|Basic info||Taxonomic history||Classification||Relationships|
|Morphology||Ecology and taphonomy||External Literature Search||Age range and collections|
Orthothecida - Gracilithecidae
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.
|J. M. Malinky and C.B. Skovsted 2004||Orthothecid hyolith with shallow ventral furrow, grading into blunt lateral edges that extend to form a distinct protrusion along the entire length of the lateral edges of the conch (emended from Syssoiev 1968: 39).|