Ectenocrinus Ordovician Crinoids from Canada

Description: This plate displays an adult and juvenile example of the Disparid crinoid Ectenocrinus simplex. Crinoids were filter feeders, and exhibited a habit known as tiering, whereby different types selected a different level of the water column in order to avoid competition for food. The Cladids specialized on an intermediate level, and thus had intermediate lengths of stems to accommodate that habit. These were buried quickly to avoid much disarticulation in death. The smaller suffered a bit of displacement in its stem due to the fact that it overlies the larger example.