BIO 385 — Invertebrate Zoology
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Invertebrate Diversity
Animal Origins

Ediacaran Period, 635-543 million years ago

(The animals illustrated here date primarily from 565-550 mya)



Clade Petalonamae

  • Rangeomorphs and relatives
  • Uncertain if they are animals
  • Generally have a quilted body plan, with no internal organs
  • May be stalked (leaf-like) or lie flat on sediments (worm-like)
Charnia fossil
Charnia sp. fossil replica (Clade Rangeomorpha)
Charniodiscus
Charniodiscus sp. fossil (Clade Rangeomorpha)
Petalonama models
Life models of various Petalonamae
See also identification labels. All are clade Rangeomorpha and from Ediacaran Period except where indicated otherwise.

Clade Proarticulata

  • Segmented animals with "gliding asymmetry" (segments offset at midline)
  • Generally with an anterior head shield

Clade Trilobozoa

  • Disk-like animals with triradial symmetry
  • Raised ridges aided in suspension feeding
Dickinsonia fossil
Dickinsonia costata fossil (Clade Proarticulata)
Proarticulate Models
Life models of Ediacaran Proarticulata.
See also with identification labels.
Trilobozoa Models
Life models of the Ediacaran Trilobozoans Tribachidium (left) and Albumares (right).

Other Ediacaran Organisms

  • Some are likely members of modern phyla while others are enigmatic and may not even be animals
Cnidaria Models
Life models of possible Ediacaran Cnidaria (the phyla of Inaria (2nd from left) and Mawsonites (far right) are debated).
See also with identification labels.
Other Extant Phyla Models
Life models of Ediacaran representatives of other extant phyla/clades.
See also with identification & phylum labels.
Ediacaran Unknown Models
Life models of some Ediacaran organisms of unknown relationships (not to scale).
See also with identification labels.


See additional Ediacaran and Cambrian fossils here


Cambrian Period, 543-495 million years ago

(The animals illustrated here date primarily from 525-505 mya)


Cambrian scene

See larger image with identification labels indicating Genus (Phylum). † indicates an extinct Phylum.

Cambrian Fossils

Trilobite fossil
Elrathia kingi trilobite (Wheeler Formation, Utah)
Agnostid Trilobite fossil
Agnostid trilobite, Ptychagnostus sp. (Wheeler Formation, Utah)
Gogia Fossil
Eocrinoid fossil, Gogia palmeri/juvalorum (Spence Shale, ID)
Cambrian Algae
Cyanobacteria, Morania fragmenta and Green Algae, Yuknessia simplex? fossils
Cambropallas
Cambropallas telesto trilobite fossil (Morocco)
Nevadotheca fossil
Hyolithid fossil, Nevadotheca (Emigrant Springs Formation, NV)
Syspacephalus
Syspacephalus longus trilobite fossil (Groom Range, NV)
Pikaia fossil
Pikaia gracilens fossil cast (Burgess Shale, BC)
Opabinia fossil
Opabinia regalis fossil cast (Burgess Shale, BC)
Leanchoilia
Leanchoilia sp. arthropod fossil (Chengjiang Biota, China)
Palaeoscolex
Palaeoscolex sinensis worm fossil (Chengjiang Biota, China)
Haikouella
Haikouella lanceolata chordate (stem vertebrate) fossil (Chengjiang Biota, China)
This page last updated 6 July 2022 by Udo M. Savalli ()
Images and text © Udo M. Savalli. All rights reserved.