''Acamptodaphne biconica'' 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). . 3 ...

Description

The length of the shell attains 10¼ mm, its diameter 4¼ mm. (Original description) The rather strong, white shell is biconical. It contains 9

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 4 form a yellowish-brown

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 moderately convex whorls, of which about 2 upper ones smooth, 2 with curved, raised striae, stronger just below the suture, crossed in their lower part by very fine, oblique striae. The subsequent whorls are angular, the upper part slightly excavated, the basal part nearly straight in outline. This lower part has rather inconspicuous axial ribs, nearly disappearing in 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 tubercled at the angle below the excavation. Otherwise the axial sculpture consists of rather strong, nearly riblike, much curved, raised striae in the excavation and very fine growth-lines. Of spirals there are 4 on penultimate whorl, below and besides that accompanying the peripheral angle, and numerous spirals on body whorl, with eventually intermediate ones. Moreover, the shell is covered with excessively small granules, only visible under a strong lens. The body whorl at first is convex below the angle, then moderately contracted. The aperture is oblong, with a sharp angle above and a compressed, gutter-like

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 ...

below. The peristome is broken. The sinus, judging after growth lines, is large but shallow, occupying the excavated space. The columellar margin shows a rather strong layer of enamel, strongest at the short siphonal canal, where it forms an oblong umbilical pit.Schepman, 1913. The prosobranchia of the Siboga expedition. Part IV -V - VI: Toxoglossa

Description

Distribution

References

External links