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A new species of the genus Tylototriton is described from Ngoc Linh Mountain, Kon Tum Province, in the Central Highlands of Vietnam based on integrative taxonomy, namely by combining molecular and morphological evidence. Tylototriton ngoclinhensis sp. nov. differs from all other congeners based on morphological data, allopatric distribution, and molecular divergence. In terms of genetic divergence, Tylototriton ngoclinhensis sp. nov. distinctly differs from the sister species T. panhai (6.77%) and from T. ngarsuensis (12.36%) based on the mitochondrial NADH dehydrogenase subunit 2 (ND2) gene. Tylototriton ngoclinhensis sp. nov. is a moderate sized and robust salamander species with large cephalic edges, parotoids, and vertebral ridge orange in coloration. The new taxon differs from its congeners by a combination of the following morphological characteristics: size medium (SVL 60.8–66.5 mm, TL 57.6–61.8 mm in males, and SVL 72.5–75.6 mm, TL 62.9–67.9 mm in females); head longer than wide; parotoids very prominent and enlarged, projecting backwards; tail length shorter than snout-vent length; vertebral ridge large, high and glandular in appearance; 14 large and distinct dorsolateral glandular warts; gular fold present; tips of fore and hind limbs overlapping when adpressed along the body; tips of fingers reaching between eye and nostril when foreleg is laid forward; dorsal surface and lateral sides of the head, upper and lower lips, dorsolateral glandular warts, vertebral ridge, the peripheral area of the cloaca and the ventral edge of the tail orange in coloration; the presence of a distinct black line extending from the posterior end of the eye towards the shoulder. Tylototriton ngoclinhensis sp. nov. is restricted to evergreen montane forests near water bodies on Ngoc Linh Mountain. We suggest that the new species should be classified as Endangered (EN) in the IUCN Red List. This new important discovery represents the eighth Tylototriton taxon described from Vietnam, and at the same time constitutes the southernmost distributional record for the whole genus in Asia.

Herein, we provided a morphological description combined with a phylogenetic analysis of the northernmost Thai Tylototriton population, which was found in Doi Pha Hom Pok National Park (DPHPNP), Chiang Mai Province, northern Thailand. Three adult males were collected from a small breeding pond during our survey in July 2020. Based on molecular (two specimens) and morphological (three specimens) evidence, all three specimens from DPHPNP were identified as Tylototriton verrucosus Anderson, 1871, and were characterized by having a blackish background, orange to light orange-brown color markings, segmented vertebral ridge, prominent rib nodules ranging from 13–15 warts, and a rough skin with granules. Hence, this second record of T. verrucosus populations in Thailand confirms a range extension of this species in northern Indochina. Additionally, the morphological variation and conservation status are discussed for the populations from Thailand.

We describe a new species of the newt genus Tylototriton from Umphang Wildlife Sanctuary, Tak Province, western Thailand based on molecular and morphological evidence and named here as Tylototriton umphangensissp. nov. The new species is assigned to the subgenus Tylototriton and differs from other species in having dark-brown to blackish-brown body and limbs, truncate snout, prominent antero-medial ends of the expansion of the dentary bones, laterally protruding quadrate regions, indistinct and small rib nodules, a well-segmented vertebral ridge, and rough dorsolateral bony ridges, which are steeper anterior, and curved medially at the posterior ends. The molecular data show that Tylototriton umphangensissp. nov. differs from T. uyenoi sensu stricto by a 5% genetic sequence divergence of the mitochondrial NADH dehydrogenase subunit 2 region gene. The new species and T. uyenoi are both endemic to Thailand, distributed along the Northwest Thai (Dawna) Uplands of Indochina. To clarify the species boundary between Tylototriton umphangensissp. nov. and T. uyenoi, additional field research is needed in adjacent areas. Tylototriton umphangensissp. nov. is restricted to evergreen hill forests in Umphang Wildlife Sanctuary. We suggest that the new species should be classified as Endangered (EN) in the IUCN Red List.

In this work, a new species of the genus Tylototriton is described from Guangdong, southern China. Tylototriton sini sp. nov. was recorded as T. asperrimus for decades, and was indicated to represent an independent lineage based on recent molecular phylogenetic analyses. After detailed molecular analysis and morphological comparisons, Tylototriton sini sp. nov. is recognized as a distinct species which can be clearly distinguished from all known congeners by a combination of morphological characteristics and the significant divergence in the mitochondrial gene. Because the genus Tylototriton is of high conservation concern and all formally described members are protected by law, we also provide first data on the conservation status and recommendations for IUCN categorization for Tylototriton sini sp. nov. A suggestion on the species groups division of the genus Tylototriton is also provided based on their morphological differences and phylogenetic relationships.

