Pyramidellidae
Encyclopedia
Pyramidellidae, common name
the pyram family, or pyramid shells, is a voluminous taxonomic family
of mostly small and minute ectoparasitic sea snail
s, marine
heterobranch
gastropod molluscs or micromolluscs.
The pyram family is distributed worldwide with more than 6,000 species in more than 350 genera and subgenera.
This family of micromollusk
s has been little studied and the phylogenetic relationships within the family are not well worked out. It is currently divided into 11 subfamilies (Ponder
& Lindberg
1997). An alternative interpretation is that the family Pyramidellidae is but one of six families within the superfamily Pyramidelloidea
(Schander
, van Aartsen & Corgan 1999). Many species are rare or infrequently recorded.
.
:
, Van Aartsen & Corgan (1999):
:
In 2010 the family Pyramidellidae has been recognized as monophyletic
of the Pyramidellidae.
The texture of these shells is smooth or sculptured
in various forms such as ribs and spirals. Their color is mostly white, cream or yellowish, sometimes with red or brown lines.
The shell
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 is dextrally coiled, but the larva
l shells are sinistral. This results in a sinistrally coiled protoconch.
The columella has usually one, but sometimes several, spiral folds
. The aperture
is closed by an 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.
s, but some are known to feed on peanut worms and crustacean
s.
They do not have a radula
. Instead their long proboscis
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
(= thin projection) is visible. This mentum is slightly indented in midline.
These gastropods are hermaphrodite
s, laying eggs in jelly-like masses on the shell of its host. Some species have spermatophore
s.
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
the pyram family, or pyramid shells, is a voluminous taxonomic family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
of mostly small and minute ectoparasitic sea snail
Sea snail
Sea snail is a common name for those snails that normally live in saltwater, marine gastropod molluscs....
s, marine
Marine (ocean)
Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...
heterobranch
Heterobranchia
Heterobranchia, the heterobranchs or Euthyneura, is a taxonomic clade of snails and slugs, which includes species from the sea, the land and freshwater; marine, aquatic and terrestrial gastropod mollusks....
gastropod molluscs or micromolluscs.
The pyram family is distributed worldwide with more than 6,000 species in more than 350 genera and subgenera.
This family of micromollusk
Micromollusk
A micromollusk is a descriptive term for 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 reach adult size at very small...
s has been little studied and the phylogenetic relationships within the family are not well worked out. It is currently divided into 11 subfamilies (Ponder
Winston Ponder
Winston F. Ponder B.Sc, M.Sc, Ph.D, D.Sc. is a noted malacologist from New Zealand who has named and described many marine animals, especially micromolluscs. He is a graduate of the University of Auckland, New Zealand....
& Lindberg
David R. Lindberg
David R. Lindberg is an American malacologist and professor of integrative biology at the University of California, Berkeley. He is also the Curator for the University of California Museum of Paleontology and co-editor of the journal Molecular Systematics and Phylogeography of Mollusks.Much of his...
1997). An alternative interpretation is that the family Pyramidellidae is but one of six families within the superfamily Pyramidelloidea
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 gastropod superfamily.Pyramidelloidea has both fossil and...
(Schander
Christoffer Schander
Christoffer Schander is professor in marine biology at the University of Bergen, Norway. He is also thematic leader at the Centre of excellence in Geobiology. He was born in Sweden in 1960. His doctoral thesis , from University of Gothenburg, Sweden, treated the evolutionary relationships of the...
, 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)Taxonomy of the Gastropoda (Bouchet & Rocroi, 2005)
The taxonomy of the Gastropoda as it was revised by Philippe Bouchet and Jean-Pierre Rocroi is currently the most up-to-date overall system for classifying gastropod mollusks...
.
1997 taxonomy
Taxonomy of Pyramidellidae by Ponder & Lindberg (1997)Taxonomy of the Gastropoda (Ponder & Lindberg, 1997)
The taxonomy of the Gastropoda, as revised by Winston Ponder and David R. Lindberg in 1997, is an older taxonomy of the class Gastropoda, the class of molluscs consisting of all snails and slugs...
:
- ChrysallidinaeChrysallidinaeChrysallidinae is a taxonomic group of very small sea snails in the family Pyramidellidae.- Taxonomy :Chrysallidinae has been one of eleven recognized subfamilies of the gastropod family Pyramidellidae...
Saurin, 1958 - CingulininaeCingulininaeCingulinini is a taxonomic tribe of very small sea snails, marine gastropod mollusks in the family Pyramidellidae.- Taxonomy :Cingulininae was first introduced by Saurin in 1959, and according to Schander, Van Aartsen & Corgan it comprises seven genera; Cingulina, Cinctigua, Coemansia,...
