Saturday, July 31, 2010

July 31, 2010 : Sunflower Starfish

Sunflower Starfish

The sunflower starfish (Pycnopodia helianthoides) is a large predatory starfish usually with 16–24 limbs called
rays. It is the largest starfish in the world. Sunflower starfish can grow to have an arm span of 1 meter (3 ft 3 in) in diameter. The color of the sunflower starfish ranges from bright orange, yellow and red to brown and sometimes to purple, with soft, velvet-textured bodies and 16–24 arms with powerful suckers. Most starfish species have a mesh-like skeleton that protects their internal organs. Easily stressed by predators such as large fish and other starfish, they can shed arms to escape, which will grow back within a few weeks. They are preyed upon by the king crab.

Sunflower starfish are quick, efficient hunters, moving at a speed of one meter per minute, using 15,000 tube feet which lie on the undersides of the body. They are commonly found around urchin barrens, as the sea urchin is a favorite food. They also eat clams, snails, abalone, sea cucumbers and other sea stars. In Monterey Bay, California, they will feed upon dead or dying squid. Although the sunflower sea star can greatly extend its mouth, for larger prey, the stomach can extend outside the mouth to digest prey, such as gastropods like abalone. Their feeding behavior was filmed for the BBC in the 2006 nature documentary Planet Earth and again in 2009 for Life.

Friday, July 30, 2010

July 30, 2010 : Lionfish


A Lionfish is any of several species of venomous marine fish in the genera Pterois, Parapterois, Brachypterois, Ebosia or Dendrochirus, of the family Scorpaenidae. The lionfish is also known as the Turkey Fish, Scorpion or Fire Fish. They are notable for their extremely long and separated spines, and have a generally striped appearance, red, green, navy green, brown, orange, yellow, black, maroon, or white. 

The lionfish is native to the Indian Pacific oceanic region. This range extends from western Australia and Malaysia east to French Polynesia and the Pitcairn Islands. In addition, the range also extends north to southern Japan and southern Korea and south to parts of coastal Australia. The Lionfish has also recently been discovered on the shores of Jamaica (W.I.) and Panama.

Although the lionfish is not native to all regions in the world, these fish continue to spread throughout many parts of the world. Due to a recent introduction, the lionfish has been spotted in the warmer coral regions of the eastern Atlantic Ocean around the Azores and extending into the Mediterranean Sea, and also in the Caribbean Sea (Cozumel, Jamaica, the Dominican Republic, Belize, Roatan, Puerto Rico, and Cuba as of 2010) and in the Red Sea . It has been speculated that this introduction may well have been caused when Hurricane Andrew destroyed an aquarium in southern Florida.. However, a more recent report states that NOAA ecologist James Morris Jr. has discovered that a Lionfish was caught off Dania, FL prior to Hurricane Andrew, as long ago as 1985. Morris indicated that the "most likely vector" was release of fish and/or eggs into the wild by people in the aquarium trade. DNA from captured lionfish in this region shows that they all originated from the same six or seven fish. The lion fish has also a low breeding system. Pterois volitans lionfish has also been found in waters near Long Island , New York, where as a 'tropical fish', it was not expected to be able to survive. 

Treatment of invasive Lionfish in the Caribbean varies - in Cozumel they are frequently captured alive in order to collect a bounty that has been placed upon them, while in Roatan they are frequently killed on sight by local divemasters, with as many as five or six killed during a single 1-hour dive.

The lionfish is one of the most venomous fish on the ocean floor. Lionfish have venomous dorsal spines that are used purely for defense. When threatened, the fish often faces its attacker in an upside down posture which brings its spines to bear. However, a lionfish's sting is usually not fatal to humans. If a human is envenomed, that person will experience extreme pain, and possibly headaches, vomiting, and breathing difficulties. A common treatment is soaking the afflicted area in hot water, as very few hospitals carry specific treatments. However, immediate emergency medical treatment is still advised, as some people are more susceptible to the venom than others.

Thursday, July 29, 2010

July 29, 2010 : Northwest Passage

Northwest Passage

The Northwest Passage is a sea route through the Arctic Ocean, along the northern coast of North America via waterways amidst the Canadian Arctic Archipelago, connecting the Atlantic and Pacific Oceans. The various islands of the archipelago are separated from one another and the Canadian mainland by a series of Arctic waterways collectively known as the Northwest Passages or Northwestern Passages. 

Sought by explorers for centuries as a possible trade route, it was first navigated by Roald Amundsen in 1903–1906. Until 2009, the Arctic pack ice prevented regular marine shipping throughout most of the year, but climate change has reduced the pack ice, and this Arctic shrinkage made the waterways more navigable. However, the contested sovereignty claims over the waters may complicate future shipping through the region: The Canadian government considers the Northwestern Passages part of Canadian Internal Waters, but various countries maintain they are an international strait or transit passage, allowing free and unencumbered passage.

There has been speculation that with the advent of global warming the passage may become clear enough of ice to again permit safe commercial shipping for at least part of the year. On August 21, 2007, the Northwest Passage became open to ships without the need of an icebreaker. According to Nalan Koc of the Norwegian Polar Institute this is the first time it has been clear since they began keeping records in 1972. The Northwest Passage opened again on August 25, 2008.

