Pyramidellidae,

common name In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often contrast ...

the pyram family, or pyramid shells, is a voluminous taxonomic

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

of mostly small and minute

ectoparasitic Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson ha ...

sea snail Sea snail is a common name for slow-moving marine gastropod molluscs, usually with visible external shells, such as whelk or abalone. They share the taxonomic class Gastropoda with slugs, which are distinguished from snails primarily by the ...

s, marine

heterobranch Heterobranchia, the ''heterobranchs'' (meaning "different-gilled snails"), is a taxonomic clade of snails and slugs, which includes marine, aquatic and terrestrial gastropod mollusks. Heterobranchia is one of the main clades of gastropods. Cur ...

gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...

molluscs. The great majority of species of pyrams are

micromollusc A micromollusk is a shelled mollusk which is extremely small, even at full adult size. The word is usually, but not exclusively, applied to marine mollusks, although in addition, numerous species of land snails and freshwater mollusks also r ...

s. The pyram family is distributed worldwide with more than 6,000 named species in more than 350 nominal genera and subgenera. This family of micromollusks has been little studied and the

phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

relationships within the family are not well worked out. There is an absence of a general consensus regarding which species belong to a specific genus or subgenus, contributing to much confusion. Schander (1999) names more than 300 supraspecific names. As there has been no serious generic revision of the genera worldwide, generic

polyphyly A polyphyletic group is an assemblage of organisms or other evolving elements that is of mixed evolutionary origin. The term is often applied to groups that share similar features known as homoplasies, which are explained as a result of converg ...

can be expected to be rampant throughout the family. However, the family itself is deemed monophyletic. However a study in 2011 seems to indicate that this family is deeply nested within the

Pulmonata Pulmonata or pulmonates, is an informal group (previously an order, and before that a subclass) of snails and slugs characterized by the ability to breathe air, by virtue of having a pallial lung instead of a gill, or gills. The group includ ...

instead of the Heterobranchia. The family is currently divided into 11 subfamilies ( Ponder &

Lindberg Lindberg is a municipality in the district of Regen in Bavaria in Germany in the immediate neighbourhood of the larger town Zwiesel. Location Lindberg lies in the Danube Forest (''Donau-Wald'') region in the middle of the Bavarian Forest on ...

1997). An alternative interpretation is that the family Pyramidellidae is but one of six families within the superfamily

Pyramidelloidea Pyramidelloidea is a superfamily of mostly very small sea snails, marine gastropod mollusks and micromollusks within the clade Panpulmonata. This is a voluminous taxon: above the species level close to 400 named taxa are referred to this gast ...

( Schander, van Aartsen & Corgan 1999). Many species are rare or infrequently recorded.

Subfamilies

Subfamilies included within the family Pyramidellidae vary according to the taxonomy consulted. The currently leading taxonomy is the taxonomy of Bouchet & Rocroi (2005).

1997 taxonomy

Taxonomy of Pyramidellidae by Ponder & Lindberg (1997): * Chrysallidinae Saurin, 1958 * Cingulininae Saurin, 1959 * Cyclostremellinae Moore, 1966 * Eulimellinae Saurin, 1958 * Odostomellinae Saurin, 1959 * Odostomiinae Pelseneer, 1928 * Pyramidellinae J.E. Gray, 1840 * Sayellinae Wise, 1996 * Syrnolinae Saurin, 1958 * Tiberiinae Saurin, 1958 *

Turbonillinae Turbonillinae is a subfamily of mostly minute parasitic sea snails, marine gastropod molluscs in the family Pyramidellidae, the pyrams and their allies.MolluscaBase (2018). Turbonillinae Bronn, 1849. Accessed through: World Register of Mari ...

Bronn, 1849

1999 taxonomy

Taxonomy of Pyramidellidae by Schander, Van Aartsen & Corgan (1999): *Superfamily

Gray, 1840 **Family

Amathinidae Amathinidae, is a taxonomic family mostly consisting of small and minute sea snails, marine heterobranch gastropod molluscs or micromolluscs in the superfamily Pyramidelloidea. Together with Pyramidellidae, Ebalidae, Turbonillidae, Odostomid ...

Ponder, 1987 **Family

Ebalidae Murchisonellidae is a taxonomic family of sea snails, marine opisthobranch gastropod mollusks in the superfamily Murchisonelloidea.Bouchet, P. (2015). Murchisonellidae Casey, 1904. Accessed through: World Register of Marine Species at http://ww ...