TYLOTOTRITON (TYLOTOTRITON) HOUI HERNANDEZ & DUFRESNES SP. NOV. (FIG. 10) Z o o b a n k r e g i s t r a t i o n: u r n: l s i d: z o o b a n k. o r g: a c t: A D B 2 E B 7 A - E A 1 C - 4 C 9 5 - 9 9 9 6 - EAF78C2FD 96F. Identity and diagnosis: A moderate size Tylototriton slightly flattened in appearance, with an oval head, a prominent vertebral ridge and 11–15 dorsolateral glandular warts. The tail is thick, laterally compressed, and smaller than the SVL. The skin is rough and finely granulated on dorsum and flanks. The background colour is dark, but with extensive orange coloration on the vertebral ridge, the glandular warts, the lower abdomen, the tail, legs as well as large parts of the head. This new species generally resembles T. panaeaensis, T. pulcherrimus and T. Ʋerrucossus, its closest relatives (Fig. 2). It was previously confounded with the shanjing morphotype of T. Ʋerrucosus. Among previous molecular work, T. houi only appears in the fine-scale phylogeography of ‘ T. shanjing ’ by Yu et al. (2013) as the Hengduan endemic clade B, the sister-lineage of clade A (now T. panaeaensis), although this phylogenetic position is not robustly supported (Fig. 1). The new species diverged from the above congeners around the Plio-Pleistocene transition (~2.3 Mya) and features mitochondrial differentiation (0.6–1.0% at 16S, 1.6– 2.4% at Cytb) comparable to other species-level splits in Tylototriton (e.g. T. aeenxianensis / maolanensis and T. pseudoƲerrucosus / taliangensis). Beside molecular characters, T. houi can be distinguished from its close congeners (notably T. pulcherrimus and T. Ʋerrucosus) by its orange abdominal region, an indistinct sagittal crest on the head, distinct nostrils, a broader head and a slimmer body. Moreover, the larvae shows distinctive morphological features compared to T. Ʋerrucosus (shanjing morphotype; Hernandez et al., 2019), such as smaller and darker gills, corrugated and dark tail fins, and a yellow dorsal stripe when reaching larval sizes of 30–36 mm (TTL). Holotype: MZL–46960, adult male found dead on 19 July 2015 by AH, M. Hou, G. Espallargas in Jade Water Village, on the southern slopes of Jade Dragon Snow Mountain (Hengduan massif), Lijiang Prefecture, Yulong Naxi Autonomous County, northern Yunnan Province, China, between 2850 and 3200 m a.s.l. (27.0744°N, 100.1906°E); curated at the Cantonal Museum of Zoology of Lausanne. The specimen was sequenced for 16S and the corresponding lineage is featured in our phylogeny (red circle of the middle clade in Fig. 2). The specimen and the type locality are depicted in Fig. 10. Description of holotype: Poor state due to early decomposition at discovery, which caused discoloration and skin damages. Slim newt (TTL: 87 mm) with fine granulation; laterally compressed tail (TAL: 40 mm), shorter than body (SVL: 47 mm); broad head (HW: 13 mm), larger than body (CW: 11 mm), with distinct nostrils as close to each other’s (IN: 3 mm) than from the eyes (ON: 3 mm); large eyes (ED: 3 mm) laterally disposed; parotids visible; vertebral ridge prominent (discoloured); 16 lateral glandular warts, disposed from axilla to the tail basis; forelimbs (AL: 16 mm) slightly shorter than hind limbs (PL: 18 mm); four fingers and five toes well developed, with no visible webbing; cloaca distinct, with longitudinal vent slit; previously coloured body parts (visible from discoloration patterns) include the lateral sides of the head, the vertebral ridge, the glandular warts, the tail and several underparts (cloaca, hind limbs, forelimbs, gular fold and jaw). Etymology: We coin the new nomen, Tylototriton (Tylototriton) houi, as a tribute to Mian Hou, a leading figure in Chinese herpetology who contributed significant advances in crocodile newt research and taxonomy, including reports on the first known populations of T. (T.) houi (Hernandez et al., 2019). Common names: Hou’s crocodile newt (English), Tylototriton de Hou (French). DiƲersity and distribution: The species is microendemic of the Hengduan Moutains in Yunnan Province, China. It is currently known from only three locations: Lijiang, Peiliang and Shuanghaizi. These populations are genetically similar (Yu et al., 2013; this study). Natural history: The new species inhabits highelevation subalpine meadows surrounded by conifer and mixed broadleaf forests, where permanent or ephemeral ponds (filled by seasonal rains) are available (Hernandez et al., 2019). On average, T. (T.) houi occurs at higher elevations than any other crocodile newt (2714–3200 m a.s.l.). Breeding is aquatic: adults and larvae (depicted in Fig. 10) were observed in vegetated and non-vegetated ponds with roughly neutral pH (6.6–7.7), shared with anuran tadpoles of Bombina maxima (Boulenger, 1905), Rana chaochiaoensis Liu, 1946, Bufo andreaesi Schmidt, 1925, Nanorana yunnanensis (Anderson, 1879). Courtship behaviour has never been observed. Eggs are round, deposited underwater on rocks and submerged terrestrial plants, with capsules of 4.4–5.7 mm in diameter, surrounding embryos of 1.2–1.8 mm (AH pers. obs.). ConserƲation: Although not specifically assessed, T. (T.) houi faces immediate danger of extinction.The few known populations are threatened by anthropogenic pressure related to mass tourism, including water pollution, the introduction of invasive fish (Gambusia Poey, 1854, AH pers. obs.), habitat alteration and destruction, electric fishing. Poaching for traditional Chinese medicine and the pet trade may also represent additional threats.

The distribution of the Ziegler's Crocodile Newt Tylototriton ziegleri Nishikawa, Matsui & Nguyen, 2013 in China has been controversial. This species was originally recorded uncertainly from Guangxi Autonomous Region, China. Subsequently, this species was recorded from Yunnan and Guangdong provinces, China. Thereafter, the record from Guangdong was denied and the record from Yunnan was questioned.Two specimens of Tylototriton Anderson, 1871 were collected from Wenshan Prefecture, Yunnan Province, China, in 2021. Phylogenetically, the sequences of these two specimens clustered with the sequences of T. ziegleri (including the holotype) from its type locality with strong support, and morphologically agree well with the original description of T. ziegleri. We confirm the record of T. ziegleri in China and present detailed collection site and morphological description of the specimens from China. In addition, we found that T. panwaensis Grismer, Wood, Quah, Thura, Espinoza & Murdoch, 2019 may be the synonym of T. verrucosus Anderson, 1871. We discussed the relationship between T. verrucosus and T. panwaensis.

