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The present work contains descriptions of two new species of Landouria and a key to Thai species of this genus. Landouria bella sp. nov. is described from isolated limestone hills in Ratchaburi and Phetchaburi provinces, western Thailand. This new species is characterized by its small depressed-globose shell without a peripheral keel, the presence of a small, thin lamella on the columellar side of the inner aperture, a long, cylindrical distally bent flagellum, a short penis with a rounded verge, and a short, thick free oviduct and vagina. The second new species, Landouria monodon sp. nov. is described from sandstone hills in Kalasin Province, northeastern Thailand. This species has a depressed-conic shell with a blunt peripheral keel, a thick prominent lamella on the columellar side of the inner aperture, a short, finger-shaped, distally bent flagellum, and a long penis with a small, short verge.

Agriculture soils play a crucial role in carbon storage and food security. However, uncertainty remains about soil carbon stocks due to spatial variability. This study estimated soil carbon stocks in agricultural land and examined the impact of land use and soil properties on soil organic carbon in Ratchaburi Province, Thailand. Soil samples were collected at three depths (0-10, 10-20, and 20-30 cm) within five different land use types: cassava, coconut, paddy fields, pineapple, and sugarcane. The results revealed that soil organic carbon decreased with increasing depth. Significant differences in soil carbon and soil properties were observed among land uses. The carbon stocks at 0-30 cm depth were as follows: coconut (35.87 mg C/ha), paddy fields (31.17 mg C/ha), sugarcane (28.02 mg C/ha), pineapple (21.79 mg C/ha), and cassava (16.12 mg C/ha). The carbon stocks were significantly correlated with sand, density, clay, silt, and pH. This study highlights the impact of land use types on carbon stocks in agricultural soils and emphasizes the role of soil properties, particularly soil texture, in influencing carbon storage variability. Furthermore, the study highlights the carbon storage potential in agricultural areas, which could guide the formulation of policies to utilize agricultural land to offset CO2 emissions from other sectors.

Five new species of the terrestrial snail genus Landouria Godwin-Austen, 1918 (Camaenidae) are described from northeastern Thailand, based on shell features, radular morphology, genital anatomy, and DNA sequence data: Landouria circinata sp. nov., L. tuberculata sp. nov., L. trochomorphoides sp. nov., L. chloritoides sp. nov., and L. elegans sp. nov. These species are phylogenetically well separated from each other by mtDNA phy-logeny and COI sequence divergences of 0.073–0.156. The record of Thaitropis Schileyko, 2004 (currently synonymized with Landouria) in Thailand is re-interpreted as referring to L. diplogramma (Möllendorff, 1902) comb. nov.

Giardia Ancey, 1907, was proposed as a generic name for Indochinese tree snails with sinistral, transparent and elongated ovate to conic shells, which comprised Bulimus siamensis Redfield, 1853, and Bulimus rhombostomus Pfeiffer, 1861. Unfortunately, this generic name was preoccupied by protozoan parasite Giardia Künstler, 1882. There are no junior synonyms available for Giardia Ancey, 1907, so we propose a replacement generic name Anceyoconcha, and therefore new combinations, Anceyoconcha siamensis (Redfield, 1853) and Anceyoconcha rhombostoma (Pfeiffer, 1861), for the two species currently assigned to the genus. External morphology of shell, living body, radula, and genital system of both species are described and compared to other related genera, and the distinctiveness of Anceyoconcha is confirmed. [ABSTRACT FROM AUTHOR]