Abyssal fauna of polymetallic nodule exploration areas, eastern Clarion-Clipperton Zone, central Pacific Ocean: Amphinomidae and Euphrosinidae (Annelida, Amphinomida)

Abstract

This is a contribution in a series of taxonomic publications on benthic fauna of polymetallic nodule fields in the eastern abyssal Clarion-Clipperton Zone (CCZ). The material was collected during environmental surveys targeting exploration contract areas ‘UK-1’, ‘OMS’ and ‘NORI-D’, as well as an Area of Particular Environmental Interest, ‘APEI-6’. The annelid families Amphinomidae and Euphrosinidae are investigated here. Taxonomic data are presented for six species from 41 CCZ-collected specimens as identified by a combination of morphological and genetic approaches; of the six species, three are here described as new, one species is likely to be new but in too poor condition to be formalised and the two others likely belong to known species. Description of three new species Euphrosinella georgievaesp. nov., Euphrosinopsis ahearnisp. nov., and Euphrosinopsis hallisp. nov. increases the number of formally described new annelid species from the targeted areas to 21 and CCZ-wide to 52. Molecular data suggest that four of the species reported here are known from CCZ only, but within CCZ they have a wide distribution. In contrast, the species identified as Bathychloeia cf. sibogae Horst, 1910 was found to have a wide distribution within the Pacific based on both morphological and molecular data, using comparative material from the abyssal South Pacific. Bathychloeia cf. balloniformis Böggemann, 2009 was found to be restricted to APEI-6 based on DNA data available from CCZ specimens only, but morphological data from other locations suggest potentially a wide abyssal distribution. The genus Euphrosinopsis was previously known only from Antarctic waters, and Euphrosinella georgievaesp. nov. was recovered as a sister taxon to the Antarctic specimens of Euphrosinella cf. cirratoformis in our molecular phylogenetic analysis, strengthening the hypothesised link between the deep-sea and Antarctic benthic fauna.

Biodiversity, biogeography, and connectivity of polychaetes in the world's largest marine minerals exploration frontier

“…Details of DNA extraction, amplification, sequence alignment, and phylogenetic methods can be found in Appendix S1. Sequences of the mitochondrial 16S rRNA (16S) and cytochrome c oxidase subunit I (COI) genetic markers were supplemented with sequences from Wiklund et al (2019), Drennan et al (2021), Wiklund et al (in press), Neal, Wiklund, Rabone, et al (2022), Neal, Wiklund, Gunton, et al (2022), Janssen et al (2015), Janssen et al (2019), Bonifácio et al (2020), Bonifácio, Neal, and Menot (2021), and Bonifácio, Neal, Omnes, and Menot (2021) available through NCBI GenBank (Altschul et al, 1990) (https://www.ncbi.nlm.nih.gov/genbank/) and BOLD (https://www.boldsystems.org). Full 16S and COI sequence alignments used in analyses can be found on Dryad (Stewart et al, 2023).…”

Checklist of newly-vouchered annelid taxa from the Clarion-Clipperton Zone, central Pacific Ocean, based on morphology and genetic delimitation

“…Our more recent taxonomic studies (e.g. Glover et al (2016) , Dahlgren et al (2016) , Wiklund et al (2017) , Wiklund et al (2019) , Drennan et al (2021) , Neal et al (2022a) , Neal et al (2022b) ), applied an integrative DNA taxonomy approach, with species delimitation principally based on a phylogenetic species concept, sensu Donoghue (1985) coupled with morphological interpretations. However, in this broader study of all of the annelids, including many poorly-preserved or fragmented individuals, we have relied more heavily on genetic data.…”

“…Based on detailed taxonomic studies that also incorporated molecular data (e.g. Wiklund et al 2019 , Bonifácio and Menot 2019 , Neal et al 2022a , Neal et al 2022b , Bonifácio et al 2021 ), over 80% of the CCZ-collected annelids are likely new to science ( Rabone et al 2023b ). To date, publications from the areas targeted in this study have yielded 60 annelid species from 327 specimen records, of which only 18 species have been formalised as new ( Wiklund et al 2019 , Drennan et al 2021 , Neal et al 2022a , Neal et al 2022b ).…”

“… Wiklund et al 2019 , Bonifácio and Menot 2019 , Neal et al 2022a , Neal et al 2022b , Bonifácio et al 2021 ), over 80% of the CCZ-collected annelids are likely new to science ( Rabone et al 2023b ). To date, publications from the areas targeted in this study have yielded 60 annelid species from 327 specimen records, of which only 18 species have been formalised as new ( Wiklund et al 2019 , Drennan et al 2021 , Neal et al 2022a , Neal et al 2022b ). However, we are left with a problem in that many specimens are in sub-optimal morphological condition and unable, therefore, to be formally described.…”

“…This paper includes a checklist of 129 annelid species, with 339 records from 18 polychaete families and four species of Sipuncula . Excluded from this study are several annelid families which are common in the CCZ, but are either ones that have already been studied ( Wiklund et al 2019 , Drennan et al 2021 , Neal et al 2022a , Neal et al 2022b ) or are currently in preparation in separate detailed taxonomic papers (e.g. order Phyllodocida and families Acrocirridae and Serpulidae ).…”