''Isodaphne perfragilis'' is a 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). . 39 ...

Description

The length of the shell attains 18.5 mm, its diameter 7.5 mm. (Original description) The white, fusiform shell has a moderately long

siphonal canal The siphonal canal is an anatomical feature of the shells of certain groups of sea snails within the clade Neogastropoda. Some sea marine gastropods have a soft tubular anterior extension of the mantle called a siphon through which water is ...

. It is very thin, fragile and hyaline. It contains eight

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 floral ...

s, of which about 2½ form 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 ...

, with convex whorls and criss-cross sculpture. The subsequent whorls are convex, separated by a deep, linear suture, the upper ones are strongly angular at the shoulder, the angle however is fainter on lower whorls and nearly disappears on 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 ...

. A second prominent liration is visible on upper whorls, but becomes likewise fainter. Moreover, the shell is crossed by numerous, fine, raised, spiral striae and finer axial ones, producing a fine cancellation. On the siphonal canal the spirals are stronger. The aperture is oval, angular above, with a rather short, moderately wide siphonal canal below. The peristome is broken, according to growth lines with a shallow sinus above, roundedly angular at the entrance of the siphonal canal. The columellar margin is convex at the body whorl, then nearly straight, slightly curved to the left, with a thin layer of enamel. Schepman, 1913. The prosobranchia of the Siboga expedition. Part IV -V - VI: Toxoglossa

Distribution

This marine species occurs in the

Makassar Strait Makassar Strait is a strait between the islands of Borneo and Sulawesi in Indonesia. To the north it joins the Celebes Sea, while to the south it meets the Java Sea. To the northeast, it forms the Sangkulirang Bay south of the Mangkalihat Pe ...

and in the Ceram Sea, Indonesia at depths between 835 m - 2029 m

References

External links

* * {{DEFAULTSORT:Isodaphne Perfragilis perfragilis Gastropods described in 1913