''Halystina umberlee'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of very small deep-water

sea snail Sea snail is a common name for slow-moving marine gastropod molluscs, usually with visible external shells, such as whelk or abalone. They share the taxonomic class Gastropoda with slugs, which are distinguished from snails primarily by the ...

, a

marine Marine is an adjective meaning of or pertaining to the sea or ocean. Marine or marines may refer to: Ocean * Maritime (disambiguation) * Marine art * Marine biology * Marine debris * Marine habitats * Marine life * Marine pollution Military * ...

gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...

mollusc Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is esti ...

in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Seguenziidae Seguenziidae is a family of very small deepwater sea snails, marine gastropod mollusks in the superfamily Seguenzioidea (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005).Bouchet, P. (2012). Seguenziidae. Accessed through ...

Taxonomy

''Halystina umberlee'' belongs in the genus '' Halystina'', a group of small-sized sea snails with a rounded shell profile, flat-sided whorls and finely granulate

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 ...

. It is considered to resemble species in the genus '' Halystes'', differing only by its much smaller size. It was named after Umberlee, a fictional goddess from the Faerûnian pantheon of the Forgotten Realms campaign setting for the Dungeons & Dragons fantasy

role-playing game A role-playing game (sometimes spelled roleplaying game, RPG) is a game in which players assume the roles of player character, characters in a fictional Setting (narrative), setting. Players take responsibility for acting out these roles within ...

Description

''Halystina umberlee'' is a very small species, barely reaching a shell height of 2 mm. It has a rounded, conic to turbinate shell, with relatively thick walls and up to 5

whorls 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). Whorls in nature File:Photograph and axial plane floral d ...

. Its bulbous

consists of a single whorl with a pitted surface, and the protoconch-teleoconch transition is marked by a thin line. The

teleoconch The gastropod shell is part of the body of a gastropod or snail, 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 storage. Some ...

has 4 convex whorls,

sculptured Sculptured is an American experimental and progressive metal band, mixing melodic and atonal segments. Biography Following the dissolution of his previous band, guitarist Don Anderson began Sculptured as mostly a one-man project in 1996. With ...

by delicate spiral cordlets crossed by axial threads, forming a delicate net-like pattern. The axial threads form an overall continuous sigmoid pattern along the shell's longitudinal axis, and the spiral sculpture becomes gradually weaker toward the basal region of last whorl. The basal part of the shell is sculptured by 10-12 spiral cords, but the

umbilical Umbilical may refer to: *Umbilical cable *Umbilical cord *Umbilical fold *Umbilical hernia *Umbilical notch *Umbilical vessels **Umbilical artery **Umbilical vein *Umbilical zone *The Umbilical Brothers, two Australian comedic performers, David a ...

region is smooth, with a well-marked margin. The

aperture In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane. An opt ...

is quadrangular, and bears three deep sinuses. The shell is colored glossy white, with a

nacre Nacre ( , ), also known as mother of pearl, is an organicinorganic composite material produced by some molluscs as an inner shell layer; it is also the material of which pearls are composed. It is strong, resilient, and iridescent. Nacre is f ...

ous shade.

Distribution

This marine species occurs off southeastern

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

, from Espírito Santo to

Rio de Janeiro Rio de Janeiro ( , , ; literally 'River of January'), or simply Rio, is the capital of the state of the same name, Brazil's third-most populous state, and the second-most populous city in Brazil, after São Paulo. Listed by the GaWC as a b ...

, at 950–1550 m depths.

References

{{Commonscat Halystina Gastropods described in 2014