Platynereis is a genus of segmented worms in the family ragworms. Individuals can grow to 100 mm. They have parental care. Reproduction is semelparous. They are sessile animals.
Definition: A tract of alluvium formed at the mouth of a river where the deposition ofsome of its load exceeds its rate of removal, crossed by the divergent channels (distributaries) of the river.
Definition: The marine benthic biome (benthic meaning 'bottom') encompasses the seafloor and includes such areas as shores, littoral or intertidal areas, marine coral reefs, and the deep seabed.