Atopos gravelyi Ghosh, 1915

Mitchueachart, Bowornluk, , Chirasak Sutcharit, Panha, & Somsak, 2025, The slug genusAtopos Simroth, 1891 (Systellommatophora: Rathouisiidae) from Myanmar with description of a new species, Raffles Bulletin of Zoology 73, pp. 43-53 : 45

Atopos gravelyi Ghosh, 1915

Atopos gravelyi Ghosh, 1915: 153 , pl. 16, figs. 1–7, pl. 17, figs. 8–17, pl. 18, figs. 18–26, pl. 19, figs. 27–29, type locality: Dawna Hills near Thingannyinaung [probably in the area of Myawaddy District, Kayin State, Myanmar]; Manganelli et al., 2023: 91, 93.

Diagnosis. Upper part of mid-lateral line sepia, decorated with dark brown blotches and small spots. Lower part of mid-lateral line blue, decorated with slaty-black blotches and spots. Mid-lateral line with pale buff blotches above and dark-clove brown band below. Mid-dorsal keel rounded and prominent. Dark clove-brown mid-dorsal line. Foot pale yellow. Right Simroth gland well-developed with evaginable part long, cylindrical, and longer than penis; interconnected duct and secretory part indistinguishable with a long slender shape.

Remarks. Unfortunately, no new specimens identified to this species were collected, and the type specimen could not be located.

Atopos gravelyi is superficially similar to Atopos maximus Collinge, 1903 from Thailand in terms of its colour pattern on the notum. However, A. gravelyi differs by possessing a prominent and dark clove-brown mid-dorsal line, pale buff blotches above and clove-brown band below the mid-lateral line, upper part of mid-lateral line sepia with dark brown blotches and spots, and lower part of mid-lateral line blue with slaty-black blotches and spots ( Ghosh, 1915: pl. 16, fig. 1). In addition, A. gravelyi has only a right Simroth gland, with its evaginable part longer than penis length; interconnected duct and secretory part indistinguishable and long and slender in shape ( Ghosh, 1915: pl. 19, fig. 27). In comparison, A. maximus possesses a yellowish-brown mid-dorsal line, a yellowish-brown band as the mid-lateral line with an irregular margin, slaty-blue mottling above the mid-lateral line, and a yellowish notum and decorated with scattered tiny black spots ( Collinge, 1903: pl. 11, figs. 5, 6). Moreover, A. maximus has well-developed left and right Simroth glands, evaginable part short and about one-fourth of the penis length, thin interconnected duct, and secretory part a long cylindrical shape ( Collinge, 1903: pl. 13, fig. 21). Therefore, we have retained this species as valid until new topotypic specimens as well as specimens from the other populations become available to verify the taxonomic status, intraspecific variation, and the relationship with A. maximus .