First record of Arcania brevifrons Chen, 1989 (Decapoda; Leucosiidae) and further record of Macrophthalmus (Macrophthalmus) indicus Davie, 2012 (Decapoda; Macrophthalmidae) in Hellenic waters

The findings of the crabs Arcania brevifrons and Macrophthalmus (Macrophthalmus) indicus, native to the Indo-West Pacific Ocean and Red Sea, and to the Indian Ocean and Red Sea, respectively, in 2021 are described from Rhodes Island, Greece. This first record of the leucosiid A. brevifrons in Hellenic waters and the Aegean Sea documents the westward expansion of its Mediterranean distribution. Two individuals of the introduced macrophthalmid M. (M.) indicus were found in the stomachs of silver-cheeked toadfish (Lagocephalus sceleratus), a fish species that itself is invasive. For both species, DNA barcoding was performed using the standard mitochondrial marker cytochrome c oxidase subunit I (COI). While the identification of A. brevifrons was genetically confirmed, M. (M.) indicus individuals were morphologically identified. There were no M. (M.) indicus genetic samples available in the nucleotide database of GenBank, hindering the ability to genetically confirm species identification. However, M. (M.) indicus had previously been detected 12 years ago in the same area.