Macrostylis metallicola spec. nov.—an isopod with geographically clustered genetic variability from a polymetallic-nodule area in the Clarion-Clipperton Fracture Zone

Type Article
Date 2020-02
Language English
Author(s) Riehl Torben1, 2, 3, de Smet Bart4
Affiliation(s) 1 : Department of Marine Zoology, Section Crustacea, Senckenberg Research Institute and Natural History Museum, Frankfurt am Main, Germany
2 : Institute for Ecology, Evolution and Diversity, Johann Wolfgang Goethe Universität Frankfurt am Main, Frankfurt am Main, Germany
3 : Centre for Natural History, Zoological Museum, Universität Hamburg, Hamburg, Germany
4 : Department of Biology, Marine Biology Research Group, Ghent University, Ghent, Belgium
Source Peerj (2167-8359) (PeerJ), 2020-02 , Vol. 8 , P. e8621 (44p.)
DOI 10.7717/peerj.8621
WOS© Times Cited 4
Keyword(s) Taxonomy, Janiroidea, Macrostylidae, Crustacea, Deep-sea mining impact, Manganese nodules, CCFZ, CCZ, Macrofauna, Abyssal
Abstract

Background: The Clarion-Clipperton Fracture Zone (CCFZ) in the Northeast Central Pacific Ocean is a region of heightened scientific and public interest because of its wealth in manganese nodules. Due to a poor ecological understanding at the abyssal seafloor and limited knowledge of the organisms inhabiting this area, huge efforts in alpha taxonomy are required. To predict and manage potential hazards associated with future mining, taxonomy is an essential first step to grasp fundamental ecosystem traits, such as biogeographic patterns, connectivity, and the potential for post-impact recolonization. Amongst samples from the Global Sea Mineral Resources NV exploration area (EA) in the CCFZ an undescribed species of the isopod crustacean family Macrostylidae was discovered. Previously, it has been reported from two other nearby regions, the Institut Français de Recherche pour l’Exploitation de la Mer and BGR EAs. There it was one of the more widely distributed and abundant species of the benthic macrofauna and exhibited geographically structured populations. It nevertheless remained taxonomically undescribed so far. Methods: The new species is described by means of integrative taxonomy. Morphologically, macro photography, confocal microscopy, scanning electron microscopy and light microscopy were used to describe the species and to get first insights on its phylogenetic origin. Additionally, mitochondrial DNA markers were used to test the morphological allocation of the two dimorphic sexes and juvenile stages, to analyze geographic patterns of genetic differentiation, and to study intra-and inter-species relationships, also in light of previously published population genetics on this species. Results: The new species, Macrostylis metallicola spec. nov., is a typical representative of Macrostylidae as recognizable from the fossosoma, prognathous cephalothorax, and styliform uropods. It can be morphologically distinguished from congeners by a combination of character states which include the autapomorphic shape of the first pleopod of the copulatory male. A sexual dimorphism, as expressed by a peculiar sequence of article length-width ratios of the male antennula, indicates a relationship with M. marionae Kniesz, Brandt & Riehl (2018) and M. longipes Hansen (1916) amongst other species sharing this dimorphism. Mitochondrial genetic markers point in a similar direction. M. metallicola appears to be amongst the more common and widely distributed components of the benthic macrofauna in this region which may suggest a resilience of this species to future mining activities because of its apparent potential for recolonization of impacted sites from adjacent areas of particular environmental interest. The genetic data, however, show geographic clustering of its genetic variability, pointing towards a limited potential for dispersal. Local extinction of populations could potentially not be compensated quickly and would mean a loss of genetic diversity of this species.

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Publisher's official version 44 23 MB Open access
Dataset used for the analysis of the 16S phylogeny of Macrostylis metallicola. Specimen collection, sequencing and publishing information of the 16S sequences collected from GenBank. 36 KB Open access
Dataset used for the analysis of the COI phylogeny of Macrostylis metallicola. Specimen collection, sequencing and publishing information of the cytochrome oxidase subunit I sequences collected from 40 KB Open access
p-distance matrix based on COI data. Uncorrected pairwise p-distances of the partial cytochrome-c-oxidase subunit 1 sequence dataset. 578 KB Open access
p-distance matrix based on 16S data. Uncorrected pairwise p-distances of the partial mitochondrial large subunit ribosomal (LSU) RNA gene (16S) sequence dataset. 336 KB Open access
MAFFT multiple sequence alignment of mt 16S data. The alignment is in FASTA format. 171 KB Open access
MAFFT multiple sequence alignment of mt COI data. The aligment is in FASTA format. 246 KB Open access
Phylogenetic construction of the 16S phylogeny of Macrostylidae. Consensus tree graph of a phylogenetic reconstruction based on 16S of the isopod family Macrostylidae. Node support labels represent b 1 2 MB Open access
Full phylogenetic reconstruction of COI phylogeny of Macrostylidae. Consensus tree graph of a phylogenetic reconstruction based on cytochrome-c-oxidase subunit I (COI) of the ... 1 2 MB Open access
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