Pelamis platura
Encyclopedia
Pelamis platura, Yellowbelly Sea Snake, Pelagic Sea Snake or the Yellow-bellied sea snake (Pelamis platurus) is a species
of sea snake found in tropical oceanic waters around the world.
It is the only member of the genus
Pelamis.
Body compressed, posteriorly more than twice the diameter of the neck; body scales juxtaposed, sub-quadrangular in shape, in 49-67 rows around thickest part of body; ventral scales, 264-406, very small and, if distinct,divided by a longitudinal groove, but usually indistinguishable from adjacent body scales; head narrow, snout elongate, head shields entire, nostrils superior, nasal shields in contact with one another; pre-frontal in contact with second upper labial; 1-2 pre- and 2-3 post-oculars; 2-3 small anterior temporals; 7-8 upper labials, 4-5 below eye but separated from border by sub-ocular; color variable but most often distinctly bi-colored, black above, yellow or brown below, the dorsal and ventral colors sharply demarcated from one another; ventrally there may be a series of black spots or bars on the yellow or brown background, or the yellow may extend dorsally so that there is only a narrow mid-dorsal black stripe, or a series of black crossbars (M A Smith 1943:476-477 gives more complete description of the color pattern variants). Total length males 720 mm, females 880 mm; tail length males 80 mm,females 90 mm.
except Alaska
south to southern California
, and in the coastal waters of the Indian Ocean
from the Persian Gulf
eastwards. It is the only sea snake to have reached the Hawaiian Islands
.
Yellowbellies (and all other sea snakes) are not found in the Atlantic or Mediterranean even though the water there is warm enough. Yellowbellies require a minimum of 16-18° C to survive long term (Dunson and Ehlert 1971). Yellowbellies have not gone around the southern tips of South America
or South Africa
because water temperatures are too cool.
A land bridge formed (at Panama
) between North and South America about 3 million years ago, making it impossible for them to enter the Caribbean Sea
from the Pacific. If they had reached the eastern Pacific Ocean
before the land bridge formed, we would almost certainly find them now in the Atlantic. The Panama canal
has not made a crossing of the isthmus possible because it is freshwater
.
They do not live in the Red Sea
because of its excessive salinity
.
s of Asia and Australia about 10 million years ago. This air-breathing sea snake has developed a flat oar-like tail and valved nostrils since leaving the land millions of years ago.
, but are currently classified in a separate family, Hydrophiidae. Two subfamilies have been listed in the past, the sea kraits (Laticaudinae), and the true sea snakes (Hydrophiinae
), though recent work suggests this subfamilial division may be inappropriate.
In 1766, Linnaeus referred to the yellow-bellied sea snake as 'Anguis platura' (Anguis meaning snake). Daudin referred to it as 'Pelamis platuros' in 1803 and usually has his name attached to the spelling 'Pelamis platurus' which people are now familiar with. In 1842 Gray transferred it to the genus Pelamis and called it 'Pelamis ornata' (ornata being a synonym of platura). The word 'Pelamis' is a feminine noun and means young or small tunny fish. In 1872 Stoliczka introduced the name 'Pelamis platurus' (still the most used scientific name by scientists today) but used the incorrect ending on 'platurus' instead of 'platura' which a feminine noun requires. There are a few recent examples where scientists have begun using the grammatically correct name 'Palamis platura' e.g. Bohme 2003 and the 'Reptile database' with its page headed 'Pelamis platura' Linnaeus, 1766' which gives a huge variety of different scientific names for the yellowbelly sea snake.
word for "tunny fish", which presumably refers to the habitat or what Daudin thought they ate. The specific name platurus is a combination of the Ancient Greek words platys "flat" and oura "tail", referring to the flattened tail..
. In Australia
, sea snakes are rarely aggressive and bites are uncommon. The subcutaneous of the venom is 0.067 mg/kg (0.07 mg/kg) and the venom yield per bite is 1.0-4.0 mg/kg.
, neuromuscular paralysis
or direct renal damage. The venoms of significant species of sea snake are neutralised with Commonwealth Serum Laboratories Ltd (of Melbourne, Australia) Sea Snake (Enhydrina schistosa
) antivenom. If that preparation is not available, Tiger Snake or polyvalent antivenom should be used. No deaths have been recorded from bites in Australian waters. The (Enhydrina schistosa) antivenom was tested specifically on Pelamus platurus and it effectively neutralised the venom.
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 snake found in tropical oceanic waters around the world.
It is the only member of the 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...
Pelamis.
