Landouria trochomorphoides, Nahok & Tumpeesuwan & Tumpeesuwan, 2021

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), European Journal of Taxonomy 767 (1), pp. 142-166 : 155-156

publication ID	https://doi.org/ 10.5852/ejt.2021.767.1495
publication LSID	lsid:zoobank.org:pub:9F019E02-95E7-4B6A-B5BC-01F8E26F3466
DOI	https://doi.org/10.5281/zenodo.5514735
persistent identifier	https://treatment.plazi.org/id/B7DBFB2E-E7BF-46E5-AFB5-1B45CA4072DE
taxon LSID	lsid:zoobank.org:act:B7DBFB2E-E7BF-46E5-AFB5-1B45CA4072DE
treatment provided by	Felipe
scientific name	Landouria trochomorphoides
status	sp. nov.

Treatment

Landouria trochomorphoides View in CoL sp. nov.

urn:lsid:zoobank.org:act:B7DBFB2E-E7BF-46E5-AFB5-1B45CA4072DE

Figs 3C View Fig , 4C View Fig , 5C View Fig , 6G–I View Fig ; Tables 1–4 View Table 1 View Table 2 View Table 3 View Table 4

Diagnosis

Shell with rather low spire, sharply keeled, with radial scaly processes ( Fig. 4C View Fig ). 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 View Fig ) GoogleMaps

Paratypes THAILAND • 17 shells, 9 living specs; same collection data as for holotype; GenBank No. MN449403 View Materials and MZ435748 View Materials ; NHMSU-00028 GoogleMaps .

Description

SHELL ( Fig. 3C View Fig , Table 1 View 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 View Fig ). Umbilicus moderately deep and very wide. Aperture lip rhombic, peristome reflexed, and expanded.

GENITAL SYSTEM (n = 3) ( Fig. 5C View Fig , Table 4 View 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 View Fig ). Lateral teeth short and broad leaf-shaped, bicuspid, larger than central tooth, with small ectocone ( Fig. 6G–H View Fig ). Marginal teeth asymmetric, tricuspid with small endocone; mesocone large and long, with curved margins; ectocone triangular with two to four cusps ( Fig. 6H–I View Fig ).

Remarks

Landouria trochomorphoides sp. nov. differs from other taxa by its very large, rather flat, sharply keeled shell with scaly surface ( Figs 3C View Fig , 4C View Fig ). Lateral teeth of radula are stout bicuspid ( Fig. 6G–I View Fig ), genital system is small and slim ( Fig. 5C View Fig ).

Distribution

Landouria trochomorphoides sp. nov. is known only from the type locality.