Hynobius owariensis, Sugawara & Fujitani & Seguchi & Sawahata & Nagano, 2022

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 : 51-54

Hynobius owariensis sp. nov.

(New standard Japanese name: Owari-sanshouo)

( Figs. 4–5 )

Hynobius nebulosus : Kuzumi and Kakegawa, 1989; Fujitani, 2000; Fujitani et al., 2016: 3, in part.

Hynobius vandenburghi : Matsui et al., 2019: 49, in part; Ichioka et al., 2021

Etymology. The specific epithet “ owariensis ” refers to the old name of the western part of Aichi Prefecture (= Owari) where the new species occurs. Holotype. An adult male (specimen number: TMNH-

AM-78) from Tenpakucho Yagotourayama , Tenpaku-ku, Nagoya-shi, Aichi Prefecture, Japan (35° 08’ N, 136° 58’ E; elevation = 50 m), collected by Takeshi Fujitani on 18 February 2020. This population is on private land; thus, we obtained permission from the landowner to collect the specimen .

Paratypes. An adult female (specimen number: KPM-NFA 940 ) from the same locality of the holotype, collected by Takeshi Fujitani on 28 February. 2020. An adult male (specimen number: KPM-NFA 941 ) from Odakacho Takayama , Midori-ku, Nagoya-shi, Aichi Prefecture, Japan (35° 03’ N, 136° 56’ E; elevation = 30 m), collected by Takeshi Fujitani on 4 March 2019. This population is also on private land; therefore, we again obtained permission from the landowner to collect specimens .

Diagnosis. A comparatively large species (mean SVL = 60.6 mm in males and 59.1 mm in females) within the Japanese lentic Hynobius species: SVL usually> 56 mm in males; ratio of hindlimb length almost always <30 %SVL in males; distinct and bright yellow stripe on the ventral edge of tail always absent in males and almost always absent in females; distinct and bright yellow stripe on the dorsal edge of tail always absent in males; distinct black dots on the dorsum almost always absent in males; distinct white dots on the ventral and lateral sides of the body usually absent in males; DGM almost always present in malEs and nEvEr prEsEnt in fEmalEs; fifth toE of hindlimb always present; U-shaped or V-shaped vomerine teeth series; 13 (rarely 12 or 14) costal grooves; number of costal folds bEtwEEn adprEssEd limbs UsUally −3.0 to − 1.5 in malEs and almost always −4.0 to − 1.5 in fEmalEs.

Description of holotype. A moderately large individual: HL slightly larger than HW; TAL shorter than SVL; body almost cylindrical; rounded snout; gular fold present; tail gradually compressed toward the tip; expanded cloaca; webbing between digits absent; four fingers on each forelimb, order of length II> III> IV> I on left and III> II> IV> I on right; fivE toEs on Each hindlimb, ordEr of length III> II> IV> I> V on left and III> IV> II> V> I on right; U-shaped vomerine teeth; skin smooth and shiny; DWDV and DWDL absent; DBDD absent; DBTYLD and DBTYLV absent; DGM present. The holotype had the following measurements (in mm): SVL =58.2, TRL = 46.4, AGD = 32.4, HL = 12.5, TAL = 44.5, MTAW = 4.0, MTAH = 7.0, BTAW = 7.6, BTAH = 6.4, VTL = 2.4, VTW = 3.2, HW = 9.8, MXHW = 10.1, LFLL = 12.3, RFLL = 10.7, LHLL = 15.1, RHLL = 14.6, L1FL = 1.3, L2FL = 2.9, L3FL = 1.8, L4FL = 1.5, R1FL = 0.9, R2FL = 1.4, R3FL = 1.8, R4FL = 1.3, L1TL = 1.5, L2TL = 3.2, L3TL = 4.1, L4TL = 2.9, L5TL = 0.7, R1TL = 0.9, R2TL = 2.9, R3TL = 3.8, R4TL = 3.1, R5TL = 1.2, IND = 2.4, IOD = 3.7, LUEW = 1.5, RUEW = 1.1, SL =3.9, LUEL =2.4, RUEL = 2.6, LJL = 6.8, CGN = 13.

Comparisons. The new species resembles H. vandenburghi in morphology but differs statistically from it in the following length measurements: SVL, RTRL, RAGD, RHL, RMTAH, RVTW, RHLL, R3TL, RUEW, RUEL, and RLJL in males and SVL and RVTL in females; the lengths of these measurements, except for SVL, RTRL, RAGD, RMTAH, and RVTW in males and SVL in fEmalEs, arE significantly shortEr in H. owariensis sp. nov. than in H. vandenburghi . In males, H. owariensis sp. nov. differs from H. vandenburghi by the following combination of characters: SVL> 56 mm (18/22 = 81.8 %) vs. SVL <56 mm (14/17 = 82.4 %); RHLL shorter than 30 % (20/22 = 90.9 %), vs. RHLL of 30 % or longer (14/17 = 82.4 %); UsUally havE CFBALN ≤ −1.5 (19/22 = 86.4 %) vs. UsUally havE CFBALN ≥ −1.0 (15/17 = 88.2 %); always lack DBTYLD and DBTYLV (22/22 = 100 %) vs. always have DBTYLD and DBTYLV (17/17 = 100 %). In females, H. owariensis sp. nov. almost always lacks DBTYLV (9/10 = 90 %), whereas H. vandenburghi always have DBTYLV (6/6 = 100 %).

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 RFLL and R2FL than females, whereas males have relatively shorter RTRL, RAGD, RUEW, and RUEL than those of females. The skin markings of H. owariensis sp. nov. are listed in Table 4. The dorsum is uniformly yellowish-brown or darkish-brown. DBDD is rarely present in males (2/22 = 9.1 %) and sometimes present in females (3/10 = 30 %). The venter is lighter than the dorsum. DWDV is rarely present in males (4/22 = 18.2 %) and sometimes absent in females (4/10 = 40 %). DWDL is rarely present in males (3/22 = 13.6 %) and rarely present in females (3/10 = 30.0 %). In females, DBTYLD is sometimes present (5/10 = 50 %) and DBTYLV is rarely present (1/10 = 10 %). DGM is rarely absent in males (2/22 = 9.1 %). CGN is rarely 12 (2/22 = 9.1 %) or 14 (2/22 = 9.1 %) in males and rarely 14 in females (1/10 = 10.0 %). CFBALN is rarEly> − 1.5 in malEs (3/22 = 13.6 %) and rarEly> −1.0 (1/10 = 10 %) in fEmalEs. ThE iris is dark brown. When preserved in 70 % ethanol, the dorsal coloration tends to fade to dark gray. The indistinct yellowish line on the dorsal and ventral sides of the tail (e.g.,

Figures

Fig. 4. Holotype of Hynobius owariensis sp. nov. (TMNH- AM-78, adult male, 58.2 mm SVL): (A) dorsal and (B) ventral views.

Fig. 5. (A) Live holotype of Hynobius owariensis sp. nov. (TMNH-AM-78), and the (B) larva, (C) banana-shaped egg sacs, and (D) type locality of the new species.