Comments -- The classic "phragmodoform" element above consists of a bowed blade-like row of denticles with an anterior cusp, and an enlarged denticle at the position of maximum inflection.  There are actually three similar elements that form the Sc, Sb and Sa portions of the apparatus, and these are similar over several species, as well as being shared by other genus such as Scyphoidus.

Some additional examples include AZ1HF04 - AZ1HF25 in the Specimen Index

References :

Bergstrom and Sweet, Conodonts from the Lexington Limestone (Middle Ordovician) of Kentucky and its Lateral Equivalents in Ohio and Indiana.  Bul of Amer Pal vol 50, No 229, pg 366

Leslie, Stephen A.  Mohawkian (Upper Ordovician) Conodonts of Eastern North America and Baltoscandia.  J of Pal.  vol 74, No. 6 p. 1124  (regarding Scyphoidus, page 1139)

Leslie, Steven A, Bergstrom, Stig M, Element Morphology and Taxonomic Relationships of the Ordovician Conodonts Phragmodus Primus Branson and Mehl 1933, the Type species of Phragmodus Branson and Mehl 1933 and Phragmodus Undatus Branson and Mehl, 1933.  J of Paleont. V. 69, NO 5, 1995