It's related to what!?Taenia saginata picture taken by Carolyn Temanson


Domain: Eukarya

Kingdom: Animalia

Phylum: Platyhelminthes

Class: Cestodes

Order: Cyclophyllidea

Family: Taeniidae

Genus: Taenia

Species: Taenia saginata

Taenia saginata is the Latin name for this tapeworm and is in the binomial nomenclature format.  Now in Latin Taenia comes from the word taedium which translates into disgust and weariness.  This does describe this organism well, but to get a better picture and foundation of Taenia saginata, one should look at the taxonomy. 


The first big group that this organism falls into is the Domain, Eukarya.  Taenia saginata falls into this category for many reasons, first it is multicellular, it contains membrane-bound organelles and can sexually reproduce.


The second classification for T. saginata is its Kingdom, the Animalia.  The Animal Kingdom is very diverse in their form and habitat, but they all share definite characteristics that put it in this group.  All animals are multicellular, heterotrophic, lack cell walls, and will have some type of locomotion in their life span.  Animals also have a diverse range of reproduction, but have one thing in common: animals do not reproduce with an alternating multicellular haploid and diploid form, (also known as alternation of generation). 


The next taxonomic level would be the Phylum, Platyhelminthes. The Platyhelminthes group is one of the thirty-four phylums in the Animal Kingdom.  These organisms share specific characteristics: they are unsegmented flatworms with bilateral symmetry, triploblastic, have an incomplete digestive system, and are acoelomates (meaning they do not have a true body cavity).  These three groups all tend to be parasitic and are considered to reproduce in a monoecious form, where the worms hold both female and male organs for reproduction (also known as hermaphroditic) and they do have some cross fertilization allowing for some genetic variability. 


Taenia saginata then falls into the class, Cestoda.  The Cestoda class is composed mainly parasites that live in a different kinds of vertebrates causing disease.  Cestodas are morphologically very flat which increases the surface area to volume ratio allowing it to absorb nutrients efficiently across its skin. 


The Order, Cyclophyllidea and this group of Cestodas live in the intestine of its host and has characteristics like the scolex and the proglottids. The purpose of a scolex is to attach to the host and purpose of the proglottids is specifically for reproduction. 


The Family, Taeniidae has a specific characteristic dealing with the reproduction of it gametes where the production of the egg that has a thick striated shell also known as an oncosphere. 


The Taenia genus is known for having two hosts, the intermediate host being an animal like a cat, dog, pig, or cow that hosts the young larval stage of the parasite in the form of a cyst.  The second host is the terminal host where the adult tapeworm lives in the intestine of a carnivore like a human or dog. 


The specific species Taenia saginata has reproductive life cycle that affects the specific intermediate host of a cow and the definitive host of a human.  It can be transmitted through eggs in the feces or by eating muscular tissue infected with the eggs contained in a cyst, also known as “beef measles.”



Phylogenetic Tree


This image below is a cladistic phylogenetic tree, revealing the relationship of the Platyhelminthes phylum to the rest of the organisms' phylum or group in the domain, Eukarya.  A cladistic tree is based off an organism's DNA and how different genes relate to other relating organisms.  These two trees below are based of a set of multiple genes. 

Make a note that Platyhelminthes are not as close as you might think to the other organism that is generally called a parasitic worm, the Nematodes.  There are many differences between the two and they should not confused to be under the same common name parasitic "worm."   Check out a few links that show how different the Nematodes are. 

Cladistic Phylogenetic Tree of the Eukarya Domain


Now this cladistic tree below reveals a closer look at the organisms and their relationship with each other in the Platyhelminthes phylum. The Platyhelminthes phylum is very complex and includes many organisms, so this is a more simplified version that shows their relationship to Taenia  saginata. 

Cladistic Phylogenetic Tree of the Platyhelminthes



Now after looking at the classification of the beef tapeworm, take a closer look at its unique morphology!