Morphological and molecular evidence uncovers hidden species diversity in the leatherleaf slug genus Valiguna (Systellommatophora, Veronicellidae) from Thailand Author Mitchueachart, Bowornluk Biological Sciences Program, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand Author Sutcharit, Chirasak 0000-0001-7670-9540 Biological Sciences Program, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand Author Tongkerd, Piyoros Biological Sciences Program, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand Author Panha, Somsak Biological Sciences Program, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand & Animal Systematics Research Unit, Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand text ZooKeys 2024 2024-09-13 1212 79 107 journal article 10.3897/zookeys.1212.126624 8A1608E5-7559-47CF-A942-8F569A35EB68 Valiguna siamensis ( Martens, 1867 ) Figs 2 , 3 B , 4 A , 5 , 6 , 7 A Vaginulus siamensis Martens, 1867: 68 , pl. 5; fig. 3. Type locality: Petshaburi [ Phetchaburi Province , Thailand ]. Veronicella bocourti Rochebrune, 1882 b: 117 . Type locality: Bangkok [ Thailand ]. Veronicella chaudoensis Rochebrune, 1882 a: 67 . Type locality: Montagnes de Chadou [Chau Doc City, An Giang Province , Vietnam ]. Veronicella titanotona Rochebrune, 1882 a: 68 . Type locality: Spiglumi-Britton [ Cochinchina ]. Vaginulus reticulatus Westerlund, 1883: 49 . Type locality: Galle [ Sri Lanka ]. Thomé 1984: 29–32 , figs 1–7. Semperula bocourti : Grimpe and Hoffmann 1925 b : 44 . Hoffmann 1925: 181 . Semperula chaudoensis : Grimpe and Hoffmann 1925 b : 44 . Hoffmann 1925: 181 . Semperula titanotoma [sic]: Grimpe and Hoffmann 1925 b : 44 [misspelling]. Hoffmann 1925: 181 . Semperula siamensis : Grimpe and Hoffmann 1925 a : 388 , 390–392. Grimpe and Hoffmann 1925 b : 17 –19, 44–47, fig. 8. Hoffmann 1925: 179–181 , 256, 257, pl. 3, fig. 29, pl. 6, fig. 45 k 3, pl. 8, figs 58, 60, 61 a, 62, pl. 9, fig. 64, pl. 10, fig. 71, pl. 11, figs 78–80. Solem, 1966: 21 . Hemmen and Hemmen 2001: 40 . Valiguna siamensis : Gomes and Thomé 2004: 595 , 596. Gomes et al. 2008: 164 , 169, figs 13–18. Inkhavilay et al. 2019: 48 , figs 19 b, 55 b. Sutcharit et al. 2020 a : 16 , 17, fig. 3 d. Material examined. Laos : • Wat Oudom , Khamkeut , Bolikhamsai ; 18 ° 10 ' 56.6 " N , 104 ° 59 ' 04.6 " E ; CUMZ 16001 . Myanmar : • Winner hotel , Kalaw , Shan ; 20 ° 37 ' 40.4 " N , 96 ° 33 ' 28.1 " E ; CUMZ 16002 . Thailand : Chiang Rai : • Wat Tham Pha Mee , Mae Sai ; 20 ° 32 ' 01.7 " N , 99 ° 52 ' 34.5 " E ; CUMZ 16003 ; • Wat Tham Pha Chom , Mae Sai ; 20 ° 26 ' 31.9 " N , 99 ° 52 ' 23.5 " E ; CUMZ 16004 ; • Wat Pa Pha Mi , Mae Sai ; 20 ° 24 ' 18.3 " N , 99 ° 51 ' 09.9 " E ; CUMZ 16005 ; • Wat Tham Pum , Mae Sai ; 20 ° 20 ' 54.1 " N , 99 ° 51 ' 37.9 " E ; CUMZ 16006 ; • Wat Tham Pla Witthayakhom School , Mae Sai ; 20 ° 19 ' 58.3 " N , 99 ° 51 ' 52.9 " E ; CUMZ 16007 ; • Wat Tham Phra ( Buddha Cave ), Mueang Chiang Rai ; 19 ° 55 ' 06.3 " N , 99 ° 47 ' 19.5 " E ; CUMZ 16008 ; • Wat Tham Phra Pha Kok , Wiang Chai ; 19 ° 52 ' 21.4 " N , 100 ° 02 ' 41.9 " E ; CUMZ 16009 ; • Mae Lao Wildlife Breeding Center , Mae Lao ; 19 ° 45 ' 57.6 " N , 99 ° 38 ' 12.6 " E ; CUMZ 16010 ; • Wat Tham Phajarui , Pa Daet; 19 ° 34 ' 19.1 " N , 99 ° 59 ' 17.3 " E ; CUMZ 16011 ; Chiang Mai : • Wat Tham Pha Phueng , Chai Prakan ; 19 ° 44 ' 19.1 " N , 99 ° 05 ' 16.2 " E ; CUMZ 16012 ; • Khun Mai Baan Suan Resort, Mae Ai; 20 ° 03 ' 46.7 " N , 99 ° 21 ' 31.6 " E ; CUMZ 16013 ; • Wat Tham Tap Tao , Chai Prakan ; 19 ° 39 ' 46.3 " N , 99 ° 07 ' 03.4 " E ; CUMZ 16014 ; • Wat Tham Klaeb , Chiang Dao ; 19 ° 33 ' 33.4 " N , 99 ° 03 ' 46.9 " E ; CUMZ 16015 ; • Tham Chiang Dao , Chiang Dao ; 19 ° 23 ' 38.3 " N , 98 ° 55 ' 43.2 " E ; CUMZ 16016 ; • Homdoi Guesthouse , Samoeng ; 18 ° 51 ' 04.5 " N , 98 ° 43 ' 37.4 " E ; CUMZ 16017 ; • B-tel Chom Thong Resort, Chom Thong; 18 ° 26 ' 19.4 " N , 98 ° 40 ' 20.9 " E ; CUMZ 16018 ; Lampang : • Tham Pha Thai , Ngao ; 18 ° 36 ' 19.7 " N , 99 ° 53 ' 51.9 " E ; CUMZ 16019 ; • Chao Por Pratu Pha Shrine, Mae Mo; 18 ° 30 ' 49.9 " N , 99 ° 49 ' 09.9 " E ; CUMZ 16020 ; Lamphun : • Wat Pa Phai , Li ; 17 ° 52 ' 22.6 " N , 98 ° 55 ' 26.8 " E ; CUMZ 16021 ; • Wat Doi Daen , Ban Hong; 18 ° 21 ' 52.5 " N , 98 ° 45 ' 42.3 " E ; CUMZ 16083 ; Phrae : • Huai Rong Waterfall, Rong Kwang; 18 ° 26 ' 31.6 " N , 100 ° 27 ' 00.9 " E ; CUMZ 16022 ; Bueng Kan : • Wat Tham Pha Khao , Si Wilai ; 18 ° 11 ' 27.3 " N , 103 ° 49 ' 59.9 " E ; CUMZ 16023 ; • Wat Tham Phra Phu Wuua , Seka; 18 ° 08 ' 12.9 " N , 103 ° 59 ' 34.8 " E ; CUMZ 16024 ; Loei : • Wat Tham Pha Baen , Chiang Khan ; 17 ° 54 ' 24.6 " N , 101 ° 43 ' 28.5 " E ; CUMZ 16025 ; • Wat Tham Pha Pu , Mueang Loei ; 17 ° 34 ' 44.6 " N , 101 ° 42 ' 40.0 " E ; CUMZ 16026 ; • Wat Thepnimitr , Phu Ruea ; 17 ° 28 ' 03.3 " N , 101 ° 16 ' 32.7 " E ; CUMZ 16027 ; • Wat Tham Erawan , Erawan ; 17 ° 20 ' 43.5 " N , 102 ° 01 ' 07.3 " E ; CUMZ 16028 ; • Wat Tham Pha Bing , Wang Saphung ; 17 ° 14 ' 03.8 " N , 101 ° 44 ' 14.6 " E ; CUMZ 16029 ; • Wat Tham Maholan , Nong Hin; 17 ° 06 ' 26.2 " N , 101 ° 52 ' 43.7 " E ; CUMZ 16030 ; Nong Bua Lam Phu : • Wat Tham Suwannakhuha , Suwannakhuha ; 17 ° 36 ' 29.2 " N , 102 ° 16 ' 57.1 " E ; CUMZ 16031 ; • Wat Tham Pha Chor , Na Wang; 17 ° 18 ' 50.6 " N , 102 ° 07 ' 05.0 " E ; CUMZ 16032 ; Sakon Nakhon : • Kham Hom Waterfall, Mueang Sakon Nakhon ; 17 ° 07 ' 25.2 " N , 104 ° 01 ' 07.3 " E ; CUMZ 16033 ; • Wat Tham Phu Pha Yon , Phu Phan; 16 ° 56 ' 28.4 " N , 104 ° 04 ' 27.5 " E ; CUMZ 16034 ; Tak : • Taksin Maharat, Mueang Tak; 16 ° 46 ' 44.3 " N , 98 ° 55 ' 42.7 " E ; CUMZ 16035 ; Phitsanulok : • Wat Ampharin Khuha (Tham Muang), Noen Maprang; 16 ° 30 ' 13.8 " N , 100 ° 41 ' 20.9 " E ; CUMZ 16036 ; Nakhon Sawan : • Wat Thep Sathaporn , Banphot Phisai; 15 ° 54 ' 49.5 " N , 99 ° 53 ' 03.9 " E ; CUMZ 16037 ; Khon Kaen : • Tham Phu Loop, Chum Phae; 16 ° 49 ' 48.6 " N , 101 ° 59 ' 07.8 " E ; CUMZ 16038 ; • Khon Kaen University , Mueang Khon Kaen ; 16 ° 28 ' 27.4 " N , 102 ° 49 ' 18.9 " E ; CUMZ 16039 ; • Sawathi, Mueang Khon Kaen; CUMZ 16040 ; Buriram : • Socool Grand Hotel , Nang Rong ; 14 ° 38 ' 12.5 " N , 102 ° 47 ' 27.4 " E ; CUMZ 16041 ; • Wat Khao Phra Ang Khan , Chaloem Phra Kiat; 14 ° 32 ' 04.6 " N , 102 ° 50 ' 04.3 " E ; CUMZ 16042 ; Chaiyaphum : • Tham Wua Daeng, Phakdi Chumphon; 16 ° 04 ' 35.2 " N , 101 ° 26 ' 23.9 " E ; CUMZ 16043 ; Nakhon Ratchasima : • Wat Pa Mongkol Tham , Pak Thong Chai ; 14 ° 42 ' 07.5 " N , 101 ° 47 ' 12.7 " E ; CUMZ 16044 ; • Wat Tham Thep Nimit , Pak Chong ; 14 ° 36 ' 14.4 " N , 101 ° 33 ' 59.1 " E ; CUMZ 16045 ; • Soken Villa Khaoyai, Pak Chong; 14 ° 32 ' 06.7 " N , 101 ° 23 ' 37.4 " E ; CUMZ 16046 ; Sa Kaeo : • Tham Khao Maka, Mueang Sa Kaeo ; 13 ° 47 ' 16.5 " N , 101 ° 56 ' 53.8 " E ; CUMZ 16047 ; • Wat Tham Thep Plub Plueng Thong , Wang Sombun ; 13 ° 26 ' 56.9 " N , 102 ° 13 ' 02.9 " E ; CUMZ 16048 ; • Tham Phet Pho Thong, Khlong Hat; 13 ° 24 ' 50.1 " N , 102 ° 19 ' 31.3 " E ; CUMZ 16049 ; Chon Buri : • Wat Tham Khao Cha Ang On , Bo Thong ; 13 ° 12 ' 33.5 " N , 101 ° 39 ' 05.6 " E ; CUM 16050 ; • Wat Khao Cha Ang , Bo Thong; 13 ° 12 ' 00.9 " N , 101 ° 34 ' 54.6 " E ; CUMZ 16051 ; Chanthaburi : • Khao Soi Dao Wildlife Sanctuary , Soi Dao ; 13 ° 06 ' 15.0 " N , 102 ° 11 ' 39.5 " E ; CUMZ 16052 ; • Palm plantation near Quan Yin shrine , Makham ; 12 ° 43 ' 37.9 " N , 102 ° 08 ' 12.7 " E ; CUMZ 16053 ; • Wat Laem Sadet , Tha Mai ; 12 ° 34 ' 18.9 " N , 101 ° 53 ' 26.3 " E ; CUMZ 16054 ; • Trok Nong Waterfall, Khlung; 12 ° 32 ' 39.6 " N , 102 ° 14 ' 13.6 " E ; CUMZ 16055 ; Trat : • Trat 101 Hotel , Mueang Trat ; 12 ° 14 ' 31.4 " N , 102 ° 30 ' 40.4 " E ; CUMZ 16056 ; • Koh Chang , Koh Chang ; 12 ° 03 ' 38.8 " N , 102 ° 19 ' 37.1 " E ; CUMZ 16057 ; • Suanya Koh Kood resort & spa, Koh Kood; 11 ° 39 ' 58.9 " N , 102 ° 32 ' 05.6 " E ; CUMZ 16058 ; Nakhon Nayok : • Ka Ang Waterfall, Ban Na; 14 ° 20 ' 35.0 " N , 101 ° 07 ' 53.0 " E ; CUMZ 16059 ; Bangkok : • Chulalongkorn University, Pathum Wan; 13 ° 44 ' 15.5 " N , 100 ° 31 ' 48.9 " E ; CUMZ 16060 ; Kanchanaburi : • Tham Khao Noi Bureau of Monks , Thong Pha Phum; 14 ° 41 ' 54.1 " N , 98 ° 31 ' 31.4 " E ; CUMZ 16061 ; • Pilok , Thong Pha Phum ; 14 ° 40 ' 16.3 " N , 98 ° 23 ' 04.1 " E ; CUMZ 16086 ; • Tham Than Lot , Si Sawat ; 14 ° 40 ' 17.3 " N , 99 ° 17 ' 19.1 " E ; CUMZ 16062 ; • Wat Pa Tham Pha Dang , Thong Pha Phum ; 14 ° 38 ' 43.6 " N , 98 ° 39 ' 31.8 " E ; CUMZ 16063 ; • Srinakarin Dam , Si Sawat ; 14 ° 24 ' 26.2 " N , 99 ° 07 ' 33.7 " E ; CUMZ 16064 ; • Hellfire Pass , Sai Yok ; 14 ° 22 ' 49.3 " N , 98 ° 55 ' 50.2 " E ; CUMZ 16065 ; • Wat Pu Ta Khian , Sai Yok ; 14 ° 17 ' 22.2 " N , 99 ° 00 ' 28.9 " E ; CUMZ 16066 ; • Tham Krasae, Sai Yok; 14 ° 06 ' 18.8 " N , 99 ° 09 ' 59.6 " E ; CUMZ 16067 ; Phetchaburi : • Wat Khao Bandai , Nong Ya Plong ; 13 ° 14 ' 09.5 " N , 99 ° 41 ' 21.3 " E ; CUMZ 16068 ; • Ban Aob Fha Resort, Kaeng Krachan; 12 ° 53 ' 55.4 " N , 99 ° 38 ' 54.8 " E ; CUMZ 16069 ; Prachuap Khiri Khan : • Wat Tham Khao Mai Ruak , Thap Sakae; 11 ° 25 ' 43.0 " N , 99 ° 36 ' 18.5 " E ; CUMZ 16070 ; Chumphon : • Tham Pisadan Monastery , Pathio ; 10 ° 45 ' 35.6 " N , 99 ° 13 ' 47.5 " E ; CUMZ 16071 , 16072 ; • Tham Rub Ror, Tha Sae; 10 ° 37 ' 26.1 " N , 99 ° 06 ' 47.2 " E ; CUMZ 16073 ; Ranong : • Tham Phra Khayang, Kra Buri ; 10 ° 19 ' 36.6 " N , 98 ° 45 ' 53.1 " E ; CUMZ 16074 ; • Baan Cueng Kao, Mueang Ranong; 9 ° 56 ' 36.4 " N , 98 ° 38 ' 01.7 " E ; CUMZ 16084 ; Surat Thani : • Khao Sok Evergreen House , Phanom ; 8 ° 54 ' 53.8 " N , 98 ° 32 ' 43.0 " E ; CUMZ 16075 ; • Khao Sok River Home Resort, Phanom; 8 ° 51 ' 02.3 " N , 98 ° 42 ' 21.3 " E ; CUMZ 16076 ; • Pa Dang, Chai Buri; 8 ° 29 ' 32.3 " N , 98 ° 58 ' 39.0 " E ; CUMZ 16077 ; Krabi : • Wat Tham Prasat Nalakiring , Plai Phraya ; 8 ° 33 ' 30.5 " N , 98 ° 51 ' 44.1 " E ; CUMZ 16078 ; • Tham Khlang, Ao Luek; 8 ° 20 ' 17.8 " N , 98 ° 44 ' 43.9 " E ; CUMZ 16079 ; Trang : • Wat Khao Lak Jan , Mueang Trang; 7 ° 42 ' 14.2 " N , 99 ° 43 ' 46.3 " E ; CUMZ 16080 ; Satun : • Khao Toh Payawang, Mueang Satun; 6 ° 37 ' 39.4 " N , 100 ° 03 ' 43.1 " E ; CUMZ 16085 ; Pattani : • Chabang Tiko , Mueang Pattani ; 6 ° 51 ' 27.3 " N , 101 ° 15 ' 12.2 " E ; CUMZ 16081 , 16082 . Diagnosis. Notum pale to dark brown with random tiny blackish spots and median dorsal line