Dictyonema retiforme, photographed by K. Carlson at the Peabody Museum of Natural History.

Belongs within: Dendroidea.

Dictyonema is a genus of dendroid graptolites known from the Upper Cambrian to the Carboniferous, characterised by a conical, net-like colonial structure. Branches of the colony are connected by transverse threads (dissepiments) that are extrathecal in origin and composed of cortical tissue. In members of the Upper Silurian subgenus Pseudodictyonema, the thecae are elongate, giving the stipe a somewhat ‘ropy’ appearance; members of the subgenus Dictyonema have thecae with a more standard length ratio (Bulman 1970).

Characters (from Bulman 1970): Rhabdosome conical, varying from almost cylindrical to almost discoidal, with thecate or nonthecate stem or rarely attached by nema; branching dichotomous, stipes straight, subparallel to parallel, united by transverse dissepiments, anastomosis rare; authothecae denticulate, commonly spined, rarely tubular and isolate; bithecae normally inconspicuous.

<==Dictyonema Hall 1851 non Agardh ex Kunth 1822 (ICBN) (see below for synonymy)B70
    |--D. (Dictyonema)B70
    |    |--*D. (D.) retiforme (Hall 1843) [=Gorgonia retiformis, *Dictyodendron retiforme, *Dictyograptus retiformis]B70
    |    `--D. (D.) crassibasaleB70
    `--D. (Pseudodictyonema Bouček 1957)B70
         `--D. (*P.) graptolithorum Počta 1894B70
Dictyonema incertae sedis:
  ‘Airograptus’ anfractusCT83
  D. campanulatumB70
  D. canadenseB70
  D. cavernosumB70
  D. cervicorneB70
  D. cotyledonB70
  D. estlandicumK48
  D. falciferumB70
  D. furciferum Ruedemann 1904 [=*Airograptus furciferum]B70
  D. inconstansB70
  D. kelanenseCT83
  D. longilingue Kozłowski 1948K48
  ‘Airograptus’ longispicusCT83
  D. parabolaJ79
  D. peltatumB70
  D. rarumB70
  D. rectithecale Kozłowski 1948K48
  D. rhinanthiformeB70
  D. scitulumB70
  D. vinculosum Sherrard 1956F71
  D. wimaniK48
  D. wutingshanenseCT83
    |--D. w. wutingshanenseCT83
    `--D. w. majorCT83
  D. wysoczkianum Kozłowski 1948K48
    |--D. w. wysoczkianumK48
    `--D. w. macrothecale Kozłowski 1948K48

Dictyonema Hall 1851 non Agardh ex Kunth 1822 (ICBN) [=Dictyodendron Westergård 1909, Dictyograptus Hopkinson 1875; incl. Airograptus Ruedemann 1916]B70

*Type species of generic name indicated


[B70] Bulman, O. M. B. 1970. Graptolithina with sections on Enteropneusta and Pterobranchia. In: Teichert, C. (ed.) Treatise on Invertebrate Paleontology pt V 2nd ed. pp. V1–V149. The Geological Society of America, Inc.: Boulder (Colorado), and the University of Kansas: Lawrence (Kansas).

[CT83] Chen J.-Y. & C. Teichert. 1983. Cambrian Cephalopoda of China. Palaeontographica Abteilung A: Paläozoologie—Stratigraphie 181 (1–3): 1–102.

[F71] Fletcher, H. O. 1971. Catalogue of type specimens of fossils in the Australian Museum, Sydney. Australian Museum Memoir 13: 1–167.

[J79] Jaanusson, V. 1979. Ordovician. In: Robison, R. A., & C. Teichert (eds) Treatise on Invertebrate Paleontology pt A. Introduction. Fossilisation (Taphonomy), Biogeography and Biostratigraphy pp. A136–A166. The Geological Society of America, Inc.: Boulder (Colorado), and The University of Kansas: Lawrence (Kansas).

[K48] Kozłowski, R. 1948. Les graptolithes et quelques nouveaux groupes d’animaux du Tremadoc de la Pologne. Palaeontologica Polonica 3: i–xii, 1–235.

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