HOW MANY SPECIES OF JELLYFISH ARE IN THE WORLD?

Jul 17, 2023

Jellyfish are mesmerizing creatures that are found in oceans all over the world. They are known for their translucent bodies, long tentacles, and their ability to glow in the dark. But how many types of jellyfish are there in the world? In this blog post, we will explore the different types of jellyfish and their unique characteristics.

There are over 3,000 species of jellyfish that have been identified, and new species are being discovered all the time. These species are grouped into several different categories based on their physical characteristics and behaviour. Here are the main categories of jellyfish:

1. Scyphozoans: This is the largest group of jellyfish, and includes many of the well-known species such as the moon jellyfish, the lion’s mane jellyfish, and the Pacific sea nettle. Scyphozoans are characterized by their bell-shaped bodies and long, flowing tentacles. They are usually found in coastal waters, but can also be found in open ocean environments.

1. Scyphozoans: This is the largest group of jellyfish, and includes many of the well-known species such as the moon jellyfish, the lion’s mane jellyfish, and the Pacific sea nettle. Scyphozoans are characterized by their bell-shaped bodies and long, flowing tentacles. They are usually found in coastal waters, but can also be found in open ocean environments.

Moon Jellyfish (Aurelia aurita)
Crystal jellyfish (Aequorea sp.)

2. Hydrozoans: This group includes many different types of jellyfish, including the Portuguese man o’ war and the immortal jellyfish. Hydrozoans are characterized by their small size and their ability to form colonies. They can be found in both freshwater and saltwater environments.

3. Cubozoans: This group includes the box jellyfish, which is known for its highly toxic venom. Cubozoans are characterized by their cube-shaped bells and their short, stocky tentacles. They are usually found in warm, shallow waters, and are most commonly found in the Pacific and Indian Oceans.

4. Staurozoans: This group includes the stalked jellyfish, which are characterized by their ability to attach themselves to hard surfaces such as rocks and shells. Staurozoans are usually found in shallow waters, and are most commonly found in the Atlantic Ocean.

5. Ctenophores: Ctenophora taxonomically is not a jellyfish, but is usually included in jellyfish in general speaking. They are classified in a separate phylum of marine animals commonly known as comb jellies or sea gooseberries. Although they share some similarities with jellyfish, such as being gelatinous and planktonic, comb jellies are distinct from jellyfish in several ways. Comb jellies have eight rows of ciliary combs that they use for locomotion, while jellyfish typically move by contracting their bell-shaped bodies. Additionally, comb jellies lack nematocysts (the stinging cells found in jellyfish) and instead capture prey using sticky cells called colloblasts. Finally, comb jellies have a more complex digestive system than jellyfish, with a complete gut that includes both a mouth and an anus.

Box jellyfish (Carybdea brevipedalia)
Ctenophore: Beloe sp.

While these are the main categories of jellyfish, there are many variations and sub-species that exist within each category. For example, within the Scyphozoan category, there are many different types of moon jellyfish, including Aurelia aurita, Aurelia labiata, Aurelia limbata, and Aurelia coerulea.

Each type of jellyfish has its own unique characteristics. For example, the lion’s mane jellyfish, which is a type of Scyphozoan, is known for its long, flowing tentacles and its bright red color. It can grow up to 2 meters in diameter, and its tentacles can be up to 30 meters long.

Lion’s mane jellyfish (Cyanea capillata)

The Portuguese man o’ war, which is a type of Hydrozoan, is not actually a jellyfish, but is often mistaken for one due to its similar appearance. It is made up of a colony of polyps that work together to form a floating, stinging organism. Its tentacles can be up to 50 meters long, and its sting can be extremely painful and even deadly.

The box jellyfish, which is a type of Cubozoan, is one of the most dangerous jellyfish in the world. Its tentacles contain a potent venom that can cause heart failure and death in humans. It is usually found in warm, shallow waters, and is most commonly found in the waters around Australia.

To sum up, jellyfish are a fascinating and diverse group of creatures that are found in oceans all over the world. While there are over 3,000 species of jellyfish that have been identified, they can be grouped into several main categories based on their physical characteristics and behaviour. Each type of jellyfish has its own unique characteristics, and studying them can help us better understand the ocean ecosystems in which they live.

All the jellyfish-related words

There is a a lot of jellyfish-related terminology that gets thrown around often when it comes to keeping and breeding jellyfish and it can get very confusing very quickly. The purpose of this post is to provide a simple and quick explanation of all the different words we use, and to give you a reference point you can come back to if you forget

Medusa

this refers to the final stage of the life cycle of a jellyfish. This is what we would traditionally imagine when we think of a jellyfish, with its familiar round shape and tentacles. The plural of a Medusa is Medusae.

A Marble jelly in medusa form

A moon jelly Ephyra

Ephyra

An Ephyra is the stage of a jellyfish life cycle that occurs right after a jelly pops off a  polyp. They are essentially baby Medusae. The primary difference between a Medusa and Ephyra is that generally they are not rounded, but more star shaped. They also don’t have visible tentacles or Oral arms. The plural of Ephyra is Ephyrae

Polyp

A polyp is a stalk-like structure that attaches itself to substrate. A polyp can duplicate itself to create a genetically identical clone. This can eventually create a colony of polyps. Polyps can also strobilate and create new Ephyrae.

A Marble jelly in medusa form