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Paleozoic echinoderms of North America (4 C, 10 P) Paleozoic echinoderms of Oceania (1 C, 1 P) B. Blastozoa (2 C, 10 P) C. Cambrian echinoderms (1 C, 17 P)
Instead, there is a spiral food groove on the outside along which food was moved to a mouth that is thought to be on the side. The respiratory system appears to be primitive. Although the animal does not look like a typical echinoderm, the plates are composed of the characteristic calcareous plates known as stereom that are common to all ...
Pages in category "Paleozoic echinoderms of North America" The following 10 pages are in this category, out of 10 total. This list may not reflect recent changes. A.
The first universally accepted echinoderms appear in the Lower Cambrian period; asterozoans appeared in the Ordovician, while the crinoids were a dominant group in the Paleozoic. It is hypothesised that the ancestor of all echinoderms was a simple, motile, bilaterally symmetrical animal with a mouth, gut and anus.
"Blastoidea", from Ernst Haeckel's Art Forms of Nature, 1904. Blastoids (class Blastoidea) are an extinct type of stemmed echinoderm, often referred to as sea buds. [1] They first appear, along with many other echinoderm classes, in the Ordovician period, and reached their greatest diversity in the Mississippian subperiod of the Carboniferous period.
However, it is now generally accepted that homalozoans were echinoderms because their calcite skeleton was composed of the typical stereom crystalline structure. [ 6 ] They include the unusual stylophorans ( mitrates and cornutes ), Homoiostelea ( solutes ), the Homostelea (cinctans), and the Ctenocystoidea (ctenoid-bearing homalozoans). [ 7 ]
This list excludes purely vernacular terms. It includes all commonly accepted genera, but also genera that are now considered invalid, doubtful (nomina dubia), or were not formally published (nomina nuda), as well as junior synonyms of more established names, and genera that are no longer considered echinoderms. The list includes thousands of ...
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