CLASS TREMATODA

Class Trematoda is characterized by a ______________ flattened, _________ and possess a ___-life body shape

dorsoventrally flattened, unsegmented, leaf-like

May be either smooth or spiny and contains embedded internal organs within parenchymal tissue, as they lack a true body cavity (acoelomate)

Tegument (body surface)

Lack of true body cavity

Acoelomate

Attachment structures of Class Trematoda

1. oral suckers

2. ventral suckers

3. hooks or clamps (in some spp.)

They possess an incomplete alimentary canal, usually ending in ______ ____

blind caeca

Excretion is managed by a

• branched _____________ system composed of flame cells (__________)

• protonephridial

• solenocytes

Hermaphroditic

monoecious

Dioecious spp. or members under Class Trematoda

1. Members of Schistosomatidae (e.g., Schistosoma spp.)

Depending on the predilection site, the eggs pass out of the final host, usually in ____or urine

feces

The larval stages develop in a ___________ intermediate host

molluscan

True or false: Few species of Trematoda may involve a secondary host

True

Two subclasses of Class Trematoda

1. Digenea

2. Aspidogastrea

Possess a complex life cycle involving one or more intermediate hosts, typically mollusks

Subclass Digenea

Adults of Subclass Digenea are found exclusively in __________ hosts, inhabiting internal organs (e.g., liver, lungs, intestines, blood vessels)

vertebrate

Spp. of veterinary significance of Digenea

1. Fasciola

2. Dicrocoelium

3. Schistosoma

Subclass Aspidogastrea is a less diverse group with a _______or _________complex life cycle

simple or facultative

• Mostly parasitize mollusks, fish, and amphibians

• Distinguished by their large ventral adhesive disc

What subclass?

Aspidogastrea