Belongs within: Tetractinellida.
The Theonellidae are sponges in which the spicules of the choanosome are tetraclone desmas (Fromont & Pisera 2011).
Characters (Fromont & Pisera 2011): Polymorphic; choanosomal spicules are tetraclone desmas; ectosomal spicules are phyllo- to discotriaenes; microscleres are spinose microrhabds and/or microxeas, and streptasters and/or pseudospherasters; large choanosomal oxeas may be present.
Theonellidae [Discodermiidae]FP11
|--DiscodermiaMC15
| |--D. claviformis Kieschnick 1896 (n. d.)BJ06
| `--D. discifera (Lendenfeld 1907)FS14
|--RacodisculaFP11
|--CollectellaMC15
|--SiliquariaspongiaMC15
|--Phyllodermia incrassata (Goldfuss 1833)RB93
|--CladodermiaRB93
|--Manihinea Pulitzer-Finali 1993FP11
| |--*M. conferta Pulitzer-Finali 1993FP11
| `--M. lynbeazleyae Fromont & Pisera 2011FP11
`--TheonellaMC15
|--T. conica (Kieschnick 1896) [=Discodermia conica]BJ06
|--T. cylindrica Wilson 1925FS14
|--T. incerta Thiele 1900BJ06
|--T. lacerata von Lendenfeld 1907BJ06
|--T. levior Lendenfeld 1907FS14
`--T. swinhoei Gray 1868FV09
*Type species of generic name indicated
References
[BJ06] Barnich, R., & D. Janussen. 2006. Die Typen und Typoide des Naturmuseums Senckenberg, Nr. 86. Type catalogue of the Porifera in the collections of the Senckenberg Museum in Frankfurt am Main, Germany. Senckenbergiana Biologica 86 (2): 127–144.
[FP11] Fromont, J., & A. Pisera. 2011. A new species of the lithistid sponge genus Manihinea (Demospongiae: Theonellidae) from Western Australian waters. Records of the Western Australian Museum 26 (2): 109–114.
[FS14] Fromont, J., & A. Sampey. 2014. Kimberley marine biota. Historical data: sponges (Porifera). Records of the Western Australian Museum Supplement 84: 69–100.
[FV09] Fromont, J., & M. A. Vanderklift. 2009. Porifera (sponges) of Mermaid, Scott and Seringapatam Reefs, north Western Australia. Records of the Western Australian Museum Supplement 77: 89–103.
[MC15] Morrow, C., & P. Cárdenas. 2015. Proposal for a revised classification of the Demospongiae (Porifera). Frontiers in Zoology 12: 7.
[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.