Thawing ocean or melting ice simultaneously opened up the Northwest Passage and the Northern Sea Route (Northeast Passage), making it possible to sail around the Arctic ice cap. Compared to 1979, Daily Mail published "Blocked: The Arctic ice, showing as a pink mass in the 1979 picture, links up with northern Canada and Russia." Awaited by shipping companies, this 'historic event' will cut thousands of miles off their routes. Warning, however, that the NASA satellite images indicated the Arctic may have entered a "death spiral" caused by global warming, Professor Mark Serreze, a sea ice specialist at National Snow and Ice Data Center (NSIDC), USA, said: "The passages are open. It's a historic event. We are going to see this more and more as the years go by." Due to Arctic shrinkage, the Beluga group of Bremen, Germany, announced plans to send the first ship through the Northern Sea Route in 2009, which may shorten the trip from Germany to Japan by 4,000 nautical miles (7,400 km; 4,600 mi). However, Canada's Prime Minister Stephen Harper announced that "ships entering the North-West passage should first report to his government."

Wednesday, July 28, 2010

July 28, 2010 : Sea Scorpion (Extinct)

Sea Scorpions

Eurypterids (sea scorpions) are an extinct group of arthropods related to arachnids which include the largest known arthropods that ever lived. They are members of the extinct class Eurypterida (Chelicerata). The word Eurypterid comes from the Greek word eury meaning "broad" or "wide" and the Greek word pteron meaning "wing". They predate the earliest fishes. The largest, such as Jaekelopterus, reached 2.5 metres (8 ft 2 in) or more in length, but most species were less than 20 centimetres (8 in). They were formidable predators that thrived in warm shallow water in the Ordovician to Permian from 460 to 248 million years ago. Although informally called 'sea scorpions', only the earliest ones were marine (later ones lived in brackish or freshwater), and they were not true scorpions. According to theory, the move from the sea to fresh water probably occurred by the Pennsylvanian period. They went extinct during the Permian-Triassic extinction event 251 million years ago, and their fossils have a near global distribution. 

About two dozen families of eurypterids are known. Eurypterus is perhaps the most well-known genus of eurypterid, of which 18 fossil species are known. The genus Eurypterus was created in 1825 by James Ellsworth DeKay, a zoologist. He recognized the arthropod nature of the first ever described eurypterid specimen found by Dr. S. L. Mitchell. In 1984, Eurypterus remipes was named the State Fossil of New York. 

Eurypterids have traditionally been regarded as close relatives of Horseshoe Crabs; together forming a group called Merostomata. Subsequent studies placed eurypterids closer to the arachnids in a group called Metastomata. There has also been a prevailing idea that eurypterids are closely related to scorpions, which they obviously resemble. This hypothesis is reflected in the common name 'sea scorpion'. More recently it has been recognised that a little-known, extinct group called chasmataspids also share features with eurypterids and the two groups were sometimes confused with one another. The most recent summary of relationships between arachnids and their relatives recognised Eurypterida, Xiphosura and Arachnida as three major groups, but was not able to resolve details between them.

Tuesday, July 27, 2010

July 27, 2010 : Flying Fish

Flying Fish 

Exocoetidae, is a family of marine fish in the order Beloniformes of class Actinopterygii. Fishes of this family are known as flying fish. They comprise about 64 species grouped in seven to nine genera.

Flying fish live in all of the oceans, particularly in warm tropical and subtropical waters. Their most striking feature is their pectoral fins, which are unusually large, and enable the fish to hide and escape from predators by leaping out of the water, taking short gliding flights through air just above the water's surface. Their glides are typically around 50 metres (160 ft). 

In order to glide upward out of the water, a flying fish moves its tail up to 70 times per second. It then spreads its pectoral fins and tilts them slightly upward to provide lift.

At the end of a glide, it folds its pectoral fins to reenter the sea or drops its tail into the water to push against the water to lift itself for another glide, possibly changing direction.

The curved profile of the "wing" has an aerodynamic shape that is comparable to that of a bird wing. The fish is able to increase its time in the air by flying straight into or at an angle to the direction of updrafts created by a combination of air and ocean currents.

Exocoetus has one pair of fins and a streamlined body to optimize for speed, while Cypselurus has a flattened body and two pairs of fins which maximizes its time in the air.

Flying fish can use updrafts at the leading edge of waves to cover distances of at least 400 m (1,300 ft). They can travel at speeds of more than 70 kilometres per hour (43 mph). Maximum altitude is 6 m (20 ft) above the surface of the sea. Some accounts have them landing on ships' decks.

Monday, July 26, 2010

July 26, 2010 : Sea Snakes

Sea Snakes 

Sea snakes are 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 even move on land, except for the genus Laticauda, which retain ancestral characteristics which allow limited land movement. They are found in warm coastal waters from the Indian Ocean to the Pacific. All have paddle-like tails and many have laterally compressed bodies that give them an eel-like appearance. However, unlike fish, they do not have gills and must come to the surface regularly to breathe. Nevertheless, they are among the most completely aquatic of all air-breathing vertebrates. Among this group are species with some of the most potent venoms of all snakes. Some have gentle dispositions and bite only when provoked, but others are much more aggressive. Currently, 17 genera are described as sea snakes, comprising 62 species.

Most sea snakes are completely aquatic and have adapted to their environment in many ways, the most characteristic of which is a paddle-like tail that has increased their swimming ability. To a varying degree, the bodies of many species are laterally compressed, especially in the pelagic species. This has often caused the ventral scales to become reduced in size, even difficult to distinguish from the adjoining scales. Their lack of ventral scales means that they have become virtually helpless on land, but as they live out their entire life cycle at sea, they have no need to leave the water. 

