Halgerda willeyi
Encyclopedia
Halgerda willeyi is a species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of sea slug
Slug
Slug is a common name that is normally applied to any gastropod mollusc that lacks a shell, has a very reduced shell, or has a small internal shell...

. It is a dorid nudibranch
Nudibranch
A nudibranch is a member of what is now a taxonomic clade, and what was previously a suborder, of soft-bodied, marine gastropod mollusks which shed their shell after their larval stage. They are noted for their often extraordinary colors and striking forms...

, and shell-less marine
Marine (ocean)
Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...

 gastropod mollusk in the family Discodorididae
Discodorididae
Discodorididae is a taxonomic family of sea slugs, specifically dorid nudibranchs, marine gastropod mollusks in the superfamily Doridoidea. Species in this family belong to the cryptobranch dorid nudibranchs, i.e. they are able to retract their gills into a gill pocket . Most are small and hard to...

.

Description

The body of the Halgerda willeyi is rigid, with soft curves and various colours. This species is a fairly large halgerdid, and can reach 5 cm.

Distribution

Halgerda willeyi can be found throughout the western Indo-Pacific
Indo-Pacific
The Indo-Pacific is a biogeographic region of the Earth's seas, comprising the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the seas connecting the two in the general area of Indonesia...

, including Taiwan
Taiwan
Taiwan , also known, especially in the past, as Formosa , is the largest island of the same-named island group of East Asia in the western Pacific Ocean and located off the southeastern coast of mainland China. The island forms over 99% of the current territory of the Republic of China following...

, Vietnam
Vietnam
Vietnam – sometimes spelled Viet Nam , officially the Socialist Republic of Vietnam – is the easternmost country on the Indochina Peninsula in Southeast Asia. It is bordered by China to the north, Laos to the northwest, Cambodia to the southwest, and the South China Sea –...

, Myanmar
Myanmar
Burma , officially the Republic of the Union of Myanmar , is a country in Southeast Asia. Burma is bordered by China on the northeast, Laos on the east, Thailand on the southeast, Bangladesh on the west, India on the northwest, the Bay of Bengal to the southwest, and the Andaman Sea on the south....

, Egypt
Egypt
Egypt , officially the Arab Republic of Egypt, Arabic: , is a country mainly in North Africa, with the Sinai Peninsula forming a land bridge in Southwest Asia. Egypt is thus a transcontinental country, and a major power in Africa, the Mediterranean Basin, the Middle East and the Muslim world...

, Indonesia
Indonesia
Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...

, Malaysia and Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

. and in the Red Sea
Red Sea
The Red Sea is a seawater inlet of the Indian Ocean, lying between Africa and Asia. The connection to the ocean is in the south through the Bab el Mandeb strait and the Gulf of Aden. In the north, there is the Sinai Peninsula, the Gulf of Aqaba, and the Gulf of Suez...

.

Further reading

  • Fahey, S. J. & Gosliner, T. M. 2001. The Phylogeny of Halgerda (Opisthobranchia, Nudibranchia) with the description of a new species from Okinawa. Zoologica Scripta, 30(3): 199-213. Abstract
  • Marshall, J.G. & Willan, R.C. 1999. Nudibranchs of Heron Island, Great Barrier Reef - A Survey of the Opisthobranchia (Sea Slugs) of Heron and Wistari Reefs. Backhuys Publishers Leiden.
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