Euryrhynchus tomasi De Grave, 2007

Examined material. Municipality of Calçoene: tributary stream on the right bank of the Amapá Grande River, downstream of Cachoeira Grande, Calafate (2°9’30.98”N, 50°55’19.83”W), 22.ix.2021, colls. I.M. Vieira and A.G.S. de Almeida and D.P. de Almeida, 14 males and 5 females (IEPA 2099) .

Geographic distribution. French Guiana, Brazil (Amapá state, northwest and north of the city of Amapá, Vilarejo and Balneário Cachoeira Grande, Amapá Grande River and Cachoeira Grande, according to De Grave (2007) and Pachelle & Tavares (2018) (Figure 1).

Distribution in Amapá state. Affluent stream of the Amapá Grande River, downstream and upstream of Cachoeira Grande.

Previous records. Pachelle & Tavares (2018)

Ecological notes. Collected in shallow and shaded stream, with plenty of leaf litter, dry season, pH (6.08), water temperature (25.5°C), dissolved oxygen (60.7%) and conductivity (10 μS/cm).

Remarks. Euryrhynchus tomasi is distinguished from E. burchelli by presenting the pereiopod carpus 2 unarmed and the grouper with a spine on each side of the distoventral region; while females have an internal appendage from the third to the fifth pleopod (Pachelle & Tavares 2018).