1971  Kayutoceras Ruzhentsev & Ganelin: 59.

Type species: Kayutoceras triangulare Ruzhentsev & Ganelin, 1971,p.60 [OD].

A:   Early whorls triangular-subglobular, involute, with moderately wide umbilicus. Later stages with narrow umbilicus and
      normal coiling.
B,F: Sculpture consisting of irregularly located longitudinal lirae; two tracks of thicker lirae on ventral side.
D:   Strong constrictions on early stages.
G:   Height of median saddle reaching two third of entire ventral lobe.

[Only type species known].

[Ruzhentsev & Ganelin, 1971, p.59]: Shell triangular-spheroconic in early stages of morphogenesis, with triangular coiling,
and pachyconic in late stages, with normal coiling. Whorls range from extremely to completely involute. Umbilicus
moderately narrow, triangular in juvenile specimens, round in adult specimens. Sculpture represented by irregularly
located lirae and lines intersecting them. Two "tracks" of thicker and sparser lirae on ventral side. Lines form well-
developed ventral and lateral sinuses separated by a projection coinciding with the "tracks". Sharp constrictions in
early stages, three per whorl, located near umbilicus perpendicular to sides of triangle; they are also maintained in
middle stages, but then die out. Ventral lobe is fairly broad (wl/hl~ 1.00).