Tylototriton tongziensis sp. nov. Holotype. Figs. 3, 4. Adult male, CIB WB2020190, collected on 21 May 2020 by Shize Li from Huanglian Nature Reserve (28° 29′ N, 107° 02′ E, ca. 1510 m a.s.l.), Tongzi County, Guizhou Province, China. Paratypes. Three adult males, CIB WB2020081511 collected on 15 August 2020 by Jing Liu, CIB WB2020191 on 21 May 2020 by Bin Wang, and CIB TZ20160714005 collected on 14 July 2016 by Shize Li; two adult females, CIB TZ20160714010 and CIB TZ20160714002 collected on July 2016 by Shize Li; two larvae, CIB WB2020201 and CIB WB2020202 on 21 May 2020 by Shengchao Shi. All paratypes were collected from the same location as the holotype. Diagnosis: Tylototriton tongziensis sp. nov. could be distinguished from its congeners by a combination of the following characters: (1) body size medium (TOL 120.5–135.1 mm, SVL 61.1–65.9 mm in males, and TOL 123.5–127.6 mm, SVL 66.7–69.2 mm in females); (2) gular fold present; (3) the tail length shorter than the snoutvent length; (4) the distal ends and ventral surfaces of digits, peripheral area of cloaca, and the lower margin of tail orange; (5) the distal tips of the limbs greatly overlapping when the fore and hind limbs being pressed along the trunk; (6) fingertips reaching to the level beyond the snout when the forelimbs being stretched forward; (7) nodulelike warts on body sides continuous and no obvious. Description of holotype. SVL 62.9 mm; TOL 131.4 mm; head slightly longer than wide (HDL/HDW = 1.02); head slightly concave on the top; snout nearly square, extending beyond the lower lip; naris nearly snout; snout truncate in dorsal view; fabial fold absent; dorsolateral bony ridges on head prominent, moderately protruding, from above snout to above anterior end of parotoid, posterior ends relatively thick and scrolled inside; mid-dorsal ridge on head distinct and thin; parotoids enlarged, projecting backwards; tinter-nasal space is smaller than the inter-orbital space; eyes protrude from the dorsolateral portion of the head; the oral fissure flat; the joint of jaw articulation lies posterior to the caudal margin of the eyes; fine teeth present on the edge of jaw, vomerine teeth long and prominent, form a “∧” shape; tongue oval and nearly entirely fixed at bottom but free at both lateral edges; neck is rounded and thick, gular fold present. Body stout; skin on lateral body with no obvious presence of small glands, glandular vertebral ridge high, slightly rough and segmented, extending from top of head to base of tail, rib nodules indistinct, with similar sizes. Four limbs relatively slender, fingers from fore-and hind limbs overlap when addressed along body; tips of fingers beyond snout when addressed along head; relative fingers length III> II> IV> I, and relative toes length III> IV> II> I> V; fingers and digits are with none webbed. The tail length shorter than the snout-vent length; the tail laterally compressed, thin and tip acuminated, distinctly thin and high; the cloaca long and narrow, and the cloacal region slightly bulbous. The skin rough, and body covered with small tubercles; the labial margin, distal limbs, ventral limbs and the ventral edge of the tail smooth; on the lateral dorsum of the body, tubercles small, appearing to form lines that extend from the shoulder to the base of the tail and the nodule-like tubercles continuously distributed with no clear separation between neighboring tubercles; the ventral tubercles dense and distinct. ......continued on the next page TABLE 4. (Continued) *: the population from Leishan County, Guizhou Province, China. Color in life. In life, the individual black or blackish-brown; the distal ends and ventral surface of digits, the peripheral area of cloaca, and the ventral edge of tail orange; the orange region between the ventral edge of the tail and the peripheral area of the cloaca connected (Fig. 3). Color in preservative. The specimen in preservative is blackish-brown. The orange coloration of the distal ends and ventral surface of digits, the peripheral area of the cloaca, and the ventral edge of the tail fades to lacte (Fig. 4). Secondary sexual characteristics. The female cloacal hole short and its inner cloacal wall have no papilla. The male has papilla on its inner cloacal wall and its cloaca is a long slit (Figs. 3H, 4F). Larva. Two larvae, body slender. The forelimbs and hindlimbs clearly fully grown up. Head longer than wide, eyes relatively large on the flank and three pairs of external gills having obtuse anterior ends, while the body and tail being laterally compressed. Skin smooth, fingers and toes transparent, body black-brown, tail black with small yellow spots. Costal grooves for muscles of larvae indistinctly. The dorsal fin fold comparatively tall and rises from the region between the posterior head and anterior body. The short and thick ventral fin fold of the tail extends from the cloaca to the end of the tail. Morphological comparisons. Tylototriton tongziensis sp. nov. is phylogenetically clustered into a clade V containing T. dabienicus, T. anhuiensis, T. broadoridgus, T. maolanensis, T. “ daloushanensis ”, T. wenxianensis, T. liuyangensis, and T. lizhengchangi, and could be identified from these closely related species on series of morphological characters (Table 5). Tylototriton tongziensis sp. nov. differs from T. dabienicus by having a shorter total length in female, TOL 123.5–127.6 mm (vs. 134.9–155.5 mm), finger tips beyond the snout when forelimbs stretched forward (vs. reaching anterior corner of eyes), and tips of fore-and hindlimbs overlapping when addressed along body (vs. not touched). Tylototriton tongziensis sp. nov. differs from T. anhuiensis by tips of fore-and hindlimbs overlapping when addressed along body (vs. just meeting). Tylototriton tongziensis sp. nov. differs from T. broadoridgus by having a shorter total length in female, TOL 123.5–127.6 mm (vs. 138.9–162.5 mm); tips of fore-and hindlimbs overlapping when addressed along body (vs. not touched); gular fold present (vs. absent). Tylototriton tongziensis sp. nov. differs from T. maolanensis by having a shorter total length, TOL 120.5–135.1 mm in males and 123.5–127.6 mm in females (vs. 151.0–172.0 mm in males and 142.7–170.5 mm in females); nodule-like warts on body sides continuous and no obvious (vs. separated and distinct). Tylototriton tongziensis sp. nov. differs from T. “ daloushanensis ” by having a shorter snout-vent length in females, SVL 66.7–69.2 mm (vs. 70.5–100.3 mm); finger tips beyond the snout when forelimbs stretched forward (vs. reaching the level between eyes to nostrils). Tylototriton tongziensis sp. nov. differs from T. wenxianensis by gular fold present (vs. absent); tips of fore-and hindlimbs overlapping when addressed along body (vs. meeting or overlapping). Tylototriton tongziensis sp. nov. differs from T. liuyangensis by having a shorter total length in females, TOL 123.5–127.6 mm (vs. 138.6–154.2 mm); finger tips beyond the snout when forelimbs stretched forward (vs. reaching the level of eye); tips of fore-and hindlimbs overlapping when addressed along body (vs. not touched). Tylototriton tongziensis sp. nov. differs from T. lizhengchangi by having a shorter total length, TOL 120.5–135.1 mm in males and 123.5–127.6 mm in females (vs. 145.6–173.0 mm in males and 150.0– 156.5 mm in females). For the species within clade III, Tylototriton tongziensis sp. nov. differs from T. panhai by the absence of orange markings on the parotoid (vs. present); from T. vietnamensis by the presence of gular fold (vs. absent). Tylototriton tongziensis sp. nov. further differs from T. pasmansi by finger tips beyond the snout when forelimbs stretched forward (vs. reaching the level of eye), and nodule-like warts on body sides continuous and no obvious (vs. separated); from T. sparreboomi by finger tips beyond the snout when forelimbs stretched forward (vs. reaching the level of nostril), and nodule-like warts on body sides continuous and no obvious (vs. separated); from T. asperrimus by nodule-like warts on body sides continuous and no obvious (vs. separated), and tips of fore-and hindlimbs overlapping when addressed along body (vs. meeting or overlapping); from T. thaiorum by nodule-like warts on body sides continuous and no obvious (vs. separated); from T. notialis by nodule-like warts on body sides continuous and no obvious (vs. separated), and orange markings on the parotoid and the rib nodules absent (vs. present); from T. sini by having a shorter total length in females, TOL 123.5–127.6 mm (vs. 144.5 mm), and nodule-like warts on body sides continuous and no obvious (vs. separated); from T. hainanensis by having a shorter total length in males, TOL 120.5–135.1 mm (vs. 137.0–148.0 mm) by finger tips beyond the snout when forelimbs stretched forward (vs. reaching the level of eye); from T. ziegleri by nodule-like warts on body sides continuous and no obvious (vs. separated), and vertebral ridge not segmented (vs. segmented). Tylototriton tongziensis sp. nov. differs from T. anguliceps, T. himalayanus, T. kachinorum, T. kweichowensis, T. ngarsuensis, T. panwaensis, T. phukhaensis, T. podichthys, T. pulcherrimus, T. shanjing, T. shanorum, T. umphangensis, T. uyenoi, T. verrucosus, and T. yangi by having black body except for tips of fingers and toes, margin of vent, and ventral edge of tail (vs. having distinct yellow to reddish brown markings on head, trunk, and tail edges in the latter). Tylototriton tongziensis sp. nov. differs from T. taliangensis by having a shorter total length TOL 120.5–135.1 mm in males and 123.5–127.6 mm in females (vs. 186.0–220.0 mm in males and 194.0–230.0 mm in females) and orange markings on the parotoid absent (vs. present); from T. pseudoverrucosus by having a shorter total length TOL 120.5–135.1 mm in males and 123.5–127.6 mm in females (vs. 156.2–173.0 mm in males and 178.2 mm in female), nodule-like warts on body sides continuous and no obvious (vs. separated), and having black body except for tips of fingers and toes, margin of vent, and ventral edge of tail (vs. distinct yellow to reddish brown markings on head, trunk, and tail edges). Distribution. Tylototriton tongziensis sp. nov. is currently known from Huanglian Nature Reserve, Tongzi County, Guizhou Province, China. ......continued on the next page TABLE 5. (Continued) Ecology. The newts inhabit a mountain stream (Fig. 6) covered by evergreen broadleaf forest, at elevations of about 1530 m. Adult individuals can be observed in a small pond with muddy bottoms from early May to mid-August. The larvae were also found in the same pond from May to August, the water of pond was clear, and 3 m long and ca 2 m wide with water depth ca. 20 cm. Other syntopic species of amphibians recorded at the type locality include: Zhangixalus omeimontis (Stejneger, 1924), Z. chenfui (Liu, 1945), Hyla annectans (Jerdon, 1870), and Rana omeimontis Ye & Fei, 1993. Conservation recommendation. Tylototriton tongziensis sp. nov. is to date known only from a single location in Huanglian Nature Reserve, Tongzi County, Guizhou Province, China. The type locality is suffering from the disturbs of the development of tourism, and the population of the species is small according to our surveys. We recommend Tylototriton tongziensis sp. nov. to be listed as Critically Endangered (CR) [IUCN Red List criteria B1ab(iii)+2ab(iii)]. Etymology. The specific name tongziensis is a Latinize toponymic adjective that refers to Tongzi County, Guizhou Province, China, where the new species was firstly found. For the common name, we suggest Tongzi Knobby Newt (English) and Tong Zi You Yuan (Chinese)., Published as part of Li, Shi-Ze, Liu, Jing, Shi, Sheng-Chao, Wei, Gang & Wang, Bin, 2022, Description of a new species of the newt genus Tylototriton sensu lato (Amphibia: Urodela: Salamandridae) from southwestern China, pp. 248-268 in Zootaxa 5128 (2) on pages 254-264, DOI: 10.11646/zootaxa.5128.2.5, http://zenodo.org/record/6479851, {"references":["Wang, B., Nishikawa, K., Matsui, M., Nguyen, T. Q., Xie, F., Li, C., Khatiwada, J. R., Zhang, B. W., Gong, D. J., Mo, Y. M., Wei, G., Chen, X. H., Shen, Y. H., Yang, D. D., Xiong, R. C. & Jiang, J. P. (2018) Phylogenetic surveys on the newt genus Tylototriton sensu lato (Salamandridae, Caudata) reveal cryptic diversity and novel diversification promoted by historical climatic shifts. PeerJ, 6, e 4384. https: // doi. org / 10.7717 / peerj. 4384"]}

