Pyramidellidae

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Pyramidellidae
Turbonilla acutissima.png
Live Turbonilla acutissima
Pyramidella maculosa - D'Orbigny.jpg
Apertural view of a shell of Pyramidella acus
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
Subclass: Heterobranchia
Superfamily: Pyramidelloidea
Family: Pyramidellidae
J. E. Gray, 1840 [1]
Type genus
Pyramidella
Lamarck, 1799
Synonyms
  • Chemnitziidae
  • Heterostropha

Pyramidellidae, common name the pyram family, or pyramid shells, is a voluminous taxonomic family of mostly small and minute ectoparasitic sea snails, marine heterobranch gastropod molluscs. The great majority of species of pyrams are micromolluscs.

Contents

The pyram family is distributed worldwide with more than 6,000 named species in more than 350 nominal genera and subgenera. [2]

This family of micromollusks has been little studied and the phylogenetic 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. [3] As there has been no serious generic revision of the genera worldwide, generic polyphyly can be expected to be rampant throughout the family. However, the family itself is deemed monophyletic. [4] However a study in 2011 seems to indicate that this family is deeply nested within the Pulmonata instead of the Heterobranchia. [5]

The family is currently divided into 11 subfamilies (Ponder & Lindberg 1997). [6] An alternative interpretation is that the family Pyramidellidae is but one of six families within the superfamily Pyramidelloidea (Schander, van Aartsen & Corgan 1999). [7] 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): [6]

1999 taxonomy

Taxonomy of Pyramidellidae by Schander, Van Aartsen & Corgan (1999): [7]

2005 taxonomy

Taxonomy of Pyramidellidae by Bouchet & Rocroi (2005): [8]

In 2010 the family Pyramidellidae has been recognized as monophyletic [9]

In 2017 the genus Helodiamea Peñas & Rolán, 2017 of deep-water Pyramidelloidea from the Central and South Pacific, was recognized. [10]

Problematic taxa

The following genera are currently difficult to place within existing subtaxa of the Pyramidellidae.

The following species is of uncertain placement within Pyramidellidae.

Synonyms

The following genera have become synonyms (but some species in this genera have not yet been reassigned) :

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. [12]

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 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 larval 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 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 or other molluscs).

Life habits

The Pyramidellidae are ectoparasites, feeding mainly on other molluscs and on annelid worms, but some are known to feed on peanut worms and crustaceans. [13] [14] A few species in the family Pyramidellidae, such as Otopleura mitralis , are symbiotic with sea anemones, such as Neoaiptasia morbilla . [15]

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 hermaphrodites, laying eggs in jelly-like masses on the shell of its host. Some species have spermatophores. [3] [16] [17]

Name derived from shape

The name of this taxonomic family comes from the shape of the shell, which is like a pyramid. [18] More specifically, the shape is like a right circular cone, [19] which is equivalent to a right pyramid whose base has many sides. [20]

Related Research Articles

Odostomiinae

Odostomiinae, 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.

Turbonillinae

Turbonillinae is a subfamily of mostly minute parasitic sea snails, marine gastropod molluscs in the family Pyramidellidae, the pyrams and their allies.

Chrysallidini

Chrysallidinae is a taxonomic group of very small sea snails, marine gastropod mollusk in the family Pyramidellidae, the pyrams and their allies.

Cingulinini is a taxonomic tribe of very small sea snails, marine gastropod mollusks in the family Pyramidellidae, the pyrams and their allies.

Cyclostremellini is a minor tribe, a taxonomic grouping, of minute sea snails, marine gastropod mollusks or micromollusks, in the family Pyramidellidae, the pyrams and their allies.

Syrnolininae is a subfamily of minute parasitic sea snails, marine heterobranch gastropod molluscs in the family Pyramidellidae, the pyrams and their allies.

Eulimellini is a tribe of minute sea snails, marine gastropod molluscs in the family Pyramidellidae, the pyrams and their allies.

<i>Tiberia</i>

Tiberia is a genus of minute parasitic sea snails, marine gastropod molluscs in the family Pyramidellidae, the pyrams and their allies. Tiberia is the only genus in the tribe Tiberiini.

Pyramidellinae

Pyramidellinae is a taxonomic subfamily of minute sea snails, marine gastropod mollusks in the family Pyramidellidae, the pyrams and their allies.

Odostomellini

Odostomellini is a taxonomic tribe of minute sea snails, marine gastropod molluscs within the family Pyramidellidae the pyrams and their allies.

Pyramidelloidea

Pyramidelloidea is a superfamily of mostly very small sea snails, marine gastropod mollusks and micromollusks within the clade Panpulmonata.

<i>Trabecula</i> (gastropod)

Trabecula is a genus of very small sea snails, marine gastropod molluscs or micromolluscs in the family Pyramidellidae, the pyrams and their allies, and the subfamily Chrysallidinae, a large taxon of minute marine gastropods with an intorted protoconch.

<i>Chrysallida</i>

Chrysallida is a speciose genus of minute sea snails, pyramidellid gastropod mollusks or micromollusks in the family Pyramidellidae within the tribe Chrysallidini.

<i>Babella</i>

Babella is a genus of very small sea snails, pyramidellid gastropod mollusks or micromollusks in the family Pyramidellidae within the tribe Chrysallidini.

<i>Odostomia</i>

Odostomia is the most speciose genus of minute sea snails, pyramidellid gastropod mollusks. This genus is placed in the family Pyramidellidae in the subfamily Odostomiinae. There are several hundred species in this diverse genus

<i>Parthenina</i>

Parthenina is a genus of very small sea snails, pyramidellid gastropod mollusks or micromollusks.

