New records on the rich loriciferan fauna of Trezen ar Skoden (Roscoff, France): Description of two new species of Nanaloricus and the new genus Scutiloricus.

Ricardo Cardoso Neves,Nadja Møbjerg,Reinhardt Møbjerg Kristensen,Marcos Rubal García

doi:10.1371/journal.pone.0250403

Ricardo Cardoso Neves, Nadja Møbjerg + Show 2 more

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https://doi.org/10.1371/journal.pone.0250403

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Journal: PloS one	Publication Date: May 5, 2021
Citations: 4	License type: CC BY 4.0

Affiliation: University of Copenhagen, Natural History Museum Aarhus

Abstract

Loricifera is a phylum of microscopic animals that inhabit marine environments worldwide. Named after their conspicuous and protective lorica, the phylum was first described from Roscoff (France) in 1983 and, hitherto, it contains only 40 species. Based on data collected from Roscoff during the past four decades, we here describe two new species of Nanaloricus, namely Nanaloricus valdemari sp. nov. and Nanaloricus mathildeae sp. nov., as well as a new genus and species, Scutiloricus hugoi gen. et sp. nov. Adults of N. valdemari sp. nov. are distinguished by a pair of unique cuticular ridges, here referred to as longitudinal stripes, spanning laterally along the anterior two thirds of the dorsal lorical plate. N. mathildeae sp. nov. is characterized by strong sexual dimorphism. Specifically, the branches composing the multiform male clavoscalids are much broader as compared to other Nanaloricus species. The two new Nanaloricus species are both characterized by unique sensory organs associated with the double trichoscalids. The size and exact position of these organs differ between the two species. Adults of Scutiloricus hugoi gen. et sp. nov. are characterized by, among other features, a square lorica composed of six cuticular plates with a total of 14 anterior spikes, of which 12 have transverse cuticular ridges and thus appear fenestrated; laterodorsal flosculi arranged linearly; a posterior lorical region characterized by an anal field with a small anal cone flanked by a pair of spurs. Notably, mature females are characterized by a pair of seminal receptacles, a character not previously reported in Loricifera. We discuss the new findings and compare N. valdemari sp. nov. and N. mathildeae sp.nov. with other species assigned to genus Nanaloricus. The distinguishing features of Scutiloricus hugoi gen. et sp. nov. are discussed from a comparative perspective with the other genera of family Nanaloricidae.

Highlights

The marine tidal and offshore localities near Roscoff (Brittany, France) are renowned for their biodiversity and exceptional animal life
Adult female collected on 15 May 2013 at the type locality at ca. 50 m water depth, mounted in glycerol on a glass slide, and deposited at the Natural History Museum of Denmark under accession number NHMD-678736
Adult female collected on 15 May 2013 at the type locality at ca. 50 m water depth, mounted in Fluoromount-G on a glass slide, deposited at the Natural History Museum of Denmark under accession number NHMD-677520

Summary

Introduction

The marine tidal and offshore localities near Roscoff (Brittany, France) are renowned for their biodiversity and exceptional animal life. This is exemplified by the description of and current research on the Roscoff worm, Symsagittifera roscoffensis (Graff, 1891) The phylum Loricifera was described in 1983 from the study of the first representative specimens found off the coast of Roscoff [8]. From this pioneering investigation a single species was described, Nanaloricus mysticus Kristensen, 1983, which was accommodated in the first loriciferan family to be proposed, Nanaloricidae Kristensen, 1983.

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