Macrostomum Flatworm

Macrostomum lignano is a tiny, transparent free-living flatworm from the coastal sands of the northern Adriatic. It is a model for regeneration, stem cells and the evolution of mating behavior.

🧬 Field Guide Specimen: Open Macrostomum Flatworm in the CRV Science Field Guide to log the specimen, see its place among the Lophotrochozoa lineages in the Cladogram Explorer, and test your recall in the Red List conservation game.

The worm is about a millimeter long, and its transparency lets researchers watch stem cells and organs in the living animal. It can regenerate the head and tail from fragments and shrink when starved, making it a useful model for studying stem cells and aging. See Stem cell biology and regenerative medicine.

Like Bedford's flatworm, Macrostomum is a hermaphrodite that can inject sperm through the skin of its partner. After mating, individuals may use a suck behavior to remove sperm received, an example of sexual conflict that researchers study in the lab.

The genome was sequenced in 2018, and techniques for gene knockdown and transgenesis have been developed, making the worm a growing model.

• Bedford's Flatworm — hypodermic insemination
• Planarian — another regenerating flatworm