Defining the Portunus pelagicus species complex using morphometric and phylogenetic analysis

Portunus pelagicus, a commercially important swimming crab species widely distributed throughout the Indo-Pacific region, is currently managed as a single species in the Philippine archipelago. Recent taxonomic work, however, indicates that P. pelagicus comprises a five-member species complex, one of which is an undescribed Portunus species from Japan. Two members of the complex are hypothesized to occur in the waters of the Philippine archipelago, P. pelagicus sensu stricto and the undescribed Portunus species, but more sampling effort is needed to identify independently evolving lineages. This study aims to assess the presence of these two Portunus species in the Philippine archipelago. We collected specimens from fish markets found in different locations around Negros and Panay Island, Philippines and conducted morphometric, geomorphometric, and genetic barcoding analyses to identify and quantify cryptic diversity in the Portunus spp. Only male specimens were used to avoid sexual dimorphism during the geomorphometric analysis. Muscle samples were collected from the pereopods for use in DNA barcoding and phylogenetic analysis. Through our analysis of the congruence between the morphometric and phylogenetic barcoding data of the COI gene region, we uncovered a novel cryptic species that requires further characterization. The results of this study can be used to develop accurate identification keys for use in Portunus fishery management, governance, and scientific research. 

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For more information email:  jquy@eckerd.edu 

Philippines International Research Experience for Students (Ph-IRES)