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Landouria bella and Landouria monodon (Camaenidae Pilsbry 1895), new species from Thailand

NEWS - Researchers described the genus Landouria (Godwin-Austen, 1918) and identified two new species, Landouria bella and Landouria monodon. The team from Chaiyaphum Rajabhat University in Chaiyaphum and Mahasarakham University in Maha Sarakham noted that the two species were distinct from each other in the genus.

Landouria bella and Landouria monodon (Camaenidae Pilsbry 1895), new species from Thailand 1

Hirano et al. (2014) suggested that Landouria is a junior synonym of Aegista. In fact, a unique characteristic shared by all Landouria members in Thailand is the absence of a dart sac and a stimulatory organ, a combination of characters that are considered to define the family Camaenidae.

Benchawan Nahok and team showed that Landouria and Aegista are two distinct genera. Landouria has a small, compressed shell, a wide, open umbilicus, and the presence of flagella of various shapes. To date, more than 50 species have been recorded in the genus.

L. bella was collected from isolated limestone hills in Ratchaburi and Phetchaburi provinces, western Thailand. Small, concave-rounded shell without peripheral keel, presence of small and thin lamellae on the columellar side of the inner aperture, long, cylindrical, bent distally flagellum, short penis with rounded verge, short and thick free oviduct and vagina.



L. monodon was collected from sandstone hills in Kalasin Province, northeastern Thailand. The shell is concave-conical with blunt peripheral keel, thick prominent lamellae on the columellar side of the inner aperture, short, finger-shaped, bent distally flagellum, long penis with small and short verge.

Landouria bella and Landouria monodon (Camaenidae Pilsbry 1895), new species from Thailand 2

L. bella differs from all other species from Thailand by its concave and rounded shell. Other Thai Landouria species usually have slightly angular to prominent keels on the edges, as seen in L. monodon. The presence of small and thin columellar lamellae on the inner aperture of L. bella resembles that of L. monodon, but is more prominent.

Original research

Nahok B, Chanlabut U, Tumpeesuwan S, Tumpeesuwan C (2024) Two new species of Landouria Godwin-Austen, 1918 (Gastropoda, Camaenidae) from Thailand, with a key to Thai species. ZooKeys 1208: 347-362. DOI:10.3897/zookeys.1208.117056

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