Drysdale Hardyhead, Craterocephalus helenae Ivantsoff, Crowley & Allen 1987

Summary:

A small dusky golden hardyhead with a silvery belly and a silvery mid-lateral stripe. The Drysdale Hardyhead is found only in the Drysdale River of the Kimberley region, Western Australia.

Cite this page as:

Vanessa J. Thompson, Craterocephalus helenae in Fishes of Australia, accessed 05 Apr 2025, https://fishesofaustralia.net.au/home/species/1380

Drysdale Hardyhead, Craterocephalus helenae Ivantsoff, Crowley & Allen 1987

More Info

Distribution	Known only from the Drysdale River, Kimberley region, north Western Australia. Inhabits rocky pools in clear still or flowing freshwater streams and channels.
Features	Dorsal fin V-VII + I, 6-7; Anal fin I, 7-8; Pectoral fin 12-13; Vertebrae 32-33; Gill rakers in 1st lower gill arch 8-10. Body laterally compressed, relatively elongate; greatest body depth 3.7-4.5 in SL; head relatively rounded and truncate; head length in SL 3.2-3.6; mouth small, protrusible with upper jaw extending slightly over lower when extended forward; gape restricted by fusion of lips; lips moderately thick; jaw teeth fine, pointing posteriorly; eye diameter in HL 3.2-3.8. Body scales large, almost rectangular and scalloped anteriorly; circuli on anterior half of scale; horizontal scale rows 6-8; vertical scale rows 30-32; preopercle with 4 scales and opercle with 4 large scale; first 4-5 scales on dorsum of head rectangular and large. Two separate dorsal fins; origin of first dorsal behind origin of ventral fin; origin of second dorsal fin above origin of anal fin; spines of first dorsal fin weak but not extended or filamentous; caudal fin forked.
Size	To 8 cm SL, commonly 5-6 cm.
Colour	Dusky dorsally with a silvery mid-lateral stripe and silver belly.
Feeding	Omnivorous feeding on aquatic insects, micro-crustaceans and some algae.
Biology	Little is known of the biology of this species but is likely to spawn in pairs depositing adhesive eggs amongst aquatic vegetation.
Conservation	Listed as Near Threatened on the IUCN Red List of Threatened Species.
Remarks	Craterocephalus helenae has been mis-identified as C. marjoriae in the past.
Similar Species	Craterocephalus helenae is most similar to C. marjoriae and C. marianae but differs in having a lower gill raker count, a higher midlateral scale count and on average a higher vertebrae count.
Etymology	Generic name Craterocephalus comes from the Greek meaning bowl or basin and head, possibly in reference to the strong head of species in this genus. Species is named helenae in honor of the senior author's wife Helena.
Species Citation	Craterocephalus helenae Ivantsoff, W., Crowley, L.E.L.M. & Allen, G.R. (1987). Descriptions of three new species and one subspecies of freshwater hardyhead (Pisces: Atherinidae: Craterocephalus) from Australia. Rec. West. Aust. Mus. 13(2): 171–188 [177, fig. 3 ]. Downstream from Gibb R. Road, Kimberley, WA [15°41'S, 126°32'E].
Author	Vanessa J. Thompson