The advent of integrative taxonomy in plankton research, employing molecular and morphology-based identification, promotes the discovery of new biodiversity records, especially of larval stages. The slipper lobster family Scyllaridae consists of planktonic phyllosoma larvae, persisting weeks to many months in the water column. High interspecific larval similarities and inconsistent delineation of stages have hindered the identification of scyllarid phyllosomata to the species level using morphological characteristics. Here we report the first record of the pygmy slipper lobster, Biarctus sordidus, in the Red Sea following the finding of its phyllosoma larva, extending its known distribution from the Persian Gulf to Australia and southern China. We identified the phyllosoma collected from the Northern Gulf of Aqaba as B. sordidus using the mitochondrial 16S and 18S rRNA genes, and described its morphology to determine the larval stage. We further discuss the potential factors contributing to the delayed detection of this species.
