Houtman Abrolhos
The Houtman Abrolhos is unusual in having a luxuriant and diverse living coral reef at such a high latitude. 194 species in 50 genera have been recorded there, all but two of which are tropical. This is a surprisingly high coral diversity, considering the high latitude of the reef, and the relatively low diversity of other biota. For a full list, see list of corals of the Houtman Abrolhos.
Maranhão mangroves
The Maranhão mangroves are home to half the total population of shorebirds in Brazil, and 7% of all shorebirds in South America.
They are also important areas for feeding and breeding for herons (family Ardeidae) and roseate spoonbills ("Platalea ajaja").
Rare and endangered species include scarlet ibis ("Eudocimus ruber"), wattled jacana ("Jacana jacana"), tucuxi ("Sotalia fluviatilis"), West Indian manatee ("Trichechus manatus") and several species of sea turtle that use the mangroves as a breeding area.