|Basic info||Taxonomic history||Classification||Relationships|
|Morphology||Ecology and taphonomy||External Literature Search||Age range and collections|
Hesperorthis australis exitis
Rhynchonellata - Orthida - Hesperorthidae
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. Williams 1962||Subcircular, piano-convex Hesperorthis with a pedicle valve almost one-third as deep as long and a slightly sulcate brachial valve nearly four-fifths as long as wide; ornamentation consisting of 30-33, less commonly 28 or 29, narrowly rounded costae with a wave-length of just over 0.5 mm. at 5 mm. antero-medianly of the dorsal umbo, as well as fine parvicostellae in the interspaces and delicate concentric lamellae; ventral muscle-field subtriangular, almost three-quarters as wide as long and extending anteriorly for about one-third the length of the pedicle valve.|