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1972 Theocalyptra tetracantha - Bjørklund and Kellogg pl. 1, figs. 3, 8a-b
1976 Theocalyptra tetracantha - Bjørklund pl. 22, figs. 15-17
1989 Cycladophora tetracantha - Lazarus and Pallant p.356; pl.2, fig.6-7
From Suzuki Paleotax db:
1972 Theocalyptra tetracantha n. sp. Bjørklund & Kellogg p. 390, pl. 1, fig. 3, 8a, 8b, text-figs. 11a, 11b
1976 Theocalyptra tetracantha Bjorklund et Kellogg Bjørklund pl. 22, figs. 15-17
1978 Theocalyptra (?) tetracantha Bjorklund et Kellogg Dzinoridze et al. pl. 26, fig. 9
1979 Eucecryphalus tetracantha (Bjorklund et Kellogg) Kozlova & Petrushevskaya p. 134-135, figs. 372, 373
1985 Theocalyptra tetracantha Bjorklund et Kellogg Tochilina pl. 8, fig. 4
2005 Theocalyptra tetracantha Bjørklund & Kellogg Funakawa & Nishi pl. 4, figs. 12a, 12b
Catalog entries: Theocalyptra tetracantha
type image: T. tetracanthaOriginal description: Test thin-walled, smooth-surfaced, divided into three segments. Cephalis small, hemispherical, bearing two stout, three-bladed horns, a vertical horn in a lateral-oblique position, anda longer apical horn with a highly distinctive structure. About halfway between its base and its tip, the apical horn branches out into four thornlike spines, one spine an extension of the horn along its vertical axis, the remaining three spines laterally and slightly upward-directed extensions of each of the three blades. There is also a rare five-spined form. Cephalic pores small, circular and shallow-set. Collar stricture indistinct. Thorax campanulate, with large, circular to oblong pores increasing in size toward the abdomen. In some of the better-preserved individuals, the thoracic pores contain a delicate meshwork, and the thorax bears a thin dorsal spine. Lumbar stricture a distinct hyaline ring. Abdomen attatched to proximal margin of lumbar ring so that ring forms an internal collar around open mouth. Abdomen variable, in some cases absent, often broken, generally containing two rows of circular to oblongpores, somewhat larger than those of thorax, set in a thin, delicate lattice which is expanded and flattened like the brim of a hat.
Lazarus and Pallant 1989 - Theocalyptra tetracantha Conical thorax having little or no upper-thorax/lower-thorax differentiation, medium-sized subspherical cephalis having small partially filled circular pores. Thorax moderately flared; regular-to-flat, uninflated outline; pores rounded, hexagonal; bars thin, circular. Thorax termination ragged in incomplete specimens, marked by strongly flared basal spines in some specimens. Two apical horns, three-bladed, one more axially located, larger, and with apical thorns in most specimens. Second apical horn smaller, projects at angle from near cephalic suture. In the recent revision of cycladophorids by Lombari and Lazarus (1988), the scope of Theocalyptra is restricted to only those forms having extremely flat, flared thoracic architecture. C. tetracantha clearly does not possess this type of thorax. Instead, it possess all diagnostic characteristics of Cycladophora (Lombari and Lazarus, 1988) and thus is transferred to this latter genus. Occurrence: Rare to few, Oligocene to early Miocene.
Published descriptions
Geological Range:
Last occurrence (top): within Paleogene Period (23.03-66.04Ma, top in Chattian stage). Data source: Lazarus et al. 2015 - "P age group"
First occurrence (base): within Paleogene Period (23.03-66.04Ma, base in Danian stage). Data source: Lazarus et al. 2015 - "P age group"
Plot of occurrence data:
Bjørklund, K. R. & Kellogg, D. E. (1972). Five new Eocene radiolarian species from the Norwegian Sea. Micropaleontology. 18(3): 386-396. gs Bjørklund, K. R. (1976). Radiolaria from the Norwegian Sea, Leg 38 of the Deep Sea Drilling Project. Initial Reports of the Deep Sea Drilling Project. 38: 1101-1168. gs Lazarus, D & Pallant, A (1989). Oligocene and Neogene Radiolarians from the Labrador Sea, ODP Leg 1051. Proceedings of the Ocean Drilling Program, Scientific Results. 105: 349-380. gs References:
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Cycladophora tetracantha compiled by the radiolaria@mikrotax project team viewed: 22-1-2026
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