The range of the sicklefin lemon shark (Negaprion acutidens) is expanded to include Palmyra Atoll, in the Northern Line Islands, central Pacific. Despite the fact that researchers have been studying reef and lagoon flat habitats of the Atoll since 2003, lemon sharks were first observed in 2010, suggesting a recent colonization event. To date, only juveniles and sub-adult sharks have been observed.