Description
- See snake scalesSnake scalesSnakes, like other reptiles, have a skin covered in scales. Snakes are entirely covered with scales or scutes of various shapes and sizes. Scales protect the body of the snake, aid it in locomotion, allow moisture to be retained within, alter the surface characteristics such as roughness to aid in...
for terminology used here
Body compressed, posteriorly more than twice the diameter of the neck; body scales juxtaposed, sub-quadrangular in shape, in 49-67 rows around thickest part of body; ventral scales, 264-406, very small and, if distinct,divided by a longitudinal groove, but usually indistinguishable from adjacent body scales; head narrow, snout elongate, head shields entire, nostrils superior, nasal shields in contact with one another; pre-frontal in contact with second upper labial; 1-2 pre- and 2-3 post-oculars; 2-3 small anterior temporals; 7-8 upper labials, 4-5 below eye but separated from border by sub-ocular; color variable but most often distinctly bi-colored, black above, yellow or brown below, the dorsal and ventral colors sharply demarcated from one another; ventrally there may be a series of black spots or bars on the yellow or brown background, or the yellow may extend dorsally so that there is only a narrow mid-dorsal black stripe, or a series of black crossbars (M A Smith 1943:476-477 gives more complete description of the color pattern variants). Total length males 720 mm, females 880 mm; tail length males 80 mm,females 90 mm.
Habits
These snakes breed in warm waters and they are ovoviviparous with a gestation period of about 6 months. They are helpless on land and they sometimes form large aggregations of thousands in surface waters. The snake has a neurotoxic venom that is used against its fish prey. No human fatalities are known.Distribution
The yellowbelly is the most widely distributed sea snake and is capable of living and giving birth entirely in the open sea (it is totally pelagic), being found in all coastal waters around the rim of the Pacific OceanPacific 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...
except Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...
south to southern California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
, and in the coastal waters of the 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...
from the Persian Gulf
Persian Gulf
The Persian Gulf, in Southwest Asia, is an extension of the Indian Ocean located between Iran and the Arabian Peninsula.The Persian Gulf was the focus of the 1980–1988 Iran-Iraq War, in which each side attacked the other's oil tankers...
eastwards. It is the only sea snake to have reached the Hawaiian Islands
Hawaiian Islands
The Hawaiian Islands are an archipelago of eight major islands, several atolls, numerous smaller islets, and undersea seamounts in the North Pacific Ocean, extending some 1,500 miles from the island of Hawaii in the south to northernmost Kure Atoll...
.
Yellowbellies (and all other sea snakes) are not found in the Atlantic or Mediterranean even though the water there is warm enough. Yellowbellies require a minimum of 16-18° C to survive long term (Dunson and Ehlert 1971). Yellowbellies have not gone around the southern tips of South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
or South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
because water temperatures are too cool.
A land bridge formed (at Panama
Panama
Panama , officially the Republic of Panama , is the southernmost country of Central America. Situated on the isthmus connecting North and South America, it is bordered by Costa Rica to the northwest, Colombia to the southeast, the Caribbean Sea to the north and the Pacific Ocean to the south. The...
) between North and South America about 3 million years ago, making it impossible for them to enter the Caribbean Sea
Caribbean Sea
The Caribbean Sea is a sea of the Atlantic Ocean located in the tropics of the Western hemisphere. It is bounded by Mexico and Central America to the west and southwest, to the north by the Greater Antilles, and to the east by the Lesser Antilles....
from the Pacific. If they had reached the eastern Pacific Ocean
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...
before the land bridge formed, we would almost certainly find them now in the Atlantic. The Panama canal
Panama Canal
The Panama Canal is a ship canal in Panama that joins the Atlantic Ocean and the Pacific Ocean and is a key conduit for international maritime trade. Built from 1904 to 1914, the canal has seen annual traffic rise from about 1,000 ships early on to 14,702 vessels measuring a total of 309.6...
has not made a crossing of the isthmus possible because it is freshwater
Freshwater
Fresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams. Fresh water is generally characterized by having low concentrations of dissolved salts and...
.
They do not live 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...
because of its excessive salinity
Salinity
Salinity is the saltiness or dissolved salt content of a body of water. It is a general term used to describe the levels of different salts such as sodium chloride, magnesium and calcium sulfates, and bicarbonates...
.
Evolution
The yellowbelly seems to have evolved from the terrestrial elapidElapidae
Elapidae is a family of venomous snakes found in tropical and subtropical regions around the world, terrestrially in Asia, Australia, Africa, North America and South America and aquatically in the Pacific and Indian Oceans...
s of Asia and Australia about 10 million years ago. This air-breathing sea snake has developed a flat oar-like tail and valved nostrils since leaving the land millions of years ago.
