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Spiniferites cruciformis

Spiniferites cruciformis Wall and Dale in Wall et al., 1973

Holotype: Wall and Dale in Wall et al., 1973, pl.1, figs.2-3
Locus typicus: Black Sea, core 1451 G
Stratum typicum: Early Holocene

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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.

Spiniferites cruciformis Wall and Dale in Wall et al., 1973. Diagnosis from Wall and Dale in Wall et al. (1973, p.21-22). Dinoflagellate cysts of the genus Spiniferites with a cruciform, moderately dorsoventrally compressed test ornamented with variable sutural septa that include perforated flanges projecting laterally from the apices and from lateral equatorial points. Sometimes there are processes rather than septa. The tips of the processes are bifurcate or trifurcate and have a wide angle of divergence, so that the branches run tangential to the body surface. The septa are more prominent at the apex, antapex, along the lateral equatorial cingular areas and in the lateral and intercalary posteroventral areas. There are four apical plates. This species is adapted to low salinity environments. Size: body length 46-65 µm, width 34-56 µm, depth ca. 28 µm, ornamentation extending up to 28 µm, archeopyle 18 x 25 to 25 x 21 µm.
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Original diagnosis: Wall and Dale, 1973, p.21
Dinoflagellate cysts of the genus Spiniferites with a cruciform, moderately dorsoventrally compressed test ornamented with variable sutural septa that include perforated flanges projecting laterally from the apices and from lateral equatorial points.

Description: Wall and Dale, 1973, p.21
The body is ornamented by sutural septa and processes, and has gonyaulacacean reflected tabulation, as typical for species of Spiniferites. The elements of ornamentation include very low sutural ridges 1 µm or less in height, more elevated sutural septa, and sometimes conspicuous membranous flanges. The latter may be entire or extensively perforate, and their distal margins are often deeply indented. The reflected tabulation can be represented by the formula 4', 0a, 6", 6c, 6''', 1p, 1'''', but, in fact, it is incompletely developed ventrally.
The apical series includes two pentagonal dorsal plate-areas (2', 3') and is typical for this genus. It probably also includes two much smaller ventral plate-areas, but these are not so clearly visible. The dorsal precingular plate-areas (2", 3", 4") are clearly demarcated by low sutural septa. The equatorial cingulum shows good reflected tabulation except mid-ventrally, where it becomes obscure as the ornamentation is progressively reduced. The posteroventral and lateral surfaces of the cyst show several interesting features as defined by the sutural septa. These include an almost square posterior sulcal platelet area (ppl) at the base of the mid-ventral area and an adjacent posterior intercalary area (1p), which frequently is surrounded by strong flanges. Two conspicuous sutural septa connect these last two areas with the cingulum.
Dimensions: Body length 46-65 µm; width 34-56 µm, depth ca. 28 µm.
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