The only genus that has retained the enlarged ventral scales is the sea kraits, Laticauda, with only five species. These snakes are considered to be more primitive, as they still spend much of their time on land, where their ventral scales afford them the necessary grip. Laticauda are also the only sea snakes with internasal scales, i.e., their nostrils are not located dorsally.

Like their cousins in the Elapidae family, the majority of sea snakes are highly venomous; however, when bites occur, it is rare for much venom to be injected, so that envenomation symptoms usually seem non-existent or trivial. For example, Pelamis platurus has a venom more potent than any other terrestrial snake species in Costa Rica, but despite its abundance in the waters off its western coast, few human fatalities have been reported. Nevertheless, all sea snakes should be handled with great caution.

Sunday, July 25, 2010

July 25, 2010 : Glass Squid

Glass Squid 

The family Cranchiidae comprises the approximately 60 species of glass squid, also known as cranchiid or cranch squid. Cranchiid squid occur in surface and midwater depths of open oceans around the world. They range in mantle length from 10 centimetres (3.9 in) to over 3 metres (9.8 ft), in the case of the Colossal Squid. The common name, glass squid, derives from the transparent nature of most species. Cranchiid squid spend much of their lives in partially sunlit shallow waters where their transparency provides camouflage. They are characterised by a swollen body and short arms, which bear two rows of suckers or hooks. The third arm pair is often enlarged. Many species are bioluminescent organisms and possess light organs on the undersides of their eyes, used to cancel their shadow. Eye morphology varies widely, ranging from large and circular to telescopic and stalked. A large fluid-filled chamber containing ammonia solution is used to aid buoyancy. Often the only organ that is visible through the transparent tissues is a cigar-shaped digestive gland, which is the cephalopod equivalent of a mammalian liver. This is usually held in a vertical position to reduce its silhouette and a light organ is sometimes present on the lower tip to further minimise its appearance in the water.

Like most squid, the juveniles of cranchiid squid live in surface waters, descending to deeper waters as they mature. Some species live over two kilometres below sea level. The body shape of many species changes drastically between growth stages and many young examples could be confused for different species altogether.

Saturday, July 24, 2010

July 24, 2010 : Humboldt Squid

Humboldt Squid 

The Humboldt Squid (Dosidicus gigas), also known as Jumbo Squid, Jumbo Flying Squid, or Diablo Rojo (Spanish for Red Devil), is a large, predatory squid found in the waters of the Humboldt Current in the Eastern Pacific Ocean. They are most commonly found at depths of 200–700 metres (660–2,300 ft), from Tierra del Fuego to California. Recent findings suggest the range of this species is spreading north into the waters of Oregon, Washington, British Columbia, and Alaska. Though they usually prefer deep water, between 1,000 and 1,500 squid washed up on the Long Beach Peninsula in southwest Washington in the fall of 2004. They have also ventured into Puget Sound. 

Generally, the tube (or body) constitutes about 40% of the animal's mass, the fin (or wing) about 12%, the tentacles about 14%, the outer skin about 3%, the head (including eyes and beak) about 5%, with the balance (26%) made up of the inner organs.

They often approach prey quickly with all ten appendages extended forward in a cone-like shape. Upon reaching striking distance, they will open their eight swimming and grasping arms, and extend two long tentacles covered in sharp 'teeth,' grabbing their prey and pulling it back towards a parrot-like beak, which can easily cause dramatic lacerations to human flesh. The whole process takes place in seconds.  

Recent footage of shoals of these animals demonstrates a tendency to meet unfamiliar objects aggressively. Having risen to depths of 130–200 metres (430–660 ft) below the surface to feed (up from their typical 700 metre (2,300 ft) diving depth, beyond the range of human diving), they have attacked deep-sea cameras and rendered them inoperable. Reports of recreational scuba divers being attacked by Humboldt Squid have been confirmed. One particular diver, Scott Cassell, who has spent much of his career videotaping this species, has developed body armor to protect against attacks. Each of the squid's suckers is ringed with sharp teeth, and the beak itself can tear flesh, although it's believed they lack the jaw strength to crack heavy bone.

Friday, July 23, 2010

July 23, 2010 : Snailfish


Snailfishes are scorpaeniform marine fish of the family Liparidae. Widely distributed from the Arctic to Antarctic Oceans including the northern Pacific, the snailfish family contains approximately 23 genera and 195 species. They are closely related to the sculpins of the Cottidae family and the lumpfish of the Cyclopteridae family. Snailfish are sometimes included within the latter family.

The snailfish family is poorly studied and few specifics are known. Their elongate, tadpole-like bodies are similar in profile to the rattails. Their heads are large with small eyes; their bodies are slender to deep, tapering to a very small tail. The extensive dorsal and anal fins may merge or nearly merge with the tail fin. Snailfish are scaleless with a thin, loose gelatinous skin; some species, such as the spiny snailfish (Acantholiparis opercularis) have prickly spines as well. Their teeth are small and simple with blunt cusps. The deep-sea species have prominent, well-developed sensory pores of the head, part of the animals' lateral line system.

In October 2008, a UK-Japan team discovered a shoal of
Pseudoliparis amblystomopsis at a depth of 7.7km (4.8 miles) in the Japan Trench, these are believed to be the deepest living fish ever recorded.

