Original publication: Landman, N. H. and K. M. Waage. 1993. Scaphitid ammonites of the Upper Cretaceous (Maastrichtian) Fox Hills Formation in South Dakota and Wyoming. Bulletin of the American Museum of Natural History, Number 215, 257 pp. [p. 112-119, figs. 60, 82-84].
Holotype (macroconch): YPM 23044.
Type locality: “inner bluffs of the Moreau River, northeast of the village of Green Grass and one mile west of the S.D. Rt. 63 bridge” (Landman and Waage, 1993, p. 113), Dewey County, South Dakota.
Type horizon: Pierre Shale (Mobridge Member).
Other specimens: YPM 23043, YPM 23071, YPM 23066, YPM 23067, YPM 23042, YPM 23068, YPM 23074, YPM 23077, YPM 23070, YPM 23072; also see Landman and Waage (1993).
PaleoDB taxon number: 145262.
Reference: Landman and Waage (1993).
Origin of name: “named for James F. Mellow, micropaleontologist at the U. S. National Museum” (Landman and Waage, 1993, p. 113).