Taxonomic Classification of the Dolphin: Data and Population

The Taxonomic classification of the dolphin Has been problematic, especially for species of the genus Delphinus, Tursiops and Stenella.

The frequent lack of correspondence between the morphological and genetic differentiation in these species raises questions about the mechanisms responsible for its evolution. Delphinus species have a worldwide distribution and show a high degree of morphological variation.

Taxonomy of the Dolphin

Two distinct morphotypes, with long and short sprues, have been considered different species called D. capensis and D. delphis, respectively.

However, the genetic differentiation between these two forms has only been demonstrated in the Pacific. Samples were analyzed from eight different geographic regions, including two morphologically defined populations with a long peak shape, and were compared with populations from the North East Pacific.

A high differentiation was found between the populations described as long peak rather than the expected monophyly, suggesting that these populations may have evolved from independent events converging on the same morphotype.

Low genetic differentiation was observed among short peak populations along a large geographic scale. We interpret these phylogeographic patterns in the context of life history and the structure of the population in related species.

Classification of dolphins

Chinese River Dolphin

  • Animalia Kingdom
  • Phylum o Filo: Chordata
  • Class: Mammalia
  • Subclass: Eutheria
  • Order: Cetacea
  • Suborder: Odontoceti
  • Family: Lipotidae
  • Genus: Lipotes
  • Species: L. Vexillifer

Bottlenose dolphin

  • Kingdom: Animalia (Animals)
  • Phylum the Phylum: Chordata (chordata)
  • Class: Mammals
  • Subclass: Euthería
  • Order: Cetacea (cetaceans)
  • Suborder: Odontoceti (Odontocetes)
  • Family: Delphinidae (Marine The Dolphins)
  • Genre: Tursiops
  • Species: Truncatus

Most dolphins, including Tursiops truncatus, are cetaceans. The Cetacean order includes whales, dolphins, and porpoises.

Cetaceans are the mammals best adapted to aquatic life. The cetacean order is further divided into two suborders: Odontoceti (toothed whales) and misticetos.

The misticetos do not have teeth but they have plates suspended in the ceiling of their mouth and they have two nasal openings. Odontocetes (which include bottlenose dolphins) have between 2 and 250 teeth and a single nasal opening.

Taxonomic notes

Until 1994, all the world's common dolphins were classified as a single species: D. delphis. However, it is now known that there are at least two species within the genus: Common Dolphins (D. delphis) and Long Peaks (D. capensis) (Heyning and Perrin 1994).

In the Black Sea there is also a distinct short-spike form, whose taxonomic status has not been sufficiently clarified (however, it is presently believed to be a subspecies of D. delphis ponticus Amaha, 1994).

Geographical range

The short-beaked common dolphin is an oceanic species that is widely distributed in tropical temperate to cool temperate waters of the Atlantic and Pacific oceans, from coastal waters to thousands of miles offshore.

They are regularly seen in some closed seas, such as the Sea of ​​Okhotsk and the Sea of ​​Japan, and there are separate subpopulations in the Mediterranean and Black Seas.

Short-spout common dolphins can be found in parts of the Indian Ocean around southern Africa and southern Australia.

Countries where they are

Albania, Algeria; Argentina; Honduras; Ireland; Israel; Italy; Japan; Republic of Korea, Democratic People's Republic of; Korea, Republic of Lebanon, Libya, Malta, Mauritania; Mexico, Monaco, Montenegro, Morocco, Namibia, Netherlands, New Caledonia, New Zealand, Nicaragua, Norway, Palestinian Territory, Occupied, Panama; Peru, Poland, Portugal, Romania, Russian Federation, Saint Bartholomew, Senegal, Slovenia, South Africa, Spain; Syrian Arab Republic, Tunisia, Turkey, Ukraine, United Kingdom, United States, Western Sahara. Australia, Belgium; Bosnia and Herzegovina; Brazil, Bulgaria, Canada, Chile, China, Colombia; Venezuela, Costa Rica; Croatia, Cyprus, Denmark, Ecuador, Egypt, El Salvador, France, Gabon, Gambia, Georgia, Germany, Gibraltar, Greece; Guatemala; Guinea; Guinea-Bissau;

Population

This is a very abundant species, with many estimates available for the various areas it inhabits.

In the Pacific, 2,963,000 were estimated and an average of 352,000 was estimated for the west coast of the United States from surveys between 1991 and 2005.

In California, common dolphins show seasonal and interannual changes in abundance due to changes in distribution.

In the Atlantic, European continental shelf life was estimated at 63,400 in 2005. West of the Bay of Biscay, in 1993, 62,000 common dolphins were estimated. In the western North Atlantic, it is estimated that there are 121,000 dolphins.

In the western Mediterranean, abundance has been estimated at 19,400. The most common species in the Mediterranean Sea, the short-toed common dolphin has experienced a widespread and major decline over the last 30-40 years.

There were dramatic negative trends in parts of the central Mediterranean, particularly in the northern Adriatic Sea and the eastern Ionian Sea.

Recent genetic studies indicate that population structure in the Mediterranean reflects differences in the pattern of distribution and habitat use by common dolphins in the eastern (where the species is predominantly coastal) and western (where it is predominantly pelagic) dolphins.

Genetic exchange between common short-sea dolphins of the Mediterranean Sea and the Atlantic Ocean, as it occurs, seems to involve predominantly the animals of the Alboran Sea.

The size of the population in the Black Sea is unknown. Some studies suggest that the current population size is between 10,000 and 100,000.

In the mid-1960s, the Black Sea sub-population declined due to long-term over-exploitation, and a 70% reduction was deducted.

However, directed catches continued until 1983, when cetacean hunting finally ceased. The population has not recovered.

Facts about the dolphin

  • Animalia Kingdom
  • Filo: Chordata
  • Class: Mammalia
  • Order: Cetaceans
  • Family: Delphinidae
  • Scientific Name: Delphinus Delphis
  • Type: Mammals
  • Diet: Carnivore
  • Size: From 2 meters to 4 meters
  • Weight: 100kg - 300kg
  • Maximum speed at swimming: 40km / h
  • Shelf life: From 20 to 45 years
  • Book Condition: Very Good.
  • Color: Black, white, gray, pink
  • Skin Type: Soft
  • Favorite Food: Fish
  • Habitat: Temperate coastal waters, harbors and bays
  • Average layer size: 1
  • Main Preserve: Fish, crab, squid
  • Predators: Humans, sharks and killer whales
  • Distinctive Features: Rounded back and striped skin

References

  1. A-Z Animals Editors. (2008-2017). Dolphin 10-3-2017, retrieved from a-z-animals.com
  2. Hammond, P.S., Bearzi, G., Bjørge, A., Forney, K., Karczmarski, L., Kasuya, T., Perrin, W.F., Scott, M.D., Wang, J.Y., Wells, R.S. & Wilson, B. (2008). Delphinus delphis. The IUCN Red List of Threatened Species 2008. Retrieved from.iucnredlist.org.
  3. Natoli, A. (2006). Taxonomic Classification for Dolphins. 10-3-2017, retrieved from ncbi.nlm.nih.gov.


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