Aaron is from Upland, California. Dorsal valve of Platystrophia acutilirata , found in the Whitewater formation. This orthid brachiopod is characterized by having a low, rounded fold, three nearly equally developed plications in the sulcus, and by having ten or more plications on each side of the sulcus. Platystrophia cypha Orthid brachiopods first appeared in the middle Lower Cambrian and are the most primitive articulate brachiopods. There are 340 genera of orthid brachiopods.
Phylogenetic analysis suggests that orthid brachiopods are polyphyletic.
The fold and sulcus of orthid brachiopods are usually very shallow and sometime are even absent. Distinct interarea are found on each valve of orthides. Through the Cambrian and Ordovician orthid brachiopods were the dominant articulates, making them one of the more common brachiopods. They almost entirely died out due to the Late Ordovician extinctions but did not fully succumb to extinction until the Permian catastrophe. They differ from other Platystrophia by only having 8 or 9 plications on each side of the sulcus.