Heteractinida
| Heteractinida | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | "Porifera" |
| Stem-group: | Hexactinellida |
| Grade: | †"Heteractinida" |
| Included groups | |
|
See text | |
The Heteractinids are a grade of sponges that are paraphyletic with respect to Hexactinellida.[1] Their distinctive trait is their six-pronged (snowflake-like) spicules, whose symmetry historically suggested a relationship with the triradial Calcarean sponges.[1] Nevertheless, they actually represent a polyphyletic grade, from which the hexactinellids arose.[1]
References
- 1 2 3 Botting, J. P.; Butterfield, N. J.; Valentine, J. W. (2005). "Reconstructing early sponge relationships by using the Burgess Shale fossil Eiffelia globosa, Walcott". Proceedings of the National Academy of Sciences of the United States of America 102 (5): 1554–1559. doi:10.1073/pnas.0405867102. JSTOR 3374469. PMC 547825. PMID 15665105.
This article is issued from Wikipedia - version of the Thursday, September 03, 2015. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.