Oospira ovata (Blanford, 1872)

Man, Nem Sian, Lwin, Ngwe, Sutcharit, Chirasak & Panha, Somsak, 2023, Further notes on the taxonomy of the land snail family Clausiliidae Gray, 1855 (Stylommatophora, Helicina) from Myanmar with description of two new species, ZooKeys 1160, pp. 1-59 : 1

6 Oospira ovata (Blanford, 1872)

Figs 3D , 9A-C , 10A-D , 15B , 19G

Clausilia (Oospira) ovata Blanford, 1872: 206, pl. 9, fig. 17. Type locality: "Ad Nattoung, juxta ripam Attaran fluminis, haud procul a Moulmain in Barma" [Shwe Nat Taung, Mawlamyine, Mon State, Myanmar]. Nevill 1878: 183. Gude 1914: 334.

Clausilia ovata -Hanley and Theobald 1874: 48, pl. 118, fig. 4. Sowerby 1875: Clausilia pl. 7, species 60. Pfeiffer 1877: 469.

Clausilia [ Phaedusa (Oospira) ] Phaedusa ovata - Boettger 1878: 56.

Oospira (Oospira) ovata - Nordsieck 2002b: 86. Nordsieck 2007: 24.

Oospira ovata - Szekeres et al. 2021a: 175, 176, fig. 8a, b.

Material examined.

Pathein Mountain , Mawlamyine Township, Mon State, Myanmar (16°14'7.5"N, 97°56'48.1"E): CUMZ 13044 (25 shells, Fig. 9A-C ), CUMZ 13045 (1 specimen in ethanol), JG-C2883 (2 shells) .

Description.

Shell ovate or pupiform, opaque and chestnut-brown; spire blunt. Shell surface nearly smooth or with very thin growth lines; suture distinct. Whorls 5- 5½ convex, rapidly growing; penultimate and antepenultimate whorls equally broad and rounded to apex. Aperture obliquely pear-shaped, basis rounded and narrowing towards parietal sinus; peristome detached, thickened, expanded and little reflexed. Superior lamella well developed, continuous with spiralis and low at transition to spiralis. Inferior lamella steeply ascending, distant from superior lamella and ending at peristome. Subcolumellaris emerged and only visible in oblique view. Principalis running along lateral-dorsal side and anterior end visible through oblique apertural view. Palatal plicae lateral, six or seven: first plica strong and longest; following plicae short, parallel, equal in length and gradually reduced towards anterior. Clausilium plate lateral side and narrow.

Genitalia (n = 1). Atrium (at) short and slender; penis (p) muscular and cylindrical. Epiphallus (ep) muscular, cylindrical, ~ 1.5 × diameter of penis, and broadest close to penis. Penial retractor muscle (pr) attaches proximally to epiphallus. Vas deferens (vd) slender and shortly bounded at atrium and penis junction (Fig. 10A ). Internal sculpture of penis consists of two parts: region near atrium, ~ 2/3 of penis length with moderately thick transverse folds arranged in V-shaped rows; region near epiphallus with smooth surface and four or five longitudinal folds (Fig. 10B, C ). Internal sculpture of epiphallus with rounded papillae arranged in oblique rows (Fig. 10D ).

Vagina (v) thick, short, and almost half of free oviduct (fo) length. Distal part of pedunculus (dpb) large and long; diverticulum (db) large, slightly longer, and larger in diameter than dpb; proximal part of pedunculus (ppb) slender, ~ 2/3 diverticulum length and bursa copulatrix (bb) with distinct ovate shape (Fig. 10A ).

Radula. Each row contains ~ 61 teeth with half-row formula: central-(lateral)-marginal teeth (1-(12-13)-26). Central tooth unicuspid with dull tip. Lateral teeth bicuspid; endocone large with curved to dull tip; ectocone very tiny to small and pointed tip. Marginal teeth asymmetrically tricuspid starting at approximately tooth number 12 or 13: mesocone large and dull tip; ectocone and endocone small with pointed tips. Outer marginal teeth increasingly asymmetrical and shorter than inner marginal teeth (Fig. 15B ).

