Gastrotrich 28-III
PROTOSTOMIA
Lophotrochozoa
 
 
A gastrotrich on a filament of algae.
[Photo © www.micrographia.com]



Chapter Outline
  1. Description of Protostomia
  2. Classification of Protostomia
  3. Lophotrochozoa
  4. Annelida
  5. Mollusca
  6. Gnathifera
  7. Ecdysozoa
  8. Panarthropoda

Tree



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Lophotrochozoa is one of two subgroups of Spiralia. The following phyla in bold are the focus of this page. Annelida and Mollusca are in Lophotrochozoa but are large enough to warrant the following two pages.

  • Protostomia
    • Spiralia
      • Lophotrochozoa (28-III)
        • Mesozoa
          • Dicyemida - Rhombozoans
          • Orthonectida - Orthonectids
        • Platyhelminthes - Flatworms
        • Nemertea - Ribbon Worms
        • Annelida - Segmented Worms (28-IV)
        • Phoronida - Horseshoe Worms
        • Brachiopoda - Lampshells
        • Mollusca - Molluscs (28-V)
        • Bryozoa - Bryozoans
        • Entoprocta - Entoprocts
        • Cycliophora - Symbion pandora
        • Gastrotricha - Gastrotrichs
        • Acanthocephala - Thorny-Headed Worms
      • Gnathifera (28-VI)
        • Rotifera - Rotifers
        • Gnathostomulida
        • Micrognathozoa
        • Chaetognatha - Arrow Worms
    • Ecdysozoa (28-VII)
      • Nematoda - Roundworms
      • Nematomorpha - Horsehair Worms
      • Scalidophora
        • Kinorhyncha - Spiny-Headed Worms
        • Loricifera - Loriciferans
        • Priapulida - Priapulid Worms
      • Panarthropoda (28-VIII)
        • Tardigrada - Tardigrades (Water Bears)
        • Onychophora - Velvet Worms
        • Arthropoda (Ch. 29) >>> (Arthropods)
DICYEMIDA 

This is the phylum of Rhombozoans. As of 2024, no observations have been recorded in iNaturalist.
Resources:
ORTHONECTIDA 

This is the phylum of Orthonectids. As of 2024, only 1 observation of Orthonectida has been recorded throughout the world in iNaturalist and it was in the US, near Santa Barbara, CA.
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PLATYHELMINTHES 

This is the order of Flatworms. As of 2024, 101 species of Platyhelminthes have been observed in iNaturalist in the US and 562 throughout the world.
Resources:
NEMERTEA 

Nemertea is the phylum of Ribbon worms.As of 2024, 35 species of Nemertea have been observed in iNaturalist in the US and 96 throughout the world.
Resources:
PHORONIDA 

This is the phylum of Horseshoe Worms. As of 2024, 3 species of Phoronida have been observed in iNaturalist in the US and 6 throughout the world.
Resources:
BRACHIOPODA 

Brachiopoda is the phylum of Lamp Shells. As of 2024, 8 species of Brachiopoda have been observed in iNaturalist in the US and 36 throughout the world.
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BRYOZOA 

This is the phylum of Bryozoans. As of 2024, 81 species of Bryozoa have been observed in iNaturalist in the US and 278 throughout the world.
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ENTOPROCTA 

Entoprocta is the phylum of Goblet worms. As of 2024, 4 species of Entoprocta have been observed in iNaturalist in the US and 7 throughout the world.
  • Goblet Worms (Barentsia)
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CYCLIOPHORA 

Symbion pandora is the only species in this phylum. It has been observed as a parasite of Norway Lobsters.
Resources:
GASTROTRICHA 

"There are some 400 species (of gastrotrichs) inhabiting both salt and fresh water. The marine forms are found living between the sand grains of the intertidal zone, and the freshwater forms are found among the plants and algae of the pond's margins." [First Link Below]

As of 2024, 8 species of Gastrotricha have been observed in iNaturalist in the US and 20 throughout the world.

  • ORDER CHAETONOTIDA
    • Chaetonotus spp.
  • ORDER MACRODASYIDA
    • Pseudostomella spp.
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ACANTHOCEPHALA 

Thorny-Headed Worms may be found as parasites in birds, mammals, reptiles, fishes, crustaceans, roaches and grubs.As of 2024, only 1 species of Acanthocephala has been observed in iNaturalist in the US and 3 throughout the world.
Resources:

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