Unexpected low genetic differentiation between Japan and Bering Sea populations of a deep-sea benthic crustacean lacking a planktonic larval stage (Peracarida: Tanaidacea)

Abstract

Information on the extent, diversity and connectivity of populations is lacking for most deep-sea invertebrates. Species of the order Tanaidacea (Crustacea), one of the most diverse and abundant macrofaunal groups in the deep sea, are benthic, lack a planktonic larval stage, and thus would be expected to have narrow distributional ranges. However, with molecular evidence from the COI gene, we show here that the deep-sea tanaidacean Carpoapseudes spinigena has a distributional range spanning at least 3700 km, from off northern Japan to the south-eastern Bering Sea. Living individuals found in a sediment core indicated that the species is a sedentary burrower. COI analyses revealed a low level of genetic diversity overall, and low differentiation (p-distance, 0.2–0.8%) between the Japan and Bering Sea populations. One hypothesis to explain the low genetic diversity over a broad region is that the Japan population was founded by individuals transported by ocean currents from the Bering Sea. However, due to limited data, other explanations cannot be ruled out. Our results indicate that continued sampling is of fundamental importance to understanding how genetic and taxonomic diversity originate and are maintained in the deep sea.

Comprehensive Transcriptome Sequencing of Tanaidacea with Proteomic Evidences for Their Silk

“…Tubes made by the Th- and Pe-systems are stout enough to be picked up by forceps whereas those made by the Pl-system are not, indicating that the components of the tubes are different among systems. The gene expression patterns in Pe- and Pl-systems are similar to Carpoapseudes spinigena , a burrower ( Kakui et al 2020 ), indicating that the silk-related genes in tube dwellers bearing Pe- and Pl-systems may not be detected in our analysis and may greatly differ from those in tube dwellers bearing the Th-system. Of the three paralogs of caddisworm fibroin-like proteins, only comp408 is conserved in Apseudoidea, suggesting duplication of these genes in the common ancestor of Paratanaoidea and Tanaidoidea, following the divergence of Apseudoidea.…”

“…To check their mode of life, living individuals of nine tanaidacean species ( Apseudes sp., Paradoxapseudes littoralis , Phoxokalliapseudes tomiokaensis , Apseudomorpha sp., Parapseudes algicola , and four tanaidid species) and Asellus hilgendorfii were reared at 4, 21, or 25 °C for weeks. The mode of Carpoapseudes spinigena was presented by Kakui et al (2020) . The mode of Pseudosphyrapus quintolongus was inferred based on the observed mode in the congener, P. malyutinae (Kakui K. unpublished data).…”

Patterns of Macrofaunal Biodiversity Across the Clarion-Clipperton Zone: An Area Targeted for Seabed Mining

“…Previous studies have used beta diversity metrics to estimate macrofaunal species ranges in the CCZ of 25 -180 km for polychaetes (Wilson, 2017;Bonifácio et al, 2020), 84 km for isopods (Wilson, 2017), and 1245 km for tanaids (Jakiel et al, 2019). Similarly, narrow geographical ranges were found in the NW Pacific (Jakiel et al, 2020;Kakui et al, 2020).…”

Meiofauna in the southeastern Bering Sea: community composition and structuring environmental factors

“…The continental shelf of the Bering Sea is known for its large populations of marine mammals and seabirds, and it hosts large fishery resources of the United States (Granger et al, 2011). However, the smaller organisms in benthic ecosystems, including macro-and meiofauna have been largely overlooked in this area, despite their potential importance in ecosystem functioning and the resultant biogeochemical cycles (e.g., Kakui et al, 2020;Langlet et al, 2020).…”