''Diloma aethiops'', whose common names include scorched monodont, spotted black topshell, and in the

Māori language Māori (), or ('the Māori language'), also known as ('the language'), is an Eastern Polynesian language spoken by the Māori people, the indigenous population of mainland New Zealand. Closely related to Cook Islands Māori, Tuamotuan, and ...

pūpū, pūpū-mai, or māihi 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 small

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 ...

Trochidae The Trochidae, common name top-snails or top-shells, are a family of various sized sea snails, marine gastropod molluscs in the subclass Vetigastropoda. This family is commonly known as the top-snails because in many species the shell resembles ...

, subfamily Monodontinae.Bouchet, P. (2013). Diloma aethiops (Gmelin, 1791). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=546856 on 2014-03-17

Description

The size of the shell varies between 15 mm and 30 mm. The thick, solid, imperforate shell has a depressed conical shape. It is blackish, dotted upon the ribs with yellow or white. The conic

spire A spire is a tall, slender, pointed structure on top of a roof of a building or tower, especially at the summit of church steeples. A spire may have a square, circular, or polygonal plan, with a roughly conical or pyramidal shape. Spires are ...

is more or less depressed with an acute apex. The five

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 are spirally strongly ridged. The ridges are nodulous and number three on the penultimate whorl. The interstices are spirally striate. 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 ...

is depressed, angulate at the periphery, and concentrically lirate below. The lirae are coarsely granulose, about 5 in number. 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 very oblique. The outer lip is edged with blackish, then nacreous, and lined with opaque white, the thickening slightly notched at the place of the periphery. The oblique columella is nearly straight, flat, opaque white and backed by nacreous. Animal: The foot is yellow below, with a brown stripe round the contour, black on the sides, with touches of yellowish-white behind; filaments greenish; mouth yellowish.Hutton F.W. (1880) Manual of the New Zealand Mollusca, Dominion Museum (N.Z.)
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Distribution and Habitat

This species is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

. It is common to abundant in rocky intertidal areas, where it is the only trochid found on open rock surfaces, in sheltered areas and semi-exposed coasts. In harbours or estuaries it often occurs with ''D. subrostrata'' on hard packed mud among empty

bivalve Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bival ...

shells.

References

* Miller M & Batt G, ''Reef and Beach Life of New Zealand'', William Collins (New Zealand) Ltd, Auckland, New Zealand 1973 * Powell A W B, ''New Zealand Mollusca'', William Collins Publishers Ltd, Auckland, New Zealand 1979 * Willan, R.C.; Marshall, B.A.; Climo, F.M.; Cernohorsky, W.O. 1980: ''Rectification of nomenclature for Melagraphia aethiops (Gmelin) and Diloma bicanaliculata (Dunker) (Mollusca: Trochidae).'' New Zealand Journal of Marine and Freshwater Research 14: 413-415 * Donald K.M., Kennedy M. & Spencer H.G. (2005) ''The phylogeny and taxonomy of austral monodontine topshells (Mollusca: Gastropoda: Trochidae), inferred from DNA sequences''. Molecular Phylogenetics and Evolution 37: 474–483.

External links

* {{Taxonbar, from=Q5277008 aethiops Gastropods of New Zealand Endemic fauna of New Zealand Gastropods described in 1791 Taxa named by Johann Friedrich Gmelin Endemic molluscs of New Zealand