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Hederellid

 

 
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Hederellid
 
 
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Hederellids are extinct colonial animal
Animal

Animals are a major group of multicellular, eukaryotic organisms of the Kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life....
s with calcitic tubular branching exoskeleton
Exoskeleton

An exoskeleton is an external skeleton that supports and protects an animal's body, in contrast to the internal endoskeleton of, for example, a human skeleton....
s. They range from the Silurian
Silurian

The Silurian is a geologic period that extends from the end of the Ordovician period, about 443.7 ? 1.5 annum , to the beginning of the Devonian period, about 416.0 ? 2.8 Mya ....
 to the Permian
Permian

The PermianThe term "Permian" was introduced into geology in 1841 by Sir Roderick Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian system" after the ancient kingdom...
 and were most common in the Devonian
Devonian

The Devonian is a geologic period of the Paleozoic era spanning from . It is named after Devon, England, where rocks from this period were first studied....
 period. They are more properly known as "hederelloids" because they were originally defined as a suborder by Bassler (1939), who described about 130 species. Although they have traditionally been considered bryozoans, they are clearly not because of their branching patterns, lack of an astogenetic gradient, skeletal microstructure, and wide range in tube diameters (Wilson and Taylor, 2001).






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Hederellids are extinct colonial animal
Animal

Animals are a major group of multicellular, eukaryotic organisms of the Kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life....
s with calcitic tubular branching exoskeleton
Exoskeleton

An exoskeleton is an external skeleton that supports and protects an animal's body, in contrast to the internal endoskeleton of, for example, a human skeleton....
s. They range from the Silurian
Silurian

The Silurian is a geologic period that extends from the end of the Ordovician period, about 443.7 ? 1.5 annum , to the beginning of the Devonian period, about 416.0 ? 2.8 Mya ....
 to the Permian
Permian

The PermianThe term "Permian" was introduced into geology in 1841 by Sir Roderick Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian system" after the ancient kingdom...
 and were most common in the Devonian
Devonian

The Devonian is a geologic period of the Paleozoic era spanning from . It is named after Devon, England, where rocks from this period were first studied....
 period. They are more properly known as "hederelloids" because they were originally defined as a suborder by Bassler (1939), who described about 130 species. Although they have traditionally been considered bryozoans, they are clearly not because of their branching patterns, lack of an astogenetic gradient, skeletal microstructure, and wide range in tube diameters (Wilson and Taylor, 2001). Work continues on assessing the true affinities of hederelloids, but they appear to be most closely related to phoronid
Phoronid

Phoronids , commonly known as horseshoe worms, are a relatively small animal phylum: twenty species are known, in two genera, Phoronis and Phoronopsis....
s and other lophophorates (Taylor and Wilson, 2008).