Figure 2

(a) The environment of the locality; site 1, mangrove forest near Ha Tien Town. (b) The environment of the locality; site 2, Ba Tai mangroves. (c) Shell morphology of Naranjia sp. (Specimen No. ScNM487). This specimen was collected from site 1 (Fig. 1). Scale bar = 1 mm. Shell length (SL) is around 6.6 mm. Deposited in Tohoku University. (d) Shell morphology of Naranjia sp. (Specimen No. ScNM488). This specimen was collected from site 1 (Fig. 1). Scale bar = 1 mm. SL is around 7.2 mm. Deposited in Tohoku University. (e) Operculum of Naranjia sp. (Specimen No. ScNM488). Above: the front side, below: the back side. Scale bar = 1 mm. Deposited in Tohoku University. (f) Live specimens of Naranjia sp. from site 1. Molecular data of these specimens were not examined. (g) Head and organs of mantle cavity of Naranjia sp. from site 1. (Specimen No. 96v2018-10/4). Deposited in Federal Scientific Center of the East Asia Terrestrial Biodiversity (FSCEATB). Scale bar = 1 mm. al anal lobe, bv blood vessel, ct opposed ciliary tracts, e eye, he heart, hg hypobranchial gland, ki kidney, m mantle, p papillae on the distal surface of the spermovipositor, pn pneumostome, pr prostate gland, s snout, so spermovipositor, te tentacle.