Hynobius sumidai, Sugawara & Naito & Iwata & Nagano, 2022

Sugawara, Hirotaka, Naito, Jun-ichi, Iwata, Takayuki & Nagano, Masahiro, 2022, Molecular Phylogenetic and Morphological Problems of the Aki Salamander Hynobius akiensis: Description of Two New Species from Chugoku, Japan, Bulletin of the Kanagawa Prefectural Museum (Natural Science) 51, pp. 35-46 : 42-44

publication ID

https://doi.org/ 10.5281/zenodo.11281013

publication LSID

lsid:zoobank.org:pub:2861D048-4805-4B5C-90E0-274A313A16EE

DOI

https://doi.org/10.5281/zenodo.11281029

persistent identifier

https://treatment.plazi.org/id/15AD2B94-A1E4-4DBD-8AF1-E7A4B2723D8A

taxon LSID

lsid:zoobank.org:act:15AD2B94-A1E4-4DBD-8AF1-E7A4B2723D8A

treatment provided by

Felipe

scientific name

Hynobius sumidai
status

sp. nov.

Hynobius sumidai sp. nov.

(New standard Japanese name: Hiroshima-sanshouo)

( Figs. 4–5 View Fig View Fig )

Hynobius nebulosus View in CoL : Okawa et al., 1990: 50, in part.

Hynobius akiensis Matsui, Okawa and Nishikawa View in CoL in Matsui et al., 2019: 75, in part.

Etymology. The specific name “ sumidai ” is dedicated to Dr. Masayuki Sumida who was the phylogenetic taxonomist of amphibians at Hiroshima University.

Holotype. An adult male (specimen number: HMNH-AM-102) from Tamaricho , Takehara-shi, Hiroshima Prefecture, Chugoku, Japan [34° 24′ N, 132° 47′ E; elevation = 340 m above sea level (a.s.l.); in all cases, datum = WGS84], collected by Jun-ichi Naito on 23 March 2021. GoogleMaps

Paratype. An adult female (specimen number: KPM-NFA 945 ) from the same locality of the holotype, collected by Jun-ichi Naito on 23 March 2021 .

Diagnosis. A comparatively small species (mean snout– vent length of 47.2 mm in males) within the Japanese lentic Hynobius ; SVL usually less than 50 mm; distinct brownish–yellow stripe on the dorsal edge of the tail always present; distinct brownish–yellow line on the ventral side of the tail never present; distinct gular mottling never present; yellowish–brown to blackish–brown on dorsum; the fifth toe of hindlimb always present; V-shaped vomerine teeth series; usually 12 costal grooves (rarely 13); costal folds between adpressed limbs always less than 1.0; coil-shaped egg sacs.

Description of holotype. A moderately large individual with HL larger than HW; TAL shorter than SVL; body almost cylindrical; rounded snout; gular fold present; tail gradually compressed toward the tip; non-expanded cloaca; webbing between digits absent; four fingers on each forelimb, order of length II> III> I> IV on left and II> III> IV> I on right; five toes on each hindlimb, order of length III> IV> II> I> V on both sides; V-shaped vomerine teeth; skin smooth and shiny; DBDD absent; DWDV and DWDL absent; DTBYLD present (it became unclear after preservation); DTBYLV absent; DGM absent. The holotype had the following measurements (in mm) : SVL = 48.2, TRL = 36.6, AGD = 26.0, HL = 11.3, TAL = 34.6, MTAW = 2.4, MTAH = 4.7, BTAW = 5.4, BTAH = 4.4, VTL = 2.6, VTW = 2.5, HW = 8.0, MXHW = 8.2, LFLL = 11.8, RFLL = 11.9, LHLL = 14.1, RHLL = 14.0, L1FL = 1.3, L2FL = 2.1, L3FL = 1.9, L4FL = 0.9, R1 FL = 0.7, R2 FL = 1.6, R3 FL = 1.2, R4 FL = 0.8, L1TL = 1.1, L2TL = 2.0, L3TL = 3.3, L4TL = 2.3, L5TL = 0.8, R1 TL = 1.3, R2 TL = 1.7, R3 TL = 2.9, R4 TL = 1.9, R5 TL = 0.7, IND = 2.3, IOD = 3.0, LUEW = 1.6, RUEW = 1.4, SL = 3.4, LUEL = 2.4, RUEL = 2.2, LJL = 6.9, and CGN = 12.

