Knowra Chaetognatha Chaetognatha Chaetognatha is a phylum of marine predatory invertebrates, commonly called arrow worms. Its members have transparent bodies and grasping spines around the mouth.
Chaetognath morphology : The body structure of arrow worms, including their fins, trunk, tail, and grasping spines. These features define the phylum’s distinctive transparent, streamlined form.
Marine food web : A network of feeding relationships among organisms in the ocean. Arrow worms link small planktonic prey to larger predators.
Copepod : A small crustacean common in marine and freshwater plankton. Copepods are frequent prey for arrow worms and major competitors in plankton food webs.
Chaetognath phylogeny : The evolutionary relationships of arrow worms to other animals and within their phylum. Their position among animal lineages has shifted across competing molecular analyses.
Chaetognath grasping spines : Curved chitinous structures beside the mouth that seize prey in arrow worms. They are the defining tools used to capture prey.
Zooplankton : Drifting animals and animal-like organisms in aquatic environments. Arrow worms are predatory members of plankton communities.
Cnidaria : An animal phylum that includes jellyfish, corals, and sea anemones. Cnidarians are gelatinous marine predators often compared with arrow worms.
Animal phylogeny : The evolutionary history and relationships of animal groups. Chaetognaths remain a consequential test case for reconstructing early animal evolution.
Chaetognath locomotion : The swimming and hovering movements of arrow worms, produced by undulations of the body and tail. Their streamlined shape and fins support movement through the water column.
Mesopelagic zone : The ocean layer roughly 200 to 1,000 meters below the surface, where sunlight is dim. Many arrow worms inhabit this layer and prey on its plankton.
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