Pachydrobiella brevis 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 mollusk in the family Pomatiopsidae

Pomatiopsidae

Pomatiopsidae is a family of small mainly freshwater snails with gills and an operculum, aquatic gastropod mollusks in the superfamily Rissooidea ....

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Pachydrobiella brevis is the only species in the genus Pachydrobiella.

Distribution

The distribution of Pachydrobiella brevis includes Khong Island

Khong Island

Khong Island or Don Khong is the main island of the Si Phan Don riverine archipelago located in the Mekong River, Khong district, Champasak Province, southern Laos.The island is long , and at its widest point...

 in the Mekong River, southern Laos

Laos

Laos Lao: ສາທາລະນະລັດ ປະຊາທິປະໄຕ ປະຊາຊົນລາວ Sathalanalat Paxathipatai Paxaxon Lao, officially the Lao People's Democratic Republic, is a landlocked country in Southeast Asia, bordered by Burma and China to the northwest, Vietnam to the east, Cambodia to the south and Thailand to the west...

. The type locality is Khong Island. This species is probably endemic to the Khong Island region.

Description

The shape of the shell

Gastropod shell

The gastropod shell is a shell which is part of the body of a gastropod or snail, one kind of mollusc. The gastropod shell is an external skeleton or exoskeleton, which serves not only for muscle attachment, but also for protection from predators and from mechanical damage...

 is ovate-conic. The shell is thick and smooth. The smooth shell is unique in the tribe Jullieniini. The outer lip is thick with growth lines.

The width of the shell is 2.5 mm. The height of the shell is 2.2–3.6 mm.

Thiele (1928) and Brandt (1970) made a drawing showing smooth teeth in the radula

Radula

The radula is an anatomical structure that is used by molluscs for feeding, sometimes compared rather inaccurately to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food enters the esophagus...

, but Davis (1979) showed multiserrate teeth in the radula.

Ecology

Pachydrobiella brevis lives primarily in freshwater habitats that lack a current or have only a slight current. However this species sometimes or rarely also lives also in places where the current is moderate or strong all the way to whitewater

Whitewater

Whitewater is formed in a rapid, when a river's gradient increases enough to disturb its laminar flow and create turbulence, i.e. form a bubbly, or aerated and unstable current; the frothy water appears white...

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This snail probably feeds on algae

Algae

Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...

on stones.