The Tylototriton asperrimus complex from northern Vietnam is reviewed based on morphological comparisons and analysis of the mitochondrial marker NADH dehydrogenase subunit 2 (ND2). Based on molecular divergences, which were revealed to be higher than in other congeners, in concert with morphological differences, two new species and one subspecies are described herein: Tylototriton pasmansisp. nov. differs from T. asperrimussensu stricto by 3.2 to 3.6 % genetic divergence and a combination of distinct morphological characters, such as head slightly longer than wide, distinct mid-dorsal ridge, relatively wide distance between the eyes, tips of fingers reaching the eye when foreleg is laid forward, labial and gular folds present, central belly skin with tubercles shaped like transverse wrinkles and distinct, pointy to round rib nodules. The population of T. pasmansisp. nov. consists of two subclades, the nominotypic one occurring on the eastern side of the Da River (or Black River, including Hoa Binh and Phu Tho provinces), and another occurring on the western side (including Son La and Thanh Hoa provinces). These two subclades differ by 2.5 to 3.1 % genetic divergence and distinct morphological characters. The western subclade is herein described as Tylototriton pasmansi obstissp. nov., which differs from the nominotypic form by a wider head, longer and narrower snout, shorter femur length, and an overall less granulose skin, without an increased concentration of warts on the body sides. A second new species, Tylototriton sparreboomisp. nov. is described from Lai Chau Province. It differs from T. asperrimussensu stricto by 4.1 to 4.2 % and from Tylototriton pasmansisp. nov. by 3.6 to 4.5 % genetic divergences as well as by a combination of distinct morphological characters, such as head longer than wide, tips of fingers reaching nostril when foreleg adpressed along head, rib nodules distinct, round and relatively enlarged, and wide distance between the eyes.

