|Basic info||Taxonomic history||Classification||Relationships|
|Morphology||Ecology and taphonomy||External Literature Search||Age range and collections|
Pterobranchia - Bireclinata - Retiolitidae
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.
|A. C. Lenz and M. J. Melchin 1987||Ancora four-pronged; corona simple, of few meshes, somewhat rhomboid in profile, and square in cross-section. Rhabdosome walls (clathrium) sharply angular. Virgula central proximally, quickly moving to ventral side and becoming incorporated in, and part of, ventral wall. Horizontal lists arise alternately on left and right sides of virgula and join outer walls. Dorsal wall either of zig-zag pleural lists connected directly to outer walls, or with very short horizontal lists connecting pleural lists to outer walls. Reticulum may or may not be present, lists generally few in number and finer than clathrium, sometimes more common in proximal region and absent in distal portions, and/-Clathrial seams face in, those of the reticulum face out.|