Thursday, July 22, 2010

July 22, 2010 : Psychedelic Fish

Psychedelic Fish  

With a swirl of beige and peach stripes stretching from its blue eyes to its tail, the newly named Histiophryne psychedelica was initially discovered by scuba diving instructors working for a tour operator a year ago in shallow waters off Indonesia.

The operator contacted Ted Pietsch, lead author of a paper published in this month's edition of the journal Copeia, who submitted DNA work identifying the psychedelic fish as a new species.

Like other frogfish—a subset of anglerfish—H. psychedelica has leglike fins on both sides of its body.

But it has several traits not previously known among frogfish, wrote Pietsch, of the University of Washington.

Each time the fish strike the seabed, for instance, they push off with their fins and expel water from tiny gill openings to jet themselves forward. That and an off-centered tail cause them to bounce around in a bizarre, chaotic manner. 

Mark Erdman, a senior adviser to the Conservation International's marine program, said, "I think people thought frogfishes were relatively well known, and to get a new one like this is really quite spectacular. ... It's a stunning animal." 

The fish, which has a gelatinous, fist-size body covered with thick folds of skin that protect it from sharp-edged corals, also has a flat face with eyes directed forward, like humans, and a huge, yawning mouth.

Wednesday, July 21, 2010

July 21, 2010 : Cone Snail

Cone Snail 

Conus is a large genus of small to large predatory sea snails, marine gastropod molluscs, with the common names of cone snails, cone shells or cones. This genus is in the subfamily Coninae within the family Conidae. Geologically speaking, the genus is known from the Eocene to the Recent periods. Conus snails are mostly tropical in distribution. They are all venomous to one degree or another. The larger species hunt fish using harpoon-like teeth and a poison gland. The smaller ones hunt and eat marine worms. 

Conus species have shells that are shaped more or less like geometric cones. Many species have colorful patterning on the shell surface.

Live cone snails should be handled with care or not handled at all, as they are capable of "stinging" humans with unpleasant results. The sting of small cones is no worse than a bee sting, but the sting of a few of the larger species of tropical cone snails can be serious, and has even occasionally been fatal to human beings.

Cone venom shows great promise as a source of new, medically important substances.

Tuesday, July 20, 2010

July 20, 2010 : Remora


A remora (pronounced /ˈrɛmərə/), sometimes called a suckerfish or sharksucker, is an elongated, brown fish in the order Perciformes and family Echeneidae. They grow to 30–90 centimetres long (1–3 ft), and their distinctive first dorsal fin takes the form of a modified oval sucker-like organ with slat-like structures that open and close to create suction and take a firm hold against the skin of larger marine animals. By sliding backward, the remora can increase the suction, or it can release itself by swimming forward. Remoras sometimes attach to small boats. They swim well on their own, with a sinuous, or curved, motion.

Remoras are primarily tropical open-ocean dwellers, occasionally found in temperate or coastal waters if they have attached to large fish that have wandered into these areas. In the mid-Atlantic, spawning usually takes place in June and July; in the Mediterranean, in August and September. The sucking disc begins to show when the young fish are about 1 centimetre long. When the remora reaches about 3 centimetres, the disc is fully formed and the remora is then able to hitch a ride. The remora's lower jaw projects beyond the upper, and there is no swim bladder.

Some remoras associate primarily with specific host species. Remoras are commonly found attached to sharks, manta rays, whales, turtles, and dugong (hence the common names sharksucker and whalesucker). Smaller remoras also fasten onto fish like tuna and swordfish, and some small remoras travel in the mouths or gills of large manta rays, ocean sunfish, swordfish, and sailfish.

Monday, July 19, 2010

July 19, 2010 : Hagfish


Hagfish are marine craniates of the class Agnatha or Myxini, also known as Hyperotreti. Some researchers regard Myxini as not belonging to the subphylum Vertebrata. That is, they are the only living animals that have a skull but not a vertebral column.

Despite their name, there is some debate about whether they are strictly fish (as there is for lampreys), since they belong to a much more primitive lineage than any other group that is placed in the category of fish (Chondrichthyes and Osteichthyes). The earliest fossil record dates back approximately 330 million years to the Late Carboniferous period.

Their unusual feeding habits and slime-producing capabilities have led members of the scientific and popular media to dub the hagfish as the most "disgusting" of all sea creatures. Although hagfish are sometimes called "slime eels", they are not eels at all.

Hagfish have elongated, eel-like bodies (so flexible they sometimes tie themselves in knots). They have four hearts, two brains, and a paddle-like tail. They have cartilaginous skulls (although the part surrounding the brain is composed primarily of a fibrous sheath) and tooth-like structures composed of keratin. Colors depend on the species, ranging from pink to blue-grey, and black or white spots may be present. Eyes are simple eyespots, not compound eyes that can resolve images. Hagfish have no true fins and have six or eight barbels around the mouth and a single nostril. Instead of vertically articulating jaws like Gnathostomata (vertebrates with jaws), they have a pair of horizontally moving structures with tooth-like projections for pulling off food. The mouth of the hagfish has two pairs of horny, comb-shaped teeth on a cartilaginous plate that protracts and retracts. These teeth are used to grasp food and draw it toward the pharynx.

