A new species of the genus Liljeborgia Spence Bate, 1862 (Crustacea: Amphipoda: Liljeborgiidae) associated with the burrows of the spoon worm Urechis unicinctus in the Sea of Japan

Ivan Marin

doi:10.5852/ejt.2020.613

Abstract

A new symbiotic species of liljeborgiid amphipods, Liljeborgia associata sp. nov., is described from the burrows of the spoon worm Urechis unicinctus (Drasche, 1880) (Annelida: Polychaeta: Echiura: Urechidae) in the southern part of Peter the Great Bay and Posjeta Bay in the Sea of Japan. The new species is mostly similar and probably related to Liljeborgia geminata Barnard, 1969, known from the Californian coasts of the USA, and Liljeborgia serratoides Tzvetkova, 1967, described from Posjeta Bay in the Sea of Japan, but can be clearly distinguished from all congeners by morphological features of mouthparts, appendages and telson. The new species is only the fourth in the family Liljeborgiidae to be described from the Russian coast of the northwestern Pacific and the first in association with spoon worms (Echiura).

Highlights

Representatives of the family Liljeborgiidae (Crustacea: Amphipoda) are relatively rare in the higher latitudes of the North Pacific
Sampling was carried out in the estuary of Volchanka River in Vostok Bay near the scientific station “Vostok” (42°51′14.48′′ N, 132°46′47.24′′ E) and in Astafieva Bay (42°36′45.6′′ N, 131°12′24.8′′ E), both within Peter the Great Bay, as well as Troitza Bay (42°38′60.0′′ N, 131°07′27.8′′ E) located within Posjeta Bay in Sea of Japan. These bays are well known by large populations of the common spoon worm U. unicinctus and other burrowing animals
Burrows of spoon worms of the genus Urechis as well as almost all large echiuroid worms are inhabited by various symbiotic animals, such as shrimps, crabs, bivalves and even fishes (e.g., Fisher & MacGinitie 1928; Anker et al 2005, 2015; Itani et al 2005; Goto & Kato 2012; Marin 2014; Goto et al 2017)

Summary

Introduction

Representatives of the family Liljeborgiidae (Crustacea: Amphipoda) are relatively rare in the higher latitudes of the North Pacific. Liljeborgia Spence Bate, 1862, Idunella G.O. Sars, 1894 (= Listriella J.L. Barnard, 1959) and Sextonia Chevreux, 1920, are known from the area. About 10+ species of the family are known from the NE Pacific (eastern coasts of the Bering Sea; Pacific coasts of North America), including four described species of the genus Liljeborgia: Liljeborgia cota Barnard, 1962 known from the Gulf of Alaska to the northern Baja California, Mexico, at a depth of 366–2000 m; L. geminata Barnard, 1969 (L. kinahani Bate, 1862 is considered as a junior synonym), described from Goleta to the northern Baja California, at a depth of 3–70 m; L. marcinabrio Barnard, 1979, known from Bahia de Los Angeles, Gulf of California, at a depth of 46 m; and L. pallida Bate, 1857, having a wide area of distribution from NE Atlantic to the Central Californian coasts, at a depth of 40–611 m (Barnard 1959; Barnard & Karaman 1991; d’Udekem d’Acoz 2010; Cadien 2015). Two undescribed species are presented in the NE Pacific: one free-living, deep-water species and one commensal

Methods

Results

Conclusion