The figure below shows the distribution of samples containing the orthid brachiopod Platystrophia.
Platystrophia is an uncommon orthid brachiopod in the MRV strata.
- Platystrophia King, 1850 [*Terebratulites biforatus Von Schlotheim, 1820]
- Spriferoid in outline, hinge line commonly mucronate, strongly biconvex, costate and finely pustulose; ventral muscle field elongate, with broad adductor scars and commonly elevated on platform of secondary shell in adult valves; cardinal process low, ridgelike.
M. Ord. - U. Sil., cosmopolitan
- Family Plectorthidae Schuchert & Le Vene, 1929
- Interareas and hinge lines of variable length, delthyrium and notothyrium open; teeth with oblique fossettes, supported by strong dental plates extending anteriorly, ventral muscle field variable but commonly elongately cordate; cardinal process almost invariably present and differentiated into crenulated myophore and shaft in adult shells; brachiophore bases either convergent onto floor of brachial valve near junction of cardinal process and median ridge dividing quadripartite adductor scars and ankylosed to concave fulcral plates, or rarely divergent and replacing fulcral plates; ventral and dorsal mantle canal systems saccate.
L. Ord. - U. Sil.
- Order Orthida Schuchert & Cooper, 1932.
Treatise on Invertebrate Paleontology, H325.