''Steromphala nivosa'', common name the Maltese top shell, 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), ...
of
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 ...
Trochidae
The Trochidae, common name top-snails or top-shells, are a family of various sized sea snails, marine gastropod molluscs in the subclass Vetigastropoda. This family is commonly known as the top-snails because in many species the shell resembles ...
, the top snails.
[MolluscaBase eds. (2020). MolluscaBase. Steromphala nivosa (A. Adams, 1853). Accessed through: World Register of Marine Species at: http://marinespecies.org/aphia.php?p=taxdetails&id=1039848 on 2020-12-30]
Description
The size of the shell varies between 6 mm and 9 mm. The umbilicate shell has an orbiculate-conoidal shape. It is gray with almost round spots. It is sulcate in a crosswise direction and longitudinally substriate. 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 almost round. 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 flexuous. The base of the shell is rounded.
Tryon (1889), Manual of Conchology XI, Academy of Natural Sciences, Philadelphia
/ref>
Distribution
This species occurs in the Mediterranean Sea off Malta
Malta, officially the Republic of Malta, is an island country in Southern Europe located in the Mediterranean Sea, between Sicily and North Africa. It consists of an archipelago south of Italy, east of Tunisia, and north of Libya. The two ...
.
References
Further reading
* Nordsieck F., 1982: ''Die europäischen Meeres-Gehäuseschnecken. 2. Auflage.'' * Gustav Fischer, Stuttgart; 539 pp., 38 pl.
* Smriglio C., Mariottini P. & Gravina F., 1991: ''Nota su alcune specie del genere Gibbula Risso, 1826 ex Leach ms''; Bollettino Malacologico 27 (5–9): 61–75
* Gofas, S.; Le Renard, J.; Bouchet, P. (2001). Mollusca, in: Costello, M.J. et al. (Ed.) (2001). ''European register of marine species: a check-list of the marine species in Europe and a bibliography of guides to their identification''. Collection Patrimoines Naturels, 50: pp. 180–213
External links
*
Adams A., 1851: ''An arrangement of Stomatellidae, including the characters of a new genus, and of several new species''; Proceedings of the Zoological Society of London 18: 29–40
Monterosato T. A. (di), 1888–1889: ''Molluschi del Porto di Palermo. Specie e varietà'' ; Bullettino della Società Malacologica Italiana, Pisa, 13 (1888[1889?
: 161–180 14 (1889): 75–81]
Affenzeller S., Haar N. & Steiner G. (2017). Revision of the genus complex Gibbula: an integrative approach to delineating the Eastern Mediterranean genera Gibbula Risso, 1826, Steromphala Gray, 1847, and Phorcus Risso, 1826 using DNA-barcoding and geometric morphometrics (Vetigastropoda, Trochoidea). Organisms Diversity & Evolution. 17(4): 789-812
{{DEFAULTSORT:Steromphala Nivosa
nivosa
Gastropods described in 1851