visible. Hyponotum and foot paler in colour, and with scattered pale blackish spots. Penis clavated with honeycomb-like glans; vas deferens opens at peak. Penial tubules consist of 19–29 long tubules and two short tubules. External characteristics. Preserved specimen . Notum pale to dark brown colour with scattered tiny blackish spots. Body elongated ovate, 24–77 mm (mean 48.9 ± 10.0 mm) long and 9–28 mm (mean 14.8 ± 3.8 mm ) wide. Some specimens with larger blackish spots scattered along left and right sides of notum. Median dorsal line thin and narrow, and a paler colour than notum. Hyponotum varies from pale yellow to beige or pale brown and with scattered tiny pale blackish spots. Foot pale yellow to beige, and narrower (width 2.0–7.0 mm, mean 3.4 ± 1.0 mm) than right hyponotum width. Male genital pore located closed to base of right lower-tentacle. Female genital pore located approximately midway of body on right hyponotum (Figs 5 A , 6 A, D ). Live specimen . Notum pale to dark brown and with scattered tiny blackish spots. Median dorsal line thin and pale colour. Hyponotum varies from beige to pale brown colour, and with scattered pale blackish spots. Foot beige (Fig. 4 A ). Figure 4. Living slugs A Valiguna siamensis , specimen CUMZ 16038 from Khon Kaen (length ~ 60 mm) B V. semicerina sp. nov. , holotype CUMZ 16087 from type locality (length ~ 34 mm), and C V. crispa sp. nov. , holotype CUMZ 16094 from type locality (length ~ 28 mm). Dorsal view (left) and ventral view (right). Genital organs . Penis acropleurocaulis type ; penis base ( pb ) cylindrical and relatively long. Penis glans ( gn ) starts from distal extremity of penis base, short cylindrical shaped, honeycomb formation at distal extremity, and bending forming pointed peak. Vas deferens ( vd ) opens at tip of peak. Peak ( pk ) cylindrical shaped and located at lateral side of penis glans (Figs 5 B , 6 B ). Young specimens with smooth cylindrical penis (without honeycomb formation; Fig. 6 E ). Penial gland with conical papilla ( pa ). Penial tubules: 19–29 long tubules ( lt ) and two short tubules ( st ). Two long tubules appear distally bifurcated in some specimens (Figs 5 C , 6 C ). Figure 5. Valiguna siamensis CUMZ 16054 from Chanthaburi A dorsal and ventral views B penis C penial gland and penial tubules D dorsal and ventral views of female genitalia, and E inset of female genitalia. Figure 6. A – C Valiguna siamensis , specimen CUMZ 16068 from Phetchaburi (topotype) and D, E specimen CUMZ 16060 from Bangkok. A, D dorsal and ventral views B, E penis of adult ( B ) and immature ( E ), and C penial gland and penial tubules. Bursa copulatrix duct ( db ) pyriform shaped, expanded in middle region, and then tapering to narrow tube on both ends. Bursa copulatrix ( bc ) almost circular shaped and connected to bursa copulatrix duct. Oviduct ( ov ) and albumen gland ( ag ) extremely enlarged, soft lobulated, and tufted; oviduct opened at female genital pore ( fg ). Distal ( dd ) and proximal ( pd ) posterior deferens inserted into somewhat oval-shaped prostate gland ( pr ). Middle deferens ( md ) penetrates into thick muscular right hyponotum then emerges near male genital pore ( mg ) before inserting into penis. Canalis junctor ( cj ) penetrated almost at middle of bursa copulatrix duct. Fertilisation complex ( fc ) short and small tube; seminal vesicle ( sv ) thin and curly, and attached to albumen gland with thin connective tissue. Spermioduct ( sd ) thin, unconvoluted, and contracts into numerous small globular hermaphroditic gland subunits. Hermaphroditic gland ( hg ) consists of many small subunits (Figs 3 B , 5 D, E ). Radula . Teeth arranged in nearly straight rows, each row containing ~ 100 teeth with half row formula 1–49. Central teeth very small and unicuspid. Lateral and marginal teeth not differentiated, monocuspid, large triangular shaped, and with slightly pointed cusp. From inner to outer, lateromarginal teeth gradually narrower, smaller, and rather pointed cusp, and outermost teeth relatively small (Fig. 7 A ). Figure 7. SEM images of radula A Valiguna siamensis , specimen CUMZ 16054 from Chanthaburi B V. semicerina sp. nov. , holotype CUMZ 16087 from type locality, and C V. crispa sp. nov. , holotype CUMZ 16094 from type locality. Central tooth indicated by ‘ C’. Distribution. Valiguna siamensis occurs throughout Thailand and some have been reported from Cambodia , Laos , Myanmar , southern China , and Sri Lanka ( Rochebrune 1882 a , b ; Gomes et al. 2008 ; Inkhavilay et al. 2019 ; Sutcharit et al. 2020 a ; GBIF 2023 ). Comparative diagnosis. Valiguna siamensis can be differentiated from V. flava in having a cylindrical penis with honeycomb-like glans, and with 21–31 unequal length (two short, 19–29 long) and two bifurcation penial tubules. In comparison, V. flava has a penis that is initially cylindrical, then tapers and bends with dentate and serrate glans. In addition, V. flava possesses only 15 short penial tubules (Table 4 ; Gomes et al. 2008 ). Table 4. External and internal morphology of Valiguna species. Superscript number indicates the reference: 1 Gomes et al. (2008) .

