Imagine being able to regrow any of your body part, or even better; imagine cutting your body in hundreds of pieces and each of these pieces would regrow into a whole new you! 😳 Flatworms are able to do just that due to special adult stem cells present all over their bodies 🤯

These special stem cells called neoblasts can become any type of cells or organ; they can regenerate the brain, the digestive, excretory, sensory or reproductive system!

Flatworms are members of the phylum Platyhelminthes, which literally means flatworms in greek, and are part of the Turbellaria class! Flatworms can measure from a few millimetres, like those from this video, to several meters, especially in parasitic tapeworms. Parasitic worms aren’t very common in the Turbellaria class though, so there’s no worries with these cute little critters! You can swim with them as much as you want! They are mostly free-living and can be observed in freshwater habitats such as ponds, streams, lakes and spring pools.

Unlike leeches and earthworms, flatworms are unsegmented, lack respiratory and circulatory system and don’t possess an anus! This means that food and wastes arrive and are ejected by the same door 👀 Although, they do have a mouth, pharynx and some intestines!

The planarian from the second video possess auricles, small ear lobes located on the side of the head, filled with tactile and chemoreceptive cells. You may also have noticed that flatworms have little eyes, they act as photoreceptors, but they also have statocysts used for equilibrium and rheoreceptors used to sense the direction of water currents.

One classic characteristic of Turbellaria is the presence of many cilia on the epidermal layer. These cilia, aided by mucus secretion, are used for locomotion! 🚂

References:
Hickman, C. P., Roberts, L. S., Larson, A., Ober, W. C., & Garrison, C. (2015). Animal diversity. WC Brown. 169-173.

Noreña, C., Damborenea, C., & Brusa, F. (2015). Phylum Platyhelminthes. In Thorp and Covich's Freshwater Invertebrates (pp. 181-203). Academic Press.

Rink, J. C. (2013). Stem cell systems and regeneration in planaria. Development genes and evolution, 223(1), 67-84.

свернуть