Trachylinae
Encyclopedia
Trachylinae are a cnidaria
n subclass
of the Hydrozoa
. They are placed at order
rank in many older classifications, and limited to contain the Narcomedusae
and Trachymedusae
. But the Actinulidae, then considered an independent order, and probably also the Limnomedusae which were traditionally placed in the paraphyletic "Hydroida
", belong to this group too. It is not entirely clear whether the Limnomedusae and the Trachymedusae as conventionally circumscribed are monophyletic
The Freshwater Jelly (Craspedacusta sowerbyi) is a well-known member of the Limnomedusae and might thus belong here.
Cnidaria
Cnidaria is a phylum containing over 9,000 species of animals found exclusively in aquatic and mostly marine environments. Their distinguishing feature is cnidocytes, specialized cells that they use mainly for capturing prey. Their bodies consist of mesoglea, a non-living jelly-like substance,...
n subclass
Class (biology)
In biological classification, class is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, order, family, genus, and species, with class fitting between phylum and order...
of the Hydrozoa
Hydrozoa
Hydrozoa are a taxonomic class of very small, predatory animals which can be solitary or colonial and which mostly live in saltwater. A few genera within this class live in freshwater...
. They are placed at order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
rank in many older classifications, and limited to contain the Narcomedusae
Narcomedusae
Narcomedusae is an order of hydrozoans in the subclass Trachylinae.-Characteristics:Members of this order do not normally have a polyp stage. The medusa has a dome-shaped bell with thin sides. The tentacles are attached above the lobed margin of the bell with usually a gastric pouch above each....
and Trachymedusae
Trachymedusae
Trachymedusae are an order in the cnidarian class Hydrozoa. They contain some 50 species, divided among about 30 genera and 5 families, of which the Rhopalonematidae are by far the most diverse. They only reproduce sexually as medusa, never forming polyps...
. But the Actinulidae, then considered an independent order, and probably also the Limnomedusae which were traditionally placed in the paraphyletic "Hydroida
Hydroida
Hydroida is an obsolete cnidarian order which united such animals as hydras, hydromedusae, and many marine attached hydroids. However, the group is paraphyletic and not composed from close relatives...
", belong to this group too. It is not entirely clear whether the Limnomedusae and the Trachymedusae as conventionally circumscribed are monophyletic
The Freshwater Jelly (Craspedacusta sowerbyi) is a well-known member of the Limnomedusae and might thus belong here.