Ogasawarana yoshiwarana is a species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of land snail with an operculum

Operculum (gastropod)

The operculum, meaning little lid, is a corneous or calcareous anatomical structure which exists in many groups of sea snails and freshwater snails, and also in a few groups of land snails...

, a terrestrial

Terrestrial animal

Terrestrial animals are animals that live predominantly or entirely on land , as compared with aquatic animals, which live predominantly or entirely in the water , or amphibians, which rely on a combination of aquatic and terrestrial habitats...

 gastropod mollusk in the family Helicinidae

Helicinidae

Helicinidae is a family of small tropical land snails which have an operculum. They are terrestrial operculate gastropod mollusks in the superfamily Helicinoidea....

, the helicinids.

Description

Ogasawarana yoshiwarana was originally described under the name Helicina yoshiwarana by American malacologist Henry Augustus Pilsbry

Henry Augustus Pilsbry

Henry Augustus Pilsbry was an American biologist, malacologist and carcinologist, among other areas of study. He was a dominant presence in many fields of invertebrate taxonomy for the better part of a century...

 in 1902.

Pilsbry's original text (the type description) appeared in the key and it reads as follows:
Pilsbry also distinguished two variants:

• H. yoshiwarana var. arata - Upper surface strongly striate spirally.
• H. yoshiwarana var. mierotheca - Smaller, delicately striate. height of the shell is 2.2 mm. The width of the shell is 4.5 mm.

Distribution

This species was endemic to Haha-jima

Haha-jima

is the second-largest island of the Ogasawara Islands or Bonin Islands south of the Japanese main island chain. It is about 21 km² in area.The highest points are Mt. Chibusa , approximately 462m, and Mt. Sakaigatake , 443m. The largest island of the group, Chichi-jima is approximately...

 in the Ogasawara Islands

Ogasawara Islands

The Bonin Islands, known in Japan as the are an archipelago of over 30 subtropical and tropical islands, some directly south of Tokyo, Japan. Administratively, they are part of Ogasawara Municipality of Ogasawara Subprefecture, Tokyo...

 (Japan

Japan

Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

).

Habitat

The ogasawarana yoshiwarana has been known to live (as lately as 2006) on Higashizaki peninsula off the eastern coast of Hahajima, the second largest island in the Ogasawara Archipelago / Bonin Islands system. The Bonin Islands have been sometimes referred to as the Galapagos Islands

Galápagos Islands

The Galápagos Islands are an archipelago of volcanic islands distributed around the equator in the Pacific Ocean, west of continental Ecuador, of which they are a part.The Galápagos Islands and its surrounding waters form an Ecuadorian province, a national park, and a...

 of the Orient due to their highly diverse fauna and flora. The island is small and only partly covered by forest, which is where the terrestrial gastropod lives out its life.

Ecological role

This animal is essentially an herbivore, eating leaves, stems, soft bark, fruit, vegetables, fungi and algae. Its behavior is like any other land snail's: it thrives in damp and wet weather: Land Snails. This is especially true of the ogasawarana yoshiwarana because it lives in a subtropical/tropical environment. Predators of the species include predatory snails, ground beetles, leeches, and parasites.

Population and Conservation Status

Estimates of the population of this species haven't been conducted. They are expected to be found exclusively in this archipelago, not far from its endemic origin of Hahajima island. It is currently unknown why its population is sparse or even if it is declining or increasing in size. Habitat loss is not a factor; in fact, its home is one of the few places in the world not affected by anthropogenic forces or introduced non-native species. Perhaps the hand of natural selection

Natural selection

Natural selection is the nonrandom process by which biologic traits become either more or less common in a population as a function of differential reproduction of their bearers. It is a key mechanism of evolution....

 plays a role in the specie's threatened status.

Extinction

Ogasawarana yoshiwarana is listed as critically endangered in the IUCN Red List of Threatened Species.

Last record of this species is from 1902 by type description by Henry Augustus Pilsbry

Henry Augustus Pilsbry

Henry Augustus Pilsbry was an American biologist, malacologist and carcinologist, among other areas of study. He was a dominant presence in many fields of invertebrate taxonomy for the better part of a century...

. The species is considered to be critically endangered.