Sunday, July 18, 2010

July 18, 2010 : Sea Pen

Sea Pen 

Sea pens are colonial marine cnidarians belonging to the order Pennatulacea. There are 14 families within the order; they are thought to have a cosmopolitan distribution in tropical and temperate waters worldwide. Sea pens are grouped with the octocorals ("soft corals"), together with sea whips and gorgonians.

Although named after their feather-like appearance reminiscent of antique quill pens, only sea pen species belonging to the suborder Subselliflorae live up to the comparison. Those belonging to the much larger suborder Sessiliflorae lack feathery structures and grow in club-like or radiating forms. The latter suborder includes what are commonly known as sea pansies.

The sea pen fossil record is patchy and disputed by some while the earliest accepted fossils are known from the Cambrian-aged Burgess Shale (Thaumaptilon), similar fossils from the Ediacaran (ala Charnia) may represent the dawn of sea pens. Precisely what these early fossils are, however, is not decided.

Saturday, July 17, 2010

July 17, 2010 : Leedsichthys (Extinct)


Leedsichthys was a giant pachycormid (an extinct group of Mesozoic bony fish) that lived in the oceans of the Middle Jurassic period. The closest living relative of the pachycormids is the bowfin, Amia calva, but this is only very distantly related.

The name Leedsichthys means "Leeds' fish", after the fossil collector Alfred Nicholson Leeds, who discovered it before 1886 near Peterborough, England. The fossils found by Leeds gave the fish the species epithet problematicus, because the remains were so fragmented that they were extremely hard to recognize and interpret.

Unfortunately, although the remains of over seventy individuals have been found, these are usually partial and fragmentary. This has made it difficult to estimate its length. Arthur Smith Woodward, who described the specimen in 1889, estimated it to be 30 feet (around 9 metres) long, by comparing the tail of Leedsichthys with another pachycormid, Hypsocormus. In 1986, Martill compared the bones of Leedsichthys to a pachycormid that he had recently discovered, but the unusual proportions of that specimen gave a wide range of possible sizes. More recent estimates, from documentation of historical finds and the excavation of the most complete specimen ever from the Star Pit near Whittlesey, Peterborough, support Smith Woodward's figures of between 30 and 33 feet (9 and 10 meters). Recent work on growth ring structures within the remains of Leedsichthys have also indicated that it would have taken 21-25 years to reach these lengths, and isolated elements from other specimens indicate that a maximum size of just over 53 feet (16 metres) is not unreasonable.

Friday, July 16, 2010

July 16, 2010 : Deep Sea Dragonfish

Deep Sea Dragonfish

The deep sea dragonfish, sometimes known as the scaleless dragonfish, is a ferocious predator that inhabits the deep oceans of the world. Known scientifically as Grammatostomias flagellibarba, it has extremely large teeth compared to its body size. In spite of its gruesome appearance, its is a small fish, measuring only about 6 inches (about 15 centimeters) in length. There are several different species of dragonfish. All are very similar in appearance.

The deep sea dragonfish is one of the many species of deep sea fish that can produce its own light through a chemical process known as bioluminescence. The light is produced by a special organ known as a photophore. It is believed that the fish can use these flashing lights in the dark waters to attract prey and even to signal potential mates. The dragonfish has a large head and mouth equipped with many sharp, fang-like teeth. It also has a long protrusion known as a barbel attached to its chin. This barbel is tipped with a light-producing photophore. The dragonfish also has photophores along the sides of its body. These light organs may be used to signal other dragonfish during mating. They may also serve to attract and disorient prey fishes from deep below.

The deep sea dragonfish lives in deep ocean waters at depths of up to 5,000 feet (1,500 meters). Although dragonfish species are found in most oceans the world, the deep sea dragonfish is limited mainly to the North and Western Atlantic Ocean and the Gulf of Mexico.

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Thursday, July 15, 2010

July 15, 2010 : Elephant Shark

Elephant Shark

The elephant shark, Callorhinchus milii, is a cartilaginous fish (Chondrichthyes) belonging to the subclass Holocephali (chimaera). Sharks, rays and skates are the other members of the cartilaginous fish group and are grouped under the subclass Elasmobranchii. Alternative names of the elephant shark include: Australian ghost shark, Makorepe, whitefish, plownose chimaeras or elephant fish. The latter is best avoided as it may be confused with elephantfishes (family Mormyridae) which are freshwater teleost fishes from tropical Africa and the Nile.

It is found off southern Australia, and south of East Cape and Kaipara Harbour in New Zealand, at depths of 200 meters to 500 meters. Their length is between 60 and 120 centimeters. Males of this species mature at about 65 centimeters. During spring, adults migrate inshore to estuaries and bays where mating takes place and the females lay their eggs on sandy or muddy substrates. The eggs are contained in large yellowish capsules. The gestation period is six to eight months.

Recently, the elephant shark was proposed as a model cartilaginous fish genome because of its relatively small genome size. The genome of the elephant shark is estimated to be 910 Mb long (Mb = megabases = 1 million basepairs) which is the smallest among all the cartilaginous fishes and one-third the size of the human genome (3000 Mb). Because cartilaginous fishes are the oldest living group of jawed vertebrates, the elephant shark genome will serve as a useful reference genome for understanding the origin and evolution of vertebrate genomes including our own genome, which shared a common ancestor with elephant shark about 450 million years ago. Interestingly, studies so far have shown that the sequence and the gene order ("synteny”) are more similar between human and elephant shark genomes than between human and teleost fish genomes (fugu and zebrafish) even though humans are more closely related to teleost fishes than to the elephant shark. Recently, an Elephant Shark Genome Project has been launched to sequence the whole genome of the elephant shark.

