Hexactinellida

Belongs within: Porifera.
Contains: Hexasterophora, Amphidiscophora.

The Hexactinellida, glass sponges, are a group of sponges with a skeleton composed of silica, around which the (relatively sparse) cellular material is mostly conjoined into a multinucleate syncytium. They are first recognised in the fossil record during the early Cambrian (Erwin et al. 2011).

Characters (Adl et al. 2012): Siliceous spicules triaxonic, hexactinic; cells forming extensive multinucleate syncytium, with some differentiated cells; electrical conductance across body; noncontractile body; larvae (poorly known) with medial region of ciliated cells.

<==Hexactinellida [Rossellimorpha, Triaxonia]
    |--+--HexasterophoraEL11
    |  |--AmphidiscophoraEL11
    |  `--Hemidiagoniella Botting 2004B04
    |       |--*H. tenax Botting 2004B04
    |       `--H. caseus Botting 2004B04
    `--+--Rufuspongia Rigby & Mehl 1994 [Rufuspongiidae]B04
       `--HintzespongioideaRB93
            |--TeganiidaeRB93
            |    |--Polyplectella mira Ruedemann 1925RB93
            |    `--Teganium subsphaerica (Walcott 1879)RB93
            `--HintzespongiidaeRB93
                 |--Hintzespongia bilamina Rigby & Gutschick 1976B04
                 `--Stephenospongia Rigby 1986RB93, B04
                      `--S. magnipora Rigby 1986RB93

Hexactinellida incertae sedis:
  Semperella schulzeiAS12, F79
  Brabbinithes churkini Allison 1975G79
  Holtenia crateromorphaH04
  Sclerothamnus spiralisH04
  Polyopogon amaduH04
  Saccocalyx pedunculataH04
  Crateromorpha meyeriH04
  Hyaloslylus divesH04
  Polylophus philippinensisH04
  Stylocalyx teneraH04
  LophocalyxAS12
  Heterochone calyxPP15
  Sympagella nuxPP15
  Mattaspongia apaches (Rigby 1970)B04
  HunanospongiaEL11
  Griphodictya epiphanies Hall & Clark 1898B04
  Itararella gracilis Kling & Reif 1969B04
  Prismodictya [Reticulosaidae]JB12
  Saetaspongia densaC12
  Conostylus Popofsky 1907SO21
  Hataina Huang 1967SO21
  Lithacanthidae LT61
    |--Lithacanthus Popofsky 1907SO21
    `--Tetracina Loeblich & Tappan 1961 LT61 [=Tetracanthus Popofsky 1907 non Hope 1834SO21]
         `--*T. simplex (Popofsky 1907) [=*Tetracanthus simplex] LT61
  Sethodisculus Haeckel 1887SO21
  Cydonium Fleming 1828SO21
  Silicosphaera Hughes 1985SO21
  Concilaspongia Robinson & Haslett 1995SO21

*Type species of generic name indicated

References

[AS12] Adl, S. M., A. G. B. Simpson, C. E. Lane, J. Lukeš, D. Bass, S. S. Bowser, M. W. Brown, F. Burki, M. Dunthorn, V. Hampl, A. Heiss, M. Hoppenrath, E. Lara, E. Le Gall, D. H. Lynn, H. McManus, E. A. D. Mitchell, S. E. Mozley-Stanridge, L. W. Parfrey, J. Pawlowski, S. Rueckert, L. Shadwick, C. L. Schoch, A. Smirnov & F. W. Spiegel. 2012. The revised classification of eukaryotes. Journal of Eukaryotic Microbiology 59 (5): 429–493.

[B04] Botting, J. P. 2004. An exceptional Caradoc sponge fauna from the Llanfawr Quarries, central Wales and phylogenetic implications. Journal of Systematic Palaeontology 2 (1): 31–63.

[C12] Chen, J.-Y. 2012. Evolutionary scenario of the early history of the animal kingdom: evidence from Precambrian (Ediacaran) Weng’an and Early Cambrian Maotianshan biotas, China. In: Talent, J. A. (ed.) Earth and Life: Global biodiversity, extinction intervals and biogeographic perturbations through time pp. 239–379. Springer.

[EL11] Erwin, D. H., M. Laflamme, S. M. Tweedt, E. A. Sperling, D. Pisani & K. J. Peterson. 2011. The Cambrian conundrum: early divergence and later ecological success in the early history of animals. Science 334: 1091–1097.

[F79] Fry, W. G. 1979. Taxonomy, the individual and the sponge. In: Larwood, G., & B. R. Rosen (eds) Biology and Systematics of Colonial Organisms pp. 49–80. Academic Press: London.

[G79] Glaessner, M. F. 1979. Precambrian. In: Robison, R. A., & C. Teichert (eds) Treatise on Invertebrate Paleontology pt A. Introduction. Fossilisation (Taphonomy), Biogeography and Biostratigraphy pp. A79–A118. The Geological Society of America, Inc.: Boulder (Colorado), and The University of Kansas: Lawrence (Kansas).

[H04] Haeckel, E. 1899–1904. Kunstformen der Natur. Bibliographisches Institut: Leipzig und Wien.

[JB12] Johnson, M. E., & B. G. Baarli. 2012. Development of intertidal biotas through Phanerozoic time. In: Talent, J. A. (ed.) Earth and Life: Global biodiversity, extinction intervals and biogeographic perturbations through time pp. 63–128. Springer.

[LT61] Loeblich, A. R., Jr & H. Tappan. 1961. Remarks on the systematics of the Sarkodina (Protozoa), renamed homonyms and new and validated genera. Proceedings of the Biological Society of Washington 74: 213-234.

[PP15] Pisani, D., W. Pett, M. Dohrmann, R. Feuda, O. Rota-Stabelli, H. Philippe, N. Lartillot & G. Wörheide. 2015. Genomic data do not support comb jellies as the sister group to all other animals. Proceedings of the National Academy of Sciences of the USA 112 (50): 15402–15407.

[RB93] Rigby, J. K., G. E. Budd, R. A. Wood & F. Debrenne. 1993. Porifera. In: Benton, M. J. (ed.) The Fossil Record 2 pp. 71–99. Chapman & Hall: London.

[SO21] Suzuki, N., L. O’Dogherty, J.-P. Caulet & P. Dumitrica. 2021. A new integrated morpho- and molecular systematic classification of Cenozoic radiolarians (class Polycystinea)—suprageneric taxonomy and logical nomenclatorial acts. Geodiversitas 43 (15): 405–573.