radiolaria - rads_cenozoic - Dictyophimus splendens

Citation: Dictyophimus splendens Clark & Campbell 1942

Basionym: Dictyophimus splendens

Synonyms:
1944 Pterocorys (Pterocyrtidium) splendens - Campbell and Clark p.46; pl. 6, figs. 16, 19, 20
1986 Dictyophimus splendens - Caulet p.852
1995 Dictyophimus splendens - Morley and Nigrini p.79; pl. 7, figs. 3, 4

From Suzuki Paleotax db:

1942 Dictyophimus (Dictyophimium) splendens n. sp. Clark & Campbell p. 66-67, pl. 9, fig. 34

Taxonomic discussion: (Campbell and Clark) 1944, p. 46, pl. 6, figs 19, 20 as Pterocorys; Morley and Nigrini 1995; l Paleogene; Lychnocanoma splendens (Clark & Cambell)

Original description: Shell smooth, generally small and bell-shaped, with a short, apical horn and long feet; apical horn very short, small, conical, tip sharp, its surface hyaline; cephalis elongate subhemispherical with asymmetrically rounded, bulging sides, its cavity globose, its aperture very wide, collar stricture well-defined, walls uniformly thin, surface reticulate with concave interspaces; thorax widely campanulate, the bosoms greatly swollen between the vertical ridges, reaching the greatest diameter at about the level of the origin of the feet, anti rounded off distally to the wide, flattened, oral region, whose diameter is approximately 0.87 of the maximum diameter, above this region forming a peristome, the surface of the thorax with regular rows of pores, about eight in a vertical row, the pores uniform in diameter and distance, large and prominent; feet three, equal, equidistant, arising from the three angles which begin at the base of the cephalis below the collar and continuing as local bands of clear shell substance, free of pores along the thorax and hardly modifying the thoracic contour save as they are slightly elevated as indistinct, vertical ridges; feet conical, their length greater than the widest diameter of the thorax, conical, strongly curved inward and resembling great claws, their bases very wide, appressed, lenticular at the base with the broad axis vertical, later conical, the bases with angles or fins strong near the base and decurrent distally, the tips bluntly pointed, the surface hyaline; aperture of thorax wide, circular, simple but with a thin rim.
Remarks on original description: [The authors here list this species under the subgeneric name Dictyophimium and include the subgeneric name in the species name.

Description

Morley and Nigrini 1995 - Pterocorys splendens

Cephalis hemisphaerical, poreless, hyaline. Inside the cephalis both the apical and vertical spines are free of the shell wall. Externally the apical spine is prolonged into an unusually long cylindrical horn tapering to a point distally. In our North Pacific material, the horn is up to four times as long as the cephalothorax, but in tropical material it may even be longer. Campbell and Clark's (1944) original description described the horn as sinuous but it may also be straight or curved. Collar stricture indistinct. thorax conical, thick-walled, sometimes thorny, with subcircular pores increasing in size distally, 4 to 6 on a half equator at the base of the thorax. Indistinct thoracic ribs become external just above the termination of the thorax and are prolonged into three weakly bladed or cylindrical wings tapering to a point distally. Wings diverge freely, forming an extension of the conical line of the thorax. Thoracic termination smooth or may have irregularly placed, inwardly curving teeth or projections or other indications of the beginnings of an abdomen. Abdomen irregular, varying in state of development and having pores similar to those on the thorax. Termination ragged. Dimesions (basd on 20 specimens). Length of cephalis= 15-22 ìm, length of thorax= 55-100ìm, length of abdomen= up to 45ìm, maximum breadth of cephalis= 18-30ìm, maximum breadth of thorax= 65-100ìm, length of wings= up to 65ìm, length of apical horn= up to 275ìm. Campbell and Clark (1944) report a length of 370ìm for the apical horn. Distinguishing characters. The extraordinary length of the apical horn of this species distinguishes it from all others.

Remarks: It is likely that the form described by Riedel (1952, p.7, pl.1, fig.2) as Pterocorys splendens Campbell and Clark albatrossensis Riedel from the western tropical Pacific is a synonym of Dictyophimus splendens, but it would be necessary to examine topotypic material to verify this synonymy.

Biogeography and Palaeobiology

Biostratigraphic distribution

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"

References:

Campbell, A. S. & Clark, B. L. (1944). Miocene radiolarian faunas from southern California. Geological Society of America, Special Papers. 51: 1-76. gs

Clark, B. L. & Campbell, A. S. (1942a). Eocene radiolarian faunas from the Mt. Diablo area, California. Geological Society of America, Special Papers. 39: 1-112. gs

Morley, J. J. & Nigrini, C. A. (1995). Miocene to Pleistocene radiolarian biostratigraphy of North Pacific Sites 881, 884, 885, 886, and 887. Proceedings of the Ocean Drilling Program, Scientific Results. 145: 55-91. gs

Missing or ambiguous references: Caulet 1986;

Dictyophimus splendens

Taxonomy

Description

Biogeography and Palaeobiology

Biostratigraphic distribution

References:

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