Fishing for scavengers: an integrated study to amphipod (Crustacea: Lysianassoidea) diversity of Potter Cove (South Shetland Islands, Antarctica)

Abstract

Amphipoda from the superfamily Lysianassoidea Dana, 1849 play an important role in Southern Ocean benthic food webs due to their high biomass, abundance and predominantly scavenging mode of feeding. Our knowledge on the lysianassoid fauna, even in well-studied areas of the Western Antarctic Peninsula, is incomplete. Here we report the findings of an integrated study of lysianassoid amphipods of Potter Cove, King George Island/ Isla 25 de Mayo (KGI), combining morphological and molecular species identification (COI barcoding) methods, investigating more than 41,000 specimens from baited traps. For comparison, 2039 specimens from the adjacent Marian Cove were analysed. Ten lysianassoid species were recorded in the deeper outer Potter Cove, whereas the inner cove (<50 m) was dominated by a single species, Cheirimedon femoratus Pfeffer, 1888 (99.44% relative abundance). It is hypothesized that the impoverished lysianassoid fauna inside the meltwater-influenced inner cove represents a 1model for future conditions along the Western Antarctic Peninsula under conditions of increased glacial melting. 2Abyssorchomene charcoti (Chevreux, 1912)

A biodiversity survey of scavenging amphipods in a proposed marine protected area: the Filchner area in the Weddell Sea, Antarctica

“…For the two morphospecies of Waldeckia, morphological differences have already been detected and described in the previous studies (Havermans 2012;Seefeldt et al 2017a) and the re-description of W. obesa s. str. (corresponding to morphospecies A) as well as the description of the new Waldeckia species (morphospecies B) is in the process of publication (d'Udekem d'Acoz, pers.…”

“…On the contrary, morphological differences can be striking and consistent, while the genetic divergences observed were quite low compared with the usual interspecific variation observed between other, welldefined, lysianassoid species. This is the case for O. rotundifrons vs. O. denticulata (Seefeldt et al 2017a), and Pseudorchomene coatsi and P. lophorachis (d'Udekem d'Acoz and Havermans 2012). Hence, for this group, it is necessary to apply an integrative approach combining DNA and morphology, to carry out an effective biodiversity survey.…”

“…From the previous integrative studies on amphipods using the barcoding gene ( Radulovici et al 2009;Havermans et al 2011Havermans et al , 2013Seefeldt et al 2017a;Jażdżewska et al 2018), the use of thresholds for species delimitation analyses appeared to be straightforward, since, in most cases, the average intraspecific variation was an order of magnitude smaller than the observed average interspecific divergence, and in many instances, a barcode gap could be detected (Havermans et al 2011;Seefeldt et al 2017a). In this study, the ABGD method using a threshold based on the level of divergence previously established for lysianassoids (Havermans et al 2011;Havermans 2012), revealed 42 clusters, which did not correspond to the 30 morphospecies isolated for the molecular analysis.…”

“…First, with all COI sequences of the lysianassoid species investigated, a neighbour-joining tree was constructed with MEGA 6.06 (Tamura et al 2013) under the Kimura-2-parameter (K2P) substitution model, with 2000 bootstrap replicates and using the pairwise deletion option. In addition to the COI sequences obtained for this study, supplementary sequences of the morphospecies identified here or those of sister species from the previous studies (Havermans et al 2011;Havermans 2012;Seefeldt et al 2017a) were added in the alignment, to assess the intraspecific variation over a wider geographical scale or for identification purposes. Detailed information on these sequences can be found in Online Resource 1.…”

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

“…Hubert and Hanner 2015, Seefeldt et al 2017). The most commonly used molecular marker, is the mitochondrial cytochrome c oxidase subunit 1 (COI) for which there are several protocols available using either universal or specific primers (e.g.…”