All Sources -
Updated Media sources (1) About encyclopedia.com content Print Topic
Graptoloidea (subphylum Stomochordata, class Graptolithina) An order of graptolites that existed from the Lower Ordovician to Lower Devonian. The rhabdosomes had up to 8 stipes in early forms, but 2 and finally 1 in later forms. The thecae are of only one type, equivalent to the autotheca of Dendroidea, occur on one or both sides of the stipe, and vary quite widely in morphology. In adults, there is always a sicula bearing a nema. There are 3 suborders: 1, to which no name has been assigned, comprises a single, paraphyletic family, Anisograptidae. The other 2 are Dichograptina and Virgellina.
Graptoloidea See GRAPTOLITHINA.