Phylum: Hemichordata
Class: Graptolithina
Order: Graptoloidea (Lapworth, 1875)
Cincinnatian Families: Diplograptidae

Geologic Range
Early Ordovician – Late Silurian

Common Paleoecology
Graptoloidea is an extinct order of passively mobile planktonic suspension feeders

Characteristics of the Order

  • Sicula pendent from nema
  • uniserial or biserial (very rarely quadriserial)
  • Rhabdosome generally of few stipes
  • Comprising only one type of theca

Published Descriptions

Treatise on Invertebrate Paleontology, Part V (1955):

  • Planktonic or epiplanktonic Graptolithina, sicula pendent from nema (virgula); stipes pendent to scandent in relation to this, uniserial or biserial (very rarely quadriserial); rhabdosome generally of few stipes, comprising only one type of theca (autotheca).