Phylum: Echinodermata
The phylum Echinodermata refers to common invertebrate animals such as the crinoids, starfish, and sand dollars. They first appeared in the fossil record during the lower Cambrian Period. There are four living classes with over 6000 species present today. However, there are also fifteen extinct classes recognized in the fossil record. Most have an exoskeleton which may be covered by five-sided plates or bony spines. All are marine animals, never living in a colony. Their nervous and digestive systems are highly developed; their respiratory and circulatory systems are poorly developed. The respiratory system consists of poorly developed gills. Two classes are well-represented in Kansas: Crinoidea and Echinoidea.
Class Crinoidea (lower Ordovician to Recent)
Crinoids are called sea lilies if they are attached to the ocean floor by a stalk (stem). They have a cup-shaped body which encloses the body organs (head or crown). Crinoids are very difficult to identify because it’s rare to find a complete animal. Therefore, it’s best to identify them at the class level and identify their parts.
Class Crinoidea (lower Ordovician to Recent)
Crinoids are called sea lilies if they are attached to the ocean floor by a stalk (stem). They have a cup-shaped body which encloses the body organs (head or crown). Crinoids are very difficult to identify because it’s rare to find a complete animal. Therefore, it’s best to identify them at the class level and identify their parts.
Class
Echinoidea (Ordovician to
Recent)
This class is made up of the sea urchins, sand dollars, and heart urchins. Their fossil record is poor in the Paleozoic Era. Their shells are made up of five-sided plates (test plates) which are interlock and protect the body organs. Sometimes these plates have spines attached, but like the crinoids, complete fossils are rarely found. Individual spines and test plates are most commonly found. Identification should be done on the class level, with the parts labeled.
This class is made up of the sea urchins, sand dollars, and heart urchins. Their fossil record is poor in the Paleozoic Era. Their shells are made up of five-sided plates (test plates) which are interlock and protect the body organs. Sometimes these plates have spines attached, but like the crinoids, complete fossils are rarely found. Individual spines and test plates are most commonly found. Identification should be done on the class level, with the parts labeled.