A related extinct species, the Tongan tooth-billed pigeon (Didunculus placopedetes), is only known from subfossil remains in several archeological sites in Tonga.

The underparts, head and neck are greyish with a slight blue-green iridescence, and the tail, wings-coverts and tertials are rufous chestnut, while the remaining remiges are blackish.

It has a large, curved, and hooked bright red bill, with tooth-like projections on the lower mandible which let them act as seed dispensers.

[4] The sexes are similar in appearance, but the juvenile is duller, with a browner head, and a black bill with pale orange at the base.

[5] Behaviourally, it is unusual – perhaps unique – among members of Columbiformes in drinking by scooping water up in its bill, in the manner of the great majority of bird species, rather than sucking it up using the tongue as a straw.

The discovery of the bird was announced by Hugh Edwin Strickland in September 1844 as being among the rarities obtained by Mr. Titian Peale, the naturalist of the expedition.

Actions to save this species will likely require conservation education to reduce hunting risk, and knowledge of the biology of the population and the reasons behind the current decline.