|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.
|E. Hitchcock 1848||Tetradactylous: three toes directed forward; the fourth being a prolongation backward of the outer toe. Heel stout, expanding posteriorly. Hind and fore feet unequal, resembling three swords, or daggers, in a complex sheath.|