Taxonomy
Sea snakes are closely related to the venomous Australian snakes of the family ElapidaeElapidae
Elapidae is a family of venomous snakes found in tropical and subtropical regions around the world, terrestrially in Asia, Australia, Africa, North America and South America and aquatically in the Pacific and Indian Oceans...
, but are currently classified in a separate family, Hydrophiidae. Two subfamilies have been listed in the past, the sea kraits (Laticaudinae), and the true sea snakes (Hydrophiinae
Hydrophiinae
Hydrophiinae, also known as sea snakes, is a group of venomous elapid snakes that inhabit marine environments for most or all of their lives. Though they evolved from terrestrial ancestors, most are extensively adapted to a fully aquatic life and are unable to move on land, except for the genus...
), though recent work suggests this subfamilial division may be inappropriate.
In 1766, Linnaeus referred to the yellow-bellied sea snake as 'Anguis platura' (Anguis meaning snake). Daudin referred to it as 'Pelamis platuros' in 1803 and usually has his name attached to the spelling 'Pelamis platurus' which people are now familiar with. In 1842 Gray transferred it to the genus Pelamis and called it 'Pelamis ornata' (ornata being a synonym of platura). The word 'Pelamis' is a feminine noun and means young or small tunny fish. In 1872 Stoliczka introduced the name 'Pelamis platurus' (still the most used scientific name by scientists today) but used the incorrect ending on 'platurus' instead of 'platura' which a feminine noun requires. There are a few recent examples where scientists have begun using the grammatically correct name 'Palamis platura' e.g. Bohme 2003 and the 'Reptile database' with its page headed 'Pelamis platura' Linnaeus, 1766' which gives a huge variety of different scientific names for the yellowbelly sea snake.
Name
The genus name Pelamis is derived from the Ancient GreekAncient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...
word for "tunny fish", which presumably refers to the habitat or what Daudin thought they ate. The specific name platurus is a combination of the Ancient Greek words platys "flat" and oura "tail", referring to the flattened tail..
Venom
The venom of this species is highly potent, like other sea snakesSea Snakes
Sea Snakes were a Canadian indie rock band, formed in 2002 and disbanded in 2005. The band consisted of vocalist and guitarist Jimmy McIntyre, guitarist Kristian Galberg, bassist and saxophonist Jeremy Strachan, keyboardist Shaw-Han Liem and drummer Nathan Lawr.Strachan played in the defunct band...
. In 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...
, sea snakes are rarely aggressive and bites are uncommon. The subcutaneous of the venom is 0.067 mg/kg (0.07 mg/kg) and the venom yield per bite is 1.0-4.0 mg/kg.
Antivenom
Sea snake venom can cause damage to skeletal muscle with consequent myoglobinuriaMyoglobinuria
Myoglobinuria is the presence of myoglobin in the urine, usually associated with rhabdomyolysis or muscle destruction. Myoglobin is present in muscle cells as a reserve of oxygen.-Causes:...
, neuromuscular paralysis
Paralysis
Paralysis is loss of muscle function for one or more muscles. Paralysis can be accompanied by a loss of feeling in the affected area if there is sensory damage as well as motor. A study conducted by the Christopher & Dana Reeve Foundation, suggests that about 1 in 50 people have been diagnosed...
or direct renal damage. The venoms of significant species of sea snake are neutralised with Commonwealth Serum Laboratories Ltd (of Melbourne, Australia) Sea Snake (Enhydrina schistosa
Enhydrina schistosa
Beaked seasnake is a species of sea snake.-Description:...
) antivenom. If that preparation is not available, Tiger Snake or polyvalent antivenom should be used. No deaths have been recorded from bites in Australian waters. The (Enhydrina schistosa) antivenom was tested specifically on Pelamus platurus and it effectively neutralised the venom.
See also
- Blue lipped sea kraitLaticauda laticaudataThe blue-lipped sea krait is a species of sea snake.-Diagnostic Characters:Ventrals large, one-third to more than one half the width of the body; nostrils lateral; nasals separated by internasals; 19 longitudinal rows of imbricate scales at midbody; no azygous prefrontal shield; rostral undivided;...
- Banded sea kraitLaticauda colubrinaThe colubrine sea krait, banded sea krait or yellow-lipped sea krait is a species of sea snake found in tropical Indo-Pacific oceanic waters....
- sea snake
Other sources
- Hecht, M. K., Kropach, C. and Hecht, B. M. 1974 Distribution of the yellow-bellied sea snake Pelamis platurus, and its significance in relation to the fossil record. Herpetologica 30: 387-395.
- Kropach, C. 1975 The yellow-bellied sea snake, Pelamis, in the eastern Pacific. Pp. 185-213 in: Dunson, W., ed., The Biology of Sea Snakes. Univ. Park Press, Baltimore, xi + 530 pp.