Hynobius vandenburghi Dunn, 1923

Sugawara, Hirotaka, Fujitani, Takeshi, Seguchi, Shota, Sawahata, Takuo & Nagano, Masahiro, 2022, Taxonomic Re-examination of the Yamato Salamander Hynobius vandenburghi: Description of a New Species from Central Honshu, Japan, Bulletin of the Kanagawa Prefectural Museum (Natural Science) 51, pp. 47-59 : 55-56

Hynobius vandenburghi Dunn, 1923

(Standard Japanese name: Yamato-sanshouo)

( Fig. 6)

Hynobius nebulosus : Fujitani et al., 2016: 3, in part.

Holotype. An adult male (specimen number: CAS 26714) from Nara, Yamato Province, Hondo, collected by Victor Kühne (an alias used by John Cheesman Thompson) ( Beolens et al., 2011) in May 1907 ( Dunn, 1923a; Dunn, 1923b). This specimen is stored in the California Academy of Sciences: 55 Music Concourse Drive, San Francisco, California, 94118, United States.

Diagnosis. A comparatively small species (with a mean SVL of 53.8 mm in males and 54.3 mm in females) within the Japanese lentic salamander species complex of Hynobius : SVL usually <56 mm in males; the ratio of hindlimb lEngth UsUally ≥ 30 %SVL in malEs; distinct and bright yellow stripe on the dorsal and ventral edges of the tail always present in both sexes; distinct black dots on dorsum usually absent in both sexes; distinct gular mottling never present in females; fifth toe of hindlimb always present; V-shaped or U-shaped vomerine teeth series; 13 (rarely 12 or 14) costal grooves; the number of costal folds bEtwEEn adprEssEd limbs UsUally> − 1.5 in malEs and always <−1.0 in fEmalEs.

Description of a specimen from the type locality (Topotype). An adult male (specimen number: KPM-NFA 942) from Nakamachi, Nara-shi, Nara Prefecture, Japan (34° 40’ N, 135° 43’ E; elevation = 230 m), collected by Shota Seguchi on 1 March 2020. This specimen was collected after obtaining collection permission from The Unit of Natural Environment, Division of Landscape and Natural Environment, Department of Water Cycle, Forest, and Landscape Environment, Nara Prefecture. A moderately large individual: HL larger than HW; TAL shorter than SVL; body almost cylindrical; rounded snout; gular fold present; tail gradually compressed toward the tip; slightly expanded cloaca; webbing between digits absEnt; foUr fingErs on Each forElimb, ordEr of lEngth II> III> IV> I on lEft and II> III> I> IV on right; fivE toEs on each hindlimb, order of length III> IV> II> I> V on left and III> II> IV> V> I on right; V-shaped vomerine teeth; skin smooth and shiny; DWDV and DWDL absent; DBDD absent; DBTYLD and DBTYLV present; DGM absent (but indistinct gular mottling present). This specimen had the following measurements (in mm): SVL =54.5, TRL = 42.0, AGD = 29.1, HL = 12.7, TAL = 40.5, MTAW = 3.2, MTAH = 5.7, BTAW = 5.1, BTAH = 5.0, VTL = 2.7, VTW = 2.8, HW = 8.5, MXHW = 8.8, LFLL = 11.7, RFLL = 11.8, LHLL = 15.6, RHLL = 14.9, L1FL = 1.1, L2FL = 3.1, L3FL = 2.8, L4FL = 1.3, R1FL = 1.2, R2FL = 3.4, R3FL = 2.7, R4FL = 1.1, L1TL = 1.5, L2TL = 3.3, L3TL = 3.9, L4TL = 3.4, L5TL = 1.3, R1TL = 1.2, R2TL = 3.3, R3TL = 3.7, R4TL = 3.1, R5TL = 1.7, IND = 2.5, IOD = 3.3, LUEW = 1.5, RUEW = 1.4, SL = 3.6, LUEL =2.5, RUEL = 2.4, LJL = 7.0, CGN = 13.

Variation. Morphometric measurements are presented in TablE 2 and thE significant valUEs of all mEasUrEmEnts between sexes are listed in Table 3. Males have relatively longer RHW, RHLL, and R2FL than those of females, whereas males have relatively shorter RTRL and RAGD than those females. Skin markings are listed in Table 4. The dorsum is uniformly yellowish-brown or darkish-brown. DBDD are rarely present in males (2/17 = 11.8 %) and females (1/6 = 16.7 %). The venter is lighter than the dorsum. DWDV are often lacking in males (11/17 = 64.7 %) and sometimes present in females (3/6 = 50.0 %). DWDL are frequently lacking in males (11/17 = 64.7 %) and sometimes present in females (3/6 = 50.0 %). DGM sometimes lacking in males (10/17 = 58.8 %). CGN rarely 12 in males (3/17 = 17.6 %) and rarely 14 in females (1/6 = 16.7 %). CFBALN rarEly <−1.0 in malEs (2/17 = 11.8 %) and sometimes> 2.0 in females (3/6 = 50 %). Iris is dark brown. When preserved in 70 % ethanol, dorsal coloration tends to fade to dark gray. DBTYLD and DBTYLV can be confirmEd aftEr prEsErvation.

