Mordacia praecox, the non-parasitic lamprey

Lamprey

Lampreys are a family of jawless fish, whose adults are characterized by a toothed, funnel-like sucking mouth. Translated from an admixture of Latin and Greek, lamprey means stone lickers...

, is a freshwater

Freshwater

Fresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams. Fresh water is generally characterized by having low concentrations of dissolved salts and...

 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 lamprey that occurs in south-eastern Australia

Australia

Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

. It has a thin eel

Eel

Eels are an order of fish, which consists of four suborders, 20 families, 111 genera and approximately 800 species. Most eels are predators...

-like body around 12 to 15 cm long, with two low dorsal fin

Dorsal fin

A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...

s on the back half. The skin is dark blue above and gray below. Its eyes are small, and located on the top of its head.

The non-parasitic lamprey is known only from the Moroya

Moruya River

The Moruya River is in southern New South Wales, Australia. Its freshwater reaches are known as the Deua River.The headwaters of the Moruya River rise as the Deua River south of Braidwood...

 and Tuross River

Tuross River

-References:...

s in southern New South Wales

New South Wales

New South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...

. Unlike most other species of lamprey, it spends its entire life in fresh water. The ammocoetes (lamprey larva

Larva

A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...

e) take around three years to reach maturity. Ammocoetes and juvenile adults are indistinguishable from Mordacia mordax

Mordacia mordax

The short-headed lamprey, Mordacia mordax, also known as the Australian lamprey and the Murray lamprey, is a species of lamprey that occurs in south-eastern Australia. It has a thin eel-like body up to 50 cm long, with two low dorsal fins on the back half. The skin is blue-gray or brown...

, which also occurs within its distribution, but the adults are easily distinguished by their size and colouration.