Recognition
''Pachylyroceras'' produced a large shell that is moderately evolute to moderately involute and thickly discoidal to subglobular, with a rather wide umbilicus. Surface sculpture consists of coarse, widely spaced longitudinal lirae. Constrictions where present are wide and deep. Its suture has a narrow bifurcated ventral lobe with slightly divergent to subparallel sides and a median saddle less than half the height.Taxonomic position
''Pachylyroceras'', named by Ruzhentsev & Bogoslovskaia (1971), is included in the Neoglyphiocerataceae, (sometimes written Neoglyphioceratoidea), but its position within the superfamily varies according to whose classification. The revised version of the Treatise, Part L (W. M. Furnish et al. 2009 ) includes ''Pachylyroceras'' as well as '' Alaoceras'', '' Caenolyroceras'', '' Dombarigloria'', and '' Lyrogoniatites'' in the Neoglyphioceratidae and subfamily Lyrogoniatitinae. Dieter Korn (2006) also included ''Pachyhlyroceras'' in the Lyrogoniatitinae, but in the family Cravenoceratidae. Saunder, Work, and Nickoleava (1999) also included Pachyhlroceras in the Cravenoceratidae, but without regarding subfamilies. Others (GONIAT) include Pachylyroceras in the Gravenoceratid subfamily Cravenoceratinae instead. The Treatise (Miller, Furnish, and Schindewolf 1957) includes ''Lyrogoniatites'', from which ''Pachylroceras'' is probably derived, in the subfamily Neoglyphioceratinae along with '' Neoglyphioceras'', but in the superfamily Goniatitaceae. The might suggest where ''Pachylyroceras'' might have been put, if it had been named and described at that time.References