Citation: Cycladophoridae - Suzuki in Sandin et al. 2019Taxonomic rank: family (new classif)Taxonomic discussion: Cycladophorids are very similar to the theopiliids (a group of plagiacanthids) in overall morphology but are quite distinct in molecular analyses (Sandin et al. 2019). In addition to comments in Sandin et al. 2019, it can also be noted that, although not completely reliable, the large majority of theopiliids have smooth, round spines extending from the cephalis, while cycladophorids generally have bladed cephalic spines. Cycladophorids usually have a better developed ring at the base of the thorax, often being expressed also internally as a narrow internal basal septum. - dl
Initial spicule with A-, V-, D- and two L-rods, and an MB. No PR and No tubular cephalis horn. Test robust, helmet-conical, consisting of two segments with or without frill-like fringe. Cephalis small, spherical, and pore-less or relict pores; distinctive from thorax; three wing-like rod or rims on upper thoracic wall. Remarks. This new family is newly proposed to separate genus Eucecryphalus, the type genus of the family Theopiliidae, from Cycladophora which was used to belong to the Theopiliidae. More study needs to determine differences between Cycladophoridae fam. nov. and Theopiliidae. The former’s test is robust whereas the latter’s one is fragile. Superfamily is not determined to Cycladophoridae because nothing is known about the phylogenetic relationship with the Mesozoic family Neosciadiocapsidae. Cycladophoridae fam. nov. differs from the Superfamily Lychnocanoidea in that the latter has three distinctive feet which are connected through thoracic rims from A-, V-, and two L-rods. Cycladophoraidae fam nov. is easily distinguished from the Superfamily Pterocorythoidea in having a pterocorythid cephalic structure with special lobes.
Biogeography and Palaeobiology
Biostratigraphic distribution
Geological Range: Last occurrence (top): Extant. Data source: Total of ranges of the species in this database First occurrence (base): within Paleogene Period (23.03-66.04Ma, base in Danian stage). Data source: Total of ranges of species in this database
Plot of occurrence data:
Range-bar - range as quoted above, pink interval top occurs in, green interval base occurs in.
Triangles indicate an event for which a precise placement has been suggested. Parent: Theoperidae
References:
Cycladophoridae compiled by the radiolaria@mikrotax project teamviewed: 17-10-2026
