Scotoplanes, the sea pig, is a genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of deep-sea

Deep sea

The deep sea, or deep layer, is the lowest layer in the ocean, existing below the thermocline and above the seabed, at a depth of 1000 fathoms or more. Little or no light penetrates this part of the ocean and most of the organisms that live there rely for subsistence on falling organic matter...

 holothurian

Sea cucumber

Sea cucumbers are echinoderms from the class Holothuroidea.They are marine animals with a leathery skin and an elongated body containing a single, branched gonad. Sea cucumbers are found on the sea floor worldwide. There are a number of holothurian species and genera, many of which are targeted...

 echinoderm

Echinoderm

Echinoderms are a phylum of marine animals. Echinoderms are found at every ocean depth, from the intertidal zone to the abyssal zone....

 of the family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 Elpidiidae, order

Order (biology)

In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...

 Elasipodida

Elasipodida

Elasipodida is an order of sea cucumbers. They are somewhat unusual in appearance, in comparison with other sea cucumbers, having numerous appendages, including conical papillae and leaf-like tentacles. Although many species are benthic, a number are pelagic, and may have their appendages modified...

.

Locomotion

Members of the Elpidiidae have particularly enlarged tube feet that have taken on a leg-like appearance, and are the only instance of legged locomotion amongst the holothurians, using water cavities within the skin (rather than within the leg itself) to inflate and deflate the appendages. These legs, in conjunction with their large, plump appearance have suggested the common name "sea pig". There are other genera of Elpidiidae with a similar appearance that have also been referred to as "sea pigs".

Ecology

Scotoplanes live on deep ocean bottoms, specifically on the abyssal plain

Abyssal plain

An abyssal plain is an underwater plain on the deep ocean floor, usually found at depths between 3000 and 6000 metres. Lying generally between the foot of a continental rise and a mid-ocean ridge, abyssal plains cover more than 50% of the Earth’s surface. They are among the flattest, smoothest...

 in the Atlantic

Atlantic Ocean

The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...

, Pacific

Pacific Ocean

The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...

 and Indian Ocean

Indian Ocean

The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...

, typically at depths of over 1000 meters. Some related species can be found in the Antarctic

Antarctic

The Antarctic is the region around the Earth's South Pole, opposite the Arctic region around the North Pole. The Antarctic comprises the continent of Antarctica and the ice shelves, waters and island territories in the Southern Ocean situated south of the Antarctic Convergence...

. Scotoplanes (and all deep-sea holothurians) are deposit feeders, and obtain food by extracting organic particles from deep-sea mud. Scotoplanes globosa has been observed to demonstrate strong preferences for rich, organic food that has freshly fallen from the ocean's surface, and uses olfaction

Olfaction

Olfaction is the sense of smell. This sense is mediated by specialized sensory cells of the nasal cavity of vertebrates, and, by analogy, sensory cells of the antennae of invertebrates...

 to locate preferred food sources such as whale corpses.

Scotoplanes, like many sea cucumbers, often occur in huge densities, sometimes numbering in the hundreds when observed. Early collections have recorded 300 to 600 individual specimens per trawl.
Sea pigs are also known to host different parasitic invertebrates, including gastropods

Gastropoda

The Gastropoda or gastropods, more commonly known as snails and slugs, are a large taxonomic class within the phylum Mollusca. The class Gastropoda includes snails and slugs of all kinds and all sizes from microscopic to quite large...

 (snails) and small tanaid

Tanaidacea

The crustacean order Tanaidacea make up a minor group within the class Malacostraca. There are about 940 species in this order.-Description:...

 crustaceans.

Taxonomy

The genus includes the following species:

• Scotoplanes angelicus
• Scotoplanes globosa
• Scotoplanes mutabilis

Threats

The main threat against Scotoplanes is deep sea trawling. A single trawler sweep might catch and ultimately kill 300 Scotoplanes. Being a substantial part of the nutrition of deep sea predators, this is a serious threat to deep sea life.

External links

• Scotoplanes article and photos on Echinoblog
• Sea pigs? Gross or cool? on Animal Planet
  Animal Planet
  Animal Planet is an American cable tv specialty channel that launched on October 1, 1996. It is distributed by Discovery Communications. A high-definition simulcast of the channel launched on September 1, 2007.-History:...
  
  website
• Sea Cucumbers: Holothuroidea – Sea Pig (scotoplanes Globosa): Species Accounts at Animal Life Resource