The elephant shark has three cone pigments for color vision (like H. sapiens).

Wednesday, July 14, 2010

July 14, 2010 : Skeleton Coast

Skeleton Coast 

The Skeleton Coast (German: Skelettküste) is the northern part of the Atlantic Ocean coast of Namibia and south of Angola from the Kunene River south to the Swakop River, although the name is sometimes used to describe the entire Namib Desert coast. The Bushmen of the Namibian interior called the region "The Land God Made in Anger", while Portuguese sailors once referred to it as "The Gates of the bad place". 

On the coast the upwelling of the cold Benguela current gives rise to dense ocean fogs (called "cassimbo" by the Angolans) for much of the year. The winds blow from land to sea, rain fall rarely exceeds 10 millimetres (0.39 in) annually and the climate is inhospitable. There is a constant, heavy surf on the beaches. In the days of human-powered boats it was possible to get ashore through the surf but impossible to launch from the shore. The only way out was by going through a marsh hundreds of miles long and only accessible through a hot and arid desert.

The coast is named for the bleached whale and seal bones which covered the shore when the whaling industry was still active, as well as the skeletal shipwrecks caused by rocks offshore in the fog. More than a thousand vessels of various sizes and areas litter the coast. Notable wrecks in the region include the Eduard Bohlen, the Otavi, the Dunedin Star, and Tong Taw.

Tuesday, July 13, 2010

July 13, 2010 : Hydrothermal Vents

Hydrothermal Vents 

A hydrothermal vent is a fissure in a planet's surface from which geothermally heated water issues. Hydrothermal vents are commonly found near volcanically active places, areas where tectonic plates are moving apart, ocean basins, and hotspots.

Hydrothermal vents are locally very common because the earth is both geologically active and has large amounts of water on its surface and within its crust. Common land types include hot springs, fumaroles and geysers. The most famous hydrothermal vent system on land is probably within Yellowstone National Park in the United States. Under the sea, hydrothermal vents may form features called black smokers.

Relative to the majority of the deep sea, the areas around submarine hydrothermal vents are biologically more productive, often hosting complex communities fueled by the chemicals dissolved in the vent fluids. Chemosynthetic archaea form the base of the food chain, supporting diverse organisms, including giant tube worms, clams, limpets and shrimp.

Active hydrothermal vents are believed to exist on Jupiter's moon Europa, and ancient hydrothermal vents have been speculated to exist on Mars.

Monday, July 12, 2010

July 12, 2010 : Horn Shark

Horn Shark 

The horn shark (Heterodontus francisci) is a species of bullhead shark, family Heterodontidae. It is endemic to the coastal waters off the western coast of North America, from California to the Gulf of California. Young sharks are segregated spatially from the adults, with the former preferring deeper sandy flats and the latter preferring shallower rocky reefs or algal beds. A small species typically measuring 1 m (3.3 ft) in length, the horn shark can be recognized by a short, blunt head with ridges over its eyes, two high dorsal fins with large venomous spines, and a brown or gray coloration with many small dark spots.

Slow-moving, generally solitary predators, horn sharks hunt at night inside small home ranges and retreat to a favored shelter during the day. Their daily activity cycles are controlled by environmental light levels. Adult sharks prey mainly on hard-shelled molluscs, echinoderms, and crustaceans, which they crush between powerful jaws and molar-like teeth, while also feeding opportunistically on a wide variety of other invertebrates and small bony fishes. Juveniles prefer softer-bodied prey such as polychaete worms and sea anemones. The shark extracts its prey from the substrate using suction and, if necessary, levering motions with its body. Reproduction is oviparous, with females laying up to 24 eggs from February to April. After laying, the female picks up the auger-shaped egg cases and wedges them into crevices to protect them from predators.

Sunday, July 11, 2010

July 11, 2010 : Pompeii Worm

Pompeii Worm

The Pompeii worm (Alvinella pompejana) is a deep-sea polychaete vermiform extremophile found only at hydrothermal vents in the Pacific Ocean, discovered in the early 1980s off the Galápagos Islands by French researchers.
They can reach up to 5 inches in length and are pale gray with red tentacle-like gills on their heads. Perhaps most fascinating, is that their tail end is often resting in temperatures as high as 176 °F (80 °C), while their feather-like head sticks out of the tubes into water that is a much cooler 72 °F (22 °C). Scientists are attempting to understand how Pompeii worms can withstand such extreme temperatures by studying the bacteria that form a "fleece-like" covering on their backs. Living in a symbiotic relationship, the worms secrete mucus from tiny glands on their backs to feed the bacteria, and in return they are protected by some degree of insulation. The bacteria have also been discovered to be chemolithotrophic, contributing to the ecology of the vent community. Recent researches suggest that the bacteria might play an important role in the feeding of the worms. 

Attaching themselves to black smokers, the worms have been found to thrive at temperatures of up to 80 °C (176 °F), making the Pompeii worm the most heat-tolerant complex animal known to science after the tardigrades (or water bears), which are able to survive temperatures over 150 °C.

