| 词条 | Heteractinida |
| 释义 |
| fossil_range = | taxon = Heteractinida | authority = | subdivision_ranks = Included groups | subdivision = 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] References1. ^1 2 {{cite journal | doi = 10.1073/pnas.0405867102 | last1 = Botting | first1 = J. P. | last2 = Butterfield | first2 = N. J. | last3 = Valentine | first3 = J. W. | year = 2005 | title = Reconstructing early sponge relationships by using the Burgess Shale fossil Eiffelia globosa, Walcott | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 102 | issue = 5 | pages = 1554–1559 | publisher = | jstor = 3374469 | url = | format = | accessdate = | pmid = 15665105 | pmc = 547825 }} {{Taxonbar|from=Q16910350}}{{sponge-stub}} 1 : Hexactinellida |
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