Taxonomy is a field of science that involves classifying and naming species. It's integral to wildlife conservation, providing the bedrock for our understanding of sharks. It’s vital to know what species are and how they’re related, so we can understand their role within the ecosystem.

Up until the 1600’s animals and plants were referred to by their common names. But common names vary within the same language, as well as across different languages. So the system was confusing and made it difficult for scientists to discuss species.

In the 1600's, a Swedish scientist called Carl Linneaus invented a new system. Creating order from chaos. Although this has altered over time, the concept has remained the same and is still used today.

The system is complex but the main classification ranks are:

KINGDOM

Organisms are grouped under very wide categories, such as Animal or Plant. Sharks belong to the Kingdom Animalia.

PHYLUM

Divides Kingdoms into smaller groups that share similar characteristics. Sharks belong to the Phylum Chordata and the Sub-phylum Vertebrata. This means they have a spinal chord, notochord and a backbone (vertebrae).

CLASS

Includes the more familiar groups: birds, mammals, reptiles and amphibians. Sharks belong to the Class Chondrichthyes. This includes all fish that have a skeleton made of cartilage. They're further divided into two Sub-classes. Elasmobranchii (sharks, skates and rays) and Holocephali (chimaera).

ORDER

Identification starts to get more complicated. The Elasmobranchii are divided into 2 super-orders. The extinct Cladoselachimorpha and the Euselachii, which has 13 Orders. Only 10 of these exist today:

  • Skates and Rays (Rajiformes) - are generally flattened in shape due to their enlarged pectoral fins (or wings). They have 5 pairs of gills on the underside of the body rather than on the side as with sharks.

  • Frilled & Cow Sharks (Hexanchiformes) - these are the most primitive sharks alive today. They have 6 or 7 pairs of gills).

  • Bramble Sharks (Echinorhiniformes) - are large, sluggish, deepwater sharks. There are only 2 species in this entire Family.

  • Dogfish Sharks (Squaliformes) - have a short mouth with a long snout and 5 pairs of gills.

  • Sawsharks (Pristiophoriformes) - have a long saw-like snout, which they use to stun prey and defend themselves against predators. They have either 5 or 6 pairs of gills.

  • Angelsharks (Squatiniformes) - with a flattened body these sharks may look more like rays, but their gills are on the side of their body.

  • Bullhead Sharks (Heterodontiformes) - have 5 pairs of gills and fin spines. Includes Port Jackson Sharks.

  • Mackerel Sharks (Lamniformes) - have a long snout and mouth, with 5 pairs of gills. Includes the White Shark, Basking Shark and Shortfin Mako.

  • Carpetsharks (Orectolobiformes) - have a short snout and 5 pairs of gills. Most have barbels near their mouth, which they use to taste food under the seabed. Includes wobbegongs, blind sharks and the Whale Shark.

  • Ground Sharks (Carcharhiniformes) - have a wide mouth with sharp-edged teeth and 5 pairs of gills. They also have a movable membrane over their eyes to protect them when they're feeding. Includes reef sharks and the hammerheads.

FAMILY

Includes species that are closely related. For example apes, monkeys and humans belong to the Family Primates. Some Families are extremely large while others contain only a few members. For example Mackerel Sharks (Lamniformes) houses 7 families. This includes the Basking Shark (Cetorhinidae), which has only 1 species, and the Thresher Shark (Alopiiidae), which has 3.

GENUS

The first word of a species' scientific name is the genus. The Shortfin Mako's scientific name is Isurus oxyrinchus and the Longfin Mako is Isurus paucus. Isurus is the Genus and shows us that these 2 species are closely related.

SPECIES

A group of animals or plants that are capable of producing fertile offspring. For example the White Shark. Whose scientific name is Carcharodon carcharias.

So what’s in a name? Quite a lot. The species name gives us valuable information about the animal and it’s relationships with the rest of the animal kingdom.

Angelshark © Tom Young

An example of a taxonomic hierarchy is:

Kingdom: Animalia
Phylum: Chordata
Class: Chrondrichthyes
Order: Squatiniformes
Family: Squatinidae
Genus: Squatina
Species: Squatina squatina (Angelshark)

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