A genetic fingerprint of Amphipoda from Icelandic waters – the baseline for further biodiversity and biogeography studies

Abstract

Amphipods constitute an abundant part of Icelandic deep-sea zoobenthos yet knowledge of the diversity of this fauna, particularly at the molecular level, is scarce. The present work aims to use molecular methods to investigate genetic variation of the Amphipoda sampled during two IceAGE collecting expeditions. The mitochondrial cytochrome oxidase subunit 1 (COI) of 167 individuals originally assigned to 75 morphospecies was analysed. These targeted morhospecies were readily identifiable by experts using light microscopy and representative of families where there is current ongoing taxonomic research. The study resulted in 81 Barcode Identity Numbers (BINs) (of which >90% were published for the first time), while Automatic Barcode Gap Discovery revealed the existence of 78 to 83 Molecular Operational Taxonomic Units (MOTUs). Six nominal species (Rhachotropis helleri, Arrhis phyllonyx, Deflexilodes tenuirostratus, Paroediceros propinquus, Metopa boeckii, Astyra abyssi) appeared to have a molecular variation higher than the 0.03 threshold of both p-distance and K2P usually used for amphipod species delineation. Conversely, two Oedicerotidae regarded as separate morphospecies clustered together with divergences in the order of intraspecific variation. The incongruence between the BINs associated with presently identified species and the publicly available data of the same taxa was observed in case of Paramphithoe hystrix and Amphilochus manudens. The findings from this research project highlight the necessity of supporting molecular studies with thorough morphology species analyses.

Amphipod family distributions around Iceland

“…The most abundant amphilochid species, Amphilochus tenuimanus , was sampled mainly from shallow waters to the shelf edge (139-905 m, with one record from 1384 m). It is worth highlighting, however, the distinct possibility that Amphilochus manudens might be a cryptic species complex (Jazdzewska et al 2018, Tandberg and Vader 2018). …”

“…It should be noted that three types of gear were used during the IceAGE expeditions: RP sled (Rothlisberg and Pearcy 1977), Brenke sled (Brenke 2005) and C-EBS (Brandt et al 2013). Within these samples, identification was concentrated on those samples which were preserved in 96% ethanol to enable genetic work (see Jazdzewska et al 2018). Only samples that would provide representatives of the most transects from the IceAGE station grid (Figure 1, red dots).…”

“…All specimens selected as molecular vouchers (Jazdzewska et al 2018) will be registered in the ZMH. At the time of manuscript preparation, the higher classification of the Amphipoda was in a state of reassessment (Lowry and Myers 2017).…”

Preface—biodiversity of Icelandic waters

“…The second societal issue is deep-sea mining. There has been growing international interest in deep-sea resource extraction and mining operations are about to begin in some areas (Halfar and Fujita 2007;Mengerink et al 2014;Nagender Nath and Sharma 2000). These operations, in particular, are targeting mid-ocean ridges and other geothermally active areas.…”

“…It presents a collection of new species descriptions (Krapp-Schickel 2018; Peart et al 2018;Tandberg and Vader 2018), information about the distribution patterns of Fig. 1 IceAGE study area with stations from both the IceAGE (yellow circle) and BIOICE (empty circle) projects amphipod families (Brix et al 2018), and results of combining morphological and molecular approaches in studies of chosen taxa (Jażdżewska et al 2018;Lörz et al 2018). …”