Pterotracheoidea

Last updated

Pterotracheoidea
Pterotracheidae.jpg
A pterotracheid
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
Subclass: Caenogastropoda
Order: Littorinimorpha
Superfamily: Pterotracheoidea
Rafinesque, 1814
Families
See text
Synonyms
  • Heteropoda Lamarck, 1812
  • Carinarioidea de Blainville, 1818

The Pterotracheoidea is, according to the Taxonomy of the Gastropoda (Bouchet & Rocroi, 2005), a taxonomic superfamily of sea snails or sea slugs, marine gastropod molluscs in the clade Littorinimorpha. They are commonly called heteropods or sea elephants.

Contents

Taxonomy

This superfamily comprises four families (classification based on Newman (superfamily Carinarioidea, pp. 804–808. In: Beesley et al., 1998), [1] that is also used by the taxonomy of the Gastropoda by Bouchet & Rocroi (2005):

Habitat

These holoplanktonic snails are found floating or swimming in tropical to subtropical open oceans and seas at a depth of maximum 200 to 300 m [2]

Anatomy

These snails have adapted themselves to a pelagic living :

The taenioglossate radula, situated at the tip of the proboscis, can be protruded to capture the prey.

They have paired, large spherical eyes, contained in a gelatinous mass, that they use to locate their prey. As the body is transparent, one can easily see the internal organs and the statocysts with its statoliths (an organ that tells the animal whether it is upside down or not). The swimming fin of the foot has a ventral or posteroventral sucker. This sucker has grown larger in the family Atlantidae where it serves to hold the prey. The fin sucker is only present in male snails of the Pterotracheidae.

The body size varies from microscopic (Atlantidae) to macroscopic (Carinariidae and Pterotracheidae). Fertilized eggs are laid in mucous strings that hatch after a few days into free swimming veliger larvae (except in Firoloida desmaresti where the eggs remain attached in a tubular filament to the female body).

All the heteropods float or swim with their ventral part upward. The atlantids are negatively buoyant, while the others have neutral buoyancy.

Shell

These snails all have a coiled shell present in their larval stage. But the shell is no longer present in the Pterotracheidae after metamorphosis. The keel (sharp ridge on a whorl of the shell) of the adult shell extends outwards in the Atlantidae and anteriorly in Carinariidae. The shell is calcareous in the Carinariidae. In the Atlantidae, however, the shell and the keel can be calcareous (genus Atlanta) or the shell calcareous and its keel composed of conchiolin (genus Protatlanta), or the shell composed exclusively of conchiolin (genus Oxygyrus). Only the Atlantidae can retract into their shell.

Related Research Articles

<span class="mw-page-title-main">Sea butterfly</span> Suborder of molluscs

Sea butterflies, scientific name Thecosomata, are a taxonomic suborder of small pelagic swimming sea snails. They are holoplanktonic opisthobranch gastropod mollusks. Most Thecosomata have some form of calcified shell, although it is often very light and / or transparent.

<span class="mw-page-title-main">Sea angel</span> Clade of gastropods

Sea angels are a large group of small free-swimming sea slugs, not to be confused with Cnidarians, classified into six different families. They are pelagic opisthobranchs in the clade Gymnosomata within the larger mollusc clade Heterobranchia. Sea angels were previously referred to as a type of pteropod.

<span class="mw-page-title-main">Neogastropoda</span> Clade of sea snails

Neogastropoda is an order of sea snails, both freshwater and marine gastropod molluscs.

<span class="mw-page-title-main">Cavolinioidea</span> Superfamily of gastropods

The superfamily Cavolinioidea is the most speciose group of sea butterflies. They belong to the suborder Euthecosomata.

Orthogastropoda was a major taxonomic grouping of snails and slugs, an extremely large subclass within the huge class Gastropoda according to the older taxonomy of the Gastropoda.

<span class="mw-page-title-main">Littorinimorpha</span> Order of gastropods

Littorinimorpha is a large order of snails, gastropods, consisting primarily of sea snails, but also including some freshwater snails and land snails.

<span class="mw-page-title-main">Buccinoidea</span> Superfamily of molluscs

Buccinoidea is a taxonomic superfamily of very small to large predatory sea snails, marine gastropod mollusks.