Characters	Valiguna flava 1	Valiguna siamensis	Valiguna semicerina sp. nov.	Valiguna crispa sp. nov.
Notum colour	Pale yellowish brown to dark reddish brown with scattered wide blackish spots	Pale to dark brown with very tiny blackish spots scattered all around	Pale to dark brown with scattered tiny blackish spots	Dark brown with randomly scattered distinct, small, pale yellow and blackish spots all around
Hyponotum colour	Paler pale yellowish brown to dark reddish brown, without spots or only few tiny blackish spots	Beige to pale brown with many tiny pale blackish spots	White to pale beige or pale brown, without blackish spots or with many tiny spots	Beige with many tiny scattered blackish spots
Teeth formula	c / 1 + l 46–47 / 2	c / 1 + l 49 / 2	c / 1 + l 31 – 35 / 2	c / 1 + l 28 / 2
Penial tubules	15 short tubules	21–31 tubules: two short and 19–29 long (some are bifurcated)	18–22 tubules: four short, six intermediate, and 8–12 long (some long tubules are bifurcated)	11 long tubules
Penis glans	Cylindrical structure covered by dentate and serrate formations on dorsum of convex side	Short cylindrical with honeycomb structure at distal most end of glans	Elongated conical with honeycomb structure on one side and smooth surface on the opposite side	Short conical with wave-like structure
Canalis junctor	Penetrates bursa copulatrix duct near to the middle of the duct’s total length	Penetrates in bursa copulatrix duct near to the middle of the duct’s total length	Penetrates in bursa copulatrix duct near to the middle of the duct’s total length	Penetrates in bursa copulatrix duct near to the proximal end of the duct
Bursa copulatrix	Almost circular and concave in the middle	Almost circular	Almost circular	Almost oval
Bursa copulatrix duct	Cylindrical shaped	Pyriform and expanding at middle region	Short and narrow bottle-shaped duct near basal part of bursa copulatrix; looks similar to a bottle with neck positioned in the centre.	Short and narrow bottle-shaped duct near basal part of bursa copulatrix; looks similar to a bottle with neck positioned off-centre to one side.

In addition, Valiguna siamensis also differs from V. semicerina sp. nov. and V. crispa sp. nov. in having their hermaphroditic glands composed of small-sized acini. In comparison, V. semicerina sp. nov. possesses hermaphroditic gland formed by medium-sized acini whereas V. crispa sp. nov. possesses hermaphroditic gland made up of large-sized acini (Figs 3 B, C, D , 5 D , 8 D , 9 D ). Figure 8. Valiguna semicerina sp. nov. , holotype CUMZ 16087 from type locality A dorsal and ventral views B penis C penial gland and penial tubules D dorsal and ventral views of female genitalia, and E inset of female genitalia. Figure 9. Valiguna crispa sp. nov. , holotype CUMZ 16094 from type locality A dorsal and ventral views B penis C penial gland and penial tubules, and D dorsal and ventral view of female genitalia. Remarks. Originally, this species was nominated based on specimens from Phetchaburi Province , Thailand , with a brief description and illustrations. After examining the syntypes , Hoffmann (1925) relocated it to the Semperula and provisionally synonymised three poorly described species Veronicella bocourti Rochebrune, 1882 , Veronicella chaudoensis Rochebrune, 1882 , and Veronicella titanotona Rochebrune, 1882 with this species. Later, Thomé (1984) examined the lectotype of Vaginulus reticulatus Westerlund, 1883 and recognised it as a synonym of Semperula siamensis . Recently Gomes and Thomé (2004) transferred this species to the Valiguna , and Gomes et al. (2008) reported the genitalia based on specimens from Yunnan and Guangxi , China . It is the predominant leatherleaf slug found in Thailand , occurring in diverse environments, including natural habitats as well as human-modified settings, such as residential areas, gardens, plantations, and greenhouses.