Estimating diversity of Indo-Pacific coral reef stomatopods through DNA barcoding of stomatopod larvae

Abstract

There is a push to fully document the biodiversity of the world within 25 years. However, the magnitude of this challenge, particularly in marine environments, is not well known. In this study, we apply DNA barcoding to explore the biodiversity of gonodactylid stomatopods (mantis shrimp) in both the Coral Triangle and the Red Sea. Comparison of sequences from 189 unknown stomatopod larvae to 327 known adults representing 67 taxa in the superfamily Gonodactyloidea revealed 22 distinct larval operational taxonomic units (OTUs). In the Western Pacific, 10 larval OTUs were members of the Gonodactylidae and Protosquillidae where success of positive identification was expected to be 96.5%. However, only five OTUs could be identified to species and at least three OTUs represent new species unknown in their adult form. In the Red Sea where the identification rate was expected to be 75% in the Gonodactylidae, none of four larval OTUs could be identified to species; at least two represent new species unknown in their adult forms. Results indicate that the biodiversity in this well-studied group in the Coral Triangle and Red Sea may be underestimated by a minimum of 50% to more than 150%, suggesting a much greater challenge in lesser-studied groups. Although the DNA barcoding methodology was effective, its overall success was limited due to the newly discovered taxonomic limitations of the reference sequence database, highlighting the importance of synergy between molecular geneticists and taxonomists in understanding and documenting our world's biodiversity, both in marine and terrestrial environments.

Figure 1

Neighbour-joining phylogeny showing the phylogenetic placement of larval haplotypes for: (a) all stomatopods except most of the Gonodactylidae and (b) most of the Gonodactylidae. All larvae from May's Reef (MR), Walindi (Wal) and the Red Sea (RS), including sample sizes, are highlighted in bold and referenced by OTU numbers corresponding to table 1. Taxa listed as c.f. indicate uncertain taxonomic identity, but affinity to a specific species. Stars indicate successful barcoding identifications, diamonds indicate gonodactylid (from superfamily Gonodactyloidea) larvae that could not be identified and circles indicate non-gonodactylid larvae that could not be identified. Branch length scale is in Kimura 2-Parameter distance.

Figure 1

Neighbour-joining phylogeny showing the phylogenetic placement of larval haplotypes for: (a) all stomatopods except most of the Gonodactylidae and (b) most of the Gonodactylidae. All larvae from May's Reef (MR), Walindi (Wal) and the Red Sea (RS), including sample sizes, are highlighted in bold and referenced by OTU numbers corresponding to table 1. Taxa listed as c.f. indicate uncertain taxonomic identity, but affinity to a specific species. Stars indicate successful barcoding identifications, diamonds indicate gonodactylid (from superfamily Gonodactyloidea) larvae that could not be identified and circles indicate non-gonodactylid larvae that could not be identified. Branch length scale is in Kimura 2-Parameter distance.