Select the search type
 
  • Site
  • Web
Search
You are here:   animal list > Sagitta tasmanica and other chaetognaths

Chaetognatha

Minimize

                   CHAETOGNATHA

                          Arrow Worms

Michael Le Roux (2011)

Fact Sheet

Overview

General Information


Physical Description

Body


Identification Resources


Ecology

Distribution


Life History & Behaviour

Behaviour


Reproduction


Evolution & Systematics

Fossil History


Systematics or Phylogenetics


Morphology and Physiology

External Morphology


Internal Anatomy


Molecular Biology & Genetics

Nucleotide Sequences


Molecular Biology


Conservation

Trends


Threats


Wikipedia


References & More Information

Content Partners


Bibliographies


Names & Taxonomy

Species List


Common Names


Page Statistics

Content Summary

Internal Anatomy

Digestion (Foster 2006):

Chaetognaths contain a simple intestine that runs the length of the trunk (fig 1), and connects to the rectum which is located at the trunk-tail boundary. The expulsion of faeces is controlled by a rectal sphincter that is composed of circular muscles.

Nervous system:

Chaetognaths possess a well developed, ganglionated nervous system which is made up of six ganglia on the head and a large ventral trunk ganglion (fig 2) (Ruppert et al 2004, Foster 2006). The largest ganglion is the ventral ganglion, which is located in the trunk of chaetognaths, and acts to innervate the muscles of the trunk and coordinate swimming.

Sensory system (Foster 2006):

The sensory organs include eyes, ciliary tufts, and the ciliary loop (corona). Chaetognaths exhibit phototaxis, and it is therefore believed that it is the eyes that play a major role in this behaviour. There are lots of ciliary tufts located along the head, trunk and tail of chaetognaths. The main role of these ciliary tufts is to detect prey in the water column. It is not fully understood what the exact purpose of the ciliary loop is, however multiple roles have been suggested, and these include: excretion of metabolic wastes, chemoreception or to guide sperm to the gonopores.

Muscular system (Foster 2006):

Depending on the species in question, there are approximately 16 head muscles which assist in manoeuvring the grasping spines, teeth and mouth during feeding.


Figure 1: Dissection microscope view of the digestive tract of a stained chaetognath.


Figure 2: Dissection microscope view of the ventral ganglion of a stained chaetognath.

Images

Minimize

(2 objects, created 5/6/2011)

Album: This is a private album that is not visible to anonymous users Great Barrier Reef Invertebrates

Summary:

Date:

Album: 2012

Album: 2011

Classification

Kingdom
Animalia
Phylum
Chaetognatha
Class
Sagittoidea
Order
Aphragmophora
Family
Sagittidae
Genus
Serratosagitta

Synonyms

Sagitta serratodentata tasmanica ()
Sagitta tasmanica (Thompson, 1947)
Serratosagitta selkirki ((Faggetti, 1958))

Common Names

arrow worm