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How to Identify Brachiopod Fossils

A brachiopod is a marine animal that has two valves, or shells. Although some brachiopods do exist today, most brachiopods can only be found in the fossil record. In fact, brachiopods existed at least 525 million years ago during the Cambrian Period. You can easily identify brachiopod fossils using a dichotomous key, which looks at various aspects of the fossils and sorts them into the following orders: Rafinesquina, Orthorhynchula, Rhynchotrema, Platystrophia and Hebertella.

Things You'll Need

Ruler or measuring tape

Instructions

- 1
  Check to see if one of the two shells in the fossil is concave. If so, the brachiopod is Rafinesquina.
- 2
  Check to see if the hinge on the brachiopod is pointed. If so, the brachiopod fossil is astrophic, and may be either Orthorhynchula or Rhynchotrema. If not, skip Step 3 because the fossil is strophic, and may be either Platystrophia or Hebertella.
- 3
  Measure the diameter of the fossil at its largest point. If the fossil is larger than 1 cm, it is Orthorhynchula. Otherwise, it is Rhynchotrema.
- 4
  Feel the fossil to see whether it has a ridged surface. If it does, it is Platystrophia. Otherwise, it is Hebertella.

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