A snail reported from Bacan Island.
The description of 5 shells from the 2022 expedition gives shell height 17.3–20.8 mm; sex and adult stage are not reported.
In the 2022 Bacan Island survey, Papuina rhynchostoma was collected at Sumae Village in karst forest at 54 m on 1 June. Table 1 lists 17 individuals, 3.1% of the survey total. The voucher entry is MZB Gst. 22.938/17. In this paper, Bacan Island is the only known locality reported for the species.
The shell description is based on five specimens: height 17.3–20.8 mm (mean 19.7), diameter 19.9–24.8 mm (mean 23.2), with 5–5.5 whorls. Aperture height is 7.0–10.0 mm and aperture diameter 9.2–14.2 mm. The shell is brownish white with yellowish stripes; its umbilicus is closed and the slanting aperture has a slightly thickened outer lip.
An extinction-risk assessment has not been added yet.