Helicostoa sinensis 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 freshwater snail

Freshwater snail

A freshwater snail is one kind of freshwater mollusc, the other kind being freshwater clams and mussels, i.e. freshwater bivalves. Specifically a freshwater snail is a gastropod that lives in a watery non-marine habitat. The majority of freshwater gastropods have a shell, with very few exceptions....

, an aquatic

Aquatic animal

An aquatic animal is an animal, either vertebrate or invertebrate, which lives in water for most or all of its life. It may breathe air or extract its oxygen from that dissolved in water through specialised organs called gills, or directly through its skin. Natural environments and the animals that...

 gastropod mollusc in the clade Littorinimorpha

Littorinimorpha

Littorinimorpha is a large clade of gastropods within Hypsogastropoda consisting primarily of marine species, but also aquatic and terrestrial species as well....

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Helicostoa sinensis is the only species in the genus Helicostoa, which in turn is the only genus in the family Helicostoidae. According to taxonomy of the Gastropoda by Bouchet & Rocroi (2005)

Taxonomy of the Gastropoda (Bouchet & Rocroi, 2005)

The taxonomy of the Gastropoda as it was revised by Philippe Bouchet and Jean-Pierre Rocroi is currently the most up-to-date overall system for classifying gastropod mollusks...

 the family Helicostoidae has no subfamilies.

Helicostoa sinensis is tentatively placed within superfamily Rissooidea

Rissooidea

Rissooidea, originally named Rissoacea by Grey, 1847, is a large taxonomic superfamily of small and minute saltwater, brackish water, freshwater, and semi-terrestrial snails which have gills and an operculum...

. Previously it was in the superfamily Vermetoidea.

Helicostoa sinensis is only found in China, more specifically in the Yangtze River

Yangtze River

The Yangtze, Yangzi or Cháng Jiāng is the longest river in Asia, and the third-longest in the world. It flows for from the glaciers on the Tibetan Plateau in Qinghai eastward across southwest, central and eastern China before emptying into the East China Sea at Shanghai. It is also one of the...

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This freshwater snail lives attached or bonded to blocks of limestone

Limestone

Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....

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