Distribution.

At present, O. ovata is only known from Myanmar. Many shells were collected in this study; it is likely endemic to the valley of Attaran River.

Remarks.

Oospira ovata and O. philippiana are generally similar in shell morphology, but O. ovata has a more expanded spire. The male internal sculpture of O. ovata has longer V-shaped folds in the region near the atrium and rounded papillae pattern in epiphallus, whereas O. philippiana has shorter V-shaped folds and more elevated and pointed papillae in epiphallus.

Figures

Figure 3. Living snails A Phaedusa shanica from Pyinyaung Village, Mandalay Region (SH ~ 14 mm) B Oospira philippiana from Kayon Cave, Mon State (SH ~ 22 mm) C Oospira bulbus from Sanbel Cave, Mon State (SH ~ 19 mm) D Oospira ovata from Pathein Mountain, Mon State (SH ~ 16 mm) E Oospira gouldiana from Kaw Ka Thuang Cave, Kayin State (SH ~ 26 mm) F Oospira shanensis from Nanthe Cave, Shan State (SH ~ 25 mm).

Figure 9. Shell and clausilial apparatus of A-C Oospira ovata, specimen CUMZ 13044 from Pathein Mountain, Mon State A, C shells B clausilial apparatus and D-F Oospira stoliczkana, specimen CUMZ 13046 from Phra Cave, Tanintharyi Region D clausilial apparatus E, F shells. White arrows indicate principalis.

Figure 10. Genital anatomy of A-D Oospira ovata, specimen CUMZ 13045 A whole reproductive system B internal sculpture of penis C transition from penis to epiphallus D internal sculpture of epiphallus and E-H Oospira stoliczkana, specimen CUMZ 13047 E whole reproductive system F internal sculpture of penis G transition from penis to epiphallus H internal sculpture of epiphallus. Yellow arrows indicate approximate transitional position from penis to epiphallus.

Figure 15. Radula morphology A Oospira philippiana, specimen CUMZ 13039 B Oospira ovata, specimen CUMZ 13044 C Oospira gouldiana, specimen CUMZ 13049 D Oospira andersoniana CUMZ 13057 E Oospira shanensis, specimen CUMZ 13061. Blue color indicates central teeth row; yellow color indicates the transition from lateral to marginal teeth. ' C' indicates central tooth.

Figure 19. Synoptic view of the clausiliid species recorded from Myanmar A Phaedusa lypra, syntype MNHN-IM- 2000 - 2502 - 7 B Oospira magna, lectotype NHMUK 1901.3.17.156 C Oospira malaisei, holotype SMNH 3014 D Indonenia masoni, lectotype NHMUK 1888.12.4.1034 E Phaedusa bocki menglunanensis, specimen NHMUK 1903.7.1.3652 F Oospira mongmitensis, holotype UF 117571 (after Szekeres et al. 2021 b: fig. 1 d) G Oospira ovata, lectotype NHMUK 1906.2.2.378 H Oospira philippiana, possible syntype SMF 62294 / 1 I Oospira sardicola, holotype UF 117570 (after Szekeres et al. 2021 b: fig. 2 c) J Oospira shanensis, holotype NHMUK 1903.7.1.3544 K Phaedusa shanica, lectotype SMF 62260 L Oospira stoliczkana, holotype NHMUK 1888.12.4.1031 M Phaedusa theobaldi, lectotype NHMUK 1888.12.4.1056 N Phaedusa bocki thompsoni, specimen NHMUK 1903.7.1.1163 O Indonenia tuba, lectotype NHMUK 1907.12.30.241 P Oospira vespa, paralectotype MCZ 169456 and Q Oospira zediopsis sp. nov., holotype CUMZ 13064. Photo: P. Maestrati, MNHN (A), A Persson, SMNH (C).