Johnius amblycephalus, the bearded croaker, also known as the green-backed croaker or sharp-nosed jewfish, is a marine ray-finned fish belonging to the family Sciaenidae, the drums and croakers. This fish is found in the Indian and Pacific Oceans.

Taxonomy Johnius amblycephalus was first formally described as Umbrina amblycephala in 1855 by the Dutch physician, herpetologist and ichthyologist Pieter Bleeker with its type locality given as Ambon Island. Bleeker's name replaced Umbrina dussumieri which had been coined by Achille Valenciennes in 1833 but which was invalid as it was preoccupied by Georges Cuvier's 1830 Corvina dussumieri. This species is classified within the nominate subgenus of Johnius. This species has been placed in the subfamily Otolithinae by some workers, but the 5th edition of Fishes of the World does not recognise subfamilies within the Sciaenidae which it places in the order Acanthuriformes.

Etymology Johnius amblycephalus has a specific name, amblycephalus, which means "blunt head" and this is an allusion to its relatively blunt snout in comparison to Johnius dussumieri.

Description Johnius amblycaphalus has its dorsal fin supported by a total of 11 spines and between 23 and 26 soft rays while the anal fin is supported by 2 spines and 7 soft rays. The second to the fifth spines in the first dorsal fin are elongated. The rear edge of the caudal fin can be truncate, rhomboidal or s-shaped.