Saurin, 1959 - CyclostremellinaeCyclostremellinaeCyclostremellini is a tribe, a taxonomic grouping, of minute sea snails, marine gastropod mollusks or micromollusks, in the family Pyramidellidae, the pyrams.- Taxonomy :...
Moore, 1966 - EulimellinaeEulimellinaeEulimellini 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 there are 17 genera in the Eulimellinae....
Saurin, 1958 - OdostomellinaeOdostomellinaeOdostomellini is a taxonomic tribe of minute sea snails, marine gastropod molluscs within the family Pyramidellidae the pyrams and their allies.- Taxonomy :...
Saurin, 1959 - OdostomiinaeOdostomiinaeOdostomiinae, Odostomia snails and their allies, is a taxonomic subfamily of minute parasitic sea snails. These are marine heterobranch gastropod mollusks, or micromollusks, in the family Pyramidellidae.-Taxonomy:...
PelseneerPaul PelseneerJean Paul Louis Pelseneer was a Belgian malacologist, morphologist, ethologist and phylogenist....
, 1928 - PyramidellinaePyramidellinaePyramidellinae is a taxonomic subfamily of minute sea snails, marine gastropod mollusks in the family Pyramidellidae, the pyrams and their allies.- Taxonomy :...
J.E. Gray, 1840 - SayellinaeSayellinaeSayellini is a taxonomic tribe of minute ectoparasitic sea snails, marine gastropod molluscs, or micromollusks, in the very large family Pyramidellidae, the pyrams and their allies.- Taxonomy :...
Wise, 1996 - Syrnolinae Saurin, 1958
- TiberiinaeTiberiinaeTiberia is a genus of minute parasitic sea snails, marine gastropod molluscs in the family Pyramidellidae, the pyrams and their allies.- Taxonomy :...
Saurin, 1958 - TurbonillinaeTurbonillinaeTurbonillinae is a subfamily of mostly minute parasitic sea snails, marine gastropod molluscs in the family Pyramidellidae, the pyrams and their allies.-Taxonomy:...
Bronn, 1849
1999 taxonomy
Taxonomy of Pyramidellidae by SchanderChristoffer Schander
Christoffer Schander is professor in marine biology at the University of Bergen, Norway. He is also thematic leader at the Centre of excellence in Geobiology. He was born in Sweden in 1960. His doctoral thesis , from University of Gothenburg, Sweden, treated the evolutionary relationships of the...
, Van Aartsen & Corgan (1999):
- Superfamily PyramidelloideaPyramidelloideaPyramidelloidea 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 gastropod superfamily.Pyramidelloidea has both fossil and...
Gray, 1840- Family AmathinidaeAmathinidaeAmathinidae, is a taxonomic family mostly consisting of small and minute sea snails, marine heterobranch gastropod molluscs or micromolluscs in the superfamily Pyramidelloidea....
PonderWinston PonderWinston F. Ponder B.Sc, M.Sc, Ph.D, D.Sc. is a noted malacologist from New Zealand who has named and described many marine animals, especially micromolluscs. He is a graduate of the University of Auckland, New Zealand....
, 1987 - Family Ebalidae Warén, 1994 - synonym: Anisocyclidae van Aartsen, 1995
- Family Odostomiidae Pelseneer, 1928
- Subfamily OdostomiinaeOdostomiinaeOdostomiinae, Odostomia snails and their allies, is a taxonomic subfamily of minute parasitic sea snails. These are marine heterobranch gastropod mollusks, or micromollusks, in the family Pyramidellidae.-Taxonomy:...
Pelseneer, 1928 - Subfamily ChrysallidinaeChrysallidinaeChrysallidinae is a taxonomic group of very small sea snails in the family Pyramidellidae.- Taxonomy :Chrysallidinae has been one of eleven recognized subfamilies of the gastropod family Pyramidellidae...
Saurin, 1958 - Subfamily OdostomellinaeOdostomellinaeOdostomellini is a taxonomic tribe of minute sea snails, marine gastropod molluscs within the family Pyramidellidae the pyrams and their allies.- Taxonomy :...
Saurin, 1958 - Subfamily CyclostremellinaeCyclostremellinaeCyclostremellini is a tribe, a taxonomic grouping, of minute sea snails, marine gastropod mollusks or micromollusks, in the family Pyramidellidae, the pyrams.- Taxonomy :...
