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|Morphology||Ecology and taphonomy||External Literature Search||Age range and collections|
Rhynchonellata - Protorthida - Skenidiidae
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If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.
|C. M. O. Rasmussen et al. 2012||Shell strongly ventri-biconvex, transverse to subtriangular in outline. Maximum width at hinge line. Anterior commissure sulcate. Ventral valve un-evenly convex, almost triangular or subpyramidal with marked umbo. Apex is positioned more posterior than hinge-line. Ventral interarea high, weakly apsacline. Delthyrium high, wide. Dorsal valve weakly convex with sulcus stronger at the anterior margin. Dorsal interarea wide, strongly anacline. Notothyrium wide. Simple costate to weakly parvicostellate ornamentation, usually with 15 costae on ventral valve and 13 costae on the dorsal valve.
Ventral interior with large deltidiodont teeth supported by dental plates that fuse medianly to form a spondylium simplex. The spondylium simplex is supported, at a low angle, by a very small ventral median septum. Dorsal interior with marked, blade-like cardinal process. Notothyrium open. Deep sockets are defined anteriorly by relatively long, moderately divergent brachiophores, supported by plates that fuse to form the cruralium converging onto linear, dorsal median septum that extends to anterior margin. Some specimens have a pair of low side septa or muscle bounding ridges that originate on the valve floor posteriorly and converge to the median septum near the anterior margin.