TRIOPS: THE TANKS OF THE PAST TRIOPS: THE TANKS OF THE PAST

Matthew Lam

Triops, also known as tadpole shrimps, are a genus of freshwater crustaceans. The word "triop" means "three eyes" in Greek because triops have two compound eyes as well as a simple organ called an ocellus eye. Here, I will discuss four species of triops.

This is the triops longicaldectus. It is also referred to as the American species of shellfish as it often occurs in South and North America, when the climate is right. Around 10 to 40mm long, this species of triop is capable of sexual reproduction, but females are also capable of parthenogenesis, which is a form of reproduction in which an egg can develop into an embryo without being fertilised by a sperm.

This is the triops cancriformis. Found in Europe, more specifically in Bavaria, this species of triop first appeared in the Triassic, earlier than any of the other triop species. There are also people who even say that it is the oldest animal on Earth. This tadpole shrimp is very frugal when it comes to temperatures. They grow best at 19-24°C. Due to the slightly cooler temperatures, this triop grows much more slowly than other triops.

This is the triops granarius. It originated from Asia, but now they can also be found in other continents such as Africa and Europe, making it the triop species with the largest geographical distribution. Due to this, it has also been indicated that, as presently defined, it is a species complex. After the water has dried up in its habitat, it is exposed to desiccation and extreme temperatures. To withstand this environment, their eggs enter anhydrobiosis, in which they lose all of their water and increase only very little in size. The eggs can hatch up to 20 years later.

This is the triops australiensis, sometimes referred to as the shield shrimp. It inhabits temporary pools of water in the arid regions of the Australian outback. When desiccated pools fill with water, the resting eggs hatch into nauplii and rapidly develop to adulthood. Reproduction follows within a few weeks of hatching. Adults can achieve a maximum size of around 3 inches (7.6 cm), which is considered large for a tadpole shrimp.