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G R A P T O L O I D E A

Diagnosis by O.M.B. Bulman (1938): GRAPTOLOIDEA Lapworth, 1875 emend. auctt. (inl. Retioloidea and Corynoidea; Rhabdophora Allman      Probably planktonic or pseudoplanktonic, sicula pendent from nema (or virgula); stipes pendent to scandent in relation to this, uniserial, biserial or rarely quadriserial; rhabdosome generally of few stipes, which are almost invariably composed of hydrothecae only.      Tremadocian to Upper Silurian (? Devonian).                                                            -  -  - Diagnosis by O.M.B. Bulman (1955): GRAPTOLOIDEA Lapworth, 1875      Planktonic or epiplanktonic Graptolithina, sicula pendent to scandent in relation to this, uniserial or biserial); rhabdosome generally of few stipes, comprising only one type of theca (autotheca). L. Ord. - U. Sil.                              -  -  - Diagnosis by O.M.B. Bulman (1970): GRAPTOLOIDEA Lapworth, 1875 [nom. transl. Ruedemann, 1904, p. 573 (ex section Graptoloidea Lapworth, in Hopkinson & Lapworth, 1875, p.633)] [=suborder Rhabdophora Allman 1872, p.380]. L. Ord. - U. Sil.

Reconstruction of Loganograptus kjerulfi Herrmann from the Lower Ordovician. From Obut (1964)

Clonograptus trochograptoides

The Graptoloidea are planktonic or epiplanktonic
graptolites. They have been reported from the
Lower Ordovician to the Middle Devonian. Before
becoming extinct, they exhibit three evolutionary
bursts.
      The Graptoloidea  are useful in stratigraphy.  
Many forms have an almost world-wide distribution.
Some genera (eg., Diplograptus, Didymograptus
and Monograptus) have been recorded from all six
continents.