Taxonomic redescription of colochirus quadrangularis (Echinodermata: Holothuroidea) from surabaya coastal waters (east java, indonesia) with notes on new distinctive haplogroup of coi gene

Sea cucumbers have been reported in Surabaya east coastal area for their existence and exploitation. Although Colochirus quadrangularis was one of species which firstly reported from Surabaya waters in 2014, this species has never been properly described. Three specimens of C. quadrangularis were obtained from Surabaya coastal waters. Morphological examination conducted by describing all morphological characteristic, including type and distribution of ossicle in their body. DNA-based identification was performed using cytochrome oxidase subunit I (COI) sequences analysis, including sequence comparation with BOLD database, NJ tree reconstruction, and haplotype network presentation. Result of this study showed that there are no noticeable differences of morphological features compared to previous study of C. quadrangularis description. Based on molecular identification, the specimens were 98.69% similar with C. quadrangularis from BOLD database. Conspecific divergence of sequence from this study and downloaded sequences from BOLD showed that average sequence variation within the species was 1.5%. Both morphological descriptions and DNA barcoding results confirmed existence of C. quadrangularis in Surabaya waters. In addition, C. quadrangularis of this study has unique haplotypes differentiated from previous study, collected from Singapore and Australia.