Marine Worms

Types of Worms

● Phylum Platyhelminthes: Flatworms○ Class Turbellaria○ Class Cestoda (tapeworms)○ Class Digenea (flukes)

● Phylum Nematoda● Phylum Annelida

○ Class Polychaete● And more!

General Characteristics

● Elongated bodies● Bilateral symmetry● Cephalized● Hydrostatic skeleton● Most are benthic

○ Some species have adapted to pelagic lifestyles

Phylum Platyhelminthes: Flatworms

● Flat bodies● Turbellarians are free living

○ Meiofauna: living in spaces between sediments

○ Ventral side ciliated and secretes mucus

● Most turbellarians are carnivores or detritivores

● Chemoreceptors

Phylum Platyhelminthes: Flatworms

● Unique, prey-capturing mechanisms○ Suffocation○ Stab with penis

● Pharynx secretes enzyme and pulls in food

● Food is digested in the gastrovascular cavity○ Lateral branches increase surface

area

Phylum Platyhelminthes: Flatworms

● Reproduction○ Asexually

■ Fission - whole animal regenerate from small piece

○ Sexually■ Hermaphroditic■ Reciprocal Copulation

Phylum Platyhelminthes: Flatworms

● Flukes and tapeworms are parasites○ Flukes generally have

intermediate hosts

Phylum Platyhelminthes: Flatworms

● Flukes and tapeworms are parasites○ Tapeworms grow

large in large hosts■ Sperm whale

tapeworms grow 30+ meters

Phylum Nematoda: Nematodes

● Roundworms, tapered at both ends

● Most numerous animals on Earth○ 1m2 of sediment may

contain 4-5 million nematodes

Phylum Nematoda: Nematodes

● Nonparasitic species are benthic scavengers are small (<5cm)

● Parasitic and carnivorous species are larger

● Reproduction varies○ Hermaphroditic or

seperate sexes

Phylum Annelida: Annelids

● Bodies divided internally to enhance leverage and mobility

● Setae: locomotion and defense● Polychaetes

○ Sandworms, clamworms, feather dusters, tubeworms, lugworms

○ 1mm to 3m range in size

Phylum Annelida: Annelids

● Polychaetes (continued)○ Sedentary

■ Burrow or build tubes of sand, calcium carbonate, and proteins

■ Filter feed with cilia that extend from tubes and the aid of chemoreceptors

○ Non-Sedentary■ Jaws with teeth■ Nocturnally hunt small invertebrates or eat algae

Phylum Annelida: Annelids

● Polychaetes (continued)○ Digestive system similar to ours○ Release fecal pellets out of tube to prevent fouling and

often form fecal casts, or castings, which accumulate outside the tube

○ Asexual reproduction via budding/regeneration○ Most reproduce only sexually

■ Distinct male and females

Phylum Annelida: Annelids

Sexual Reproduction in Polychaetes

● Epitoky○ Sexually immature worm (atoke) transforms into

sexually mature form (epitoke)■ Male and females

○ Swarming is controlled by lunar cycle, tides, and time of year

Other Marine Worms

● Spoon worms have a large proboscis used for feeding

● Bearded fireworms lack digestive tracts and absorb nutrients from seawater with tentacles instead

Other Marine Worms

● Ribbon worms are primarily benthic and have been measured up to 30m

● Peanut worms are primarily benthic suspension feeders. They contract their bodies o that they resemble a peanut kernel

Other Marine Worms

● Horsehair worms are free-living as adults but are parasites of arthropods as juveniles

● Spiny-headed worms are parasites of fish, birds, and mammals. Their proboscis has rows of tiny spines used to puncture the intestines of the host.

Tubeworms

Tubeworms

Tubeworm Facts- http://www.seasky.org/deep-sea/giant-tube-worm.html- https://science.psu.edu/news-and-events/2000-news/Fisher2-2000.htm

- https://sites.google.com/site/groupbioproject/giant-tube-worm

- http://faculty.montgomerycollege.edu/gyouth/FP_examples/student_examples/sathya_ramachandran/tubeworms.html