This form was described in 1941; it is known from the forested areas of Mt. Tonomwan on Tonowas Island as well as from Mt. Tonnachau on Weno Island, both in the east of the Chuuk lagoon in Micronesia. [1]

The name of this form does appear in listings of extinct mollusks; thus, I will mention it here as well. [2]

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References:

[1] H. Burrington Baker: Zonitid Landsnails from Pacific islands; parts 3 and 4. Bishop Museum Bulletin 166: 201-370. 1941
[2] Claire Régnier; Guillaume Achaz; Amaury Lambert; Robert H. Cowie; Philippe Bouchet; Benoît Fontaine: Mass extinction in poorly known taxa. Proceedings of the National Academy of Sciences. 1-6. 2015

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edited: 22.01.2022