''Pyramidella alfredensis'' 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 ...

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

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.MolluscaBase eds. (2022). MolluscaBase. Pyramidella alfredensis Bartsch, 1915. Accessed through: World Register of Marine Species at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=588522 on 2022-03-13

Description

The milk-white shell has an elongate-conic shape. The 1¾

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 very small. They are planorboid, having their axis at right angles to that of succeeding turns. The left side of the nucleus projects considerably beyond the outline of the

spire A spire is a tall, slender, pointed structure on top of a roof of a building or tower, especially at the summit of church steeples. A spire may have a square, circular, or polygonal plan, with a roughly conical or pyramidal shape. Spire ...

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 ...

. The ten whorls of the teleoconch are almost flat and are feebly shouldered at the summit. They are marked by exceedingly fine, retractive, incremental lines, and numerous microscopic spiral striations. The suture is moderately constricted. The periphery 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 ...

is well rounded. The base of the shell is well rounded, decidedly umbilicated, and marked like the spire. 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 subquadrate. The posterior angle is acute. The outer lip is thin. The inner lip is very oblique, and decidedly reflected. It is provided with a strong fold near its insertion. The parietal wall is glazed with a thin callus. P. Bartsch (1915), Report on the Turton Collection of South African Marine Mollusks, with Additional Notes on Other South African Shells Contained in the United States National Museum; Bulletin of the United States National Museum, (91): i-xii, 1-305, 54 pls
/ref>

Distribution

This marine species occurs off

Port Alfred Port Alfred is a small town with a population of just under 26,000 in the Eastern Cape province of South Africa. It is situated on the eastern seaboard of the country at the mouth of the Kowie River, almost exactly halfway between the larger ci ...

, South Africa.

References

External links

World Register of Marine Species
{{Taxonbar, from2=Q7102706, from1=Q63710070 Pyramidellidae Gastropods described in 1915