CATALOG OF ORIGINAL DESCRIPTIONS: Cyrtophormis grandis Campbell & Clark 1944

This page provides data from the catalog of type descriptions. The catalog is sorted alphabetically. Use the current identification link to go back to the main database.

Higher levels: rads_cat -> C -> Cyrtophormis -> Cyrtophormis grandis
Other pages this level: C. aculeata, C. aerostatica, C. armata, C. cingulata, C. cornuta, C. corona, C. cylindrica, C. gargantua, C. grandis, C. ob, C. ovata, C. petrushevskayae, C. pila, C. spiralis, C. tabulata, C. turricula, C. turrita

Cyrtophormis grandis

Citation: Cyrtophormis grandis Campbell & Clark 1944
Rank: species
Type locality: LL462
Type age (chronostrat): Late Cretaceous, Mesozoic.
Type specimens: pl.8, figs.18, 39
Type repository: University of California, Museum of Paleontology, Berkeley, Holotype: Slide No.34522.
Repository city: San Francisco
Described on page(s) : p.38

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Current identification:

Original Description
Shell very large, generally spindle-shaped, as a whole in upper part generally conical (55° regularly decreased to 20°) and thence in lower shell an inverted cone (16°), widest level of shell at level of union of 2 conical sections (2.5 times apertural diameter) at approximately 0.5 total length; lateral shell contour locally irregular with strictly localized bulges and dents in addition to generally rounded sides of several shell joints; apical horn acentric, conical (2°), minutely stublike, with free end squared and with 3 minute spurlike prongs; cephalis (first joint) subhemispherical, inconspicuous; thorax (second joint) larger, with bulged sides and longer than cephalis; abdomen (third joint) wider and longer than thorax and with similar contour; postabdomen (composed of 5 joints) with unequal segments, second and ultimate ones longer than others, final one 0.46 total in length; wall of cephalis thick and cavity hemispherical, wall in other parts rather uniformly thin, especially in ultimate joint; surface of first 6 joints very spiny with short, conical, thickly scattered sepaloid points which arise from subhexagons of pore frames, in lower shell, wall not so thickly bristly, final segment almost entirely free of projections; cephalis free of pores and hyaline, remaining shell joints with small, circular, very closely and fairly deeply set pores, in ultimate joint pores much more irregular (often polygonal), and much larger than elsewhere in shell; margin of shell aperture with about 12 projecting, subvertical, divergent spines which are produced from shell framework; shell framework heavy and coarse in upper joints, with concave subhexagonal frames, while in lower shell there is barely more than a thin lattice with polygonal patterns.

Size: Length, total, upward of 780µm, of apical horn, 30µm, of cephalis, 20µm, of thorax, 30µm, of abdomen, 40µm, of ultimate joint, 300µm; diameter, of aperture, 70µm, of widest level, 175µm, of pores in upper shell, 6.6µm, of pores in lower shell, up to 16.6µm.

Etymology: No information given

Extra details from original publication
Distinguishing features: There are a number of variants of this wonderful, huge species, chiefly forms with reduced length and with fewer postabdominal joints. Cyrtophormis grandis, n. sp., differs from other described species not only in its great length, but also in the strikin

Editors' Notes
The authors here list Cyrtophormis grandis under the subgeneric name Acanthocyrtis and include the subgeneric name in the species name.[comment from RadWorld database]


Campbell, A. S. & Clark, B. L. (1944b). Radiolaria from Upper Cretaceous of middle California. Geological Society of America, Special Papers. 57: 1-61. gs


Cyrtophormis grandis compiled by the radiolaria@mikrotax project team viewed: 12-5-2021

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