nematogen phase

biology

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July 1, 2026

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The nematogen phase is a stage in the life cycle of certain parasitic animals called mesozoans, specifically those in the order Dicyemida. These organisms parasitize marine invertebrates, such as squids and octopuses.12

During the nematogen phase, which occurs in the immature host, specialized cells called axoblasts (or agametes) give rise to new wormlike individuals that are similar to the parent organism. These new individuals remain within the same host, increasing the parasite population. This asexual reproduction is a key characteristic of the nematogen phase, contrasting with the subsequent rhombogen phase where sexual reproduction occurs. The simple structure of mesozoans may be primitive or a result of their parasitic lifestyle.12

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mesozoan
During a phase called the nematogen phase, axoblast cells (also called agametes) give rise to wormlike individuals similar to their parents. These remain in the same host, thus increasing the parasite population within the host’s kidney. In the next phase, known as the rhombogen phase, a few axoblasts differentiate into…
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During a phase called the nematogen phase, axoblast cells (also called agametes) give rise to wormlike individuals similar to their parents. These remain in the same host, thus increasing the parasite population within the host’s kidney. In the next phase, known as the rhombogen phase, a few axoblasts differentiate into…
Read More