Im Tierreich unterscheiden sich bei zahlreichen Arten die Weibchen und Männchen in ihrer äußeren Gestalt. Dies kann sich in unterschiedlichen Ausprägungen widerspiegeln wie der Größe, Farbe oder Körperschmuck und -anhänge. Während endotherme Wirbeltiere in dieser Hinsicht schon lange erforscht werden, besteht bei den ektothermen Wirbeltieren noch Forschungsbedarf. Vermehrt werden Unterschiede in der Form von Köper oder Körperteilen untersucht. Diese sind meist recht schwach ausgeprägt und daher nicht sofort ersichtlich und auch mit traditionellen Methoden nur bedingt zu erfassen. Die genauen evolutiven Mechanismen hinter diesen sexuellen Größen- und Formendimorphismen beginnen wir gerade erst in den Blickpunkt zu rücken und zu verstehen. Ein integrativer Ansatz, der verschiedene Ausprägungen von Sexualdimorphismen mit der Ökologie der Arten vereinbart, kann dabei helfen einzelne Mechanismen der Evolution aufzulösen. Derartige Korrelationen zwischen der Morphologie und der Lebensweise rezenter Arten sind ein Schlüsselfaktor für die Rekonstruktion von ausgestorbenen Arten. Bei Wirbeltieren sind meist nur die Knochen fossil überliefert. Daher wird mehr Wissen über die Osteologie der rezenten Arten benötigt, um diese auf die fossilen Vorfahren zu übertragen. Die sogenannten Echten Salamander der Familie Salamandridae stellen ein ideales Modelsystem für die Untersuchung von Sexualdimorphismen im Zusammenhang mit der Ökologie dar, da die Arten dieser Gruppe in vielerlei Hinsicht hier Unterschiede aufweisen und so ein Vergleich möglich ist. Im Rahmen dieser Arbeit sollte intensiv untersucht werden, welche weiteren bisher unentdeckten Größen- und im speziellen Formdimorphismen bei basalen echten Salamandern auftreten, wie diese sich in der Osteologie wiederspiegeln und wie die Osteologie mit der Ökologie korreliert um daraus Rückschlüsse auf ausgestorbenes Leben schließen zu können. Das erste Kapitel behandelt das Ausmaß von Sexualdimorphismen am Nördlichen Brillensalamander Salamandrina perspicillata (SAVI, 1821), welcher dem phylogenetisch ursprünglichsten Abstammungszweig der Salamandridae angehört. Die ursprünglichen Brillensalamander dienen dazu auch die Evolutionsgeschichte des Sexualdimorphismus innerhalb der Salamandriden zu verstehen. Es wurden Messstrecken der äußeren Morphologie sowie der Osteologie genutzt und mittels eines neuen statistischen Ansatzes wurde explizit auf sexuelle Formdimorphismen hin getestet. Obwohl vergleichbare Messstrecken der äußeren und inneren Morphologie/Osteologie ein gleiches Bild ergaben, kamen im Knochenbau weitere, bisher unbekannte, dimorphe Merkmale zum Vorschein. Das Ausmaß des Formdimorphismus stellte sich als weitaus größer dar als bisher bekannt war. Im zweiten Kapitel wird die Osteologie des Brillensalamanders an den gleichen Individuen mittels Geometrischer Morphometrie (GM) untersucht, um den Formendimorphismus genauer aufzulösen und diese neue Methode mit der traditionelleren Methode aus dem ersten Kapitel zu vergleichen. Besonders im Beckengürtel konnten größenunabhängige Geschlechtsunterschiede nachgewiesen werden, die wahrscheinlich auf die unterschiedliche Rolle der Geschlechter während der Reproduktion zurück zu führen sind. Im dritten Kapitel wurde die Schädelmorphologie der ebenfalls phylogenetisch ursprünglichen Rippen- und Krokodilmolche (Pleurodelini) untersucht und in den Zusammenhang zu ausgewählten Reproduktionsmerkmalen gesetzt. Rippen- und Krokodilmolche besitzen einen guten Fossilbericht, welcher vom Eozän bis in das Pliozän hineinreicht. Folglich schloss die Analyse die fossile Gattung Chelotriton ein, um weitere Rückschlüsse auf die verwandtschaftlichen Beziehungen, die Evolutionsgeschichte aber auch auf die Ökologie ziehen zu können. Die europäischen Rippenmolche waren weit von den asiatischen Krokodilmolchen differenziert. Ebenfalls konnten die zwei Untergattungen der Krokodilmolche (im engeren Sinne) – Tylototriton und Yaotriton – erstmals morphologisch getrennt werden. Das Paarungsverhalten korrelierte mit den unterschiedlichen Schädelmorphologien. Fossile Chelotriton repräsentiert mehrere Arten und wies eine eher terrestrisch orientierte Lebensweise und Reproduktion auf. Im vierten Kapitel wurde die Ausprägung von Geschlechtsunterschieden bei verschiedenen Arten der Krokodilmolche untersucht und diese in Relation zum Paarungsmodus, der bei den Krokodilmolchen variiert, gesetzt. Die Ausprägungen zwischen den Arten unterscheiden sich dabei deutlich. Der Paarungsmodus konnte jedoch nur in der Schädelmorphologie als erklärender Faktor bestätigt werden, während dies für den Oberarmknochen nicht zutraf. Da Letzterer dennoch Unterschiede aufweist, müssen hier andere selektive Faktoren einwirken. Sexual dimorphism (SD) i.e., the difference in morphology between males and females, is a common phenomenon in the animal kingdom. SD can be observed in various forms such as gender-dependent differences in size, colouration or the presence of ornaments. While warm-blooded vertebrates are well investigated in the context of SD, cold-blooded vertebrates i.e., amphibians and reptiles are still neglected. Often sexes are differentiated in terms of size, termed sexual size dimorphism (SSD) or even in terms of shape differences, so termed sexual shape dimorphism (SShD). Sexual size and shape dimorphisms are often rather subtle and hard to capture when employing traditional analysing methodology. The evolutionary mechanism underlying those features are still under debate. An integrative approach in a phylogenetic context including different patterns of SD connected to the ecology of a respective species can help to reconstruct and understand the evolutionary historical patterns leading to differences between males and females. This is of significant interest for the reconstruction of ancient life in a paleontological sense. The most prominent remains of fossil vertebrates are hard tissues e.g., bones and teeth. Hence, more knowledge on the osteology of extant taxa is needed to allow conclusions on their fossil relatives. True salamanders of the family Salamandridae are a perfectly suited model system for the investigation of SD and its evolutionary history, because this group exhibits diverse reproductive modes and life history strategies linked to different patterns of SD. In this thesis, I investigated extensively patterns of sexual size and shape dimorphism in basal salamandrid salamanders. Further, I wanted to set morphology into context with a species’ ecology to allow conclusions on the ecology of extinct salamander taxa. In the first chapter, I used the spectacled salamander Salamandrina perspicillata (SAVI, 1821), the phylogenetically most basal genus of the Salamandridae, to extensively investigate patterns of sexual size and shape dimorphism in the external morphology and osteology by linear measurements. Therefore, I employed a novel integrative statistical approach. The results showed that comparable characters in the soft and hard tissue revealed similar patterns of SD. The osteology harbours also so far unknown pattern of SD. In the second chapter, I used geometric morphometrics (GM), which represents a novel upcoming technique in morphology research, to reveal even more subtle shape differences. To this end, I used the same set of specimens as in chapter one. This enabled me to compare GM with the traditional approach of capturing morphological differences. Generally, the outcome of both methods is similar if appropriate data is gathered, but via GM, smaller shape differences were revealed. Especially, the pelvic girdle harboured size independent shape differences likely corresponding to the different roles of males and females during reproduction. In the third chapter, I investigated the cranial morphology of the ribbed and crocodile newts (Pleurodelini) and set it into context to selected reproductive traits. Ribbed and crocodile newts bear an extensive fossil record spanning from the Eocene towards the Pliocene. Consequently I included the closely related but extinct genus Chelotriton into my analyses to obtain further hints on the relationship of extinct and extant taxa and to draw conclusions on the ecology of Chelotriton based on morphology-ecology correlations. European ribbed newts were well separated from the Asian crocodile newts. For the first time it was possible to define clear-cut morphological differences for the two subgenera of crocodile newts i.e., Tylototriton and Yaotriton. Regarding the selected reproductive traits, the mating mode affected the cranial shape evolution. Fossil Chelotriton likely represents several species exhibiting a rather terrestrial lifestyle and reproduction. In the fourth chapter, I investigated patterns of SSD and SShD in several species of crocodile newts and in relation with their mating mode, which variably includes an amplexus or mating dances. Trajectories of shape changes from males to females differed interspecifically. The mating mode could explain interspecific SD trajectory differences in cranial but not humerus morphology. Nevertheless, humerus morphology differed also in shape among species exhibiting different mating modes, indicating other selective forces are acting on limb morphology. An interaction of allometric trajectories different between species but similar between the sexes are likely responsible for the variable SD patterns among polymorphic crocodile newts.

