1940  Diaboloceras Miler & Furnish: 527.
     1947  Trigonogastrioceras Librovich: 63 (nom.nud.).
     1957  Diaboloceras.- Treatise: L65.
     1957  Trigonogastrioceras Librovich: 255.
?   1960  Diaboloceras.- Ruzhentsev: 219.
     1962  Diaboloceras.- Osnovy: 383.
     1963  Diaboloceras.- Quinn & Carr: 111.
     1965  Paralegoceras (Diaboloceras).- Gordon: 270.
     1966  Diaboloceras.- Furnish & Knapp: 302.
     1968  Diaboloceras.- McCaleb: 65.
     1971  Rodiezmoceras Wagner-Gentis: 349.
     1975  Diaboloceras.- Nassichuk: 147.
     1977  Diaboloceras.-Saunders, Manger & Gordon: 124.
     2001 Diaboloceras.-Menning, Weyer, Wendt, Riley & Davidov: 733.

Type species: Diaboloceras varicostatum Miller & Furnish, 1940, p. 527 [OD].

[= Trigonogastrioceras LIBROVICH, 1957, p.255, type T. uralicum, p.256, OD (subj.); =  Rodiezmoceras WAGNER-GENTIS, 1971, p.349, type R. bisati, p.349, OD (subj.)].

A:    Conch large, umbilicus always wide; inner whorls exhibit triangular coiling.
B-C: Ribs on flanks weak, ornamentation reticulate.
G:    Second umbilical lobe on dorsal side of lateral lobe, not yet separate; sutural formula: [Germ.] (E1EmE1)A(LU2)U1I,
        [Russ.] (V1V1)L(U1U2):ID.

[Trigonogastrioceras has been based on an immature specimen; for discussion see GORDON, 1965, p.267. Rodiezmoceras, based on one poorly preserved specimen, has also coarse ribs, but lateral lobe lying completely on lateral side; it may be a representative of Diaboloceras or Paralegoceras - for discussion see SAUNDERS, MANGER & GORDON, 1977, p.124. For discussion of genus see NASSICHUK, 1975, p.147, see below].
 
[Nassichuk, 1975, p.147: The conch of Diaboloceras is subdiscoidal and evolute; the umbilicus is at least one-third of the diameter at maturity. Inner whorls are triangular. Shell ornament is reticulate in all stages of development. Umbilical nodes persist through all growth stages but are relatively subdued at full maturity. The suture typically has 10 lobes but only the ventral lobe is completely subdivided; an incipient lobe derived from
the umbilical lobe may occur on the umbilical wall. On several species there is no indication of incipient subdivision of the lobe and thus the suture has only 8 lobes].