Marine Worms

• Types of Worms


  • Flatworms (Phylum: Platyhelminthes)
  • Ribbon Worms (Phylum Nemertea)
  • Nematodes (Phylum Nematoda)
  • Segmented Worms (Phylum Annelida)
  • Peanut Worms (Phylum Sipuncula)
  • Echiurans (Phylum Echiura)

  
• Flatworms (Phylum: Platyhelminthes)


  • Dorsoventrally flattened (flat backs and bellies)
  • Simplest animals with tissues organized into real organs and organ systems

  
• Flatworms


  • Turbellarians (free-living carnivores)
  • Flukes/Trematodes (parasites, largest group of flatworms with over 6,000 species)
  • Tapeworms/Cestodes (parasitic flatworms with long bodies consisting of repeated units)

  
• Ribbon Worms (Phylum Nemertea)

  • Complete digestive tract with mouth and anus
  • Circulatory system
  • Distinctive proboscis
  • Most common in shallow temperate waters
  • Some are nocturnal
  • Longest invertebrate (100ft)

  
• Nematodes (Phylum Nematoda)


  • Mostly small with slender, cylindrical bodies pointed at both ends
  • Body cavity filled with fluid that transports nutrients
  • Hydrostatic skeleton with layer of muscles pushing and squeezing against fluid
  • Most species are parasitic

  
• Nematodes

  • Anisakis sp.

  
• Segmented Worms (Phylum Annelida)


  • Segmentation
  • Coelom (fluid-filled body cavity) entirely surrounded by different tissue, divided by partitions corresponding to external segments
  • Coelom acts as hydrostatic skeleton

  
• Segmented Worms


  • Polychaetes (body segments with flattened extensions called parapodia)
  • Beard worms/Pogonophorans
  • Oligochaetes (small worms in mud and sand)
  • Leeches (highly specialized with suckers at each end and no parapodia)

  
• Peanut Worms (Phylum Sipuncula)


  • Soft, unsegmented bodies with coelom
  • Burrow in muddy bottoms, rocks, and corals or hide in empty shells

  
• Echiurans (Phylum Echiura)


  • Soft, unsegmented sausage-like bodies buried in mud or coral
  • Non-retractable, spoon-like or forked proboscis

  
• Echiura (Echiurans)Look like soft unsegmented sausages buried in the mud or in a coralSimilar to peanut worms in shape and size except having a non-retractable, spoon-like or forked proboscis
• Marine Worms


  • Have elongated bodies and lack any external skeleton
  • Gain support for their body from fluid contained in body compartments known as hydrostatic skeleton(a layer of muscles pushes and squeezes against fluids)
• Platyhelminthes (flatworms)


  • Show bilateral symmetry with head and posterior end
  • Have eye spots that allow them to sense differences in light intensity
  • Some are free-living while some are parasitic
• Platyhelminthes (flatworms)


  • Turbellarians (free-living carnivores)
  • Flukes (trematodes, largest group of flatworms with 6,000 species, are parasitic)
  • Tapeworms (cestodes, parasitic flatworms, live in the digestive tract of fish)
• Nemertea (Ribbon worms)


  • Have several features that indicate a more complex degree of organization
  • Digestive tract is complete (with mouth and anus)
  • Has circulatory system
  • Have proboscis
  • Common in shallow temperate waters
  • Some are nocturnal
  • Longest invertebrate (100ft.)
• Phylum Nematoda (Roundworms)


  • Adapted to live in sediments or the tissues of other organisms
  • Body is cylindrical and elongated, tapered in both ends
  • Can be scavengers, parasite (mostly), predators, or eat algae and bacteria
• Annelids (Segmented worms)


  • Are divided internally and externally into repeated segments
  • Body plan includes innovations that have been incorporated in some of the more structurally complex groups of animals (body wall is longitudinal and circular muscles for: swimming, crawling, and burrowing)
  • The skin often has bristles (setae) that can be used for locomotion, digging, or protection
  • Have complete digestive tract (with mouth and anus)
• Annelids (Segmented worms)


  • Polychaetes (each of the body segment has a pair of flattened extensions, or parapodia)
  • Beard worms or pogonophorans
  • Oligochaetes (small worms found in mud and sand)
  • Leeches (are highly specialized annelids, distinguished by a sucker at each end and no parapodia)
• Sipuncula (Peanut worms)


  • Have small, unsegmented bodies with a coelom
  • They burrow in muddy bottom, rocks, and corals, or hide in empty shells
• Echiura (Echiurans)


  • Look like soft unsegmented sausages buried in the mud or in a coral
  • Similar to peanut worms in shape and size except having a non-retractable, spoon-like or forked proboscis
• Marine Worms


  • Have elongated bodies and lack any external skeleton
  • Gain support for their body from fluid contained in body compartments known as hydrostatic skeleton(a layer of muscles pushes and squeezes against fluids)
• Platyhelminthes (flatworms)


  • Show bilateral symmetry with head and posterior end
  • Have eye spots that allow them to sense differences in light intensity
  • Some are free-living while some are parasitic
• Platyhelminthes (flatworms)


  • Turbellarians (free-living carnivores)
  • Flukes (trematodes, largest group of flatworms with 6,000 species, are parasitic)
  • Tapeworms (cestodes, parasitic flatworms, live in the digestive tract of fish)
• Nemertea (Ribbon worms)


  • Have several features that indicate a more complex degree of organization
  • Digestive tract is complete (with mouth and anus)
  • Has circulatory system
  • Have proboscis
  • Common in shallow temperate waters
  • Some are nocturnal
  • Longest invertebrate (100ft.)
• Phylum Nematoda (Roundworms)


  • Adapted to live in sediments or the tissues of other organisms
  • Body is cylindrical and elongated, tapered in both ends
  • Can be scavengers, parasite (mostly), predators, or eat algae and bacteria
• Annelids (Segmented worms)


  • Are divided internally and externally into repeated segments
  • Body plan includes innovations that have been incorporated in some of the more structurally complex groups of animals (body wall is longitudinal and circular muscles for: swimming, crawling, and burrowing)
  • The skin often has bristles (setae) that can be used for locomotion, digging, or protection
  • Have complete digestive tract (with mouth and anus)
• Annelids (Segmented worms)


  • Polychaetes (each of the body segment has a pair of flattened aqextensions, or parapodia)
  • Beard worms or pogonophorans
  • Oligochaetes (small worms found in hmud and sand)
  • Leeches (are highly specialized annelids, distinguished by a sucker at each end and no parapodia)
• Sipuncula (Peanut worms)


  • Have small, unsegmented bodies with a coelom
  • They burrow in muddy bottom, rocks, and corals, or hide in empty shells
• Echiura (Echiurans)


  • Look like soft unsegmented sausages buried in the mud or in a coral
  • Similar to peanut worms in shape and size except having a non-retractable, spoon-like or forked proboscis