The Dalhousie hardyhead (''Craterocephalus dalhousiensis'') is a species of silverside in the family

Atherinidae The Old World silversides are a family, Atherinidae, of fish in the order Atheriniformes. Atherinidae are abundant and considered bony fish (teleost) that are widespread globally, living in rivers, estuaries, and coastal waters. They occur worl ...

. It is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...

to the warm waters of

Dalhousie Springs Dalhousie Springs, also known as Witjira-Dalhousie Springs, is a group of over 60 natural artesian springs located in Witjira National Park on the western fringe of the Simpson Desert, 180 kilometres northeast of Oodnadatta in northern South Aus ...

in the

Lake Eyre Lake Eyre ( ), officially known as Kati Thanda–Lake Eyre, is an endorheic lake in east-central Far North South Australia, some north of Adelaide. The shallow lake is the depocentre of the vast endorheic Lake Eyre basin, and contains th ...

basin, Australia, along with the similar '' Craterocephalus gloveri''. It inhabits shady areas in tropical freshwater streams at 20-39 °C, but has been recorded at 41.8 °C. Its food consists of gastropods, aquatic plants, green filamentous algae, detritus and small invertebrates; food is mainly taken from the substrate. The species is generally golden brown with a darker brown back. A dark midlateral band runs from the snout to the base of the caudal fin. Two to three rows of pigmented scales form discontinuous lines below the midlateral band. It is the only species in the genus '' Craterocephalus'' known to be

sexually dimorphic Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most ani ...

. Adult males are smaller and exhibit a rounded belly compared to the flattened belly of females. Males also lack the forehead concavity exhibited by females.

References

Dalhousie hardyhead Vulnerable fauna of Australia Freshwater fish of South Australia Dalhousie hardyhead Taxonomy articles created by Polbot {{Atheriniformes-stub