Contributions to Zoology, 70 (3) (2001)Carlos Neira*; Gunnar Gad; Nina L. Arroyo; Wilfrida Decraemer: Glochinema bathyperuvensis sp. n. (Nematoda, Epsilonematidae): A new species from Peruvian bathyal sediments, SE Pacific Ocean

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Introduction

Epsilonematidae is a well defined family of Nematoda currently comprising thirteen genera and eighty-one species distributed in three subfamilies (Epsilonematinae, Keratonematinae and Glochinematinae). Hitherto, all representatives of Epsilonematidae have been found worldwide in supralittoral or intertidal sandy shores (Gourbault & Decraemer 1996).

In the last years, considerable attention has been focused on the study of the benthic communities living within oxygen minimum zones (OMZs, oxygen concentrations < 0.5 ml l–1) (Kamykowski & Zentara 1990; Levin et al., 1991). These OMZs are well developed along the eastern Pacific Ocean (Wyrtki 1966; Kamykowski & Zentara 1990) where high productivity associated to upwellings and poor water circulation occur. Where OMZs impinge on the continental margin, strong gradients are formed in bottom-water oxygen and organic matter input (Levin et al., 1991; Levin et al., 2000). These influence biogeochemical properties of sediments and benthic fauna distributions (Sanders 1969; Tyson & Pearson 1991).

Examination of bathyal sediment samples obtained during the cruise Panorama Leg 3a along a transect through and beneath the OMZ off Peru, resulted in the discovery of a new species of the genus Glochinema (Glochinematinae). In this paper, we describe this new nematode species, which was found exclusively in the core of the OMZ (O2 < 0.02 ml l–1). This represents the first record of the family from Pacific Ocean continental slope sediments.