Description of Pseudeuchaeta vulgaris n. sp. (Copepoda: Calanoida), a new aetideid species from the deep Pacific Ocean with notes on the biogeography of benthopelagic aetideid calanoids

Abstract

A new aetideid species Pseudeuchaeta vulgaris sp. nov. is described from females collected at abyssal depths above the seabed from the Clarion Clipperton Fracture Zone in the equatorial northeastern Pacific. It belongs to the benthopelagic group of Pseudeuchaeta Sars, 1905 species. The new species is distinguished from all congeners by two setae present on the maxillule proximal basal endite. It is closely related to P. magna Bradford, 1969 and P. major (Wolfenden, 1911), as all three species share a mandible endopod segment 2 with 4-5 setae and the P1 exopod segment 1 lacking a lateral spine. The new species is the fourth benthopelagic representative of the genus found in the abyssal near-bottom environment of the Pacific Ocean and the first benthopelagic Pseudeuchaeta species recorded in the tropical Pacific. An illustrated overview on the distribution of the genus Pseudeuchaeta is given together with notes on the biogeography of benthopelagic aetideid calanoids in the world's ocean. While some genera show a nearly worldwide distribution, only few species have been reported in more than one ocean so far. This reflects the undersampling of the benthopelagial in the deep ocean.

Editorial: Biodiversity of the Clarion Clipperton Fracture Zone

“…3). New species descriptions, in particular for previously neglected groups, illustrate a taxonomically more balanced view and represent one of many smaller steps for diversity estimations (Kamenskaya et al 2016;Markhaseva et al 2017;Molodtsova and Opresko 2017;Zinssmeister et al 2017). In situ observations from video and still imagery using manned and unmanned (ROV, AUV) submersibles have led to discoveries of new habitats and also yielded valuable biogeographic information (Amon et al 2016a;Durden et al 2017;Vecchione 2016), while community analyses provide important insights into the patterns and processes driving (macro-)faunal diversity and turnover at local to regional scales (Wilson 2017).…”

“…Markhaseva et al (2017) provide a description of a new species within the cosmopolitan family Aetideidae, which is complemented by biogeographic information. While this is the first record of the genus Pseudeuchaeta from the equatorial Pacific, the few records of benthopelagic calanoid taxa in general points towards great undersampling of the deep benthopelagic realm (Markhaseva et al 2017). …”

“…& Among the first biological data from APEIs (Amon et al 2016a;Durden et al 2017) & The first study of dinophysoid dinoflagellates from the CCZ (Zinssmeister et al 2017) & The first record of wood falls from the CCZ (Amon et al 2016a) & The first record of Paleodictyon nodosum from the eastern equatorial Pacific (Durden et al 2017) & New species and/or new distributional records of xenophyophores, benthopelagic calanoids, antipatharian corals and cirrate octopods (Kamenskaya et al 2016;Markhaseva et al 2017;Molodtsova and Opresko 2017;Vecchione 2016) …”

New genus and species of calanoid copepods (Crustacea) belonging to the group of Bradfordian families collected from the hyperbenthic layers off Japan

“…In the Clausocalanoidea, however, some genera of the family Aetideidae have 3 setae on their counterparts (cf. Pseudeuchaeta vulgaris Markhaseva, Mohrbeck & Renz, 2017;Paracomantenna profunda Markhaseva & Renz, 2019). This retention in setae can be considered as an ancestral state in the clausocalanoideans.…”

Deep-sea Kinorhyncha diversity of the polymetallic nodule fields at the Clarion-Clipperton Fracture Zone (CCZ)

“…Regarding the meiofauna diversity, most of the studies have focused on the dominant groups, such as Nematoda and Copepoda (Markhaseva et al, 2017;Miljutin et al, 2011;Singh et al, 2016), whereas the groups of low abundance, the so-called "minor phyla", have been neglected so far. Kinorhyncha, free-living marine ecdysozoan of small size (0.1-1 mm) exclusively meiobenthic, belongs to this pool of "minor phyla".…”