Morphological observations (LM, TEM, SEM) of olfactory organs were conducted on three representatives of the family Salamandridae which differ in post-metamorphic habitat: the terrestrial fire salamander Salamandra salamandra, the semiaquatic alpine newt Ichthyosaura alpestris and the semiaquatic Himalayan newt Tylototriton verrucosus which exhibit increasing specialization towards life in water. We demonstrated variability in proportional size and shape of the main olfactory chamber (MOC), as well as in the degree of development of the vomeronasal organ (VNO) among the three species. In the fire salamander, the olfactory sensory epithelium was distributed throughout the MOC, while in the alpine and Himalayan newt the olfactory sensory epithelium was organized in strips. The presence of two types of olfactory receptor neurons (ciliated receptor neurons, microvillar receptor neurons) was confirmed in olfactory organs of all examined species. For the first time in amphibians, a subtype of ciliated receptor neuron – the giant neuron (rod-shape neuron), was detected in the MOC of all three salamandrids. The olfactory epithelium also consists of ciliated supporting cells and secretory supporting cells. The presence of goblet cells, mucociliary epithelial cells and squamous epithelial cells was demonstrated in the olfactory organs of all examined species. Our results indicate that the olfactory organs of salamandrids may differ in size, shape and distribution of olfactory epithelium depending on habitat type during the post-metamorphic stages of ontogeny.

A new species of crocodile newt from populations on opposite sides of the Ayeyarwady Basin, Myanmar, previously referred to as Tylototriton cf. verrucosus, is described on the basis of colour patte...

We describe a new species of the genus Tylototriton from Ingyin Taung Mt., Mohnyin Township, Kachin State, Myanmar, based on morphological and molecular evidence. The new species is assigned to the subgenus Tylototriton s. str. and is clearly distinct from all known congeners by the following characters: medium body size; thin, long tail, lacking lateral grooves; rough skin; truncate snout; wide, protruding supratemporal bony ridges on head, beginning at anterior corner of orbit; weak, almost indistinct sagittal ridge; long, thin limbs, broadly overlapping when adpressed along body; distinct, wide, non-segmented vertebral ridge; 13 or 14 rib nodules; brown to dark-brown background coloration with dull orange-brown to yellowish-brown markings on labial regions, parotoids, rib nodules, whole limbs, vent, and ventral tail ridge. We also briefly discuss biogeography and species diversity of the genus Tylototriton in Myanmar.

