Author:
Qjure
Book:
Qjurious
Type:
Info
Chapter:
4-320.00.00
Platyzoa
Synonym: Rouphozoa
Zoology
They have bilateral symmetry, so they have and up and down side and a front and backside; this makes the development of a head with senses possible.
They have 3 germ layers: endoderm, ectoderm and mesoderm; they triploblast.
Gnatifera: srmall, flat, unsegmented animals; protostome; no respiration system; no circulation system; flat body or parasitic lifestyle.
Taxonomy
Platyzoa is proposed by Thomas Cavalier-Smith in 1998. He included in Platyzoa the phylum Platyhelminthes, flatworms, and a new phylum, the Acanthognatha, several phyla of microscopic animals. More recently it has been described as the Rouphozoa and the Gnathifera.
Rouphozoa, Platyhelminthes and Gastrotricha, are acoelomate.
Gnathifera: have a pseudocoel; characteristic structure of their jaws and pharynx.
Gnathifera
Gnathostomulida
Micrognathozoa
Chaetognatha
Rotifera
Seisonida
Acanthocephala
Bdelloidea
Monogononta
Platytrochozoa
Rouphozoa, acoelomate
Platyhelminthes, flatworms
Gastrotricha
Gnathifera
Syndermata
Rotifera, no flat, round
Seisonida
Acanthocephala, parasitic
Gnathostomulida
Micrognathozoa
Cycliophora