Type of seasonally-inundated floodplain forest in the Amazon region.

The term is normally used for those forests flooded by whitewater rivers but is sometimes used to refer to blackwater environments for which the more traditional term is igapó. Continue reading »

Minor tributary stream or small river in the Amazon region, the name deriving from the native nheengatu language. It literally translates as ‘canoe path’ since most igarapés are navigable by canoe or small boat and they are traditionally important as a means of transport and communication.

A small igarapé in Maranhão state, Brazil. © Fernando Cunha

A marking on the body in the area analogous to the humerus, or shoulder. In fishes it’s normally located above the pectoral-fin and behind the opercle.

There may be more than a single such spot in some species.

Many characids possess a humeral spot, as shown here. © H-J Chen

Abbreviation of the Latin ex grege, meaning ‘from the herd, of the group’.

Sometimes used between the generic and specific parts of a binomial name when the precise species is not known but the organism can be identified as belonging to a named group of species.

A thin layer of bone, membrane, or other tissue.

Barbel originating from the distal end of the maxilla on the side of the mouth.

Tooth-like projection in the middle of the upper jaw in certain loach genera which may fit into a notch in the lower jaw. Also referred to as dentiform process.

Type of stream or river that branches off and flows away from a main channel. Particularly common in river deltas, but also occur inland in some cases.

Cauldron-like volcanic feature usually formed by the collapse of land following a volcanic eruption, sometimes confused with volcanic craters. Often fill with water to form lakes.

Sailko

Satellite photograph of the caldera on Fernandina Island in the Galapagos archipelago, clearly showing the collapsed summit. © NASA

Process by which live prey is raised and fed nutritious foods prior to use, e.g., feeding crickets on dried fish food or fresh vegetables before being offered to the fish.