Niche conservatism underlies the process of speciation in amphibians on the global scale. However, high tropical diversity is partly attributable to niche shifts within evolutionary lineages. Crocodile newts (genera Echinotriton and Tylototriton) are a monophyletic group endemic to south-east Asia, and are one of the few lineages of urodeles that appear in tropical regions. Here, we examined the patterns of ecological diversification within the crocodile newts based on 207 records of 23 species. The niche space was described according to topographic, climatic variables (temperature, rainfall, and seasonality) and forest cover. Our analysis showed that the occurrence of most of these species was strongly associated with the precipitation regime and seasonality. The diversification patterns of the crocodile newts are complex, showing both conservatism and divergence. These patterns can be related to the Tibetan uplift phase during the Neogene, resulting in the emergence of new montane habitats and subsequent changes in the palaeo-drainage system and climate. The range of ecological diversification within a lineage is possibly the result of several interacting processes, including environmental heterogeneity, the regional climatic history, and physiological constraints on species.

Tylototriton ziegleri is distributed in northern Vietnam and is a new member of the genus Tylototriton. The conservation status of this species has not yet been assessed by the IUCN, but several other species of Tylototriton have been listed as near threatened or vulnerable due to habitat destruction and illegal hunting. We determined the complete sequence and structural characteristics of the mitochondrial genome of T. ziegleri. The entire mitogenome is 16,266 bp in length, and contains 13 protein-coding genes, 22 tRNA genes, two rRNA genes, a control region, and a non-coding region. The length, gene arrangement, and composition are similar to mitogenomes of other species of Tylototriton. A phylogenetic tree based on the mitogenome sequences of several Asian species within Salamandridae confirmed the genus Tylototriton as monophyletic, with T. ziegleri being the sister species of T. asperrimus and both constituting the sister group of T. wenxianensis. This work provides basic molecular data which are critical for further genetic research and conservation of the genus Tylototriton.

The diversity of the vertebrate cranial shape of phylogenetically related taxa allows conclusions on ecology and life history. As pleurodeline newts (the genera Echinotriton, Pleurodeles and Tylototriton) have polymorphic reproductive modes, they are highly suitable for following cranial shape evolution in relation to reproduction and environment. We investigated interspecific differences externally and differences in the cranial shape of pleurodeline newts via two‐dimensional geometric morphometrics. Our analyses also included the closely related but extinct genus Chelotriton to better follow the evolutionary history of cranial shape. Pleurodeles was morphologically distinct in relation to other phylogenetically basal salamanders. The subgenera within Tylototriton (Tylototriton and Yaotriton) were well separated in morphospace, whereas Echinotriton resembled the subgenus Yaotriton more than Tylototriton. Oviposition site choice correlated with phylogeny and morphology. Only the mating mode, with a random distribution along the phylogenetic tree, separated crocodile newts into two morphologically distinct groups. Extinct Chelotriton likely represented several species and were morphologically and ecologically more similar to Echinotriton and Yaotriton than to Tylototriton subgenera. Our data also provide the first comprehensive morphological support for the molecular phylogeny of pleurodeline newts., We applied geometric morphometrics to cranial morphology in extant and extinct crocodile newts. Our data provides the first comprehensive morphological support for the molecular phylogeny of these newts. Further, we could show that life history traits correlate with head shape and that fossil Chelotriton show similarities in shape with some extant taxa allowing conclusions on its ecology.

The existence of two or more distinctly coloured phenotypes among individuals of an interbreeding population is known as colour polymorphism. In amphibians, this phenomenon is pervasive among anurans, but rare or absent among salamanders and caecilians, respectively. Here, we examine whether various distinct phenotypes of Salamandra salamandra in North Spain, used as a basis to describe the subspecies S. s. bernardezi and S. s. alfredschmidti, indeed warrant separate taxonomic status or that these co-occur and belong to a single taxon. Based on a sample of 1147 individuals from 27 local populations, six phenotype classes were designated. Although two phenotypes that are attributable to S. s. alfredschmidti show some degree of geographical restriction, these co-occur with those representing typical S. s. bernardezi. A fifth phenotype class could not be unambiguously attributed to either subspecies due to an overlap in previously suggested diagnostic characteristics. Mitochondrial (cytochrome b) and nuclear (β-fibrinogen) DNA analyses revealed S. s. alfredschmidti to be nested within several subclades of S. s. bernardezi, without displaying unique lineages. Furthermore, no significant divergence was recovered by means of niche overlap analyses. As a result, we revoke the subspecies status of S. s. alfredschmidti, which should be regarded as a junior synonym of S. s. bernardezi. The current findings confirm the existence of colour polymorphism in S. salamandra and the family Salamandridae, which provides exciting possibilities for future research.

Tylototriton shanorum, an endemic species of Myanmar, is threatened by illegal capture and environmental destruction. Here, the complete mitochondrial genome (mitogenome) of T. shanorum is described. The entire mitogenome sequence of T. shanorum is 17,096 bp long, containing 13 protein coding genes, two ribosomal RNA, 22 transfer RNA genes, one control region. In addition, two additional 3′ Cytb like sequences and two complete tRNAThr genes, one pseudo tRNAThr, and three noncoding sequences (NC1, NC1′ and NC2) were situated between Cytb and tRNAPro genes. The new complete mitogenome sequence of T. shanorum will be useful for conservation genetics, evolutionary biology, phylogeography, as well as phylogenetic relationships studies of this threatened species.

