Campanulithus falcatus, from Afanasieva et al. (2005).

Belongs within: Radiozoa.
Contains: Triangulata, Albaillellata.

The Aculearia are a group of radiolarians known from the Cambrian to the Jurassic, in which the skeleton consists of several intersecting spines. The initial form of the skeleton is a four-rayed spicule that forms the basis for subsequent modifications (Afanasieva et al. 2005).

Characters (from Afanasieva et al. 2005): Heteropolar and bilaterally symmetrical Polycystina with skeleton consisting of several intersecting spines: (1) spines intersecting in one or two centres; (2) three interconnecting spines form subtriangular frame; (3) two long columellae connected below aperture by horizontal bar, form H-frame in basal part of skeleton and subsagittal structure in apical region.

<==Aculearia [Fasciculata]AA05
    |    |--Palacantholithus Deflandre 1973AA05
    |    |    `--P. stellatusAA05
    |    `--Palaeoumbraculum Amon & Braun 1995AA05
    |         `--P. expandum Amon et al. 1995MB07
    |--Plagiacanthidae [Plagiacanthinae]AA05
    |    |--Arachnoplecta Dumitrica & Zügel 2003DZ03
    |    |    `--*A. architectonica Dumitrica & Zügel 2003DZ03
    |    |--Archaeothamnulus Dumitrica 1982AA05
    |    |--Conostylus Popofsky 1907AA05
    |    |--Cytocladus Schroder 1906AA05
    |    |--Neosemantis Popofsky 1913AA05
    |    |--Pseudocubus Haeckel 1887AA05
    |    |--Pentaplagia Cachon & Cachon 1969AA05
    |    |--Plagoniscus Haeckel 1887AA05
    |    |--Tetraplagia Haeckel 1881AA05
    |    |--Triassothamnus Kozur & Mostler 1981AA05
    |    |--Triplagia Haeckel 1881AA05
    |    |--Plagiacantha Claparède 1858AA05
    |    |    `--P. arachnoides Claparède 1855BC98
    |    |--Deflandrella Loeblich & Tappan 1961AA05 [=Campylacantha Jörgensen 1905 non Scudder 1897Lt61]
    |    |    `--*D. cladophora (Jörgensen 1905) [=*Campylacantha cladophora]LT61
    |    `--Plectophorina Loeblich & Tappan 1961LT61 [=Plectophora Haeckel 1881 non Gray 1834AA05]
    |         |--*P. triomma (Haeckel 1887) [=*Plectophora triomma]LT61
    |         `--‘Plectophora’ triacantha Popfsky 1908BC98
            |--Bissylentactinia Nazarov 1975AA05
            |--Grosmorneus Won & Iams 2002AA05
            |--Palhindeolithus Deflandre 1973AA05
            |--Xiphocabrium Deflandre 1973AA05
            |--Xiphochistrella Deflandre 1973AA05
            |--Xiphocladiella Deflandre 1973AA05
            |    `--X. cujaAA05
            `--Campanulithus Nazarov & Rudenko 1981AA05
                 `--C. falcatusAA05

*Type species of generic name indicated


[AA05] Afanasieva, M. S., E. O. Amon, Y. V. Agarkov & D. S. Boltovskoy. 2005. Radiolarians in the geological record. Paleontological Journal 39 (Suppl. 3): S135–S392.

[BC98] Bjørklund, K. R., G. Cortese, N. Swanberg & H. J. Schrader. 1998. Radiolarian faunal provinces in surface sediments of the Greenland, Iceland and Norwegian (GIN) Seas. Marine Micropalaeontology 35: 105–140.

[DZ03] Dumitrica, P., & P. Zügel. 2003. Lower Tithonian mono- and dicyrtid Nassellaria (Radiolaria) from the Solnhofen area (southern Germany). Geodiversitas 25 (1): 5–72.

[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.

[MB07] Maletz, J., & D. L. Bruton. 2007. Lower Ordovician (Chewtonian to Castlemainian) radiolarians of Spitsbergen. Journal of Systematic Palaeontology 5 (3): 245–288.

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