1987  Kosmoclymenia (Muessenbiaergia) Korn & Price: 35.
     2002  Muessenbiaergia.-Korn & Klug: 256.
     2005  Muessenbiaergia.-Nikolaeva & Bogoslovskii: 163.

     Type species: Planulites sublaevis Münster, 1832, p.10; OD.

A:   Conch form discoidal; venter flattened, broadly rounded or narrowly rounded; flanks usually convex, sometimes
       flattened or concave; umbilicus wide or moderately wide.
B:   Fine growth lines with prorsiradiate to rursiradiate direction and biconvex course; weak ventrolateral salient; deep
       external sinus.
C-D: No ribs or spines, usually no constrictions.
E:   Stratigraphically younger species with ventrolateral groove.
G:   Suture line as in Kosmoclymenia.