Semilaoma Lidgbirdensis
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''Semilaoma lidgbirdensis'', also known as the Mount Lidgbird pinhead snail, is a tiny
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
land snail A land snail is any of the numerous species of snail that live on land, as opposed to the sea snails and freshwater snails. ''Land snail'' is the common name for terrestrial gastropod mollusks that have shells (those without shells are known as ...
that 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 ...
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 ...
's
Lord Howe Island Lord Howe Island (; formerly Lord Howe's Island) is an irregularly crescent-shaped volcanic remnant in the Tasman Sea between Australia and New Zealand, part of the Australian state of New South Wales. It lies directly east of mainland P ...
in the
Tasman Sea The Tasman Sea (Māori: ''Te Tai-o-Rēhua'', ) is a marginal sea of the South Pacific Ocean, situated between Australia and New Zealand. It measures about across and about from north to south. The sea was named after the Dutch explorer Abe ...
.


Description

The depressedly turbinate shell of the mature snail is 0.8–0.9 mm in height, with a diameter of 1.5–1.6 mm, and a low
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 ...
. It is pale golden in colour. The
whorls 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 d ...
are rounded above and below an angular periphery. The sutures are weakly impressed, with closely spaced, sinuate radial ribs. It has an ovately lunate
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 ...
, and a very narrow, sometimes closed, umbilicus. The animal is unknown.


Distribution and habitat

The snail is common and widespread across the island in lowland forest,
rainforest Rainforests are characterized by a closed and continuous tree canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforest can be classified as tropical rainforest or temperate rainfores ...
and scrub.


References

* lidgbirdensis Gastropods of Lord Howe Island Taxa named by Tom Iredale Gastropods described in 1944 {{Punctidae-stub