Comparisons. The new species statistically differs from H. geiyoensis sp. nov. in the following length measurements: SVL, RHL, RTAL, RFLL, R3FL, R3TL, R5TL, RUEW, and RUEL in males; the lengths of these measurements, except for RHL, RFLL, RUEW, and RUEL, are significantly longer in H. sumidai sp. nov. relative to the measurements in H. geiyoensis sp. nov.. The new species differs from H. geiyoensis sp. nov. by the following characters: SVL <50 mm (7/7 = 100 %) vs. SVL> 50 mm (19/19 = 100 %); R5TL <1.9 % (7/7 = 100 %) vs. R5TL> 1.8 % (18/19 = 94.7 %); RUEW> 3.1 % (7/7 = 100 %) vs. RUEW <3.2 % (18/19 = 94.7 %); RUEL> 4.3 % (7/7 = 100 %) vs. RUEL <4.3 % (18/19 = 94.7 %). The new species statistically differs from H. akiensis in the following length measurements: SVL (shorter), RVTL (longer), and R3FL (shorter) in males. The most distinct characteristic between the two species is the presence of DTBYLD: H. sumidai sp. nov. always has this characteristic (7/7 = 100 %), whereas H. akiensis usually lacks it (25/28 = 89.3 %).

Variation. Morphometric measurements and observations are presented in Tables 2 View Table 2 and 4 View Table 4 , respectively. The dorsum is uniformly yellowish–brown or darkish– brown. The venter is lighter than the dorsum. DBDD rarely absent (2/7 = 28.6 %), DWDV and DWDL sometimes absent (3/7 = 42.9 %), sometimes it has 13 CGN (3/7 = 42.9 %), and rarely has more than 0 CFBALN (1/7 = 14.3 %). The iris is dark brown or light brown. When preserved, the dorsal coloration tends to fade to dark gray and DTBYLD becomes unclear after preservation.

Distribution. This new species is endemic to Hiroshima Prefecture, and it is known from Higashihiroshima-shi (only former Higashihiroshima-shi and Akitsucho) and Takehara-shi. Its distribution is thought to bein the former Kurose-cho and Kure-shi areas, but no supporting evidence is available to confirm this hypothesis. Further phylogenetic studies using more samples from Higashihiroshima-shi and Kure-shi are therefore essential.

Natural History. The dominant vegetation type in the type locality is a mixed forest of evergreen oak ( Quercus spp. ) and Japanese cypress ( Chamaecyparis obtusa ). The larval and egg sac morphologies of this new species are similar to those of H. geiyoensis sp. nov. The breeding season of the new species is February to April.

Remarks. The new species forms a monophyletic group with the Highland and Aki groups ( Matsui et al., 2019). The morphology of females is unclear; hence, additional studies to clarify the morphology of females are needed.

DGM

Divisao de Geologia c Mineralogia

TL

Université Paul Sabatier

Kingdom

Animalia

Phylum

Chordata

Class

Amphibia

Order

Caudata

Family

Hynobiidae

Genus

Hynobius

Loc

Hynobius sumidai

Sugawara, Hirotaka, Naito, Jun-ichi, Iwata, Takayuki & Nagano, Masahiro 2022
2022
Loc

Hynobius nebulosus

Okawa, H. & T. Utsunomiya & Y. Utsunomiya & J. Naito 1990: 50
1990
Loc

Hynobius akiensis

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