Landouria chloritoides sp. nov.

urn:lsid:zoobank.org:act: 740CA614-D17B-47A3-A719-7DFC7D2CE2D5

Figs 3D, 4D, 5D, 6J–L; Tables 1–4

Landouria sp.1 – Ounchareon 2015: 29–32, 44–50, 54–56, 59, 61, figs 4.2c, 4.3c, 4.4. 4.5i–l, 5.5, 5.7.

Landouria sp.2 – Buddharaksa 2016: 37–38, 41–42, figs 4.19, 4.20, 5.1, 5.2.

Landouria sp.4 – Yingkhamhang 2016: 25–26, 39–41, 43–45, 49–52, figs 4.7, 4.8, 4.21d, 4.22d, 5.3a, 5.4a.

Diagnosis

Shell shape similar to that of the genus Chloritis Beck, 1837 (Camaenidae), but with last whorl stout and usually slightly angular, peripheral keel blunt, suture deep, aperture oval and oblique. Flagellum small ovate, penis very large and stout compared to vagina; vagina and free oviduct short (Fig. 5D). Radula with lanceolate teeth.

Etymology

The specific epithet ‘ chloritoides ’ refers to the conchological similarity between the shell of the new species and that of the camaenid genus Chloritis .

Type material

Holotype THAILAND • shell (SH = 12.0 mm, SW = 19.0 mm, AH = 7.7 mm, AW = 7.3 mm, UW = 3.9 mm); Khon Kaen Province, Chum Phae District, Wat Thep Udom Wanaram; 16°45′29″ N, 101°57′55.03″ E; alt. 406 m; 9 Jun. 2017; B. Nahok, S. Tumpeesuwan and C. Tumpeesuwan leg.; NHMSU-00029. (Fig. 3D)

Paratypes THAILAND • 8 shells, 14 living specs; same collection data as for holotype; GenBank No. MN449404 and MZ435749; NHMSU-00030 .

Other material examined

THAILAND • 4 shells, 8 living specs; North East, Khon Kaen Province, Chum Phae District, Pu Lup Cave; 16°49′49.78″ N, 101°59′9.97″ E; alt. 336 m; NHMSU-00031 .

Description

SHELL (Fig. 3D, Table 1). Dextral, somewhat depressed, relatively large-sized. Whorls 6½, suture deep, apex obtuse, and moderately depressed, with low conical spire. Body whorl rounded, slightly keeled, red-brown in living specimens (Fig. 4D), empty shells are paler (Fig. 3D). Umbilicus very deep and wide. Aperture almost circular, with slightly thickened and weakly expanded lip.

GENITAL SYSTEM (n = 3) (Fig. 5D, Table 4). Penis very large and stout, longer than vagina, cylindrical, gradually tapering towards epiphallus, internally with six rather thick, corrugated longitudinal pilasters; opening of the short, grooved verge surrounded by 2–3 lobes. Epiphallus short and thick. Flagellum short, elongate ovate, without nodes, internally with three large longitudinal pilasters. Vas deferens long and slender, entering in the lower half of the flagellum. Vagina short, as long as free oviduct, internally with seven, corrugated longitudinal pilasteres varying in size. Gametolytic sac thickened at base, with a long narrow cylindrical tube, and a small oval sac at distal end. Uterus swollen, prostate gland long.

RADULA (n = 3). Comprises 125–129 transverse rows with 75–83 teeth per row; radular formula: (26–28)- (11–13)-1-(11–13)-(26–28). Central tooth short lanceolate, symmetric, unicuspid (Fig. 6J). Lateral teeth large and elongated lanceolate (Fig. 6J). Marginal teeth lanceolate, gradually changing from unicuspid to bicuspid and finally tricuspid; endocone small; ectocone slightly oblique, with wide triangular notch and two to four lateral cusps (Fig. 6K–L).

Remarks

Landouria chloritoides sp. nov. can be distinguished from other species of Landouria in Thailand by its conchological similarity to the genus Chloritis and its much larger and stout penis (Fig. 5D). The radula of L. chloritoides sp. nov. is similar to that of L. tuberculata sp. nov. but differs by its unicuspid lateral teeth (Fig. 5J) vs the bicuspid lateral teeth of L. tuberculata sp. nov.

Distribution

Landouria chloritoides sp. nov. is currently known only from the limestone area around Phu Pha Man National Park, Chum Phae District, Khon Kaen Province, Thailand.