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Pervosphaeridium monasteriense

Pervosphaeridium monasteriense Yun, 1981

Holotype: Yun, 1981, pl.5, fig.3; Fensome et al., 1991, fig.1 - p.681
Paratype: Yun, 1981, pl.5, fig.5
Locus typicus: Timmermann brickyard near Esbeck, Germany
Stratum typicum: Early Santonian
Translation Yun, 1981: Fensome, 1991, p. 682-683

Original diagnosis: Yun, 1981, p. 28
The rounded, triangular central body bears slender, occasionally bifurcate processes, most of which are basally interconnected by ribs. The processes consist of a solid, always simple inner spine, which is formed by the endophragm and which may be more or less reduced, and a transparent, distally open outer envelope which arises from the periphragm and may enclose two spines simultaneously.

Original description: Yun, 1981, p. 28
The ovoidal central body, which is wider antapically, consists of a perforated, finely folded and ribbed endophragm and a very delicate smooth periphragm. The three different endophragmal structures are radially arranged around each spine. The rows of fine folds and the perforations which are parallel to the folds are numerous around each spine, whereas only 3-4 strong ribs occur. These structures, which are especially evident at the spine bases, unite with those of the neighboring spines. The thin, long inner spines expand sharply immediately below their distal ends and have truncate tips. They show no surface structure, except basally, and usually extend into the tip of the surrounding envelope. The outer envelopes loosely enclose the individual spines with a relatively large pericoel. However, two outer envelopes occasionally unite in the lower half of the spines to form a common envelope around two neighboring inner spines. The outer envelope tapers more rapidly than the inner spine so that both layers are in contact distally. Only rarely does an outer envelope occur which does not enclose an inner spine. The length of the processes varies between 1/2 and 2/3 of the maximum diameter of the central body. A large precingular archeopyle is formed by the loss of 2 paraplates.
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