Primitive koa finch Primitive koa finch The primitive koa finch ("Rhodacanthis litotes") is a species of Hawaiian honeycreeper. It was endemic to Hawaii. Of the four species in the genus "Rhodacanthis", it and the scissor-billed koa finch became extinct before the arrival of the first Europeans to Hawaii in 1778. It is known as the ancestor of all koa finches. An adult primitive koa finch was slender and had a total length of about . There was probably a small distinct difference between the sexes. Based on fossils, it is known that the adult primitive koa finch had a slightly curved, thick bill.
Acacia koa survives best in pasture when planted under koa. This is because koa trees reduce radiative cooling, preventing frost damage to ōhia lehua seedlings. Koa is the preferred host plant for the caterpillars of the green Hawaiian blue ("Udara blackburni"), which eat the flowers and fruits. Adults drink nectar from the flowers. Koa sap is eaten by the adult Kamehameha butterfly ("Vanessa tameamea"). The koa bug ("Coleotichus blackburniae") uses its rostrum to suck the contents out of koa seeds. Koa is vulnerable to infection by koa wilt. Acacia koa Acacia koa is a species of flowering tree in the pea family,