<span class="mw-page-title-main">Basommatophora</span> Informal group of gastropods

Basommatophora was a term that was previously used as a taxonomic informal group, a group of snails within the informal group Pulmonata, the air-breathing slugs and snails. According to the taxonomy of the Gastropoda, whenever monophyly has not been tested, or where a traditional taxon of gastropods has now been discovered to be paraphyletic or polyphyletic, the term "group" or "informal group" was used.

<span class="mw-page-title-main">Atlantidae</span> Family of gastropods

Atlantidae is a family of sea snails, holoplanktonic gastropod molluscs in the clade Littorinimorpha.

<span class="mw-page-title-main">Carinariidae</span> Family of gastropods

Carinariidae, known by the common name "heteropods" like their relatives in the Pterotracheoidea, is a taxonomic family of swimming or floating sea snails, pelagic marine gastropod molluscs in the clade Littorinimorpha.

<i>Carinaria</i> Genus of gastropods

Carinaria is a genus of medium-sized floating sea snails, pelagic gastropod molluscs in the family Carinariidae.

<span class="mw-page-title-main">Pterotracheidae</span> Family of gastropods

Pterotracheidae is a family of medium-sized to large floating sea snails, pelagic gastropod molluscs. They are in the superfamily Pterotracheoidea along with two other similar pelagic families, the Atlantidae and the Carinariidae.

<span class="mw-page-title-main">Vermetidae</span> Family of gastropods

The Vermetidae, the worm snails or worm shells, are a taxonomic family of small to medium-sized sea snails, marine gastropod molluscs in the clade Littorinimorpha. The shells of species in the family Vermetidae are extremely irregular, and do not resemble the average snail shell, hence the common name "worm shells" or "worm snails".

<span class="mw-page-title-main">Neotaenioglossa</span> Group of molluscs

The Neotaenioglossa is a taxonomic name for a large group of mostly sea snails. The name was originally created by Haller in 1882. Ponder and Warén (1988), and Marquet (1997), assigned this name to the superorder Caenogastropoda. ITIS considers the order Neotaenioglossa to be a synonym of Cerithioidea Férussac, 1819 .

<span class="mw-page-title-main">Vetigastropoda</span> Clade of sea snails

Vetigastropoda is a major taxonomic group of sea snails, marine gastropod mollusks that form a very ancient lineage. Taxonomically the Vetigastropoda are sometimes treated as an order, although they are treated as an unranked clade in Bouchet and Rocroi, 2005.

<span class="mw-page-title-main">Cymbulioidea</span> Superfamily of gastropods

Cymbulioidea is a taxonomic superfamily of pelagic "sea butterflies", one group of swimming sea snails. They are holoplanktonic opisthobranch gastropod molluscs in the clade Thecosomata.

<i>Atlanta echinogyra</i> Species of gastropod

Atlanta echinogyra is a species of sea snail, a holoplanktonic marine gastropod mollusk in the family Atlantidae.

<i>Oxygyrus</i> Genus of gastropods

Oxygyrus keraudrenii is a species of sea snail, a holoplanktonic marine gastropod mollusk in the family Atlantidae.

<i>Carinaria cristata</i> Species of gastropod

Carinaria cristata, commonly known as the glassy nautilus, is a species of pelagic marine gastropod mollusc in the family Carinariidae. It is found in the Pacific Ocean and is described as being holoplanktonic, because it spends its entire life as part of the plankton. It was first described by Carl Linnaeus in 1767. Its fragile shell was much prized by early conchologists for their collections, being so rare that it was said to be worth more than its weight in gold.

Carinaria galea, common name the helmeted carinaria, is a species of sea snail, a marine pelagic marine gastropod mollusc in the family Carinariidae. It was first described in 1835 by William Henry Benson, an amateur malacologist in the Bengal Civil Service.

References

  1. Beesley P.L., G.J.B. Ross & A. Wells (1998). Mollusca, the southern synthesis - Fauna of Australia 5. Melbourne: CSIRO. pp. Part B : viii 565–1234.
  2. Arie W. Janssen (2007). "Holoplanktonic Mollusca (Gastropoda: Pterotracheoidea, Janthinoidea, Thecosomata and Gymnosomata) from the Pliocene of Pangasinan (Luzon, Philippines)". Scripta Geologica . 135.
  3. Lalli, Carol M; Gilmer, Ronald W (1989). Pelagic snails: the biology of holoplanktonic gastropod mollusks. Stanford University Press. ISBN   978-0-8047-1490-7.