Tunicates

15th July, 2023 Environment

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Context

A 500-million-year-old tunicate fossil species is recently described by researchers.
For now it is concluded that after Cambrian Explosion the modern tunicate body was established and the species observed a dramatic rise in its population on earth.

Tunicates

These are marine invertebrate species belonging to subphylum Tunicata.
A total of 3,000 species of tunicates are believed to have existed in the oceans of this planet.
Their body structure is sac or barrel like with two siphons, a tubular opening.
These siphons are used to draw and expel water, filtration of water and also help in feeding.
Though this species is invertebrate, these are considered as closest relatives of vertebrates such as fish, mammals, and people, and are connected through a tadpole-like link.
They have evolutionary history going as back as 500 million years

Lineages – mainly 2 types

Ascidiaceans –
- These are most occurring type and are commonly referred as sea squirts.
- In the beginning, these look like tadpoles and are mobile, which eventually developed to a barrel-shaped adult
- These mostly spent their adult life attached to the seafloor.
Appendicularias –
- These look like tadpoles in both the phases of life- in the beginning and when they developed as adults.
- They are not attached to seafloor their whole life and can swim freely in the upper waters.

Significance of Tunicates

Study of this species can expand our knowledge about evolutionary history of species.
It contains a chemical compound Didemnins which may be useful against viral diseases, Cancer.
- Aplidine – is found effective for many types of cancer and trial are being conducted for ascertaining the efficacy against viral diseases like Covid-19.
- Trabectedin- This is also effective against many types of cancer.
Tunicates, especially Ascidiaceans, are used as food and a part of many delicacies around the world
They can be a potential biofuel source. Researches are underway.