Landouria trochomorphoides Nahok & Tumpeesuwan & Tumpeesuwan 2021, sp. nov.
Creators: name: Nahok, Benchawan
name: Tumpeesuwan, Sakboworn
name: Tumpeesuwan, Chanidaporn
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Stylommatophora
Camaenidae
Landouria
Landouria trochomorphoides

description: Landouria trochomorphoides sp. nov.
urn:lsid:zoobank.org:act: B7DBFB2E-E7BF-46E5-AFB5-1B45CA4072DE
Figs 3C, 4C, 5C, 6G–I; Tables 1–4
Diagnosis
Shell with rather low spire, sharply keeled, with radial scaly processes (Fig. 4C). Basal portion of flagellum thickened, tapering towards tip; penis narrow and cylindrical; base of gametolytic sac narrow. Radula, with lanceolate central and lateral teeth.
Etymology
The specific epithet ‘ trochomorphoides ’ refers to the conchological similarity between the shell of the new species and that of the land snail genus Trochomorpha Albers, 1850 (Trochomorphidae Möllendorf, 1890).
Type material
Holotype THAILAND • shell (SH = 10.0 mm, SW = 21.3 mm, AH = 7.4 mm, AW = 9.1 mm, UW = 6.2 mm); Loei Province, Pha Khao District, Pha Sawan Cave; 17°7′8.42″ N, 101°56′3.59″ E; alt. 359 m; 6 Oct. 2017; B. Nahok, S. Tumpeesuwan and C. Tumpeesuwan leg.; NHMSU-00027. (Fig. 3C)
Paratypes THAILAND • 17 shells, 9 living specs; same collection data as for holotype; GenBank No. MN449403 and MZ435748; NHMSU-00028.
Description
SHELL (Fig. 3C, Table 1). Dextral, relatively large-sized. Whorls six, suture shallow, spire only slightly elevated. Protoconch with radially elongated scars. Body whorl sharply keeled, brownish-corneous with a brown zone at periphery, scaly processes all over shell surface (Fig. 4C). Umbilicus moderately deep and very wide. Aperture lip rhombic, peristome reflexed, and expanded.
GENITAL SYSTEM (n = 3) (Fig. 5C, Table 4). Penis slightly longer than vagina, slender cylindrical, internally with parallel, transverse robust folds; verge absent. Epiphallus slender cylindrical with thickened end. Flagellum as long as epiphallus, basal portion thick and progressively tapering towards tip, without nodes, inner surface smooth. Vas deferens is a thin cylindrical tube, entering epiphallus apically. Vagina thinner than penis, internally with parallel, transverse robust folds. Free oviduct very short. Gametolytic sac slightly narrower at base, with a long narrow cylindrical tube, and a small, oval sac at the distal end. Prostate gland and uterus very long.
RADULA (n = 3). Comprises 107–111 transverse rows with 65–73 teeth per row; radular formula: (24– 26)-(8–10)-1-(8–10)-(24–26). Central tooth unicuspid triangular (Fig. 6G). Lateral teeth short and broad leaf-shaped, bicuspid, larger than central tooth, with small ectocone (Fig. 6G–H). Marginal teeth asymmetric, tricuspid with small endocone; mesocone large and long, with curved margins; ectocone triangular with two to four cusps (Fig. 6H–I).
Remarks
Landouria trochomorphoides sp. nov. differs from other taxa by its very large, rather flat, sharply keeled shell with scaly surface (Figs 3C, 4C). Lateral teeth of radula are stout bicuspid (Fig. 6G–I), genital system is small and slim (Fig. 5C).
Distribution
Landouria trochomorphoides sp. nov. is known only from the type locality.
description: Published as part of Nahok, Benchawan, Tumpeesuwan, Sakboworn & Tumpeesuwan, Chanidaporn, 2021, Five new species of the land snail genus Landouria Godwin-Austen, 1918 (Gastropoda, Camaenidae) from northeastern Thailand, with note on genitalia and radula morphology of Landouria diplogramma (Möllendorff, 1902), pp. 142-166 in European Journal of Taxonomy 767 (1) on pages 155-156, DOI: 10.5852/ejt.2021.767.1495, http://zenodo.org/record/5514839