''Comitas wynyardensis'' 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 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

Pseudomelatomidae Pseudomelatomidae is a family of predatory sea snails, marine gastropods included in the superfamily Conoidea (previously Conacea) and part of the Neogastropoda ( Bouchet & Rocroi, 2005). In 1995 Kantor elevated the subfamily Pseudomelatomina ...

, the turrids and allies.

Description

The length of this species attains 27 mm, its diameter 8 mm. (Original description) The shell is of small to medium size, somewhat narrow elongate fusiform. The aperture and the

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 ...

have about the same length as the spire. The spire is acute, made up of a rather small embryonic portion, succeeded by numerous, gradually increasing, convex, and more or less strongly costated whorls. The apical angle is about twenty-five to thirty degrees. 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 ...

is rather small, consisting of about smooth convex

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. The spire consistis of seven or eight regularly convex whorls, with their greatest convexity about the middle of each whorl, and with a well-impressed suture.. The aperture is oval. The outer lip is rather thin and smooth internally, with a well-defined broad but comparatively shallow sinus just below the suture. From the sinus the lip projects slightly forward with a regular convex arch, then curving downwards to join the anterior canal. The sinuses about one to one-and-a-half millimetre broad, but usually only about half this measurement in depth. At the anterior end the aperture opens into a long, straight, slender and open siphonal canal, which is much longer than the aperture. The inner lip shows a thin enamel coating. The columella is simple and smooth, straight, slender, and gently tapering to the anterior end. The surface is ornamented with oblique ribs, which are most highly elevated about the middle of each whorl, and fade off more rapidly towards the posterior suture than the anterior. The ribs number usually nine to a whorl, an occasional example shows as many as eleven or twelve 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 ...

. The strength of development of the ribs is somewhat variable, especially on the anterior whorls, where they are occasionally only just visible. The ribs are traversed by comparatively coarse and fine spiral threads. Of these there are four to six coarser and more prominent than the rest, situated in the anterior two-thirds of each whorl, especially prominent where they cross the ribs, more numerous, amounting to about eight or nine, on the body whorl, with much broader interspaces between each of which has a medial finer thread with a pair of still tinier threads on either side of it. The posterior third is occupied by from about ten to fifteen very fine spiral threadlets, also the fine lines of growth of the sinus are in this space. Both ribs and spiral threads are traversed by the fine oblique forwardly directed lines of growth.Pritchard, G. B., "A Revision of the Fossil Fauna of the Table Cape Beds." ; Proceedings of the Royal Society of Victoria v. 8 (1896)

Distribution

This marine species is endemic to

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

. Fossils have been found in Eocene strata of Table Cape, Tasmania

References

External links

* {{Taxonbar, from=Q55608124 wynyardensis Gastropods described in 1896 Gastropods of Australia