Genetic evidence from embryos suggests a new species of skate related to Bathyraja parmifera (Rajiformes: Arhynchobatidae) in the Bering Sea

I Spies,P Goddard,Jw Orr,De Stevenson,Gr Hoff,J Guthridge,Cn Rooper

doi:10.3354/meps13768

Abstract

Several new species of oviparous skates of the genus Bathyraja have been identified over the past 2 decades, yet it is possible that a complete understanding of species diversity among this group has not been achieved. We used genetics and morphology to screen for the presence of species-level differentiation among embryos from nursery areas in the eastern Bering Sea that were initially identified as the Alaska skate B. parmifera. A sample of 57 embryos from Pervenets Canyon differed significantly at single nucleotide polymorphism loci from 297 other B. parmifera samples, and differences were on the order of those observed between B. parmifera and the leopard skate B. panthera. This sample of embryos was similar to B. parmifera at the cytochrome c oxidase subunit I (COI) mitochondrial locus. We discuss whether this group of embryos may represent an undescribed cryptic species. Although morphological description of adults is required for a complete species description, only embryo samples were available. Even so, results presented here are a step toward understanding, managing, and conserving the diversity of skate species in the North Pacific Ocean.

Highlights

Accurate recognition of species diversity and associated geographic ranges are essential steps towards management and conservation
No new c oxidase (COI) sequences were present in the embryos of Bathyraja cf. parmifera that had not been previously observed in B. parmifera (Fig. 3) (Spies et al 2011)
We used restriction-site-associated DNA sequencing (RADseq) to examine broad-scale differences among embryos identified as B. parmifera followed by the traditional approaches of mtDNA sequencing and morphology, for examination of specimens with anomalous single nucleotide polymorphism (SNP) genotypes

Summary

Introduction

Accurate recognition of species diversity and associated geographic ranges are essential steps towards management and conservation. Sequence diversity in the mitochondrial gene cytochrome c oxidase (COI), coined the ‘Barcode of Life’ (Hebert et al 2004), can be used to discriminate a high proportion of species within diverse groups (e.g. 92.1% of beetles, Pentinsaari et al 2014; 93% of Canadian freshwater fishes, Hubert et al 2008; 98% of Pacific Canadian marine fishes, Steinke et al 2009). This tool is not universally diagnostic (e.g. Spies et al 2006), and species identification may require morphological examination and taxonomic evaluation (Will & Rubinoff 2004).

Methods

Results

Conclusion