Saturday, July 10, 2010

July 10, 2010 : Packhorse Crayfish

Packhorse Crayfish

Sagmariasus verreauxi is a species of spiny lobster that lives around northern New Zealand, the Kermadec Islands the Chatham Islands and Australia from Queensland to Tasmania. It is probably the longest decapod crustacean in the world, alongisde the American lobster Homarus americanus, growing to lengths of up to 60 centimetres (24 in). The species has many common names in English, including Australian crayfish, common crayfish, common Sydney crayfish, eastern crayfish, Eastern rock lobster, green cray, green crayfish, green lobster, green rock lobster, marine crayfish, New South Wales spiny lobster, packhorse crayfish, packhorse lobster, sea crayfish, smooth-tailed crayfish and Sydney crayfish. In Māori, it is called pawharu. S. verreauxi was formerly included in the genus Jasus, but has been separated into a monotypic genus Sagmarasius due to the lack of sculpturation on the abdomen, which is found in all other Jasus species. The name Sagmarasius derives from the Greek σαγμαριον (sagmarion), meaning packhorse, and the genus name Jasus, in reference to the common name "packhorse crayfish".

Friday, July 9, 2010

July 9, 2010 : Squirrelfish


The Holocentridae is a family of ray-finned fish, belonging to the order Beryciformes with the members of the subfamily Holocentrinae typically known as squirrelfish, while the members of Myripristinae typically are known as soldierfish. In Hawaii they are known as menpachi.

They are found in tropical parts of the Indian, Pacific and Atlantic Oceans, with the greatest species diversity near reefs in the Indo-Pacific. Most are found at depths from the shoreline to 100 m (330 ft), but some, notably the members of the genus Ostichthys, are generally found far deeper. Being largely or entirely nocturnal, they have relatively large eyes. During the day they typically remain hidden in crevices, caves, or under ledges. Red and silvery colours dominate. The preopercle spines (near the gill-opening) of the members of the subfamily Holocentrinae are venomous, and can give painful wounds. Most have a maximum length of 15-35 cm (6-14 in), but Sargocentron iota barely reaches 8 cm (3 in), and S. spiniferum and Holocentrus adscensionis can reach more than 50 cm (20 in). The squirrelfishes mainly feed on small fishes and benthic invertebrates, while the soldierfishes typically feed on zooplankton. The larvae are pelagic, unlike the adults, and can be found far out to sea.

Thursday, July 8, 2010

July 8, 2010 : Wonder-fish

Wonder-fish (Thaumatichthys)

Thaumatichthys is a genus of deep-sea anglerfish in the family Thaumatichthyidae, with three known species. Its scientific name means "wonder-fish" in Greek; oceanographer Anton Bruun described these fishes as "altogether one of the oddest creatures in the teeming variety of the fish world." In contrast to other anglerfishes, the bioluminescent lure (called the "esca") of Thaumatichthys is located inside its cavernous mouth. They are worldwide in distribution and are ambush predators living near the ocean floor.

The first specimen of Thaumatichthys was collected by an American expedition in Indonesia in 1908 and given the species name pagidostomus ("trap-mouthed"). A subsequent specimen from the north Atlantic was placed by Regan and Trewavas (1932) into a new genus, Amacrodon, based on differences in dentition. Bruun assigned a specimen collected by the Galathea Expedition of 1950–52 to a third genus, Galatheathauma ("Galathea's wonder"), as it was much larger than the previous specimens. However, a later examination of the then-32 known specimens showed that these differences were attributable to age, and thus there was only one valid genus, Thaumatichthys, with three species.
The closest relative of Thaumatichthys is Lasiognathus, which also possesses enlarged, hinged premaxillaries, denticles on the esca, and a branched upper operculum. There are also significant differences between the two genera though, and Lasiognathus shares many more traits with the Oneirodidae (in which it was formerly placed) than does Thaumatichthys.

Wednesday, July 7, 2010

July 7, 2010 : Wolf-Trap Anglerfish

Wolf-Trap Anglerfish (Lasiognathus)

Lasiognathus is a genus of deep-sea anglerfish in the family Thaumatichthyidae, with five species known from the Atlantic and Pacific Oceans. It has been called a "compleat angler", in that its lure apparatus consists of a fishing rod (the projecting basal bone or pteropterygium), a fishing line (the illicium, a modified dorsal fin ray), bait (the bioluminescent esca), and hooks (large dermal denticles). It is also distinctive for an enormous upper jaw with premaxillaries that can be folded down to enclose the much shorter lower jaw. 

The closest relative of Lasiognathus is Thaumatichthys, which also has enlarged and hinged premaxillaries, escal denticles, and a branched upper operculum. However, there are significant differences between those two taxa as well, which includes characters that Lasiognathus shares with the oneirodids not found in Thaumatichthys. Bertelsen and Struhsaker (1977) noted that, given the undefined cladistics of the Oneirodidae, it was somewhat subjective whether Lasiognathus and Thaumatichthys were placed in their own family, in separate families, or in the Oneirodidae. Lasiognathus comes from the Ancient Greek lasios, meaning "hairy", and gnathos, meaning "jaw".

Tuesday, July 6, 2010

July 6, 2010 : Xiphactinus (Extinct)


Xiphactinus (from Latin and Greek for "sword-ray") was a large, 4.5 to 5 m (15 to 20 feet) long predatory bony fish that lived in the Western Interior Sea, over what is now the middle of North America, during the Late Cretaceous. When alive, the fish would have resembled a gargantuan, fanged tarpon (to which it was, however, not related). The Portheus molossus described by Cope is a junior synonym of the species. Skeletal remains of Xiphactinus have come from Kansas, Alabama, and Georgia in the United States, as well as Europe and Australia.

