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You are here:   OldClasses > 2012 > Myzostoma sp. | Samantha Eady




Myzostoma sp.

(Samantha Eady 2012)



Fact Sheet



Physical Description


Life History & Behaviour

Anatomy & Physiology

Evolution & Systematics

Biogeographic Distribution

Conservation & Threats

References & Links

Evolution & Systematics

The first Myzostomid was described in 1827 by Leuckart (Helm et al. 2012). Through the use of fossil records, it was found that Myzostomids entered into symbiosis with Echinoderms more than three hundred million years ago (Lanterbecq et al. 2010). It has been suggested that the ancestor of Myzostomids lived in association with crinoids (Lanterbecq et al. 2010).

The large diversity of body forms within the Myzostomids has caused great controversy over their location in the metazoan phylogenetic tree (Lanterbecq et al. 2010). Myzostomids have previously been described as Trematodes (within Platyhelminthes), Crustaceans, Tardigrades and Pentastomids (Helm et al. 2012). More recently, Myzostomids have been suggested as part of the Annelida phylum due to their similarities in morphological traits such as a ladder-like nervous system, trochophore-like larvae and parapodia (Helm et al. 2012). Helm et al. (2012) very recently determined -through the use of miRNAs of Myzostoma cirriferum- that Myzostomids strongly support an Annelid affinity. 

According to Grygier (2000), Myzostomida is a class located within the Annelid phylum. This class can be broken down into two orders; Pharyngidea and Proboscidea. The order Pharyngidea encompasses seven families                                     (Pulvinomyzostomatidae, Endomyzostomatidae, Mesomyzostomatidae, Protomyzostomatidae, Asteromyzostomatidae, Asteriomyzostomatidae, Stelechopidae) while the order Proboscidea only contains one family (Myzostomatidae). The family Myzostomatidae represents more than 90% of the already described species, most of which are associated with Crinoids (Helm et al. 2012).

Phylogenetic tree illustrating the orders and families of class;
Myzostomida (Adapted from Lanterbecq et al. 2006)



(2 objects, created 5/6/2011)

Album: This is a private album that is not visible to anonymous users Great Barrier Reef Invertebrates



Album: 2012

Album: 2011