Heteractinida
Group of sponges
From Wikipedia, the free encyclopedia
Heteractinida is an extinct grade of Paleozoic (Cambrian–Permian) sponges, sometimes used as a class or order. They are most commonly considered paraphyletic with respect to Calcarea (calcareous sponges),[1][2][3] though some studies instead argue that they are paraphyletic relative to Hexactinellida (glass sponges).[4] Heteractinids can be distinguished by their six-pronged (snowflake-shaped) spicules, whose symmetry historically suggested a relationship with the triradial calcarean sponges.[4]
Hinde, 1887
| Heteractinida Temporal range: | |
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| Species of Jawonya | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Porifera |
| Informal group: | †Heteractinida Hinde, 1887 |
| Included groups | |
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See text | |
| Synonyms | |
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The sponge-like Cambrian Hetairacyathidae may be related to heteractinids,[5] though most instead consider hetairacyathids to be closer to archaeocyaths.[6] An example of a species in the Heteractinida class is the Gondekia lancifer; the Gondekia lancifer specimen is only the second articulated specimen known and is more complete than the holotype. It has an intact skeleton of felted sexiradiates of three orders of spicules.[7]
Subgroups
From Treatise on Invertebrate Paleontology:[5]
- Order †Octactinellida Hinde, 1887
- Family †Astraeospongiidae Miller, 1889 [Cambrian–Devonian]
- Family †Eiffeliidae Rigby, 1986 [Cambrian–Mississippian]
- Family †Nuchidae Pickett, 2002 [Cambrian]
- Family †Wewokellidae King, 1943 [Mississippian–Permian]