Warén, 1994 - synonym: Anisocyclidae van Aartsen, 1995 **Family Odostomiidae Pelseneer, 1928 ***Subfamily Odostomiinae Pelseneer, 1928 ***Subfamily Chrysallidinae Saurin, 1958 ***Subfamily Odostomellinae Saurin, 1958 ***Subfamily Cyclostremellinae Moore, 1966 **Family Pyramidellidae J. E. Gray, 1840 ***Subfamily Pyramidellinae J. E. Gray, 1840 ***Subfamily Sayellinae Wise, 1996 **Family

Syrnolidae Syrnolininae is a subfamily of minute parasitic sea snails, marine heterobranch gastropod molluscs in the family Pyramidellidae, the pyrams and their allies. Taxonomy According to the taxonomy of Ponder & Lindberg (1997), this was one of eleve ...

Saurin, 1958 ***Subfamily Syrnolinae Saurin, 1958 ***Subfamily Tiberiinae Saurin, 1958 **Family Turbonillidae Bronn, 1849 ***Subfamily

Bronn, 1849 ***Subfamily Eulimellinae Saurin, 1958 ***Subfamily Cingulininae Saurin, 1959

2005 taxonomy

Taxonomy of Pyramidellidae by Bouchet & Rocroi (2005): *Subfamily Pyramidellinae Gray, 1840 **Tribe Pyramidellini Gray, 1840 - synonyms: Obeliscidae A. Adams, 1863 (inv.); Plotiidae Focart, 1951 (inv.) **Tribe Sayellini Wise, 1996 - formerly subfamily Sayellinae *Subfamily Odostomiinae Pelseneer, 1928 **Tribe Odostomiini Pelseneer, 1928 - synonyms: Ptychostomonidae Locard, 1886; Liostomiini Schander, Halanych, Dahlgren & Sundberg, 2003 (n.a.) **Tribe Chrysallidini Saurin, 1958 - formerly subfamily Chrysallidinae, synonyms: Menesthinae Saurin, 1958; Pyrgulininae Saurin, 1959 **Tribe Cyclostremellini D. R. Moore, 1966 - formerly subfamily Cyclostremellinae **Tribe

Odostomellini Odostomellini is a taxonomic tribe of minute sea snails, marine gastropod molluscs within the family Pyramidellidae the pyrams and their allies. Taxonomy Odostomellinae has been one of eleven recognised subfamilies of the family Pyramidelli ...

Saurin, 1959 - formerly subfamily Odostomellinae *Subfamily Syrnolinae Saurin, 1958 - formerly subfamily Syrnolinae **Tribe Syrnolini Saurin, 1958 **Tribe Tiberiini Saurin, 1958 - formerly subfamily Tiberiinae *Subfamily

Bronn, 1849 **Tribe Turbonillini Bronn, 1849 - synonym: Chemnitziinae Stoliczka, 1868 **Tribe

Cingulinini Cingulinini is a taxonomic tribe of very small sea snails, marine gastropod mollusks in the family Pyramidellidae, the pyrams and their allies. Taxonomy Cingulininae was first introduced by Saurin in 1959, and according to Schander, Van Aarts ...

Saurin, 1958 - formerly subfamily Cingulininae **Tribe

Eulimellini Eulimellini is a tribe of minute sea snails, marine gastropod molluscs in the family Pyramidellidae, the pyrams and their allies. Taxonomy According to Schander, Van Aartsen & Corgan (1999) there are 17 genera in the Eulimellinae. As "Eulimel ...

Saurin, 1958 - formerly subfamily Eulimellinae * Pyramidellidae incertae sedis ** '' Bulimoscilla'' Robba, 2013 ** '' Maricarmenia'' Peñas & Rolán, 2017 ** '' Pyrabinella'' Faber, 2013 ** '' Pyramidellidae incertae sedis insularis'' Oliver, 1915 In 2010 the family Pyramidellidae has been recognized as

monophyletic In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro ...

In 2017 the genera '' Helodiamea'' Peñas & Rolán, 2017 of deep-water Pyramidelloidea from the Central and South Pacific, and the '' Perheida'' Peñas & Rolán, 2017 were recognized.

Problematic taxa

The following genera are currently difficult to place within existing subtaxa of the Pyramidellidae. * '' Charilda'' Iredale, 1929 * '' Contraxiala'' Laseron, 1956 * '' Cossmannica'' Dall & Bartsch, 1904 * '' Eulimotibera'' Nomura, 1939 * '' Finlayola'' Laws, 1937 * '' Morrisonetta'' Brandt, 1968 * '' Peristichia'' Dall, 1889 * ''

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'' Dall & Bartsch, 1904 * '' Vagna'' Dall & Bartsch, 1904 The following species is of uncertain placement within Pyramidellidae. * '' "Epigrus" insularis'' Oliver, 1915

