Sea pig

Sea Pig is a colloquial name given to the species of sea cucumbers belonging to the taxonomic genus Scotoplanes.

Anatomy
The anatomy of the sea pig is affected by the deep sea where it lives. A shallow water sea cucumber has a dark, leathery covering with longitudinal colored stripes. Scotoplanes, however have translucent, colorless skin because they live in the dark without light. Scotoplanes have a fat, gelatinous, oval body approximately four inches in length. They have a mouth with ten feeding tentacles that are used for feeding on organic particles in deep sea-mud.

There are five to seven pairs of walking "feet". The enlarged tube feet are used for locomotion by which the sea pig uses water cavities within the skin, rather than in the legs itself, to inflate and deflate the appendages. This is the only instance of legged locomotion among the holothurians. These legs and the plump shape of the Scotoplanes gives it the common name "sea pig".

Scotoplanes have three pairs of papillae on the dorsal surface of the body, two pair of the papillae are long and whip-like, but the third pair is short and probably helps the sea pig to smell its way to tasty sediments.

Reproduction: Scientists have limited knowledge of the lifecycle, mode of reproduction, and related behaviors of the Scotoplanes due to the depths at which they live. Scientists do know that they travel in groups and the number depends on currents. This information has been gathered by robotic photography to the depths of 3.7 miles and by trawling the ocean bottom.

The reproduction of elasipodia scotoplanes is known from the study of sea cucumbers. Holothuroids have gonads but show no anatomical sexual dimorphism. To determine sex the tissues of the gonad must be examined under the microscope. . As with most echinoderms, the sexes are separate and fertilization is external.

Ecology
Location:

Sea pigs live on the abyssal plains of all the oceans of the earth; the Atlantic, the Pacific, the Indian, the Southern. They make up 95% of the total weight of the sea floor's living creatures.

Diet:

The Sea Pig is a deposit feeder and extracts organic food from deep-sea mud where dead carcesses decompose, falling from the ocean's surface. The Scotoplanes usually face into the prevailing current where they smell their way to food. Thousands of Sea Pigs have been found around a decaying whale carcass.

Environmental challenges and benefits:

They get parasites, snails, and crustaceans which feed on the inside of their bodies.

Some sea cucumbers are valued for their antimicrobial activity and anti-anflammatory agents .It has not been established if deep sea Scotoplanes serve such use. The benefit to the ocean environment is that Scotoplanes introduce oxygen into the sediments as they feed, which makes the seafloor more inhabitable by small animals..

The population of scotoplanes is influenced by what falls to the ocean during such oceanographic phenomenon such as El Nino and La Nina. Therefore with weather changes their density fluctuates depending on death rates of sea life and deposits on the ocean bottom.

History
In 1875 a specimen of Scotoplanes was dredged in the Arctic Ocean during a Swedish Expedition to the Yenisei. Dr. Hjalmar Theel a Swedish zoologist, was asked to examine it. Because of Theel's research, the whole of the Holothurioidea specimens from the H.M.S. Challenger Expedition was placed in his hands. He then wrote an extensive monograph along with other scientists findings in 1882.

The H.M.S. Challenger was outfitted and designed for the first oceanographic study of the earth's oceans by the English government. It set sail and traveled around the world during the years 1873-76. Sir Wyville Thomson was the ship's superintendent from the University of Edinburgh. 'He hoped to disprove the recently proposed azoic theory, which postulated a 'dead zone' below 1800 feet in all the world's oceans, and to prove the findings of Darwin"

Although Theel was not on board, he received the holothuria in labeled bottles with recordings of locations and depths at which they were found. By his own words he was excited by the findings. "When, at the request of Sir Wyvill Thomson, F.R.S., I undertook to work out the Holothurioidea dredged during the Challenger Expedition, I had not the least idea of the value and richness of the material confided to my care. But the first inspection made it evident that the forms from great depths, now displayed for the first time, were of the greatest interest by making it manifest that Holothurians are living there not merely in great numbers but belonging to many species, and that a large majority of them present certain peculiarities that render them strikingly different from the literal forms hitherto known, and make them constitute perhaps the most characteristic group of the whole abyssal fauna. As will be seen further on, I have considered myself justified in placing them under a new order-Elasipoda".