marine snails among them conches cones cowries limpets murexes periwinkles volutes and whelks as well as numerous freshwater groups and some land snails with an operculum Description edit nbsp Three views of a shell of a Harpa species a prosobranch gastropod nbsp Chicoreus ramosus a prosobranch gastropod The majority of prosobranchs have an operculum a corneous or calcareous plate situated on the dorsal surface of the foot In many prosobranchs the animal can completely close the aperture with the operculum The nervous system of prosobranchs is twisted into a figure 8 due to a developmental process known as torsion The eyes are situated at the base of the tentacles Taxonomic context editThe taxonomy of the gastropods is changing rapidly The old classification Johannes Thiele divided Gastropoda into three subclasses Prosobranchia Opisthobranchia and Pulmonata The subclass Prosobranchia Henri Milne Edwards was further divided into the orders Archaeogastropoda Mesogastropoda and Neogastropoda The new version of the gastropod classification is explained in Taxonomy of the Gastropoda Ponder amp Lindberg 1997 References editThiele J 1929 1935 Handbuch der Systematischen Weichtierkunde 2 vols 1154 p 584 figs Bieler R amp P M Mikkelsen eds 1992 Handbook of Systematic Malacology Part 1 Loricata Polyplacophora Gastropoda Prosobranchia Smithsonian Institution and National Science Foundation xviii 625 pp 470 1 text fig Annotated English language edition of Thiele J Handbuch der systematischen Weichtierkunde Teil 1 Also published in 1993 by Gustav Fischer Verlag Stuttgart Jena New York Bieler R 1992 Gastropod phylogeny and systematics Annual Review of Ecology and Systematics 23 311 338 doi 10 1146 annurev es 23 110192 001523 Haszprunar G 1988 On the origin and evolution of major gastropod groups with special reference to the Streptoneura Journal of Molluscan Studies 54 4 367 441 doi 10 1093 mollus 54 4 367 Bieler R 1990 Haszprunar s clado evolutionary classification of the Gastropoda a critique Malacologia 31 2 371 380 Retrieved from https en wikipedia org w index php title Prosobranchia amp oldid 1109930167, wikipedia, wiki, book, books, library,
