UK Ammonite Menuites
Menuites portlocki complexus
Pierre Formation
Upper Cretaceous (Campanian)
Lyman County, South Dakota
This is a wonderful example of this rare genus. It is the macroconch form and has very well preserved original shell. In several spots the shell is thin and the suture pattern can be seen. The ammonite is 7 inches across. This specimen has no repair or restoration.
The genus Menuites shows the varied differences between macroconch and the microconch. It is characterized by moderately involute coiling, very broad rounded flanks, a well rounded venter, and deep rounded umbilical walls. Strong, widely spaced ribs are present on the inner coils and at the aperture. Microconchs of the genus possess tubercles around the umbilical shoulder and ventrolateral tubercles on the living chamber, whereas the macroconch has smooth ventrolateral shoulders and either small umbilical tubercles or none.
Menuites portlocki complexus has been found in the Baculites gregoryensis Zone in South Dakota as well as other localities in Wyoming and Colorado.