New species of bone-eating worm Osedax from the abyssal South Atlantic Ocean (Annelida, Siboglinidae)

Yoshihiro Fujiwara,Paulo Y.G Sumida,Hiroshi Kitazato,Masaru Kawato,Naoto Jimi

doi:10.3897/zookeys.814.28869

Abstract

A new species of bone-eating annelid, Osedaxbraziliensissp. n., found in a sunken whale carcass at a depth of 4,204 m at the base of the São Paulo Ridge in the South Atlantic Ocean off the Brazilian coast is described. The organism was retrieved using the human-occupied vehicle Shinkai 6500 during the QUELLE 2013 expedition. This is the 26th species of the genus and the first discovery from the South Atlantic Ocean, representing the deepest record of Osedax worldwide to date. This species morphologically resembles Osedaxfrankpressi but is distinguished by the presence of a yellow bump or patch behind the prostomium and its trunk length. Molecular phylogenetic analysis using three genetic markers (COI, 16S, and 18S) showed that O.braziliensissp. n. is distinct from all other Osedax worms reported and is a sister species of O.frankpressi.

Highlights

Whale falls provide an extensive food supply to the oligotrophic deep-sea environments and harbour a unique biological assemblage, which is considered a “whale-fall ecosystem” (Smith et al 1989, 2015)
After the depletion of organic materials in the whale bones, the exhausted bones are thought to act as colonisation substrata primarily for suspension feeders but have never been observed in situ (Smith and Baco 2003)
A sunken whale carcass was discovered at a depth of 4,204 m at the base of the São Paulo Ridge in the South Atlantic Ocean (Sumida et al 2016)

Summary

Introduction

Whale falls provide an extensive food supply to the oligotrophic deep-sea environments and harbour a unique biological assemblage, which is considered a “whale-fall ecosystem” (Smith et al 1989, 2015). One of the most unique organisms that has appeared in the whale-fall environment is an annelid polychaete of genus Osedax Rouse, Goffredi & Vrijenhoek, 2004 (Annelida, Siboglinidae), commonly known as bone-eating worms, discovered in whale carcasses in Monterey Bay (Rouse et al 2004).

Results

Conclusion