Classification of Platyhelminthes

Questions and Answers

What does the phylum Platyhelminthes include? (Select all that apply)

More than 34000 species (correct)

Sponges

Flatworms (correct)

Bilateral acoelomates (correct)

Name the four classes in the phylum Platyhelminthes.

Turbellaria, Monogenea, Trematoda, Cestoidea

Describe the class Turbellaria.

Mostly free living and aquatic; external surface usually ciliated; predaceous; possess rhabdites, protrusible proboscis, frontal glands, and many mucus glands; mostly hermaphroditic. Includes Convoluta, Notoplana, and Dugesia. More than 3000 species.

Describe the class Monogenea.

Flukes, mostly ectoparasites on vertebrates; one life cycle form in only one host; bear opishaptor. Includes Disocotyle, Garodactylus, and Polystoma. About 1100 species. Signup and view all the answers

Describe the class Trematoda.

All are parasitic, with several holdfast devices present and complicated life cycles involving both sexual and asexual reproduction. Has two subclasses: Aspidogastria and Digenea. More than 10,000 species. Signup and view all the answers

Describe the subclass Aspidogastria.

Subclass of Trematoda; mostly endoparasites of molluscs, possess large opishaptor, most lack an oral sucker. Includes Aspidogaster, Cotylapsis, Multicotyl. About 32 species. Signup and view all the answers

Describe the subclass Digenea.

A subclass of Trematoda; adult endoparasites in vertebrates, at least two different life cycle forms in two or more hosts, have oral sucker and acetabulum. Includes Schistosoma, Fasciola, and Clonarchis. About 1,350 species. Signup and view all the answers

Describe the class Cestoidea.

All parasitic with no digestive tract; have great reproductive potential; tapeworms. Has two subclasses: Cestodaria and Eucestoda. About 3500 species. Signup and view all the answers

Describe the subclass Cestodaria.

Subclass of Cestoidea; body not subdivided into proglottids, larva in crustaceans, adult in fishes. Includes Amphilina and Gyrocotyle. About 15 species. Signup and view all the answers

The subclass Eucestoda includes _____ species.

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Study Notes

Overview of Phylum Platyhelminthes

Comprises flatworms, bilateral acoelomates, with over 34,000 species.

Classes in Phylum Platyhelminthes

Four main classes: Turbellaria, Monogenea, Trematoda, and Cestoidea.

Class Turbellaria

Predominantly free-living and aquatic organisms; external surfaces are usually ciliated.
Characterized by predatory behavior and the presence of rhabdites, protrusible proboscis, frontal glands, and numerous mucus glands.
Reproductive mode is mostly hermaphroditic.
Notable examples include Convoluta, Notoplana, and Dugesia, counting over 3,000 species.

Class Monogenea

Consists of flukes, primarily ectoparasites found on vertebrates, especially fish, as well as occasional hosts like turtles and frogs.
Lifecycle involves a single host with one form.
Distinguished by the presence of an opishaptor.
Includes species such as Disocotyle, Garodactylus, and Polystoma, with approximately 1,100 species.

Class Trematoda

Entirely parasitic with complex life cycles featuring both sexual and asexual reproduction.
Subdivided into two subclasses: Aspidogastria and Digenea.
Comprises more than 10,000 species.

Subclass Aspidogastria

Mainly endoparasites of mollusks; characterized by a large opishaptor and typically lack an oral sucker.
Notable examples include Aspidogaster, Cotylapsis, and Multicotyl, with around 32 species.

Subclass Digenea

Contains adult endoparasites in vertebrates, requiring multiple hosts with at least two lifecycle forms.
Features an oral sucker and acetabulum.
Includes significant species like Schistosoma, Fasciola, and Clonarchis, totaling about 1,350 species.

Class Cestoidea

Entirely parasitic organisms, notably lacking a digestive tract and exhibiting significant reproductive potential.
Commonly known as tapeworms; categorized into two subclasses: Cestodaria and Eucestoda, with around 3,500 species.

Subclass Cestodaria

Body structure is not divided into proglottids; larval forms inhabit crustaceans while adults live in fishes.
Examples include Amphilina and Gyrocotyle, totaling about 15 species.

Subclass Eucestoda

Details on this subclass are unspecified in the provided text.

Description

Dive into the fascinating world of the phylum Platyhelminthes through these flashcards. Learn about flatworms, their classes, and unique characteristics. This quiz is perfect for biology students focusing on invertebrate classification.