|Basic info||Taxonomic history||Classification||Relationships|
|Morphology||Ecology and taphonomy||Age range and collections|
Lingulata - Lingulida - Lingulidae
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.
|Emig and Herrera 2006||Shell thin, elongate oval in shape; externally, two diverging medio-lateral grooves (internally ridges) extend from the umbonal region to the anterior margin, and a narrow median groove (a septum internally) extends from the umbonal region to the anterior margin of the dorsal valve but in the ventral valve only over the anterior half of the shell. Asymmetrical muscle system with three internal oblique muscles; unpaired posterior adductor muscle; no vascula media observed. (Note: these three characters are prerequisite to a diagnosis of the family Lingulidae – see Emig 2003).|