Xiphactinus audax was a voracious predator fish. At least a dozen specimens have been collected with the remains of large, undigested or partially digested prey in their stomachs. In particular, one 13 feet (4.0 m) fossil specimen was collected by George F. Sternberg with another, nearly perfectly preserved 6 feet (1.8 m) long ichthyodectid Gillicus arcuatus, inside of it. The larger fish apparently died soon after eating its prey, most likely due to the smaller fish prey struggling and rupturing an organ as it was being swallowed. This fossil can be seen at the Sternberg Museum of Natural History in Hays, Kansas.

Monday, July 5, 2010

July 5, 2010 : Colossal Squid

Colossal Squid

The Colossal Squid (Mesonychoteuthis hamiltoni, from Greek mesos (middle), nychus (claw), and teuthis (squid)), sometimes called the Antarctic or Giant Cranch Squid, is believed to be the largest squid species in terms of mass. It is the only known member of the genus Mesonychoteuthis. Though it is known from only a few specimens, current estimates put its maximum size at 12–14 metres (39–46 feet) long, based on analysis of smaller and immature specimens, making it the largest known invertebrate.

Unlike the giant squid, whose arms and tentacles only have suckers lined with small teeth, the Colossal Squid's limbs are also equipped with sharp hooks: some swiveling, others three-pointed. Its body is wider and stouter, and therefore heavier, than that of the giant squid. Colossal Squids are believed to have a longer mantle than giant squids, although their tentacles are shorter.

The squid exhibits abyssal gigantism. The beak of Mesonychoteuthis hamiltoni is the largest known of any squid, exceeding that of Architeuthis (giant squid) in size and in robustness. The Colossal Squid also has the largest eyes documented in the animal kingdom.

Sunday, July 4, 2010

July 4, 2010 : Dumbo Octopus

Dumbo Octopus

The octopuses of the genus Grimpoteuthis are also known as "Dumbo octopuses" from the ear-like fins protruding from the top of their head-like bodies, resembling the ears of Walt Disney's flying elephant. They are bathyal creatures, living at extreme depths: 3000-4000 meters, and are some of the rarest of the Octopoda species. They can flush the transparent layer of their skin at will, and are pelagic animals, as with all other cirrate octopuses.

They hover above the sea floor, searching for worms, bivalves, pelagic copepods, and other crustaceans. They move by pulsing their arms, shooting water through their funnel, or by waving their ear-like fins. They can use each of these techniques separately or all simultaneously. The males and females are different in their size and sucker patterns. The females lay eggs consistently, with no distinct breeding season.

Saturday, July 3, 2010

July 3, 2010 : Glaucus atlanticus

Glaucus atlanticus

Glaucus atlanticus (common names sea swallow, blue glaucus, blue sea slug and blue ocean slug) is a species of medium-sized blue sea slug, a pelagic aeolid nudibranch, a marine opisthobranch gastropod mollusk in the family Glaucidae. This is the only species in the genus Glaucus, but is closely related to Glaucilla marginata, another member of the family Glaucidae.

This species normally has a length of 5 to 8 cms in length. It is silvery grey on its dorsal side and dark and pale blue ventrally. It has dark blue stripes along the edge of its foot. It has a tapering body which is flattened and has six appendages which branch out into rayed cerata.

This nudibranch is pelagic, and is distributed throughout the world's oceans, in temperate and tropical waters. Regions where this slug is found include the East and South Coast of South Africa, European waters and Mozambique. This species floats upside down on the surface tension of the ocean.

Friday, July 2, 2010

July 2, 2010 : Boxer Crab

Boxer Crab

Lybia (common names include
boxer crabs, boxing crabs and, especially in the aquarium trade, pom-pom crabs) is a genus of small crabs, including Lybia tesselata and Lybia edmondsoni. They are notable for their mutualism with sea anemones, which they hold in their claws for defense. In return, the anemones find new places to eat and mate. Boxer crabs use at least three different species of anemones, including Bundeopsis sp. and Triactis producta. The bonding with the anemone is not required for survival, however, and boxer crabs have frequently been known to live without them, sometimes substituting other organisms such as sponges and corals.

Thursday, July 1, 2010

July 1, 2010 : Gulper Eel

Gulper Eel

The pelican eel, or Eurypharynx pelecanoides, is a deep-sea fish rarely seen by humans, though the creatures are occasionally snagged in fishermen's nets. It is an eel-like fish, the only member of the genus Eurypharynx and the family Eurypharyngidae. It belongs to the order Saccopharyngiformes which is closely related to the true eels in Anguilliformes. It is also sometimes referred to as the umbrella mouth gulper.

The pelican eel's most notable feature is its enormous mouth, much larger than its body. The mouth is loosely-hinged, and can be opened wide enough to swallow a fish much larger than itself. The pouch-like lower jaw resembles that of a
pelican, hence its name. The stomach can stretch and expand to accommodate large meals, although analysis of stomach contents suggests that the eels primarily eat small crustaceans. Despite the great size of the jaws, which occupy about a quarter of the animal's total length, it has only tiny teeth, which also would not be consistent with a regular diet of large fish.