Landouria diplogramma Nahok & Tumpeesuwan & Tumpeesuwan 2021, comb. 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 diplogramma

description: Landouria diplogramma (Möllendorff, 1902) comb. nov.
Figs 3F, 4F, 5F, 6P–R; Tables 1–4
Plectotropis diplogramme Möllendorff, 1902: 158–159.
Ganesella diplogramme – Panha 1996: 36.
Aegista (Plectotropis) diplogramma – Hemmen & Hemmen 2001: 47.
Thaitropis sp. – Sutcharit et al. 2017: 249, fig. 6–32e.
Diagnosis
Shell small, low-conical, weakly keeled, with a slightly elevated spire, whitish corneous with a pale brown band above periphery. Flagellum like a short protrusion, with rounded tip. Penis short swollen. Central and the first few lateral radular teeth triangular.
Material examined
THAILAND • 29 shells, 14 living specs; Nakhon Ratchasima Province, Pak Chong District, Wat Thep Phithak Punnaram; 14°36′54.57″ N, 101°15′55.25″ E; alt. 451 m; 23 Jun. 2017; B. Nahok and U. Chanlabut leg.; GenBank No. MN449411 and MZ435752; NHMSU-00034. (Fig. 3F)
Description
SHELL (Fig. 3F, Table 1). Dextral, small, depressed conical. Whorls 5½, suture rather shallow, apex obtuse and depressed, whitish corneous, with a pale brown peripheral band. Protoconch almost smooth. Umbilicus moderately deep and wide. Aperture oval oblique, with thin, solid, and weakly reflected lip.
GENITAL SYSTEM (n = 3) (Fig. 5F, Table 4). Penis divided into two short portions, the portion that connects to epiphallus is swollen and the portion that connects to atrium is constricted; internally with three corrugated longitudinal pilasters; with short, rather rounded verge. Flagellum like a short protrusion, internally with two narrow longitudinal pilasters. Vas deferens long, cylindrical, entering the epiphallus at base. Free oviduct very short. Vagina twice as long as free oviduct, internally with five thick, corrugated longitudinal pilasters. Proximal part of gametolytic sac slightly thicker than the cylindrical tube, with a medium-sized oval sax at distal end. Uterus and prostate gland long.
RADULA (n = 3). Comprises 121–125 transverse rows with 61–69 teeth per row; radular formula: (23–25)- (7–9)-1-(7–9)-(23–25). Central tooth usually symmetric, unicuspid, triangular (Fig. 6P). Lateral teeth longer and larger than central teeth, bicuspid, ectocone small, with sharp cusp (Fig. 6Q). Marginal teeth gradually changing from bicuspid to tricuspid, small endocone; mesocone large lanceolate; ectocone triangular with two to four tiny cusps (Fig. 6R).
Remarks
Specimens deposited in the Leiden Museum, The Netherlands, RMNH.MOL.309867 and RMNH. MOL.309851 (https://images.app.goo.gl/PgrpqKaWuSrgjdvN9), are identified as Plectotropis diplogramme Möllendorff, 1902. These specimens appear identical to specimens from Khao See Siad Ah in Nakhon Ratchasima Province, therefore we used the name “ Landouria diplogramma (Möllendorff, 1902) ” for this species in the present study. Landouria diplogramma differs from other Thai species of Landouria by its relatively small lustrous shell without peripheral keel, but with a pale brown band present above periphery (Figs 3F, 4F). Its radular teeth are relatively short (Fig. 6P–R). Its penis and flagellum are relatively short (Fig. 5F).
The genus Thaitropis Schileyko, 2004 was recently reported in Thailand (Schileyko 2004; Sutcharit et al. 2017). Yet, this genus was synonymized with Landouria by Nurinsiyah et al. (2019). Based on the illustration provided by Sutcharit et al. (2017: fig. 6–32e), we identify their Thai Thaitropis sp. as L. diplogramma, because it has the same shell morphology and colours: Plectotropis diplogramme Möllendorff, 1902, RMNH.MOL.309867, and L. diplogramma (Möllendorff, 1902) from Khao See Siad Ah, Nakhon Ratchasima (NHMSU-00034) (Figs 3F, 4F). Unfortunately, the whereabouts of the type specimen of Plectotropis diplogramme are unknown. Yet, it might be deposited in the collections of the Senckenberg Museum in Frankfurt, Germany where it should be looked up and checked in a further study.
Distribution
Landouria diplogramma was collected by local people in the mountain range known as Khao See Siad Ah, Pak Chong District, Nakhon Ratchasima Province, Thailand. Other reported localities comprise Bangkok, Hinlap, Muoklek, Kanburi (Kanchanaburi) (Möllendorff 1902).
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 159-161, DOI: 10.5852/ejt.2021.767.1495, http://zenodo.org/record/5514839