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| Landouria tumpeesuwanorum & L. flagellolonga Nahok & K. Tanmuangpak, in Nahok, Chanlabut et Tanmuangpak, 2026. |
Abstract
The molecular phylogeny and morphological–anatomical characteristics of the terrestrial snail genus Landouria Godwin-Austen, 1918 from Thailand are investigated, and we describe two new species. Phylogenetic analysis of 11 recognised Thai Landouria species reveal that these species are phylogenetically well separated from each other by mtDNA phylogeny and COI sequence divergences of 0.048–0.192. Landouria tumpeesuwanorum sp. nov. is described from a limestone hill in Nong Bua Lamphu Province, northeastern Thailand; it is characterised by its angulated whorls, a strongly keeled shell, and small flagellum with curved ends. The second new species, Landouria flagellolonga sp. nov. is described from a limestone hill in Sa Kaeo Province, eastern Thailand. It has a conical-lenticular, sharply keeled shell, and a very long, slender flagellum.
Key words: 16S rRNA, Camaenidae, COI, genitalia, integrative systematics, phylogeny, taxonomy, terrestrial snail, Thailand
Systematics
Family Camaenidae Pilsbry, 1895
Subfamily Bradybaeninae Pilsbry, 1934
Tribe Aegistini Kuroda & Habe, 1949
Genus Landouria Godwin-Austen, 1918
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| Living adults of two Landouria new species. A. Landouria tumpeesuwanorum sp. nov. (paratype: NHLRU027); B. L. flagellolonga sp. nov. (paratype: ZCPRU-0050). |
Landouria flagellolonga Nahok & K. Tanmuangpak, sp. nov.
Etymology. Specific epithet derived from Latin word longus, meaning “long” and referring to the elongated flagellum of this species.
Diagnosis. Shell small, light brown-corneous, sharply keeled. Flagellum very long, epiphallus long and slender; penis long, cylindrical, dilated at its middle part; vagina and free oviduct short. Radula with lanceolate central and lateral teeth.
Landouria tumpeesuwanorum Nahok & K. Tanmuangpak, sp. nov.
Diagnosis. Shell large, brownish-corneous, angulated whorls, strongly keeled. Flagellum small with blunt ends; epiphallus cylindrical and abruptly tapering at its distal part; penis swollen at its basal; vagina large and bulged. Radula with triangular central and lateral teeth.
Etymology. In honour of Assoc. Prof. Chanidaporn Tumpeesuwan and Sakboworn Tumpeesuwan, Thai malacologists and our beloved advisor and co-advisor, respectively, who initiated the taxonomic study of Landouria in Thailand and whose inspiration has led to our study of molluscs.
Benchawan Nahok, Utain Chanlabut and Kitti Tanmuangpak. 2026. Molecular Phylogeny of recognised Thai Landouria Species (Gastropoda, Camaenidae), with Descriptions of Two New Species. ZooKeys. 1278: 181-200. DOI: doi.org/10.3897/zookeys.1278.172545 [28 Apr 2026]
