''Longchaeus auricoma'' is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

sea snail Sea snails are slow-moving marine (ocean), marine gastropod Mollusca, molluscs, usually with visible external shells, such as whelk or abalone. They share the Taxonomic classification, taxonomic class Gastropoda with slugs, which are distinguishe ...

, a marine

gastropod Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and fro ...

mollusc Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...

in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Pyramidellidae 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 micromol ...

, the pyrams and their allies.Bouchet, P. (2015). Longchaeus auricoma (Dall, 1889). In: MolluscaBase (2015). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=866674 on 2016-05-24Keen M. (1971). Sea shells of Tropical West America. Marine mollusks from Baja California to Perú. (2nd edit.). Stanford University Press pp. 1064

Description

The shell has a regularly elongate-conic shape. It is yellowish-white, with fine golden yellow spiral lines between the sutures and on the base. Its length measures 10.6 mm. The

whorl A whorl ( or ) is an individual circle, oval, volution or equivalent in a whorled pattern, which consists of a spiral or multiple concentric objects (including circles, ovals and arcs). In nature File:Photograph and axial plane floral diagra ...

s of the

protoconch A protoconch (meaning first or earliest or original shell) is an embryonic or larval shell which occurs in some classes of molluscs, e.g., the initial chamber of an ammonite or the larval shell of a gastropod. In older texts it is also called " ...

are small, deeply obliquely immersed in the first succeeding turn. The ten whorls of the

teleoconch The gastropod shell is part of the body of many gastropods, including snails, 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 ...

are well rounded, feebly shouldered at the summit, scarcely at all contracted at the sutures. The sutures are weakly impressed. The periphery and the base of the

body whorl The body whorl is part of the morphology (biology), morphology of the gastropod shell, shell in those gastropod mollusks that possess a coiled shell. The term is also sometimes used in a similar way to describe the shell of a cephalopod mollusk ...

are well rounded and smooth. The

aperture In optics, the aperture of an optical system (including a system consisting of a single lens) is the hole or opening that primarily limits light propagated through the system. More specifically, the entrance pupil as the front side image o ...

is irregularly oval. The outer lip is thin. It is reinforced deeply within by five strong spiral cords, one of which is at the periphery, two divide the space between this and the summit into three equal parts, and two a little less strong are on the base. The

columella Lucius Junius Moderatus Columella (, Arabic: ) was a prominent Roman writer on agriculture in the Roman Empire. His in twelve volumes has been completely preserved and forms an important source on Roman agriculture and ancient Roman cuisin ...

is strong and straight. The posterior fold is oblique, very strong and lamellar. The anterior two are about one-fourth as high as the posterior, very oblique. The parietal wall is glazed by a thin callus.Dall & Bartsch, A Monograph of West American Pyramidellid Mollusks, United States National Museum Bulletin 68, p. 19: 1909
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Distribution

This marine species occurs in the

Gulf of California The Gulf of California (), also known as the Sea of Cortés (''Mar de Cortés'') or Sea of Cortez, or less commonly as the Vermilion Sea (''Mar Vermejo''), is a marginal sea of the Pacific Ocean that separates the Baja California peninsula from ...

and off

Mazatlán Mazatlán () is a city in the Mexican list of states of Mexico, state of Sinaloa. The city serves as the municipal seat for the surrounding , known as the Mazatlán Municipality. It is located on the Pacific Ocean, Pacific coast across from th ...

, Mexico.

References

External links

USNM Invertebrate Zoology Mollusca Collection

World Register of Marine Species
{{Taxonbar, from=Q7263309 Pyramidellidae Gastropods described in 1889