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| Erinaceusyllis simonlledoi Nilsson, Wiklund, Glover, Bribiesca-Contreras & Dahlgren, 2024 |
Highlights:
• A novel polychaete species was discovered on an abyssal wood-fall.
• Its high abundance on degraded wood displays a tolerance to sulfidic environments.
• Morphology and genetics support placement in Erinaceusyllis of the family Syllidae.
• This constitutes the first finding of abundant syllids on a natural wood-fall.
• Sulfide-tolerant syllids in the East Pacific may originate from the same lineage.
Abstract
In the deep sea, organic falls provide temporary localized enrichments of organic matter to the otherwise nutrient-poor abyssal seafloor. Areas where organic falls land become ephemeral patches of increased biodiversity. Often rich in opportunistic species which are tolerant to the sulfidic environment formed from anaerobic breakdown of organic matter. On a wood-fall at abyssal depths in the eastern Clarion-Clipperton Zone, the novel species Erinaceusyllis simonlledoi (Annelida: Syllidae) was discovered in high abundance. This study entails the first description of a novel syllid species found in high density on a naturally occurring organic fall. Phylogenetic position was investigated using three genetic markers (16S, 18S, COI) and morphology was studied through light- and scanning electron microscopy. Genetic data and morphological analysis supported placement in the syllid genus Erinaceusyllis. Distinguishing features were lack of eyes, dorsal brooding of one egg per egg-bearing segment, lack of visible papillae across the body, incomplete fusion of palps, bidentate chaetae, as well as pyriform antennae and tentacular cirri. Erinaceusyllis simonlledoi sp. nov. is highly similar to a species found on hydrothermal vents belonging to the closely related genus Sphaerosyllis. The similarity between the two species, as well as findings of unspecified Sphaerosyllis species in various types of sulfidic habitats evoke questions of a possible syllid lineage adapted to sulfidic environments.
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Keywords: Erinaceusyllis, Sphaerosyllis, Wood-falls, Sulfidic habitats, Clarion-Clipperton zone, Abyssal zone
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| The piece of wood on which Erinaceusyllis simonlledoi sp. nov. was discovered. In situ image during collection. Photo: University of Gothenburg. |
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| Full body light microscopy images of Erinaceusyllis simonlledoi sp. nov. A – Holotype NHM_9029 dorsal view, chaetigers 13–16 on left side removed for DNA extraction. B – NHM_9029 ventral view. C – Paratype NHM_9081A dorsal view. D – Paratype NHM_9070B lateral view, left side. E – NHM9073 dorsal view, 3 posterior chaetigers and pygidium removed for DNA extraction. Scale bar: 100 μm. la – lateral antenna; ma – median antenna; tc – tentacular cirrus; dc – dorsal cirrus; ac -anal cirrus; px – pharynx; pr – proventricle. |
Systematics
Phylum: Annelida Lamarck, 1802.
Class: Polychaeta Grube, 1850.
Family: Syllidae Grube, 1850.
Genus: Erinaceusyllis San Martín, 2005
Species: Erinaceusyllis simonlledoi sp. nov.
Etymology: The species is named in honor of Dr. Erik Simon Lledo, a member of the group of scientists onboard the Maersk Launcher on the NORI-D 5E biodiversity baseline research expedition of November–December 2021.
Christian L. Nilsson, Helena Wiklund, Adrian G. Glover, Guadalupe Bribiesca-Contreras and Thomas G. Dahlgren. 2024. A New Species of Erinaceusyllis (Annelida: Syllidae) discovered at A Wood-fall in the eastern Clarion-Clipperton zone, central Pacific ocean. Deep Sea Research Part I: Oceanographic Research Papers. 214, 104415. DOI: doi.org/10.1016/j.dsr.2024.104415