1925  Neodimorphoceras Schmidt: 512, 600.
     1927  Texites.- Smith: 73.
     1934  Neodimorphoceras.- Schindewolf: 164.
     1937  Neodimorphoceras.- Plummer & Scott: 340.
     1950  Neodimorphoceras.- Miller & Downs: 200.
     1957  Neodimorphoceras.- Treatise: L68.
     1960  Neodimorphoceras.- Ruzhentsev: 209.
     1962  Neodimorphoceras.- Osnovy: 373.
     1975  Neodimorphoceras.- Nassichuk: 69 [see MEM5587].
     1978  Neodimorphoceras.- Yang: 160.

Type species: Dimorphoceras texanum Smith, 1903, p.126 [M].

A:   Conch form lenticular or discoidal; umbilicus almost closed. Venter rounded, rarely concave.
C:   Ribs confined to early whorls; shell surface at maturity usually rather smooth, biconvex growth lines being very faint.
G:   Prongs of ventral lobe prominently bifid; first lateral saddle subangular.

Subgenera: Neodimorphoceras (Neodimorphoceras) SCHMIDT, 1925,
Neodimorphoceras (Pinoceras) RUZHENTSEV, 1947

Neodimorphoceras (Neodimorphoceras) SCHMIDT, 1925, p.512 [* Dimorphoceras texanum SMITH, 1903, p.126; M] [= Texites SMITH, 1927, p.73, same type, OD (obj.)].

A:   Ventral side with pronounced groove appearing at a diameter of about 20 mm.

Neodimorphoceras (Pinoceras) RUZHENTSEV, 1947, p.523 [* N. (P.) daixense, p.523; OD]

A:   Ventral side broadly or narrowly rounded, without groove, even at large whorls. [Only type species known].

[Nassichuk,1975, p.69: Neodimorphoceras has a discoidal conch and the umbilicus is
nearly closed. The venter is typically narrow with a median concavity but in some
species the venter is broadly rounded and lacks a median concavity. During early
ontogenetic stages, shell ornament consists of prominent ribs which for shallow
ventrad and lateral sinuses; ribs become increasingly subdued during growth. At
maturity, ribs are absent but conspicuous growth lamellae form a moderately deep
ventral sinus and a relatively shallow lateral sinus. Delicate longitudinal lirae
occur on the mature venter of some species.

The external suture best characterize the genus; the ventral lobe is broad and
subdivided into 2 lobes by a median saddle of variable height. Prongs of the ventral
lobe are bifid with the subdivision of each prong initiating on the ventral flanks of
the prong. Tertiary lobes on each prong are subequal and asymmetric. The most
ventrad of these tertiary elements is invariably the shorter and may be narrowly
rounded or accuminate. The longitudinal axes of the tertiary elements are essentially
parallel. The first lateral saddle is broad, asymmetric, and narrowly rounded, whereas
the first lateral lobe considerably narrower and distinctly accuminate.

Sutural formula is: (V1.1 V1.2 V1.2 V1.1) LU:ID ]