Moore, 1966
- Subfamily Odostomiinae
- Family Pyramidellidae J. E. Gray, 1840
- Subfamily PyramidellinaePyramidellinaePyramidellinae is a taxonomic subfamily of minute sea snails, marine gastropod mollusks in the family Pyramidellidae, the pyrams and their allies.- Taxonomy :...
J. E. Gray, 1840 - Subfamily SayellinaeSayellinaeSayellini is a taxonomic tribe of minute ectoparasitic sea snails, marine gastropod molluscs, or micromollusks, in the very large family Pyramidellidae, the pyrams and their allies.- Taxonomy :...
Wise, 1996
- Subfamily Pyramidellinae
- Family Syrnolidae Saurin, 1958
- Subfamily Syrnolinae Saurin, 1958
- Subfamily TiberiinaeTiberiinaeTiberia is a genus of minute parasitic sea snails, marine gastropod molluscs in the family Pyramidellidae, the pyrams and their allies.- Taxonomy :...
Saurin, 1958
- Family Turbonillidae Bronn, 1849
- Subfamily TurbonillinaeTurbonillinaeTurbonillinae is a subfamily of mostly minute parasitic sea snails, marine gastropod molluscs in the family Pyramidellidae, the pyrams and their allies.-Taxonomy:...
Bronn, 1849 - Subfamily EulimellinaeEulimellinaeEulimellini 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 there are 17 genera in the Eulimellinae....
Saurin, 1958 - Subfamily CingulininaeCingulininaeCingulinini is a taxonomic tribe of very small sea snails, marine gastropod mollusks in the family Pyramidellidae.- Taxonomy :Cingulininae was first introduced by Saurin in 1959, and according to Schander, Van Aartsen & Corgan it comprises seven genera; Cingulina, Cinctigua, Coemansia,...
Saurin, 1959
- Subfamily Turbonillinae
- Family Amathinidae
2005 taxonomy
Taxonomy of Pyramidellidae by Bouchet & Rocroi (2005)Taxonomy of the Gastropoda (Bouchet & Rocroi, 2005)
The taxonomy of the Gastropoda as it was revised by Philippe Bouchet and Jean-Pierre Rocroi is currently the most up-to-date overall system for classifying gastropod mollusks...
:
- Subfamily PyramidellinaePyramidellinaePyramidellinae is a taxonomic subfamily of minute sea snails, marine gastropod mollusks in the family Pyramidellidae, the pyrams and their allies.- Taxonomy :...
Gray, 1840- Tribe Pyramidellini Gray, 1840 - synonyms: Obeliscidae A. Adams, 1863 (inv.); Plotiidae Focart, 1951 (inv.)
- Tribe Sayellini Wise, 1996 - formerly subfamily Sayellinae
- Subfamily OdostomiinaeOdostomiinaeOdostomiinae, Odostomia snails and their allies, is a taxonomic subfamily of minute parasitic sea snails. These are marine heterobranch gastropod mollusks, or micromollusks, in the family Pyramidellidae.-Taxonomy:...
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 Saurin, 1959 - formerly subfamily Odostomellinae
- Subfamily Syrnolinae Saurin, 1958 - formerly subfamily Syrnolinae
- Tribe Syrnolini Saurin, 1958
- Tribe Tiberiini Saurin, 1958 - formerly subfamily Tiberiinae
- Subfamily TurbonillinaeTurbonillinaeTurbonillinae is a subfamily of mostly minute parasitic sea snails, marine gastropod molluscs in the family Pyramidellidae, the pyrams and their allies.-Taxonomy:...
Bronn, 1849- Tribe Turbonillini Bronn, 1849 - synonym: Chemnitziinae Stoliczka, 1868
- Tribe Cingulinini Saurin, 1958 - formerly subfamily Cingulininae
- Tribe Eulimellini Saurin, 1958 - formerly subfamily Eulimellinae
In 2010 the family Pyramidellidae has been recognized as monophyletic
Problematic genera
The following genera are currently difficult to place within existing subtaxaTaxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...
of the Pyramidellidae.
- Contraxalia LaseronCharles Francis LaseronCharles Francis Laseron , was an American-born Australian naturalist and malacologist.Charles Laseron was born on 6 December 1887 at Manitowoc, Wisconsin, United States of America, to English parents the Rev...
, 1956 - CossmannicaCossmannicaCossmannica is a genus of sea snails, marine gastropod mollusks in the family Pyramidellidae, the pyrams and their allies.-Species:Species within the genus Cossmannica include:* Cossmannica aciculata A...
