Lake Pedder Earthworm - Hypolimnus pedderensis

Image: Reconstruction of the Lake Pedder Earthworm. Based on an image from Threatened Species Unit (2000). Created by Peter Maas for The Sixth Extinction. This image has been released under the Creative Commons Attribution Non-commercial No Derivatives 3.0 Licence.

Perionychella (Vesiculodrilus) pedderensis Jamieson, 1974; Diporochaeta pedderensis (Jamieson, 1974)

Initially described as Perionychella (Vesiculodrilus) pedderensis by Jamieson (1974). Taxonomy revised by Blakenmore in 1996.

The Lake Pedder Earthworm is 50 mm in length and 1.6 mm in diameter. This species has 129 body segments and is coloured pale brown. It has multiple gizzards that occur on the fifth, sixth and part of the seventh segment, which is an important taxonomic character. (Threatened Species Unit 2000)

It probably fed on microbes and/or algae on sand particles or organic matter amongst the sand, because the gut contents of the single specimen contained sand (Threatened Species Unit 2000).

The Lake Pedder earthworm was endemic to Tasmania, Australia. It was collected from a substrate sample on the main beach of Lake Pedder, near where Maria Creek came to the lake. No information on habitat was provided in the original description of the Lake Pedder earthworm by Jamieson (1974) other than that the specimen was sorted from interstitial fauna. From this it is assumed that the Lake Pedder earthworm favoured living in sandy, waterlogged sediments (Blakemore 1996). (Threatened Species Unit 2000)

Images: The left-hand image shows a map with the global location of Lake Pedder in Tasmania (Australia), the historical distribution of this worm species (in red). Created by Peter Maas for The Sixth Extinction website. This image has been licensed under the Creative Commons Attribution Non-commercial No Derivatives 3.0 licence. The right-hand photo shows the original Lake Pedder, 1970. Photographed by Jon Deeprose. This photo is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license (source: Wikimedia Commons).

The Lake Pedder Earthworm is only known by the type specimen collected from a beach on Lake Pedder, Tasmania in 1971. In 1972, the area was inundated for hydroelectric power generation. The world heritage area fauna program has commissioned two surveys to search for populations of this species. The first, by Dyne (1991), surveyed severalsites around the new Lake Pedder. A second, more extensive survey was conducted by Blakemore (1996), to determine the conservation and taxonomic status of Lake Pedder earthworms and to determine whether the Lake Pedder Earthworm still existed in the area. Both surveys failed to locate any Lake Pedder Earthworms. Several new species were found, however, none are conspecific to the Lake Pedder Earthworm and the species is likely to be extinct due to inundation of its original and unique habitat. (Blakenmore 2003) No new surveys are likely to be funded unless new information is made available (Threatened Species Unit 2000).

The Lake Pedder Earthworm's extinction is caused by the destruction of its original habitat (Dyne 1991; Blakemore 1996). The original natural Lake Pedder was flooded by damming in 1972 by Hydro Electric Commission (Wikipedia contributors 2008).

The only location where the Lake Pedder earthworm was known to occur was within the Southwest National Park which is part of the Tasmanian Wilderness World Heritage Area (Threatened Species Unit 2000).

Only the type specimen is known. Do you know where it is kept? Please contact this website.

The Lake Pedder Earthworm is included in the Megascolecidae, a large family of earthworms which has native representatives in Australia, New Zealand, Southeast and East Asia, and North America.

Lake Pedder earthworm - Wikipedia, the free encyclopedia

Blakemore, R. J. (1996). The Taxonomic Status of the Earthworm Fauna of Lake Pedder, Western Tasmanian World Heritage Area. Report to the Parks and Wildlife Service, Tasmania. 40pp.

Blakenmore, R.J. (2003). Hypolimnus pedderensis. In: IUCN (2010). IUCN Red List of Threatened Species. Version 2010.4. <www.iucnredlist.org>. Downloaded on 6 February 2011.

Dyne, G. R. (1991). The status of the Lake Pedder earthworm, Perionychella pedderensis and investigations into the new or little-known earthworms from the Western Tasmanian World Heritage Area. A report to the Department of Parks, Wildlife & Heritage.

Jamieson, B. G. M. (1974). The Indigenous Earthworms (Megascolecidae: Oligochaeta) of Tasmania. Bulletin of the British Museum of Natural History (Zoology). 26(4): 201-328.

Threatened Species Unit. (2000). Listing Statement Lake Pedder Earthworm Diporochaeta pedderensis. Nature Conservation Branch, Department of Primary Industry, Water and Environment, Tasmania.

Wikipedia contributors, (2008). "Lake Pedder," Wikipedia, The Free Encyclopedia, http://en.wikipedia.org/w/index.php?title=Lake_Pedder&oldid=203644218 (accessed April 6, 2008).