Parasecuicollacta bipola, from Won et al. (2002).

Belongs within: Spumellaria.

The Haplentactiniidae are a group of radiolarians known from the Middle Cambrian to the Early Permian, characterised by a simple initial spicule formed by the intersection of spines in a single center (Afanasieva et al. 2005).

Characters (from Afanasieva et al. 2005): Latticed wall of external shell and inner frame in shape of six-rayed spicule, rays of which are connected to external three-bladed or rodlike main spines.

    |--Pseudorotasphaerinae [Pseudorotasphaeridae]AA05
    |    |--Pseudorotasphaera Noble 1994AA05
    |    |--Cancellosphaera Afanasieva 2000AA05
    |    |--Intracorpus Won 1997AA05
    |    |--Parvalanapila MacDonald 1998AA05
    |    |--Stylactinosphaera Noble 1994AA05
    |    |--Syntagentactinia Nazarov 1980AA05
    |    |--Russirad Afanasieva 2000AA05
    |    |    `--R. kazintsovaeAA05
    |    `--Diparvapila MacDonald 1998AA05
    |         |--*D. hicocki MacDonald 1998WBN02
    |         |--D. pygmaea Won, Blodgett & Nestor 2002WBN02
    |         `--D. saintrochae MacDonald 1998WBN02
    `--Haplentactiniinae [Rotasphaeridae]AA05
         |--Archeoentactinia Won in Won & Below 1999AA05
         |--Gracilentactinia Kozur & Mostler 1989AA05
         |--Haplopolus Li 1995AA05
         |--Magnentactinia Won 1997AA05
         |--Protobiramus Won in Won & Below 1999AA05
         |--Rotasphaera Noble 1994AA05
         |--Wonella Afanasieva 2000AA05
         |--Haplentactinia Foreman 1963AA05
         |    |--H. alekseeviAA05
         |    |--H. aperticuvaAA05
         |    |--H. armillataAA05
         |    |--H. barskoviAA05
         |    `--H. labirinthicaAA05
         `--Parasecuicollacta Won, Blodgett & Nestor 2002WBN02
              |--*P. bipola Won, Blodgett & Nestor 2002WBN02
              |--P. glaebosa (MacDonald 1998) [=Secuicollacta glaebosa]WBN02
              |--P. hexactinia Won, Blodgett & Nestor 2002WBN02
              |--P. multispinosa Won, Blodgett & Nestor 2002WBN02
              |--P. nannoglobosa Won, Blodgett & Nestor 2002WBN02
              |--P. resodiosae (MacDonald 1998) [=Secuicollacta resodiosae]WBN02
              `--P. teli (MacDonald 1998) [=Secuicollacta teli]WBN02
Nomen nudum: Labyrinthia magna Maletz & Bruton 2007MB07

*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.

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

[WBN02] Won, M.-Z., R. B. Blodgett & V. Nestor. 2002. Llandoverian (Early Silurian) radiolarians from the Road River Formation of east-central Alaska and the new family Haplotaeniatumidae. Journal of Paleontology 76 (6): 941–964.

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