Fig. 3 in Thomasaria vs. Pyramidalia conundrum in Devonian brachiopod systematics solved: An argument to formalize epitypification under the ICZN

Fig. 3. Transverse serial sections of spiriferide brachiopod Thomasaria simplex (Phillips, 1841) through shell NHMUK PI B 2807 (topotype) from the Givetian of Wolborough, England, UK. Sections through ventral (A) and dorsal (B) valves. The schematic drawings on the left of each section describe the direction of sectioning (see text). Distances measured in millimetres from the tip of the ventral and dorsal umbos, respectively. Gray areas denote local silicification.