Craterocephalus marjoriae Whitley, 1948
Marjorie's hardyhead
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Family:  Atherinidae (Silversides), subfamily: Craterocephalinae
Max. size:  8.5 cm SL (male/unsexed)
Environment:  benthopelagic; freshwater
Distribution:  Oceania: endemic to Australia.
Diagnosis:  Distinguished from Craterocephalus marianae and Craterocephalus munroi and all other members of the genus by a combination of the following: head 3.0-3.4 (3.1); greatest body depth 3.6-4.7 (4.1); least body depth 8.8-11.0 00.0); origin of pectoral fin to anus 2.7-3.1 (2.9), all in SL. Dorsal process of premaxilla 1.1-1.70.4 in eye. Midlateral scale count 28-30 (29.1); transverse scale count 5.5-6.5 (6.0); vertebral count 30-32 (31.4). Position of anus in relation to tip of pelvic fin from 0.5 scales in front to 2 scales behind tip of pelvic fin. Differs osteologically from all other Craterocephalus species by a combination of the following: shape of anterior medial process of maxilla; lack of interdorsal pterygiophores (but shared with some other members of C. eyresii group); minute anterior process usually present on cleithrum; dorsal process of cleithrum also present; basisphenoid short and thick. Differs genetically from Craterocephalus marianae at the following loci: ADA, CK, FDP, GPI-l,MPI, PGM and from C. munroi at CK, FDP, GLDH, GPI-l, MPI, PGM. Unique at GPI-lf (Ref. 26703).
Biology:  Lives in clear flowing streams where it is common along the vegetated margin. Generally in shallow water over sandy or gravelly substrates. A shoal-forming species. Capable of multiple spawnings between September and January (with peak activity early in the season). It has reproduced in captivity (Ref. 44894). Feeds mostly on aquatic insects and their larvae, micro-crustaceans, algae and fish eggs (Ref. 44894).
IUCN Red List Status: Least Concern (LC); Date assessed: 15 February 2019 Ref. (124695)
Threat to humans:  harmless
Country info:   
 

Entered by: Torres, Armi G. - 01.05.96
Modified by: OrtaƱez, Auda Kareen - 11.07.06

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