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| Sitala chorchati Tanmuangpak & S. Tumpeesuwan, in Tanmuangpak, Nahok, Chanlabut, Taesuk, S. Tumpeesuwan et C. Tumpeesuwan, 2026. หอยยอดเจดีย์ช่อฉัตร | DOI: doi.org/10.3390/taxonomy6040061 |
Abstract
A new species of the tiny tree stylommatophoran snails in the genus Sitala H. Adams, 1865, is described based on specimens recently discovered in dry evergreen and dry dipterocarp forests on limestone hills and in agricultural plantations near limestone hills in Loei Province, northeastern Thailand. The new species is characterized by a high, pyramid-shaped, thin, and translucent yellowish-brown shell with a sharp peripheral keel. Although its external shell morphology resembles that of Sitala liricincta (Stoliczka, 1871), the new species can be distinguished by its greater number of whorls (9¼). Comparative anatomical analysis further revealed significant interspecific differences in genital organs, particularly in the length and shape of the vagina, and in the proportions of the penis, epiphallus, and penial caecum. This discovery is the first verified record of the genus Sitala in Thailand.
Keywords: shell morphology; radula; epiphallic retractor caecum; leaf inhabitant; limestone hill
Taxonomy
Superfamily Helicarionoidea Bourguignat, 1877
Family Helicarionidae Bourguignat, 1877
Subfamily Durgellinae, Godwin-Austen, 1888
Tribe Durgellini Godwin-Austen, 1888
Genus Sitala H. Adams, 1865
Type species. Helix infula Benson, 1848
Diagnosis of genus. Shell turbinoid, thin and translucent, conic or pyramid in shape, outlines, spire conical, consisting of 5.5–7 convex striated whorls. Protoconch and subsequent whorls covered with spiral sculpture, base convex. Umbilicus minute, partially covered. Aperture lack teeth. Peristome thin, simple and not expanded. Penis, vagina, and spermatheca (gametolytic sac) connect to atrium; Penis long, subcylindrical. Epiphallus short, with a simple epiphallic caecum produce into penial retractor. Vas deferens entering epiphallus laterally. Vagina very short (or absent), depending on the position at which the spermatheca enter the genital tract near the atrium. Free oviduct relatively long. Spermathecal stalk enlarges basally; reservoir elongated and embedded in spermoviduct. Amatorial organ (Sarcobellum) present or absent.
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| Live snail, Sitala chorchati sp. nov., paratype NHLRU080. Photograph: Kitti Tanmuangpak. |
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| Shell morphology of Sitala chorchati sp. nov., holotype NHLRU079. (A), Apertural view; (B), Lateral view; (C), Ventral view; (D), Dorsal view. Photograph: Kitti Tanmuangpak. |
Sitala chorchati Tanmuangpak & S. Tumpeesuwan, sp. nov.
Diagnosis. Sitala chorchati sp. nov. is similar in shell morphology to Sitala attegia (Benson, 1859) and Sitala liricincta (Stoliczka, 1871), particularly in having shell conical, high spire shell, thin and translucent. Differing from both species in smaller shell and a greater number of whorls, 4.12–5.28 mm and 9¼ whorls, whereas 5.8 mm and 6½–7 whorls in S. liricincta, and 7–12 mm and 6½–8 whorls in S. attegia (Table 4).
Etymology. The specific epithet “chorchati” is given in honour of Admiral Chorchat Gra-tes of the Royal Thai navy, former Deputy Chief of Defence, an independent conchologist and owner of a private shell collection in Bangkok, Thailand.
Kitti Tanmuangpak, Benchawan Nahok, Utain Chanlabut, Nonthiwat Taesuk, Sakboworn Tumpeesuwan and Chanidaporn Tumpeesuwan. 2026. A New Species of the Tiny Tree Snail Genus Sitala H. Adams, 1865 (Gastropoda, Eupulmonata, Helicarionidae) from Northeastern Thailand. Taxonomy. 6(4), 61. DOI: doi.org/10.3390/taxonomy6040061 [7 October 2026]






































