Nereis succinea (common clam worm) in Epitoky stage

Epitoky is a form of reproduction observed for polychaete marine worms. The genus Nereis is one of many categorized within the class Polychaete. ... For other uses, see Reproduction (disambiguation) Reproduction is the biological process by which new individual organisms are produced. ... Subclasses Palpata Scoleoida The Polychaeta or polychaetes are a class of annelid worms, generally marine. ...

The worms undergo a partial or complete transformaiton into an epitoke, a pelagic morph capable of sexual reproduction. The pelagic zone is the part of the open sea or ocean comprising the water column, i. ... A Morph, meaning form (from the Latin morpha), is a zoological term that descibes local populations or subpopulations of a single species of animal that may or may not be phenotypically distinct from the larger population as a whole. ... Sexual reproduction is a type of reproduction that results in increasing genetic diversity of the offspring. ...

Often an epitoke is the posterior part of the worm, that separates from the anterior part (called atoke) and gametes are produced inside. Gametes, from the ancient Greek γαμετης (spouse), are the specialized germ cells that come together during fertilization (conception) in organisms that reproduce sexually. ...

Epitoke may also form by asexual budding from the posterior. // A new organism is formed by the protrusion of part of another organism. ...

In the third form, characteristic, e.g., to Nereidae, the whole worm becomes epitoke: sperm and ova form in its posterior. This form may be accompanied by partial or full degeneracy of digestive organs (causing the animal to die quickly) and enhancement of motoric and sensory organs; in particular, while normally crawling, the worm develops swimming appendages: broad parapodia with paddle-shaped chaetae. Digestion is the process whereby a biological entity processes a substance, in order to chemically convert the substance into nutrients. ... Parapodia (almost feet) are paired lateral outgrowths, bearing bristles known as chaetae. ... Chatae (singular cheta) are bristles or seta found on annelid worms such as the earthworm. ...

Epitokes swim to the surface rich in plankton, where the gametes are released by eruption of the body, and the larvae are hatched to live swimming in plankton. This action is often synchronized with moon cycles, and epitokes swim in swarms. This article or section does not cite its references or sources. ... A larva (Latin; plural larvae) is a juvenile form of animal with indirect development, undergoing metamorphosis (for example, insects or amphibians). ...

In the past it was thought that epitokes were separate species from polychaete marine worms. Subclasses Palpata Scoleoida The Polychaeta or polychaetes are a class of annelid worms, generally marine. ...