''Daphnella ryukyuensis'' is an extinct species of

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

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 ...

mollusk in the family

Raphitomidae Raphitomidae is a family of small to medium-sized sea snails, marine gastropod mollusks in the superfamily Conoidea.Bouchet P. & Rocroi J.-P. (Ed.) (2005). "Classification and nomenclator of gastropod families". '' Malacologia'' 47(1-2). . 3 ...

Description

The length of the shell attains 30 mm. (Original description) The shell is of medium size, medium to moderately slender, lymneiform. The whorls are flattened in the young state but rounded in adults. 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 ...

consists of 2¾

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). Whorls in nature File:Photograph and axial plane flo ...

s, the first very small and smooth, the remainder microscopically diagonally cancellate, the diagonal lines being rough and irregular. The aperture is of medium width. The outer lip is thin and gently rounded. The

anal sinus The anal sinuses (rectal sinuses) are furrows in the anal canal, that separate the anal columns from one another. The anal sinuses end below in small valve-like folds, termed anal valves The anal valves are small valve-like folds at the lower ends ...

is shallow, located nearly adjacent to the suture. The sculpture on the juvenile whorls consists of a row of small rounded beads set on a low shoulder directly beneath the suture and with weak spiral lines below. The adult sculpture consists of very faint spiral lines, somewhat more evident and coarser on the lower part of the

body whorl The body whorl is part of the morphology of the 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. In gastropods In gastropods, the b ...

and columella.MacNeil, Tertiary and Quaternary Gastropoda of Okinawa; USGS Geological Survey Professional Paper 339, 1960
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Distribution

Fossils of this species were found in Miocene strata on the Ryukyu Islands

References

{{DEFAULTSORT:Daphnella Ryukyuensis ryukyuensis Gastropods described in 1960