''Mordacia'' is a genus of

lamprey Lampreys (sometimes inaccurately called lamprey eels) are a group of Agnatha, jawless fish comprising the order (biology), order Petromyzontiformes , sole order in the Class (biology), class Petromyzontida. The adult lamprey is characterize ...

, the sole genus of the family Mordaciidae, also known as the southern topeyed lampreys. The family Mordaciidae is most closely related to the lamprey family Geotriidae, which has a similar

Gondwana Gondwana ( ; ) was a large landmass, sometimes referred to as a supercontinent. The remnants of Gondwana make up around two-thirds of today's continental area, including South America, Africa, Antarctica, Australia (continent), Australia, Zea ...

n distribution, and both families diverged during the

Early Cretaceous The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 ...

. Together, their common ancestor diverged from the Petromyzontidae during the

Middle Jurassic The Middle Jurassic is the second Epoch (geology), epoch of the Jurassic Period (geology), Period. It lasted from about 174.1 to 161.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relativel ...

. They are found in

Chile Chile, officially the Republic of Chile, is a country in western South America. It is the southernmost country in the world and the closest to Antarctica, stretching along a narrow strip of land between the Andes, Andes Mountains and the Paci ...

and

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 ...

; the Chilean and one Australian species (''M. lapicida'' and ''M. mordax'') are

anadromous Fish migration is mass relocation by fish from one area or body of water to another. Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousa ...

fish that spawn in

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is bounded by the cont ...

-draining river basins and mature in the ocean, while the other Australian species (''M. praecox'') spends its whole life in freshwater. Phylogenetic evidence indicates ancient divergences within this genus, with the Chilean and Australian lineages diverging from one another during the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

(100 mya), although both Australian species only diverged from each other during the

Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

Species

There are currently three recognized species in this genus: * '' Mordacia lapicida'' ( J. E. Gray, 1851) (Chilean lamprey) * '' Mordacia mordax'' ( J. Richardson, 1846) (Australian lamprey) * '' Mordacia praecox''

Potter A potter is someone who makes pottery. Potter may also refer to: Places United States *Potter, originally a section on the Alaska Railroad, currently a neighborhood of Anchorage, Alaska, US *Potter, Arkansas *Potter, Nebraska *Potters, New Jerse ...

, 1968 (Australian brook lamprey)

References

Fish of the Pacific Ocean Jawless fish genera Taxa named by John Edward Gray {{jawless-fish-stub