Synonyms

The following genera have become synonyms (but some species in this genera have not yet been reassigned) : * ''Actaeopyramis'' P. Fischer, 1885: synonym of '' Monotigma'' G.B. Sowerby II, 1839 * ''Amaura'' Møller, 1842: synonym of '' Aartsenia'' Warén, 1991 * ''Auriculina'' Gray, 1847: synonym of '' Ondina'' de Folin, 1870 * ''Besla'' Dall & Bartsch, 1904: synonym of '' Parthenina'' Bucquoy, Dautzenberg & Dollfus, 1883 * ''Brachystomia'' Monterosato, 1884: synonym of '' Odostomia'' Fleming, 1813 * ''Chemnitzia'' d'Orbigny, 1839: synonym of ''

Turbonilla ''Turbonilla'' is a large genus of ectoparasitic sea snails, marine gastropod molluscs in the family Pyramidellidae, the pyrams and their allies.Bouchet, P.; Gofas, S. (2011). ''Turbonilla'' Risso, 1826. Accessed through: World Register o ...

'' Risso, 1826 * ''Elusa'' A. Adams, 1861: synonym of '' Tropaeas'' Dall & Bartsch, 1904 * ''Folinella'' Dall & Bartsch, 1904: synonym of '' Chrysallida'' Carpenter, 1856 * ''Iole'' A. Adams, 1860: synonym of '' Iolaea'' A. Adams, 1867 * ''Iolina'' Baily, 1948: synonym of '' Iolaea'' A. Adams, 1867 * ''Ividella'' Dall & Bartsch, 1909: synonym of '' Chrysallida'' Carpenter, 1856 * ''Lonchaeus'' : synonym of '' Longchaeus'' Mörch, 1875 * ''Moerchiella'' Thiele, 1924 : synonym of '' Moerchia'' A. Adams, 1860 * ''Moerchinella'' Thiele, 1931: synonym of '' Moerchia'' A. Adams, 1860 * ''Monoptygma'': synonym of '' Monotigma'' G.B. Sowerby II, 1839 * ''Monotygma'' G.B. Sowerby II, 1839: synonym of '' Monotigma'' G.B. Sowerby II, 1839 * ''Noemia'' de Folin, 1870: synonym of '' Noemiamea'' de Folin, 1886 * ''Obeliscus'' Gray, 1847: synonym of '' Pyramidella'' Lamarck, 1799 * ''Obex'' Laws, 1940: synonym of '' Obexomia'' Laws, 1941 * ''Odontostoma'' Philippi, 1853: synonym of '' Odostomia'' Fleming, 1813 * ''Odontostomia'' G.B. Sowerby I, 1839: synonym of '' Odostomia'' Fleming, 1813 * ''Parthenia'' Lowe, 1840: synonym of '' Parthenina'' Bucquoy, Dautzenberg & Dollfus, 1883 * ''Parthenina'' Bucquoy, Dautzenberg & Dollfus, 1883: synonym of '' Chrysallida'' Carpenter, 1856 * ''Partulida'' Schaufuss, 1869: synonym of '' Chrysallida'' Carpenter, 1856 * ''Planipyrgiscus'' ic synonym of ''

Planpyrgiscus ''Planpyrgiscus'' is a genus of sea snails, marine gastropod mollusks in the family Pyramidellidae Pyramidellidae, common name the pyram family, or pyramid shells, is a voluminous taxonomic family of mostly small and minute ectoparasitic sea s ...

'' Laws, 1937 * ''Plotia'' Röding, 1798: synonym of '' Pyramidella'' Lamarck, 1799 * ''Ptychostomon'' Locard, 1886: synonym of '' Odostomia'' Fleming, 1813 * ''Pyrgulina'' A. Adams, 1864: synonym of '' Chrysallida'' Carpenter, 1856 * ''Raoulostraca'' Oliver, 1915: synonym of ''

Eulimella ''Eulimella'' is a genus of sea snails, marine gastropod mollusks in the family Pyramidellidae, the pyrams and their allies.Bouchet, P.; Gofas, S. (2011). ''Eulimella'' Forbes & M'Andrew, 1846. Accessed through: World Register of Marine Species ...

'' Forbes & M'Andrew, 1846 * ''Tragula'' Monterosato, 1884: synonym of '' Chrysallida'' Carpenter, 1856 * ''Tropeas'' ic synonym of '' Tropaeas'' Dall & Bartsch, 1904

Distribution

This family is found worldwide, but many species are only found in relatively small geographical ranges. The species found at the Cape Verdes are mainly

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

species.

