DNA barcoding of the spider crab Menaethius monoceros (Latreille, 1825) from the Red Sea, Egypt

BACKGROUND: Most spider crab species inhabiting the Red Sea have not been characterized genetically, in addition to the variation and complexity of morphological identification of some cryptic species. The present study was conducted to verify the identification of two morphotypes of the spider crab Menaethius monoceros (Latreille, 1825) in the family Epialtidae Macleay, 1838, collected from the Red Sea, Egypt. DNA barcoding of two mitochondrial markers, cytochrome oxidase subunit I (COI) and 16S, was used successfully to differentiate between these morphotypes. RESULTS: DNA barcoding and genetic analyses combined with morphological identification showed that the two morphotypes were clustered together with low genetic distances ranged from 1.1 to 1.7% COI and from 0.0 to 0.06% 16S. Hence, this morphological variation is considered as individual variation within the same species. CONCLUSION: The present study successively revealed that genetic analyses are important to confirm the spider crab's identification in case of morphological overlapping and accelerate the accurate identification of small-sized crab species. Also, DNA barcoding for spider crabs is important for better future evaluation and status records along the Red Sea coast.