Stull Shale, Neochonetes granulifer
The brachiopod Neochonetes granulifer (Owen) is inferred to be an “opportunistic species" of the Stull Shale Member, Kanwaka Formation (Upper Pennsylvanian) in southwestern Iowa. The "opportunism" of this species is restricted to Horizon B of the Stull, but this restriction is evidently masked by the abnormally high number of N.granulifer in Horizons C and D, its shells inferred to have been reworked from B. The presence of this species as an opportunist is characteristic of the high physiological stress on the community of Horizon B as evidenced by the low brachiopod (and overall) diversity. Neochonetes granulifer satisfies most of Levinton' s (1970) criteria for recognition of "explosive opportunists," primarily by its sudden "population explosion" in a narrow stratigraphic range, its dominance of the fauna by 95%, the poor sorting of its shell size fractions, and its presence in a relatively young, low diversity-community.
Proceedings of the Iowa Academy of Science
©1976 Iowa Academy of Science, Inc.
Jacobs, Stephen Emanuel
"Neochonetes Granulifer, An Explosive Opportunist from the Stull Shale (Upper Pennsylvanian) in Southwestern Iowa,"
Proceedings of the Iowa Academy of Science, 83(1), 20-22.
Available at: https://scholarworks.uni.edu/pias/vol83/iss1/5