Cryptic diversity of the slipper lobster genus Scyllarides (Crustacea: Decapoda: Scyllaridae) in the Pacific

Fourteen extant species of slipper lobsters have been described in the genus Scyllarides, with six species known from the Indo-Pacific. Previous DNA barcoding of Scyllarides phyllosoma larvae collected from the western and central North Pacific revealed two enigmatic types, labeled as Scyllarides sp-B and sp-C, which could not be conclusively identified. In this study, mitochondrial COI and 16S rDNA sequences from museum specimens of Scyllarides species were examined, revealing that these two types represent previously undescribed species. The lineages most closely related to the Scyllarides sp-B and sp-C phyllosoma larvae were S. squammosus and S. deceptor, respectively, with substantial differentiation. Scyllarides squammosus was thought to be distributed in the Indo-Central Pacific, but no larvae of this species were collected in the central North Pacific where Scyllarides sp-B larvae were collected. This suggests that the population referred to as S. squammosus in the Hawaiian Islands is Scyllarides sp-B. Additionally, substantial genetic differentiation was observed between the western and central to eastern Pacific samples of S. haanii. These findings not only reveal previously unknown species within the genus Scyllarides but also significant genetic differentiation between populations, highlighting the cryptic diversity and the need for further taxonomic revision.