ammocoete

zoology

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June 18, 2026

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The ammocoete is the larval stage of lampreys, which are primitive, jawless vertebrates belonging to the class Agnatha. These larvae are blind, wormlike, and burrow in silt. They possess rudimentary eyes and feed on microorganisms filtered from the water they draw in for respiration. After approximately three years, the ammocoete undergoes a significant metamorphosis. During this transformation, their eyes develop, their mouth develops into a sucking disk, and their fins grow. Once metamorphosis is complete, they typically transition to an adult stage, often becoming parasitic by attaching to other fish to feed on their blood and tissues.123

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chordate
Digestion and nutrition
…the vertebrates in the “ammocoetes” larva stage of the primitive jawless fish called the lamprey. The difference is that the food consists of somewhat larger particles that have been deposited on the bottom (detritus), and, instead of the feeding current being driven by cilia, the pharyngeal musculature pumps water…
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…the vertebrates in the “ammocoetes” larva stage of the primitive jawless fish called the lamprey. The difference is that the food consists of somewhat larger particles that have been deposited on the bottom (detritus), and, instead of the feeding current being driven by cilia, the pharyngeal musculature pumps water…
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agnathan
General features
The egg hatches into an ammocoete larva—a blind, wormlike animal that burrows in silt. The larva’s mouth is overhung by a hoodlike upper lip that protrudes above the surface of the silt. A continuous stream of water passes in through the mouth and out through the seven pairs of gills.…
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The egg hatches into an ammocoete larva—a blind, wormlike animal that burrows in silt. The larva’s mouth is overhung by a hoodlike upper lip that protrudes above the surface of the silt. A continuous stream of water passes in through the mouth and out through the seven pairs of gills.…
Read More