''Pernastela howensis'', also known as the Lord Howe pinhead snail, is a tiny
species
A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...
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 molluscs, terrestrial gastropod mollusks that have gastropod shell, shel ...
that is
endemic
Endemism is the state of a species being found only 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 foun ...
to
Australia
Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...
'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 Port ...
in the
Tasman Sea
The Tasman Sea 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 Abel Janszoon Tasman, who in 1642 wa ...
.
Description
The trochoidal shell of the mature snail is 1.8–2.1 mm in height, with a diameter of 3–3.3 mm, and a raised spire. It is cream to pale golden-brown in colour. The whorls are shouldered and
sutures impressed, with widely spaced radial ribs. It has an roundly lunate aperture, flattened on the upper side by the reflected lip, and a moderately wide
umbilicus. The animal is unknown.
Distribution and habitat
The snail is known only from three worn shells collected from the summit of
Mount Gower
Mount Gower (also known as Big Hill), is the highest mountain on Australia's subtropical Lord Howe Island in the Tasman Sea. With a height of above sea level, and a relatively flat summit plateau, it stands at the southern end of Lord Howe, jus ...
in 1912, and it may be
extinct
Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...
.
References
*
howensis
Gastropods of Lord Howe Island
Taxa named by Tom Iredale
Gastropods described in 1944
{{Punctidae-stub