Scalidophora

Body parts and anatomy of a Scalidophoriden.

The Scalidophora (Size: Skaliden bearing ) is a rank -less taxon in the three strains of invertebrates are combined, the Priapswürmer ( Priapulida ), the corset animals ( Loricifera ) and the Hakenrüssler ( Kinorhyncha ). All species of the group are ground-dwelling marine animals.

Features

The Scalidophora have a body that can be divided into three sections, the front body, called an Introvert, the "neck" and the trunk or rear body as a common feature.

The Introvert is formed by an eversible proboscis, with the help of which Scalidophora can move and also carries the sense organs. He is covered with special scales, the Skaliden. Each Skalide contains sensory cells, is hollow and terminates in a terminal pore. The mobility of the Introvert is ensured by retractor muscles that are arranged in two rings and attach to long ectoderm. At the top of Introverts is the mouth, which is surrounded by sensory cells, directly behind it is the brain. The Introvert is radially symmetrical. The outer integument ( Endokutikula ) contains chitin.

Legend for the image:

• Body portions (right): mc = mouth cone
• In = Introvert
• Nk = neck
• Tk = hull

• Rb = annular ganglion
• Sc = Skalide
• Ng = ganglion
• Ir = Introvertretraktoren
• Vn = ventral nerve cord
• Gn = gonad
• Gt = intestine
• Pn = protonephridia
• Cg = Caudalganglion
• Ca = bristles

Most types of Scalidophora are very small, corset creatures reach lengths of only 100 to about 500 microns, Hakenrüssler be between 200 micrometers and a millimeter and Priapswürmer between 0.05 centimeters and 39 centimeters long.

The Scalidophora can be since the Cambrian fossil evidence (eg Markuelia ) and just make the rest of a once much larger species group dar.