Tylototriton daloushanensis Zhou, Xiao & Luo, 2022

Luo, Tao, Yan, Shasha, Xiao, Ning, Li, Wei, Deng, Huaiqing & Zhou, Jiang, 2022, A new species of the genus Tylototriton (Amphibia: Urodela: Salamandridae) from the Eastern Dalou Mountains in Guizhou, China, Zoological Systematics 47 (1), pp. 66-88 : 73-82

Tylototriton daloushanensis Zhou, Xiao & Luo , sp. nov. ( Figs 4–5 ; Tables 3, S1)

Chresonymy. Tylototriton asperrimus: Wu et al., 1986 ; Fei et al. 2005 (Suiyang and Zunyi, Guizhou). Yaotriton wenxianensis: Fei et al., 2012 (Suiyang and Zunyi, Guizhou). Tylototriton wenxianensis: Gu et al., 2012 (Suiyang, Guizhou). Yaotriton wenxianensis: Fei & Ye, 2016 (Suiyang and Zunyi, Guizhou). Tylototriton wenxianensis lineage 1: Wang et al., 2018 (Suiyang, Guizhou). Tylototriton sp. 1 : Poyarkov et al., 2021 (Suiyang, Guizhou).

Material examined. Holotype. GZNU20180806001, adult male, Huoqiuba Nature Reserve, Suiyang, Guizhou, China, August 6, 2018, leg. Tao Luo (28.4805°N, 107.0764°E, elev. 1501 m; Fig. 1 ).

Paratypes. Three adult females ( GZNU20180607001 , GZNU20180607003, and GZNU20180607009) and six adult males ( GZNU20180607002 , GZNU20180607004–07008), same data as holotype. One adult male ( GZNU20180608001 ), Kuankuoshui National Nature Reserve, Suiyang, Guizhou, China, June 22, 2021, leg. Tao Luo. Five adult males ( GZNU19980712001–12003 , GZNU19980712005–12006) and two adult females ( GZNU19980712004 , GZNU19980712 007), Kuankuoshui National Nature Reserve , Suiyang, Guizhou, China, July 12, 1998, leg. Xiaoming Gu. Four adult males ( GZNU20160409001–09004 ), Kuankuoshui National Nature Reserve , Suiyang, Guizhou, China, April 9, 2016, leg. Gang Li.

Etymology. The specific epithet, daloushanensis , is in reference to the type locality, Mt. Dalou in Guizhou Province, China. For the common name, we suggest “Mt. Dalou’s Knobby Newt,” and for the Chinese name, “Da Lou Shan You Yuan (kş山NJDz).”

Diagnosis. The new species is assigned to the T. wenxianensis species group of the subgenus Yaotriton based on phylogenetic analysis and on the following morphological characters: body almost black, except for the orange cranial region, palms and soles, vent region, and ventral ridge of tail ( Yang et al., 2014, Fei & Ye, 2016); head longer than wide; tubercles on dorsal and ventral surfaces almost equal in size; ventral skin without transverse wrinkles; and indistinct interspaces between rib nodules.

The new species can be distinguished from its congeners by a combination of the following characters: (1) large body size ( SVL 64.7–83.6 mm in males and 70.5–100.3mm in females); (2) head longer than wide, prominent bony ridges present; (3) snout rounded in dorsal view; (4) tail length less than snout-vent length in both males and females; (5) dark black body coloration, except for bright orange cranial region, palms and soles, vent region, and ventral ridge of tail; (6) relative length of toes III> IV> II> I> V; (7) fingertips reaching to between the eyes and nostrils when the forelimbs are stretched forward; (8) distal tip of the limbs greatly overlapping when the fore and hind limbs are pressed along the trunk; (9) presence of gular fold; (10) vertebral ridge slightly segmented, slightly flattened rib nodules, indistinct interspaces between rib nodules; and (11) lacking orange color markings on posterior parotoids and rib nodules.

Description (holotype). GZNU20180806001 ( Figs 4–5 ), adult male. Large body size, TOL 142.2 mm, SVL 83.6 mm; head length significantly longer than head width, HDL / HDW ratio 1.31; head slightly concave on the top; snout rounded in dorsal view, extending beyond the lower lip, SL 26.13% of HDL; naris nearly snout; bony supratemporal ridges on the head are long, steep, and notable, extending from the dorsal region of the rostral side and through the interior side of the upper eyelid to the occiput; a pair of short and protruding ridges on middle of supratemporal ridges; two bony ridges on the dorsal head surface form a “V” shape that is low and flat and distinctly not connected with the dorsal ridge of body; internasal distance slightly smaller than the interorbital distance, IND / IOD ratio 0.95; eyes protrude from the dorsolateral portion of the head, ED 22.07% of HDL, eyelids oval and slightly concave; the oral fissure is flat and straight and extends a distance greater than two-thirds the length of the head; the joint of jaw articulation lies posterior to the caudal margin of the eyes; fine teeth present on the edge of the jaw, vomerine teeth long and prominent forming a “∧” shape and are completely separated from each other at the tip of the “∧” shape; tongue oval and nearly entirely fixed at bottom but free at both lateral edges; and neck is rounded and thick, with a distinct neck groove.

