Papilloderma altonagai is a species of air-breathing land slug, a terrestrial pulmonate gastropod mollusk in the informal group Sigmurethra. Papilloderma altonagai is the only species in the genus Papilloderma, which is the only genus within the family Papillodermatidae, which in turn is the only family within the superfamily Papillodermatoidea. This species is endemic to northern Spain.