Opselater is a genus of click beetle (family Elateridae). They are one of several genera in the tribe Pyrophorini, all of which are bioluminescent. This genus was established by in 1975. After a revision of the genus by , she stated some members of this genus are polyphyletic with ' , which discouraged her from establishing any new genus in this part of Pyrophorini due to alternative resolutions and ambiguity.
Small; dark-brown. short, dense yellowish or grey. Eyes in males slightly more developed than in females. Front prominent. Antennae reaching the hind angles of the prothorax, from fourth segment onwards; third segment little longer than second, the two together of the same length of the fourth. Prothorax slightly convex, variable. Luminous spots small, lateral, flat and visible also in the . cavity and a little raised behind. plates little enlarged inwardly. Abdominal luminous organ small and . Elytral sides subparallel and rounded to apices. Male genitalia: median lobe very enlarged at the middle, with or without minute scales. Female genitalia: more or less spiraled, with long spines; accessory glands well developed; spermatheca well developed and median oviduct with plates.
Opselater is mainly distributed in the Atlantic forest and some species are apparently disjunct.
The following 8 species are recognized by (with each type locality given):