Leander tenuicornis (Say, 1818 [in Say, 1817-1818)

Examined material. Municipality of Calçoene: Mouth of Cassiporé River, State of Amapá (03°52’53,40”N, 51°08’36,03”W), 1 male and 1 female (IEPA1625) (Figure 2) .

Geographic distribution. Western Atlantic Ocean - Canada, USA (Massachusetts, Virginia, Carolina, Florida, Louisiana and Texas), Bermudas, Mexico, Panama, Bahamas, Cuba, Jamaica, Porto Rico, Island Virginia, Colombia, Venezuela, Brazil (states of Maranhão, Piauí, Ceará, Rio Grande do Norte, Paraíba, Pernambuco [Atol das Rocas], Alagoas, Sergipe, Bahia, Espírito Santo, Rio de Janeiro and São Paulo), Malvinas Islands. Eastern Atlantic Ocean: Azores archipelago, Portugal. Mediterranean- Spain, France, Italy and Libya. Pacific and Indian Ocean - Red Sea, India, Japan, Papua New Guinea, Australia and New Zealand (Ferreira et al. 2010; Herrera-Barquín et al. 2018; Ramos-Porto 1985).

Distribution in Amapá state. Estuary of the Cassiporé River.

Previous records. present study

Ecological notes. Species found in shallow waters, up to 72 m deep, on gravel, sandy bottoms with algae meadows and/or phanerogams (Ramos-Porto 1985). In the Cassiporé River estuary, it was found in mangrove areas and river with very mud.

Remarks. Leander tenuicornis presents sexual dimorphism in relation to the shape of the face, in the female the rostrum is wider in the ventral part (Ferreira et al. 2010).