Pachycara crassiceps was first formally described as Lycenchelys crassiceps by the French zoologistLouis Roule with its type locality given as the Gulf of Gascony. The specific namecrassiceps means "thick headed" and allusion to the head being larger than the head of Lycenchelys paxillus, with which it was presumed to be congeneric.
Pachycara crassiceps is found in the eastern Atlantic Ocean where it has been recorded off southwest Ireland, in the Bay of Biscay, the Canary Islands and off Mauritania and Senegal. This is a benthic specieswhich lives on muddy substrates at depths ranging between.