Shell description

The length of the slender, elongated (turreted or conical) shells varies between 0.5 mm and 3.5 cm, but most species in the family have shells which are smaller than 13 mm. The texture of these shells is smooth or

sculptured Sculptured is an American experimental and progressive metal band, mixing melodic and atonal segments. Biography Following the dissolution of his previous band, guitarist Don Anderson began Sculptured as mostly a one-man project in 1996. With ...

in various forms such as ribs and spirals. Their color is mostly white, cream or yellowish, sometimes with red or brown lines. The

shell Shell may refer to: Architecture and design * Shell (structure), a thin structure ** Concrete shell, a thin shell of concrete, usually with no interior columns or exterior buttresses ** Thin-shell structure Science Biology * Seashell, a hard o ...

of these snails has a blunt, heterostrophic (i.e. whorls appear to be coiled in the opposite direction to those of the teleoconch) protoconch, which is often pointed sideways or wrapped up. The

teleoconch The gastropod shell is part of the body of a gastropod or snail, a kind of mollusc. The shell is an exoskeleton, which protects from predators, mechanical damage, and dehydration, but also serves for muscle attachment and calcium storage. Some ...

is dextrally coiled, but the

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. ...

l shells are

sinistral Sinistral and dextral, in some scientific fields, are the two types of chirality ("handedness") or relative direction. The terms are derived from the Latin words for "left" (''sinister'') and "right" (''dexter''). Other disciplines use different ...

. This results in a sinistrally coiled protoconch. The

columella Lucius Junius Moderatus Columella (; Arabic: , 4 – ) was a prominent writer on agriculture in the Roman Empire. His ' in twelve volumes has been completely preserved and forms an important source on Roman agriculture, together with the wo ...

has usually one, but sometimes several, spiral folds. The

aperture In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane. An ...

is closed by an oligogyrous operculum. The operculum is ovoid and paucispiral, with the apex anterior, a thread-like arcuate ridge on the proximal side, the inner margin notched in harmony with the plaits of the pillar when prominent. The species are characterized by the lack of jaw or radula, because they are ectoparasites (mostly on

polychaetes Polychaeta () is a paraphyletic class of generally marine annelid worms, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made ...

or other molluscs).

Life habits

The Pyramidellidae are ectoparasites, feeding mainly on other molluscs and on annelid

worm Worms are many different distantly related bilateral animals that typically have a long cylindrical tube-like body, no limbs, and no eyes (though not always). Worms vary in size from microscopic to over in length for marine polychaete wo ...

s, but some are known to feed on

peanut worms The Sipuncula or Sipunculida (common names sipunculid worms or peanut worms) is a class containing about 162 species of unsegmented marine annelid worms. The name ''Sipuncula'' is from the genus name ''Sipunculus'', and comes from the Latin ' ...

and

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...

s. A few species in the family Pyramidellidae, such as '' Otopleura mitralis'', are symbiotic with sea anemones, such as '' Neoaiptasia morbilla''. They do not have a radula. Instead their long

proboscis A proboscis () is an elongated appendage from the head of an animal, either a vertebrate or an invertebrate. In invertebrates, the term usually refers to tubular mouthparts used for feeding and sucking. In vertebrates, a proboscis is an elong ...

is used to pierce the skin of its prey and suck up its fluids and soft tissues. The eyes on the grooved tentacles are situated toward the base of the tentacles. These tentacles have a concave surface. Between the head and the propodium (the foremost division of the foot), a lobed process called the

mentum The mentum is an anatomical structure, a projecting feature that is near the mouth of a variety of animals: *In insects, the mentum is the distal part of the labium. The mentum bears the palps, glossae, paraglossae, and/or ligula. *On the huma ...

(= thin projection) is visible. This mentum is slightly indented in midline. These gastropods are

hermaphrodite In reproductive biology, a hermaphrodite () is an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes. Many Taxonomy (biology), taxonomic groups of animals (mostly invertebrate ...

s, laying eggs in jelly-like masses on the shell of its host. Some species have

spermatophore A spermatophore or sperm ampulla is a capsule or mass containing spermatozoa created by males of various animal species, especially salamanders and arthropods, and transferred in entirety to the female's ovipore during reproduction. Spermatophores ...

Name derived from shape

The name of this taxonomic family comes from the shape of the shell, which is like a

pyramid A pyramid (from el, πυραμίς ') is a structure whose outer surfaces are triangular and converge to a single step at the top, making the shape roughly a pyramid in the geometric sense. The base of a pyramid can be trilateral, quadrilat ...

. More specifically, the shape is like a right circular

cone A cone is a three-dimensional geometric shape that tapers smoothly from a flat base (frequently, though not necessarily, circular) to a point called the apex or vertex. A cone is formed by a set of line segments, half-lines, or lines con ...

, which is equivalent to a right pyramid whose base has many sides.Robbins, Edward.
Plane and Solid Geometry
', p. 349 (American Book Company, 1907).

References

External links

*
Gallery of pyramidellids
{{Taxonbar, from=Q14550957 Taxa named by John Edward Gray Gastropod families