Nectozoa

	Nectozoa
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Classification
	Eudiktya
	Episcleria
Distribution
	Miavegr
Time Range
	0.55 Ga - Present

Nectozoans are one of the three independently evolved animal-like kingdoms on Miavegr . Living Nectozoans are all aquatic and can be found across all Miavegr.

Description

Nectozoans have a reproducing cycle with a main haploïd organism that is parasitized by diploïd tissues. The haploïd organism is basally a tubular plasmodium with one opening, but more complex tissues evolved (mainly in Eunectozoa).

Reproduction

The adult haploid organism has diploid gonads, these can produce gametes. In most species these can be differentiated in male and female but they can be undifferentiated (both gametes develop as female). After being liberated in the water column female gametes undergo mitosis and develop in a small plasmodium; while male gametes remain as a ciliated single cell. In Eunectozoans the female gamete already undergoes divisions inside the gonads. Then somewhere in the development of the plasmodium, it is fecundated by a male gamete. Some Nectozoans are fecundated early in their development and they can further their development only if they meet a male gamete, for example in some cases the female gamete is fecundated internally and is liberated by the gonads only after. Others can develop in a full organism before being fecundated. The diploid cell usually develops to form the gonads and usually other essential parts of the adult organism. Nevertheless some Nectozoans have completely lost their gonads and fully reproduce asexually.

Evolution

Nectozoans evolved in the open seas of the Arizimian (beginning of the Neopoïkiloic). Their history begins from earlier Episclerian colonies that thrived by the end of the Mesopoïkiloic. These formed benthic diploïd stromatolithes and had a secondary free floating haploïd plasmodium phase. This free floating phase lost its Lithochondria and therefore its capability to fix carbonates. In some of these organisms the haploïd phase became more and more important, until the sessile diploid organism persisted only as a parasite of the free floating haploid. The nearest common ancestor of Nectozoans evolved from these, it was a simple plasmodium 1cm long with a single opening in the front, it fed by filtration thanks to its ciliated mouth. It could digest by liberating enzymes in its internal cavity.