Ophiuroids (Echinodermata) of southern Chile and the Antarctic: taxonomy, biomass, diet and growth of dominant species

Corinna Dahm

doi:10.3989/scimar.1999.63s1427

Abstract

This study aims on a first comparison of the shallow water (< 550 m) ophiuroid fauna of the Magellan region and the high-Antarctic Weddell Sea. Five species are common to both the Magellan region (22 species) and the Weddell Sea (42 species). The most abundant Magellan species is Ophiuroglypha lymani, contributing 33% to total ophiuroid abundance and 44% to total ophiuroid biomass. The diets of O. lymani and of three closely related (same sub-family Ophiurinae) also dominant, Antarctic species are similar, indicate however slightly different feeding strategies. The Magellan species tends more towards microphageous grazing, whereas the Weddell Sea species act more like scavengers. Within the sub-family Ophiurinae growth performance of O. lymani is higher than in Antarctic species and in the range of boreal species.

Highlights

World-wide there are about 1600 existing species of ophiuroids; this class surpasses all other classes of echinoderms in number of surviving species, except asteroids
How do ophiuroids contribute to total macrozoobenthos biomass in these regions? 3
In the Magellan region 22 species were found (15 of these identified to the species) belonging to 14 genera and 7 families in comparison to 42 species belonging to 21 genera and 6 families in the Weddell Sea. 5 species, 6 genera and 4 families are common to both regions (Table 1)

Summary

Introduction

World-wide there are about 1600 existing species of ophiuroids; this class surpasses all other classes of echinoderms in number of surviving species, except asteroids. The world oceans ophiuroids contribute significantly to species diversity, abundance and biomass of the fauna Echinoderms, and especially ophiuroids, are very common on either side of the Drake Passage (Larraín, 1995) and in the high Antarctic (Voß, 1988; Dahm, 1996). This paper is a first attempt to compare the Magellan and high Antarctic ophiuroid fauna. How similar are the Magellan and the high Antarctic ophiuroid fauna from a taxonomic point of view? 3. Is the diet of the dominant species from the Magellan region comparable to the diet of closely related as well as dominant species from the Antarctic? Are there differences in growth and age between closely related species from these regions?

Objectives

Methods

Results

Discussion

Conclusion