|Basic info||Taxonomic history||Classification||Relationships|
|Morphology||Ecology and taphonomy||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||Virgula free, attached only to ancora, extends only to level of theca 4 or 5. Corona of few lists, weakly rounded, rectangular in cross-section. Clathrium and reticulum complex and disorderly, meshes polygonal to triangular to quadrate, relatively fine proximally, becoming coarser distally. Thecae generally climacograptid proximally (pi. 3, fig. 13), more or less orthograptid distally. Thecae marked by one or two shorter, transverse, curved lists, the outer margins of which are sometimes joined by a vertical list, and by a longer and more projecting lower apertural lip. Rhabdosome rectangular in crosssection, widening abruptly proximally, and then maintaining constant width or widening very gradually. Occasional specimens narrow slightly distally. Seams of lists all face inward making distinction between clathrium and reticulum difficult; in this way it differs from other plectograptids.|