Landouria tuberculata sp. nov.

urn:lsid:zoobank.org:act: 84133944-D5C9-49A3-9997-8E1C7B335938

Figs 3B, 4B, 5B, 6D–F; Tables 1–4

Diagnosis

Shell moderately keeled, with numerous tiny tubercles on shell surface (Fig. 4B). Flagellum like a short protrusion with a pointed tip, penis swollen, base of gametolytic sac narrow. Radula with slender, lanceolate central teeth.

Etymology

The specific epithet ‘ tuberculata ’ refers to the shell sculpture consisting of numerous tiny tubercles (Fig. 4B).

Type material

Holotype THAILAND • shell (SH = 9.6 mm, SW = 14.4 mm, AH = 5.2 mm, AW = 5.5 mm, UW = 3.5 mm); Loei Province, Phu Rua District, Wat Thepnimit; 17°26′15.09″ N, 101°16′41.46″ E; alt. 647 m; 23 Sep. 2017; B. Nahok, K. Tanmuangpak and U. Chanlabut leg.; NHMSU-00025. (Fig. 3B)

Paratypes THAILAND • 10 shells, 7 living specs; same collection data as for holotype; GenBank No. MN449402 and MZ435747; NHMSU-00026 .

Description

SHELL (Fig. 3B, Table 1). Dextral, medium-sized, tightly coiled, with 6½ slightly convex whorls. Suture rather shallow, apex obtuse with high conical spire. Body whorl angular, with tubercles all over its surface, without distinct incised spiral lines. Colour red brown in living specimens (Fig. 4B), empty shells are paler (Fig. 3B). Umbilicus deep and wide. Aperture obliquely oval, reflexed, and slightly thickened.

GENITAL SYSTEM (n = 3) (Fig. 5B, Table 4). Penis cylindrical, swollen in the middle part, internally with rather wavy, corrugated longitudinal pilasters and a short, hollow verge with 2–3 lobes around its opening. Epiphallus evenly cylindrical, as long as penis. Flagellum like a short protrusion with a pointed tip, without nodes, internally with longitudinal slender pilasters. Vas deferens cylindrical, narrow, entering in the lower half of the flagellum. Vagina relatively short, internally with five corrugated longitudinal pilasters. Free oviduct very short. Gametolytic sac slightly thicker at base, with a long, narrow and thin cylindrical tube, and at its distal end a small, swollen spherical sac. Prostate gland very long. Uterus long and thin.

RADULA (n = 3). Comprises 126–130 transverse rows with 79–87 teeth per row; radular formula: (28– 30)-(11–13)-1-(11–13)-(28–30). Central tooth symmetric, slender lanceolate, and unicuspid (Fig. 6D). Lateral teeth larger than the central tooth, lanceolate, bicuspid, with large endocone and sharp cusp (Fig. 6D). Marginal teeth tricuspid, with small sharp endocone; large, slender mesocone; and small v-shaped ectocone with two cusps (Fig. 6E–F).

Remarks

Landouria tuberculata sp. nov. differs from other Thai species of Landouria, by the shell sculpture of numerous tiny tubercles (Fig. 4B). Lateral teeth of radula bicuspid and lanceolate (Fig. 6D–E).

Distribution

Landouria tuberculata sp. nov. is currently only known from the area surrounding Phu Rua National Park, Phu Rua District, Loei Province, Thailand.