Megastomia is a genus of sea snails, marine gastropod mollusks in the family Pyramidellidae, the pyrams and their allies.

Syrnola is a genus of sea snails, marine gastropod mollusks in the family Pyramidellidae, the pyrams and their allies.

<i>Turbonilla</i>

Turbonilla is a large genus of ectoparasitic sea snails, marine gastropod mollusks in the family Pyramidellidae, the pyrams and their allies.

References

  1. Gray, J. E. (1840). Synopsis of the contents of the British Museum, 42nd edition. London. p. 370 pp.
  2. Schander, Christoffer; Halanych, Kenneth M.; Dahlgren, Thomas; Sundberg, Per (2003). "Test of the monophyly of Odostomiinae and Turbonilliinae (Gastropoda, Heterobranchia, Pyramidellidae) based on 16S mtDNA sequences". Zoologica Scripta. 32 (3): 243–254. doi:10.1046/j.1463-6409.2003.00112.x.
  3. 1 2 Schander, Christoffer; Hori, Shigeo; Lundberg, Joakim (2011). "Anatomy, phylogeny and biology of Odostomella and Herviera, with the description of a new species of Odostomella (Mollusca, Heterostropha, Pyramidellidae)". Ophelia. 51 (1): 39–76. doi:10.1080/00785326.1999.10409399.
  4. Dinapoli, A.; Zinssmeister, C.; Klussmann-Kolb, A. (2010). "New insights into the phylogeny of the Pyramidellidae (Gastropoda)". Journal of Molluscan Studies. 77 (1): 1–7. doi: 10.1093/mollus/eyq027 .
  5. Dinapoli A, Zinssmeister C, Klussman-Kolb A. 2011. New insights into the phylogeny of the Pyramidellidae (Gastropoda). Journal of Molluscan Studies 77:1-7.
  6. 1 2 Ponder, W.F. & Lindberg, D. R. (1997). "Towards a phylogeny of gastropod molluscs: an analysis using morphological characters". Zoological Journal of the Linnean Society. 119 (2): 88–265. doi: 10.1111/j.1096-3642.1997.tb00137.x .
  7. 1 2 Schander, C.; van Aartsen, J.J.; Corgan, J. X. (1999) [1998]. "Families and genera of the Pyramidelloidea (Mollusca: Gastropoda)" (PDF). Bollettino Malacologico. 34 (9–12): 145–166. Archived (PDF) from the original on 2017-02-11. Retrieved 2017-02-09.
  8. Bouchet, P. & Rocroi, J.-P. (2005). "Classification and Nomenclator of Gastropod Families". Malacologia. 47 (1–2): 1–397.
  9. Dinapoli, Angela; Carmen Zinnsmeister; Annette Klussmann-Kolb (10 September 2010). "New insights into the phylogeny of the Pyramidellidae (Gastropoda)". Journal of Molluscan Studies. 77 (1): 1–7. doi: 10.1093/mollus/eyq027 . Retrieved 2011-10-25.
  10. Bouchet, P. (2017). Helodiamea Peñas & Rolán, 2017. In: MolluscaBase (2017). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=955936 Archived 2017-09-10 at the Wayback Machine on 2017-09-10
  11. WoRMS (2010). Peristichia. In: Bouchet, P.; Gofas, S.; Rosenberg, G. (2010) World Marine Mollusca database. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=415795 Archived 2012-11-05 at the Wayback Machine on 2011-03-15
  12. "J.J. van Aartsen, E. Gittenberger & J. Goud, Pyramidellidae (Mollusca, Gastropoda, Heterobranchia) collected during the Dutch CANCAP and MAURITANIA expeditions in the south-eastern part of the North Atlantic Ocean (part 2)". Archived from the original on 2015-04-09. Retrieved 2011-11-12.
  13. Sneli, J.-A. (1972). "Odostomia turrita found on Hommarus gammarus". Nautilus. 86 (1): 23–24.
  14. Robertson, R.; Mau-Lastovicka, Terry (1979). "The ectoparasitism of Boonea and Fargoa (Gastropoda: Pyramidellidae)". Biological Bulletin. Marine Biological Laboratory. 157 (2): 320–333. doi:10.2307/1541058. JSTOR   1541058.
  15. Roger H. Goodwill et. al. (2009), A sea anemone symbiotic with gastropods of eight species in the Mariana Islands; Micronesica 41(1): 117–130, 2009 Archived 2010-06-18 at the Wayback Machine
  16. Høisæter, T. (1965). "Spermatophores in Chrysallida obtusa (Brown) (Opisthobranchia, Pyramidellidae)". Sarsia. 18: 63–68. doi:10.1080/00364827.1965.10409548.
  17. Robertson, R. (1967). "The life history of Odostomia bisuturalis and Odostomia spermatophores (Gastropoda: Pyramidellidae)". American Philosophical Society Yearbook. 1967: 368–370.
  18. Tenney, Sanborn and Tenney, Abby. Natural history of animals; Containing brief descriptions of the animals figured on Tenney's Natural history tablets, but complete without the tablets , p. 202 (Scribner, Armstrong & Co., 1875): "The Pyramid-Shells are so named from their shape"
  19. Step, Edward. Shell Life: An Introduction to the British Mollusca , p. 250 (F. Warne & Company, 1901).
  20. Robbins, Edward. Plane and Solid Geometry , p. 349 (American Book Company, 1907).

Further reading