Dall & Bartsch, 1904 - Eulimotibera Nomura, 1939
- Morrisonetta Brandt, 1968
- PeristichiaPeristichiaPeristichia is a genus of sea snails, marine gastropod mollusks in the family Pyramidellidae, the pyrams and their allies.-Species:Species within the genus Peristichia include:* Peristichia agria Dall, 1889...
Dall, 1889 - Ulfa Dall & Bartsch, 1904
- Vagna 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 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
Sculpture (mollusc)
The sculpture of a mollusc shell is the three-dimensional ornamentation on the outer surface, as distinct from the basic shape of the shell itself or colouration. Sculpture may be concave as well as convex. Sometimes it has microscopic detail. Sculpture refers to the calcareous outer layer, not the...
in various forms such as ribs and spirals. Their color is mostly white, cream or yellowish, sometimes with red or brown lines.
The shell
Gastropod shell
The gastropod shell is a shell which is part of the body of a gastropod or snail, one kind of mollusc. The gastropod shell is an external skeleton or exoskeleton, which serves not only for muscle attachment, but also for protection from predators and from mechanical damage...
of these snails has a blunt, heterostrophic (i.e. whorls appear to be coiled in the opposite direction to those of the teleoconch) protoconch
Protoconch
A protoconch is an embryonic or larval shell of some classes of molluscs, e.g., the initial chamber of an ammonite or the larval shell of a gastropod...
, which is often pointed sideways or wrapped up. The teleoconch is dextrally coiled, but the larva
Larva
A larva 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. This results in a sinistrally coiled protoconch.
The columella has usually one, but sometimes several, spiral folds
Plait (gastropod)
A plait is an anatomical feature which is present the shells of some snails, or gastropods. This sculpture occurs often in the shells of marine gastropod mollusks in the clade Neogastropoda, but it is also found in some pulmonate land snails....
. The aperture
Aperture (mollusc)
The aperture is an opening in certain kinds of mollusc shells: it is the main opening of the shell, where part of the body of the animal emerges for locomotion, feeding, etc....
is closed by an operculum
Operculum (gastropod)
The operculum, meaning little lid, is a corneous or calcareous anatomical structure which exists in many groups of sea snails and freshwater snails, and also in a few groups of land snails...
.
The operculum
Operculum (gastropod)
The operculum, meaning little lid, is a corneous or calcareous anatomical structure which exists in many groups of sea snails and freshwater snails, and also in a few groups of land snails...
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.
Life habits
The Pyramidellidae are ectoparasites, feeding mainly on other molluscs and on annelid wormWorm
The term worm refers to an obsolete taxon used by Carolus Linnaeus and Jean-Baptiste Lamarck for all non-arthropod invertebrate animals, and stems from the Old English word wyrm. Currently it is used to describe many different distantly-related animals that typically have a long cylindrical...
s, but some are known to feed on peanut worms and crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
s.
They do not have a radula
Radula
The radula is an anatomical structure that is used by molluscs for feeding, sometimes compared rather inaccurately to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food enters the esophagus...
. Instead their long proboscis
Proboscis
A proboscis is an elongated appendage from the head of an animal, either a vertebrate or an invertebrate. In simpler terms, a proboscis is the straw-like mouth found in several varieties of species.-Etymology:...
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
Mentum
The mentum refers to a projecting structure near the mouth of any of several animals:#In insects, the mentum is the distal part of the labium. The mentum bears the palps, glossae, paraglossae, and/or ligula....
(= thin projection) is visible. This mentum is slightly indented in midline.
These gastropods are hermaphrodite
Hermaphrodite
In biology, a hermaphrodite is an organism that has reproductive organs normally associated with both male and female sexes.Many taxonomic groups of animals do not have separate sexes. In these groups, hermaphroditism is a normal condition, enabling a form of sexual reproduction in which both...
s, laying eggs in jelly-like masses on the shell of its host. Some species have spermatophore
Spermatophore
A spermatophore or sperm ampulla is a capsule or mass created by males of various animal species, containing spermatozoa and transferred in entirety to the female's ovipore during copulation...
s.
Further reading
- Dinapoli A., Zinssmeister C. & Klussmann-Kolb A. (2010). "New insights into the phylogeny of the Pyramidellidae (Gastropoda)". Journal of Molluscan StudiesJournal of Molluscan StudiesThe Journal of Molluscan Studies is a peer-reviewed scientific journal covering research in malacology.Previous names of this journal include Proceedings of the Malacological Society, Proceedings of the Malacological Society of London The Journal of Molluscan Studies is a peer-reviewed scientific...
doi:10.1093/mollus/eyq027.