Goblin Shark

>> Friday, March 16, 2012

Goblin Shark also called Mitsukurina owstoni, is a deep-sea shark, the sole living species in the family Mitsukurinidae. The most distinctive characteristic of the goblin shark is the unusual shape of its head. It has a long, trowel-shaped, beak-like rostrum or snout, much longer than other sharks' snouts. Some other distinguishing characteristics of the shark are the color of its body, which is mostly pink, and its long, protrusible jaws. When the jaws are retracted, the shark resembles a pink grey nurse shark, Carcharias taurus, with an unusually long nose.

Mitsukurina owstoni is found in the deep ocean, far below where the sun's light can reach at depths greater than 200 m. They can be found throughout the world, from Australia in the Pacific Ocean to the Gulf of Mexico in the Atlantic Ocean. They are best known from the waters around Japan, where the species was first discovered.
Scientific classification
Kingdom - Animalia
Phylum - Chordata
Class - Chondrichthyes
Subclass - Elasmobranchii
Order - Lamniformes
Family - Mitsukurinidae D. S. Jordan, 1898
Genus - Mitsukurina D. S. Jordan, 1898
Species -  M. owstoni

Distribution and habitat
Mitsukurina owstoni is a bathydemersal deep-water shark usually found near the sea bottom, at depths of around 250 m. The deepest specimen ever caught was found at 1,300 m. Most goblin sharks that have been caught were from Japan (where it was first discovered), specifically in an area between Tosa Bay and Boso Peninsula. The species' Pacific range is rather large. M. owstoni specimens have been found in the waters off South Africa, from various sites throughout the western Pacific Ocean. Goblin sharks have also been found off the coasts of Australia and New Zealand.

Anatomy and appearance
Goblin sharks can grow to 11 feet (3.3 m) long and weigh 350 lb (159 kg). They have the typical shark's semi-fusiform body. Unlike the common image of sharks, M. owstoni's fins are not pointed and instead are low and rounded, with the anal and pelvic fins significantly larger than the dorsal fins. Their heterocercal tails are similar to the thresher shark's, with the upper lobe significantly longer proportionately than other sharks'. In addition, the goblin shark's tail lacks a ventral lobe. The pink coloration, unique among sharks, is due to blood vessels underneath a semi-transparent skin (which bruises easily), thereby causing the coloring. The fins have a bluish appearance. Goblin sharks lack a nictitating membrane. They have no precaudal pit and no keels. The front teeth are long and smooth-edged, while the rear teeth are adapted for crushing. Up to 25% of the goblin shark's body weight can be its liver. This is similar to other sharks, such as the basking shark and the frilled shark, and contributes to the buoyancy of the shark, which, like all sharks, lacks a swim bladder.
Goblin sharks hunt by sensing the presence of prey with electro-sensitive organs in the rostrum, or snout, due to the absence of light in the deep waters where it swims. Once a shark finds its prey, it suddenly protrudes its jaws, while using a tongue-like muscle to suck the victim into its sharp front teeth. They have been known to feed on deep-sea rockfish (Helicolenus dactylopterus was found in one specimen), cephalopods and crustaceans.

Next to nothing is known of the goblin shark's reproductive habits. Even though a pregnant goblin shark has never been caught or found, as members of the order Lamniformes, they are assumed to be ovoviviparous; their eggs mature and hatch inside the mother's body and the shark gives birth to live young.
Role in the ecosystem
The goblin shark is an upper-level carnivore in its natural habitat. As a macro-organism, it has its fair share of external and internal parasites. Two new species of tapeworm were discovered in a specimen captured off Australia, Litobothrium amsichensis and Marsupiobothrium gobelinus.

Conservation status
In 2004, Mitsukurina owstoni was classified by the IUCN's Shark Red List Authority as a species of "Least Concern". The rationale given was that despite the fact that goblin shark sightings have been relatively rare, the worldwide distribution of the species, combined with the fact that it was not accidentally taken often as bycatch in fisheries, ensured that the species is most probably not in any reasonable danger of extinction. The IUCN described the major threats to M. owstoni populations' as either harvesting (as an intentional target for fishing), accidental mortality (bycatch) and to a lesser extent, water pollution. There are no active conservation efforts being made toward this specific species.
READ MORE - Goblin Shark

Classification of Animals

>> Wednesday, March 7, 2012

To identify animals and learn more about them, it helps to become familiar with the way they are classified. Biologists arrange animals into groups on the basis of traits Which they share with other animals and their genetic relationships with each other. This orderly way of classifying animals forms the basis of the field of study called taxonomy. Modern scientific taxonomy is based on physical characteristics (analyzed as teeth, skin, fur, feather, or scale patterns, size, or the structure of body parts) and on genetic characteristics. Some key characteristics are basic to taxonomic descriptions. Others are not part of the basic description, but evolutionary relationships CORRESPONDING to taxonomic classifications are based upon Which.

