Stromboideans have medium to large shells, attaining a wide variety of lengths depending on the species. A stromboidean shell has a medium to high spire, and a thickened and frequently expanded outer lip that may be ornamented by long spines or digitations. The anterior portion of the outer lip may present a stromboid notch, an indentation through which one of the animal's long eyestalks may protrude. The shell morphology of some stromboideans is not solely determined by the animal's genes; environmental conditions such as location, diet, temperature and depth, and biological interactions such as predation, can greatly affect it. Juvenile individuals of some species develop heavier shells when exposed to predators. They also develop wider and thicker shells with fewer but longer spines in deeper water.
Taxonomy
This superfamily was previously known as Strombacea. Prior to the recent ruling by the ICZN, many invertebrate superfamily names ended in the suffix -acea, or -aceae, not -oidea as now required according to ICZN article 29.2. The suffix -oidea used to be used for some subclasses and superorders, where it is still found. In much of the older literature including Keen 1958, Moore and colleagues 1952, and the Treatise on Invertebrate Paleontology, gastropod superfamilies are written with the suffix -acea.
2005 taxonomy
According to the classification proposed by Bouchet & Rocroi, the families and subfamilies in the superfamily Stromboidea are as follows. Fossil families are marked with a dagger †.
AporrhaidaeGray, 1850 - the pelican's foot shells, synonyms: Aporrhaididae, Aporrhaiidae,
The phylogenetic relationships among the Stromboidea have been addressed in 2005, by Simone. The author proposed a cladogram based on an extensive morpho-anatomical analysis of representatives of Aporrhaidae, Strombidae, Xenophoridae and Struthiolariidae. In his analysis, Simone recognized Strombidae as a monophyletic taxon supported by 13 synapomorphies, with at least eight distinct genera. He considered the genus Terebellum as the most basaltaxon, distinguished from the remaining strombids by 13 synapomorphies, including a rounded foot. Though the genus Tibia was left out of the analysis, Simone regarded it as probably closely related to Terebellum, apparently due to some well known morphological similarities between them.
Ecology and behavior
Stromboideans are exclusively marine, and most species inhabit shallow waters. Adult individuals may be epifaunal, remaining partially buried in the sand or never burying at all, but may also be infaunal, remaining buried for most of their lifetime.
is the most common feeding habit among stromboideans. Snails in the family Strombidae were widely accepted as carnivores by several authors in the 19th century, a concept that persisted until the first half of the 20th century. This erroneous idea evidently originated in the writings of Jean-Baptiste Lamarck, who classified strombids with other supposedly carnivorous snails. This idea was subsequently repeated by other authors, but were not supported by observation. Nowadays, strombids are known to be specialized herbivores and occasional detritivores. They are usually associated with shallow water reefs and seagrass meadows. Struthiolariids are ciliarymucous feeders, obtaining their nutrition from particles and organic matter suspended in the water. While remaining completely buried in the sand, struthiolariids are connected to the surface by two artificially produced holes. These holes are made by the animal's proboscis, held in place with mucus, and are used for inhalating and exhalating water. Feeding particles are captured as the inhaled water flows over the animal's gills, become embedded in mucus, and are moved along a ciliary tract that leads to the animal's mouth, where they are finally ingested.
