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Transcript of Phylum Priapula
By: Alexander Perez
What is a Phylum Priapula?
A Priapula or Priapulida is a small phylum of small worm like animals
They are yellow or brown carnivorous worms.
There are 16 species of priapulas
They range from 0.5 mm (Tubuluchus species) to around 200 mm (Priapulus species)
Where do they
In most seas, both tropical and polar, from shallow to very deep waters.
They live in or on the sea floor.
Where did their name originate?
Originally, scientists named them Priapulida because they looked like a human penis, but they actually look more like a cactus worm
What is their body like?
The Priapula body is covered by a thin cuticle and has two parts; 1) the prosoma and 2) the trunk.
1) What is the prosoma?
The prosoma has a mouth at the front-end for feeding that has adhesive to easily capture prey.
It is sometimes called an “introvert” because the prosoma can be drawn into the trunk
The mouth has 5 spines called “scalids” around its opening which provide flexibility and better reflexes for capturing prey.
The mouth extends during feeding with their oral teeth being used to seize prey
What is their body like? -Continuation
What is the trunk?
The trunk often has spines or scales and may have caudal appendages (which look like a bundle of worms at the end of the animals body).
These are believed to be their respiratory system
The trunk has 20 to 30 external annuli (superficial rings)
Other Interesting Facts!
They have different sexes and normally there is only one ovary or one testis;
Eggs and sperm are released into the sea for fertilization
Body has more than two cell layers, tissues and organs.
They have a complete gut with a mouth and anus;
Excretion (removal of waste) is by means of protonephridia (a hollow cell in the irexcretory system )
They are believed to be predators feeding on smaller worms they find in the mud.
Some are deposit feeders which consume bacteria
The alimentary canal is straight, consisting of an eversible pharynx, an intestine, and a short rectum. The pharynx is muscular and lined by teeth. The anus is terminal
There are no vascular or respiratory systems
They feed on slow-moving invertebrates, such as polychaete worms.
The nervous system consists of a nerve ring around the pharynx and a prominent cord running the length of the body with ganglia and longitudinal and transversal neurites consistent with an orthogonal organisation.