The field of study called evolutionary systematics Focuses specifically on the relationships between living organisms. A Swedish scientist named Carolus Linnaeus laid the foundation of modern systematics with a work called Systema Naturae, Which He published in 1758. Linnaeus wrote in Latin, the international language at the time, and Latin continues to be the basis of most scientific names. Sometimes the names of the various taxonomic categories are converted into forms that are more comfortable to everyday English, for example, instead of Mammalia we usually just say mammal.

Linnaeus designed his system of classification that each animal and plant Sun not that he Described had one and only one correct name and this name would be shared with any other organism. Then he presented a method for organizing all of these organisms into a series of named nested groups, based on their similarities and differences. In essence, it became a type of filing system, with the top levels including many, many different kinds of organisms and the lowest levels containing but a single type of plant or animal. This hierarchical Linnaean system uses clearly defined shared characteristics to classify organisms into each group Represented by these different levels.

The most important categories in this hierarchical system, from higher to lower and more inclusive and more specific, are kingdom, phylum, class, order, family, genus, and species. A kingdom is one of the highest primary divisions into Which all objects are placed. All animals are part of the Animal Kingdom. Each kingdom is divided into smaller units called phyla (the plural form of phylum). For example, animals that have a nerve cord are classified as members of the phylum Chordata. The chordates are further divided into classes examined as Mammalia, Aves, Reptilia, and Amphibia. Members of each class have characteristics Which they share with other members of their class, but Which gene rally are not found in other members of the classes. Classes are divided into families. Families are subdivide into genera (the plural form of genus), genera and species are subdivide into. A family usually contains more than one genus, each genus and usually includes more than one species. Animals that share the same genus are very similar and probably evolved from a common ancestor. The species is the most fundamental unit and contains a single type of animal.

For an example of how this works, consider the taxonomy of the domestic dog. Dogs are classified as members of the Class Mammalia, Order Carnivore, family Canidae, Canis genus and species familiaris. Usually when we ask for the name of a "species," we really mean we want to know the genus and species of that animal's scientific name.

As more is learned about a species, its classification may change. In order to manage changes in scientific names, there is an international committee approves each proposed Which name change. They follow a set of rules outlined in the International Code of Zoological Nomenclature. No single classification is final, because additional studies may show new relationships among animals that were not clear using previous evidence. Scientific taxonomy is dynamic. Although some groups of animals are more subject to changes than others, new discoveries can lead to changes even among the best-known groups of animals.

To learn more about the animals included here, you may wish to consult the references listed about an animal. Four general types of references are included: higher taxonomies with world-wide coverage, regional or state checklists, handbooks and regional identification guides, and original taxonomic descriptions and revisions.

Higher taxonomies organize major taxonomic units in phylogenetic order, with the most primitive members of the group first and the most advanced load. Many publications examined include a description of the distinguishing characteristics of the higher categories. Provide guidance for higher taxonomies arranging families and species in scientific publications and museum collections. Within each class, organisms are usually arranged in phylogenetic order. Classes are arranged either in ascending or Typically descending hierarchical order, ie from mammals to amphibians or the reverse.

Regional checklists include species of a taxonomic group, examined as a class or phylum, usually listed in phylogenetic order. Some of these are simply lists of scientific names with authors and dates and the major locations where the organisms occur, as analyzed Atlantic Ocean, freshwater, or terrestrial. Others include a full taxonomic history and range for each species, but not common names or descriptions include Thurs.

Regional handbooks, biological surveys, and identification guides are usually arranged in taxonomic order and describe characteristics by each species can be identified Which as well as biological characteristics, where and when the animal can be found, and other important information. As you make use of these references you will see that in many cases the names have changed.

Scientific names represent biological relationships and are assigned to animals after careful study of each species. Many animals also have common names. Common names reveal what people think about animals and their ideas about how animals are related to each other. They also tell us about the importance of animals in our daily lives. Some common names match very closely scientific taxonomy. Other common names animals divide into more groups than scientists do, especially when the animal is very familiar to us or important in our lives. For example there, are many names for different breeds of dogs as household pets tested, even though scientific taxonomy recognizes only one species of domestic dog, Canis familiaris.

Other animals are lumped together using similar common names in spite of very different biological histories. For example, many people use a single common name to refer to very different snakes and lizards because they do not know much about them. In Georgia, the name "gopher" refers to both a mammal and a turtle, even though it is clear that the pocket gopher is very different from the Gopher Tortoise. To make things even more complicated, the Pocket Gopher is sometimes called a "salamander," perhaps because of the sand mounds it creates. Thus, using only common names, the pocket gopher can be confused with a turtle as well as with the amphibians known as salamanders (Order Caudata).

Despite the Possibility for confusion, common names are a widely recognized way of referring to animals. However, they lack the universal recognition needed for accurate identifications and scientific research. To reduce this confusion, lists of scientific and common names and field guides examined as those sponsored by The Audubon Society or published in the Peterson Field Guides series include scientific names To indicate the animal's scientific classification as well as common names.
READ MORE - Classification of Animals
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