|Basic info||Taxonomic history||Classification||Relationships|
|Morphology||Ecology and taphonomy||External Literature Search||Age range and collections|
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.
|W. Hantzschel 1975||Bent or cracked borings, generally radiating in one plane to all sides from very small central cavity; commonly branching dichotomously; diameter several mm; always etched into shell or some host animal.|