Body rounded and stout; two sides of the ridge are slightly concave; each lateral corner of the dorsal ridge without enlarged knob-like dorsal warts; vertebral ridge on the dorsal side, slightly segmented, consisting of 16 knob-like vertebral ridges with a fine transverse stripe between each two nodal ridges; and rib nodules not separated, almost in continuous longitudinal rows.

Limbs slender, forelimb and hindlimb overlapping when pressed toward each other along the body; fingers and toes well developed, lacking webbing or fringes; fingertips reaching between the eyes and nostrils when the forelimbs are stretched forward; relative finger lengths III> II> IV> I, relative toe lengths III> II> IV> V> I; and fingers and toes relatively flat, without subarticular tubercles, with metacarpal and metatarsal tubercles not visible.

Tail length, TAL / SVL ratio 0.80; tail notably compressed laterally; dorsal fin fold of the tail, starting from the tail base, distinctly thin and high; ventral fin fold of tail, starting from posterior to the cloaca, is thick and short; tail height greater than the width at the tail base, and the distal tail tip is oval in shape; and cloaca long and narrow, with the cloacal region slightly uplifted.

Body skin extremely rough, and body covered with tubercles and warts; the labial margin, distal limb, ventral limb, and ventral edge of tail are relatively smooth; the dorsal ridge, running along the middle of the dorsum and extending from the neck to the base of the tail, is rough and relatively narrow; each lateral corner of the dorsal ridge consists of a row of tiny and dense dorsal tubercles; on the lateral dorsum of the body, the tubercles and warts are large and slightly flattened to nearly indistinct and ill defined, appearing to form lines extending from the shoulder to the base of the tail; ventral tubercles and warts are relatively flat and smaller; unlike the dorsal tubercles, the ventral tubercles and warts are relatively flat; and the dorsal edge of the tail is covered with prominent tubercles, and the lateral tail and peripheral area of the cloaca contain warts.

Coloration in life (holotype, Figs 4A–C, G–I ). In life, specimen dark black on the dorsal and ventral surfaces; the distal digit ends, ventral digits, the peripheral area of cloaca and the ventral edge of tail are bronze-orange; and the bronze-orange region between the ventral edge of the tail and the peripheral area of the cloaca is connected.

Color in preservative (holotype, Figs 5A–B ). The specimen in preservative is black, and the ventral color is blackish brown. It has orange coloration of the distal digit ends, ventral digits, and the peripheral area of the cloaca, and the ventral edge of the tail is a creamy yellow.

Variations. Table S1 gives measurements of the type series. A large proportion of specimens were similar in morphology with the holotype, but some individuals were different. The single female paratype GZNU20180607009 possesses a larger and more robust body; however, its tail is relatively longer, TAL / SVL ratio 1.00 vs 0.80 in holotype GZNU20180806001. In males GZNU20160409001 and GZNU20160409004, the tail length is longer than the snout-vent length. All males show little variation in coloration and are similar to the holotype. Female cloaca peripheral area same as body coloration or with a light bronze-orange band.

Secondary sexual characteristics. Male cloaca relatively long, slightly uplifted, with small papillae on the inner wall of the cloaca. The female cloaca is very short and has no papillae on the inner wall of the cloaca.

Comparisons. The new species was previously identified as T. asperrimus ( Wu et al., 1986; Fei et al., 2005) or T. wenxianensis ( Fei et al., 2012; Gu et al., 2012; Fei & Ye, 2016), but molecular phylogenetic results indicate that the species is genetically closer to T. broadoridgus , T. maolanensis , T. dabienicus , and T. anhuiensis . The new species can be further distinguished from these closely related species by combining the following morphological features. Comparative morphological information about the new species, along with 16 species of the T. asperrimus species group of the genus Tylototriton , is provided in Table S2.

The new species differs from T. asperrimus by the head length being longer than wide (vs. wider than long); the relative toe lengths III> IV> II> I> V (vs. III> IV> II> V> I); snout rounded in dorsal view (vs. snout truncate in dorsal view); the distal tip of limbs greatly overlapping when the fore and hind limbs are pressed along the trunk (vs. slightly overlapping, meeting or not meeting); fingertips reaching to between the eyes and nostrils when the forelimbs are stretched forward (vs. just reaching to the nostril or eye); slightly flattened rib nodules (vs. enlarged knob-like rib nodules); and rib nodules not separated, almost in continuous longitudinal rows (vs. rib nodules swollen and distinctly isolated from each other).