Distribution. It is known from Tahara-shi (only former Tahara-cho and Atsumi-cho), Aichi Prefecture ( Matsui et al., 2019), Gifu-shi (only former Gifu-shi), Seki-shi (only former Seki-shi), Kakamigahara-shi (only former Kakamigahara-shi), and Kaizu-shi (only former Nanno-cho), and Ibigawa-cho (only former Tanigumimura), Gifu Prefecture ( Matsui et al., 2019; Sakai et al., 2019; Gifu High School, 2018), Nagahama-shi (only former Nagahama-shi, and Azai-cho and Kinomotocho), Maibara-shi (former Maibara, Omi-cho, and Santo-cho), Hikone-shi, Omihachiman-shi (only former Omihachiman-shi), Konan-shi (only former Kosei-cho), Higashiomi-shi (only former Yokaichi-shi and Gamo-cho), Koka-shi (only former Minakuchi-cho, Konan-cho, Kokacho, and Tsuchiyama-cho), Ritto-shi, Kusatsu-shi, Otsu-shi (only former Otsu-shi), Takashima-shi (only former Adogawa-cho, Shin-asahi-cho, Imazu-cho, and Makinocho), and Hino-cho and Ryuo-cho, Shiga Prefecture ( Tago, 1931; Kokashi-Minakuchi-Kodomonomori-Shizenkan, 2013; Mito et al., 2018; Matsui et al., 2019), Kuwana-shi (only former Tado-cho), Inabe-shi (only former Inabe-cho), Suzuka-shi, Kameyama-shi (only former Kameyama-shi), Iga-shi (only former Ueno-shi), Tsu-shi (only former Tsu-shi and Hisai-shi, and Kawage-cho, Anocho, Hakusan-cho, and Ichishi-cho), Matsusaka-shi (only former Matsusaka-shi and Ureshino-cho), and Shima-shi (only former Ago-cho, Daio-cho, and Shima-cho), Mie Prefecture ( Miyamoto, 2001; Shimizu, 2014; Matsui et al., 2019), Nara-shi (only former Nara-shi), Yamatokoriyamashi, and Ikoma-shi, and Oyodo-cho, Nara Prefecture ( Matsui et al., 2019), Kyoto-shi (only former Kyoto-shi of Nishikyo-ku, Higashiyama-ku, and Fushimi-ku), Nagaokakyo-shi, Kyotanabe-shi, Kizugawa-shi (only former Kizu-cho and Kamo-cho), Uji-shi and Kameokashi, Oyamazaki-cho, Seika-cho, and Ujitawara-cho, and Minamiyamashiro-mura, Kyoto Prefecture ( Tanabe & Matsui, 2002; Matsui et al., 2019), Toyonaka-shi, Mino-shi, Ibaraki-shi, Takatsuki-shi, Hirakata-shi, Katano-shi, Shijonawate-shi, Higashiosaka-shi, Tondabayashi-shi, Sakai-shi (only former Sakai-shi), Izumi-shi, and Hannan-shi, Osaka Prefecture ( Osaka Prefecture, 1978; Matsui et al., 2019). Populations from Nantan-shi (only former Sonobe-cho) of Kyoto Prefecture ( Tanabe & Matsui, 2002) are lacking DNA data. This population is adjacent to the distribution area of Hynobius setouchi , so there is a possibility that this is the H. setouchi population. DNA analyses including samples from this population are essential for deciding the distribution range of H. vandenburghi .

Remarks. We examined a male specimen (specimen number: TMNH-AM-70) from Tahara-shi stored in the Toyohashi Museum of Natural History (1-238, Oiwacho Oana, Toyohashi-shi, Aichi Prefecture, 441-3147), but DBTYLD was not clear. The line of this specimen may have already faded; thus, the presence of DBTYLD still requires confirmation in several living individuals from the area after obtaining Hynobius vandenburghi collection permission from Tahara-shi. H. vandenburghi is also parapatrically distributed with H. setouchi , but it has no DBTYLD and DBTYLV.