sea spider Nymphon australe

Nymphon australe is found throughout Antarctica and Peter I Island, South Shetland Islands, South Sandwich Islands, Cook Strait in New Zealand, Falkland Islands, Bouvet Island, Argentina, Chile, and southern Indian Ocean at depths from 8 to 3,000 meters [1,2,3,4,6,7].

N. australe has a robust trunk with a short neck; its eight legs span up to three centimeters and usually have long or short spines in rows [1,4].

N. australe is the most common and most often collected pycnogonid species in Antarctic and subantarctic waters [1,4,5,6]. There is a wide range of variations among specimens in this species [4].

Here is Nymphon australe cruising on the tubular sponge Sphaerotylus antarcticus.

The genus Nymphon has more species in Antarctic and subantarctic waters then in other bodies of water of similar size; they occur in a large diversity of species and are collected in great numbers [1,4]. The Nymphon genus has two character groupings -- Australe and Hamatum; the remaining species of Nymphon are unrelated by character groups [1]. Nymphon sp. have eight legs with the ocular tubercle toward the posterior of the cephalic segment [1].

Antarctic and subantarctic sea spiders comprise 251 species, representing 21.5% of worldwide species, with 101 species endemic to Antarctica and 60 endemic to subantarctic areas [5].

Here's a closer view of Nymphon australe.

Sea spiders are exclusively marine and mostly bottom dwelling (benthic) [4]. Adult sea spiders either suck the juices from soft-bodied invertebrates or browse on hydroids and bryozoans. Male sea spiders carry cemented egg clutches gathered from females until hatching and often after hatching in the larval stages [4]. Since sea spider larvae are not planktonic, sea spider dispersal is slow and intermittent leading to the development of many endemic species among shallow-water sea spiders [4].

1: Antarctic and Subantarctic Pycnogonida : Nymphonidae, Colossendeidae, Rhynchothoraxidae, Pycnogonidae, Endeididae, and Callipallenidae. CA Child Antarctic Research Series Volume 69, Biology of the Antarctic Seas 24. Washington DC : American Geophysical Union, 1995; 2: US National Museum Polar Invertebrate Catalog at http://www.nmnh.si.edu/iz/usap/usapdb.html; 3: Tethys Supplement 4:135-156, 1972; 4: Marine Fauna of New Zealand: Pycnogonida (Sea Spiders). CA Child.. Wellington : National Institute of Water and Atmospheric Research, 1998. NIWA Biodiversity Memoir 109; 5: Polar Biology 24:941-945, 2001; 6: Antarctic Science 13(2):144-149, 2001; 7: Polar Biology 29(2):83-96, 2006

Text ©Peter Brueggeman. Identification of Brueggeman photos provided by C Allan Child. Photographs ©Steve Alexander & Peter Brueggeman. Photographs may not be used in any form without the express written permission of Steve Alexander & Peter Brueggeman.