The new species differs from T. wenxianensis by the relative toe lengths III> IV> II> I> V (vs. IIII> IV> II> V> I); presence of gular fold (vs. absence); the distal tip of limbs greatly overlapping when the fore and hind limbs are pressed along the trunk (vs. slightly meeting or slightly overlapping); fingertips reaching to between the eyes and nostrils when the forelimbs are stretched forward (vs. reaching to the nostril); having significantly longer TOL, UEW, HL, LLA, TIIIL, and TAL in males; having significantly longer TOL, UEW, HL, LLA, FIIIL, TL, and TIIIL in females; and having significantly higher ratios of TRL to SVL in females.

The new species differs from T. broadoridgus by the prominent bony ridges on the head (vs. less developed ridges on the head); the relative toe lengths III> IV>II> I> V (vs. III>IV> II> V>I); snout rounded in dorsal view (vs. snout truncated in dorsal view); presence of gular fold (vs. absence); having significantly longer TOL, HDL, IFE, and UEW in males; having significantly higher ratios of TRL to SVL, and IAE to HDW in males; prominent bony ridges on head (vs. less developed ridges on head).

The new species differs from T. maolanensis by the tail length less than snout-vent length in males (vs. tail length longer than snout-vent length); snout rounded in dorsal view (vs. snout truncate in dorsal view); fingertips reaching to between the eyes and nostrils when the forelimbs are stretched forward (vs. reaching to the level beyond the snout); slightly flattened rib nodules (vs. enlarged knob-like rib nodules); indistinct interspaces between rib nodules (vs. distinct interspaces between rib nodules); having significantly longer TOL, SVL, HDW, TRL, SL, ED, IAE, UEW, IND, HL, LLA, and TIIIL in males; and having significantly higher ratios of SVL to TOL, HDL, TAL, TRL, and ED to SVL, and HDL, IFE, IAE, and IND to HDW in males.

The new species differs from T. dabienicus by the relative toe lengths III> IV> II> I> V (vs. III> IV> II> V> I); prominent bony ridges on the head (vs. less developed ridges on head); the distal tip of limbs greatly overlapping when the fore and hind limbs are pressed along the trunk (vs. slightly meeting or not meeting); fingertips reaching to between the eyes and nostrils when the forelimbs are stretched forward (vs. reaching to the eye); having significantly longer HDW, IFE, UEW, HL, and LLA in males; having significantly higher ratios of SVL to TOL, and IAE to HDW in males; and prominent bony ridges on head (vs. less developed ridges on head).

The new species differs from T. anhuiensis by the relative toe lengths III> II> IV> V> I (vs. III> IV> II> V> I); prominent bony ridges on the head (vs. less developed ridges on the head); the distal tip of limbs greatly overlapping when the fore and hind limbs are pressed along the trunk (vs. slightly overlapping); having significantly longer HDL, HDW, SL, and ED in females; having significantly higher ratios of HDL, IFE, IAE, IND, and IOD to HDW, and IND to IOD in females; prominent bony ridges on head (vs. less developed ridges on head); and having long and strong vomerine tooth (vs. vomerine teeth short).

The new species differs from T. liuyangensis by the head length being longer than wide (vs. long equal to wider); the relative toe lengths III> IV> II>I> V (vs. III>IV>II> V>I); snout rounded in dorsal view (vs. snout truncate in dorsal view); the distal tip of limbs greatly overlapping when the fore and hind limbs are pressed along the trunk (vs. slightly overlapping, meeting or not meeting); fingertips reaching to between the eyes and nostrils when the forelimbs are stretched forward (vs. reaching to the eye); indistinct interspaces between rib nodules (vs. distinct interspaces between rib nodules); and rib nodules not separated, almost in continuous longitudinal rows (vs. rib nodules swollen and distinctly isolated from each other).

The new species differs from T. lizhenchangi by the relative toe lengths III> IV> II> I> V (vs. III> IV> II> V> I); having prominent bony ridges on the head (vs. less developed ridges on the head); and lacking orange color markings on posterior parotoids (vs. present).

The new species differs from T. hainanensis by the head length longer than wide (vs. head wider than long); the relative toe lengths III> IV> II> I> V (vs. III> IV> II> V> I); and rib nodules not separated, almost in continuous longitudinal rows (vs. rib nodules swollen and distinctly isolated from each other).

The new species differs from T. sini by the relative toe lengths III> IV> II> I> V (vs. I = V <II <III= IV), and rib nodules not separated, almost in continuous longitudinal rows (vs. rib nodules swollen and distinctly isolated from each other).

