This species is in the western Indian Ocean, including the Red Sea and the Mediterranean, having invaded as a Lessepsian migrant through the Suez Canal.

The tentacled flathead was first formally described as Platycephalus longiceps by the French zoologist Georges Cuvier in 1829 from specimens collected by Ehrenberg at Massawa in Eritrea.

[3] In 1873 the French zoologist Henri Émile Sauvage described a new species Platycephalus grandidieri from Madagascar and in 1956 the American zoologist Henry Weed Fowler and the Israeli ichthyologist Heinz Steinitz proposed a new monotypic genus, Papilloculiceps, with Sauvage's Platycephalus grandidieri as its type species.

[6] The tentacled flathead has an elongate body with a depressed head with 5 prominent nuchal spines.

[1] It also occurs in the Mediterranean Sea,[8] having first been reported there off the coast of Israel in 1986, probably having migrated through the Suez Canal.