The new species differs from T. notialis and T. pasmansi by the snout being rounded in profile view (vs. slightly angular) and absence of orange markings on the parotoid (vs. present); from T. panhai by absence of orange markings on the parotoid (vs. present); from T. sparreboomi by rib nodules not separated, almost in continuous longitudinal rows (vs. rib nodules swollen and distinctly isolated from each other); from T. vietnamensis by the presence of gular fold (vs. absent) and rib nodules not separated, almost in continuous longitudinal rows (vs. rib nodules swollen and distinctly isolated from each other); from T. ziegleri by the head longer than wide (vs. head wider than long) and ridge not segmented (vs. segmented, forming a row of tubercles); and from T. thaiorum by the head longer than wide (vs. head wider than long) and rib nodules not separated, almost in continuous longitudinal rows (vs. rib nodules swollen and distinctly isolated from each other).

The new species differs from T. taliangensis by the absence of orange markings on the parotoid (vs. present); from T. anguliceps , T. himalayanus , T. kachinorum , T. pseudoverrucosus , T. ngarsuensis , T. panwaensis , T. phukhaensis , T. podichthys , T. pulcherrimus , T. shanorum , T. shanjing , T. uyenoi , and T. verrucosus by limbs dark brown except for the orange digits, palms, and soles (vs. limbs uniformly orange or light brown); and from T. kweichowensis and T. yangi by tail dark brown, except fin with dorsal orange margin and ventral tail ridge orange (vs. tail uniformly orange).

Distribution and ecology. The new species is only known from the type locality, Huoqiuba Nature Reserve, Suiyang, Guizhou, China, and Kuankuoshui National Nature Reserve, Suiyang, Guizhou, China, at elevations of 900–1600 m. All specimens were collected in a still pond within a relatively well-preserved bamboo forest, with the bottom covered in humus, such as fallen bamboo leaves, and the surrounding area dominated by grasses and kudzu, as well as accompanying tall broadleaf forests ( Figs 6A–B, D ). In the Huoqiuba Nature Reserve and the Kuankuoshui National Nature Reserve, the new species is sympatric with Leptobrachella suiyangensis Luo, Xiao, Gao & Zhou, 2020 , Boulenophrys jiangi (Liu, Li, Wei, Xu, Cheng, Wang & Wu, 2020) , Boulenophrys qianbeiensis (Su, Shi, Wu, Li, Yao, Wang & Li, 2020) , Quasipaa spinosa David, 1875 , Quasipaa boulengeri Günther, 1889 , Odorrana margaretae Liu, 1950 , Odorrana yizhangensis Fei, Ye & Jiang, 2007 , Odorrana kweichowensis Li, Xu, Lv, Jiang, Wei & Wang, 2018 ( Li et al., 2018a), Rana omeimontis Ye & Fei, 1993 (Ye, Fei & Hu, 1993), and Zhangixalus chenfui Liu, 1945 . In addition, specimen GZNU2018016, collected at the type locality on June 7, 2018, laid 39 eggs on the same night ( Fig. 6C ). We speculate that its breeding date was around June to September, with stacking behavior observed in individuals reared indoors. At present, information about population size, specific breeding dates, and behavior is still lacking.

Figures

Figure 1. Sampling localities of the Tylototriton daloushanensis Zhou, Xiao & Luo, sp. nov., T. maolanensis, and T. kweichowensis in Guizhou, China.A. Huoqiuba Nature Reserve, Suiyang County. B. Kuankuoshui National Nature Reserve, Suiyang County. C. Maolan National Nature Reserve, Libo County. D. Nayong County.

Figure 4. Tylototriton daloushanensis Zhou, Xiao & Luo, sp. nov. in life. A–C. Male holotype, GZNU20180806001, dorsal, ventral, and dorsolateral views. D–F. Female paratype, GZNU20180607001, dorsal, ventral, and dorsolateral views. H–I. Male holotype, GZNU20180806001, ventral view of the hand, foot, and cloaca. J–L. Female paratype, GZNU20180607001, ventral view of the hand, foot, and cloaca (yellow arrow). All photos were taken at around 9:00 am.

Figure 5. Tylototriton daloushanensis Zhou, Xiao & Luo, sp. nov. in preserved status. A–B. Male holotype, GZNU20180806001, dorsal and ventral views. C–D. Female paratype, GZNU20180607001, dorsal and ventral views. E. Female paratype, GZNU20180607001, dorsal view of head. F. Female paratype, GZNU20180607001, view of oral cavity (yellow arrows represent vomerine teeth). Scale bars: A–D=5.0mm; E–F=4.0mm.

Figure 6. Habitat and eggs of Tylototriton daloushanensis Zhou, Xiao & Luo, sp. nov. at the type locality. A. Microhabitats. B. Individual found in the type locality. C. Eggs laid by GZNU20180607001 on 7 June 2018. D. Individual GZNU20180608001 collected on 8 June 2018 in Kuankuoshui National Nature Reserve.