A phylogenetic taxonomic analysis of a monophyletic subgroup of the salamandrid genus Tylototriton revealed that a newly discovered population from Ngar Su Village, 1 km south of Ywangan, Shan State, Myanmar is a new species and most closely related to T. shanorum from approximately 80 km to the west in the vicinity of Taunggyi, Shan State. Tylototriton ngarsuensis sp. nov. differs from other closely related species of Tylototriton on basis of varying combinations of characteristics associated with it shorter head, larger size, rib nodule morphology, and overall drab, very dark, coloration, along with its genetic differentiation. Tylototriton ngarsuensis sp. nov. also appears to breed later in the year than most other species. Unfortunately, this species like many other Asian newts, is being harvested for the pet and medicinal trade and given its restricted distribution, this could pose a serious threat to its long-term survival.

Global climatic transitions and Tibetan Plateau uplifts are hypothesized to have profoundly impacted biodiversity in southeastern Asia. To further test the hypotheses related to the impacts of these incidents, we investigated the diversification patterns of the newt genus Tylototriton sensu lato, distributed across the mountain ranges of southeastern Asia. Gene-tree and species-tree analyses of two mitochondrial genes and two nuclear genes revealed five major clades in the genus, and suggested several cryptic species. Dating estimates suggested that the genus originated in the early-to-middle Miocene. Under different species delimitating scenarios, diversification analyses with birth-death likelihood tests indicated that the genus held a higher diversification rate in the late Miocene-to-Pliocene era than that in the Pleistocene. Ancestral area reconstructions indicated that the genus originated from the northern Indochina Peninsula. Accordingly, we hypothesized that the Miocene Climatic Transition triggered the diversification of the genus, and the reinforcement of East Asian monsoons associated with the stepwise uplifts of the Tibetan Plateau promoted the radiation of the genus in southeastern Asia during the Miocene-to-Pliocene period. Quaternary glacial cycles likely had limited effects on speciation events in the genus, but mainly had contributions on their intraspecific differentiations.

The natural history of newly discovered species among the genus Tylototriton in South-Eastern Asia is poorly known to date, and most of the species are threatened by extinction. The description of their ecology is crucial to determine their survival status and successful reproduction for conservation purposes. In this study, we assessed the microhabitat preferences of Tylototriton yangi at the type locality, Gejiu, Yunnan province, China, with the Visual Encounter Survey method and by using new important materials. The main habitat is located within a humid subtropical climate and is composed of a large karstic mountain containing some patch of secondary mixed forests and plantations such as tomato fields, pepper and cabbage that are surrounded by scrubs, grasses and small ponds. We provided a complete diagnosis with new morphological data analysing ten adult individuals from the type series to establish a formal description which is absent from the first original description. We compared our results with other related taxa of the genus Tylototriton to updated key determinants between similar species. Thus, we analysed the population structure and the behaviour of T. yangi during a period of ten years, 2008–2017, to assess its survival status and to determine the main threat factors. A total of 186 specimens were found during the whole study predicting a small population inhabiting the type locality, Gejiu. Consequently, T. yangi is now regarded as a highly threatened species that need more attention of Chinese authorities and we suggest regarding it as Endangered due to its small distribution range, the low number of adult specimens observed and ongoing exploitation.

In vertebrates, the relative proportion of the number of trunk and caudal vertebrae is an important determinant of body shape. While among amphibians frogs and toads show low variation in vertebrae numbers, in salamanders the numbers of trunk and caudal vertebrae vary widely, giving rise to phenotypes in the range from short-bodied and long-tailed to long-bodied and short-tailed. We analysed vertebral numbers in the family Salamandridae in a phylogenetic context and calculated the relationship between vertebral changes and changes in climate and other environmental parameters. A significant association was found between morphological change with precipitation and temperature. However, annual precipitation affected the two main groups of salamandrid salamanders differently, with trunk elongation in the terrestrial ‘true salamanders’ and tail elongation in the more aquatic ‘newts’. A - male biased - sexual dimorphism was only observed in Lissotriton vulgaris vulgaris in the number of trunk vertebrae and in Ommatotriton ophryticus and Lissotriton species for the number of caudal vertebrae. Our data indicated that the number of trunk and caudal vertebrae are highly evolvable traits with frequent evolutionary reversals. In some groups (e.g. Cynops, Lyciasalamandra, Neurergus and the Laotriton- Pachytriton-Paramesotriton clade) the number of trunk vertebrae is stable, while in many groups it is subject to change (e.g. Tylototriton). This latter, species-rich genus appears to be an excellent group to further test effects of the environment on body shape.

We assessed taxonomic relationship of Tylototriton daweishanensis Zhao, Rao, Liu, Li and Yuan, 2012 and T. yangi Hou, Li and Lu, 2012 using mitochondrial DNA sequence data and found them to be as closely related as to be regarded as conspecific. This result, together with available morphological information, strongly indicates that T. daweishanensis is a junior synonym of T. yangi.

We describe a new species of Tylototriton from northwestern Vietnam and northern Thailand based on morphological and molecular evidence. Tylototriton anguliceps sp. nov. is distinguishable from all the other congeners by the bright to dark orange markings on the head, body, and tail, prominent dorsal and dorsolateral ridges (crests) on the head, skeletal connection between maxillary and pterygoid, and unique mitochondrial and nuclear DNA sequences. Our molecular data show that the new species is nested within the clade comprising T. uyenoi, T. shanjing, T. verrucosus, and T. yangi. The new species is expected to be recorded from other countries in the Indochina region such as southern China, western Myanmar and northern Laos in the future.

Abstarct Tylototriton anhuiensis (Salamandridae, Urodela), collected from Yaoluoping Nature Reserve, was identified as a new species. The complete mitogenome sequence of T. anhuiensis is 16,259 by in length, including 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and D-loop region. The base composition of the mitogenome was 33.6%A, 26.3% C, 14.5% G, and 25.6% T. The ND6 subunit gene and eight tRNA genes were encoded on the L-strand, the others were encoded on the H-strand.

A new species of salamandrid is named and described from the Miocene of Randeck Maar, a long-term vol- canic lake deposit in southern Germany. Based on a fully articulated specimen, Ichthyosaura randeckensis is named and described as a 3-4 cm long newt with a robust posterolateral process of the frontal, a heavily ornamented skull roof, and a premaxilla with spike-like, parallel alary processes framing a slender fontanelle posteriorly. In a phylogenetic analysis of 14 salamandrid taxa and 38 morphological characters, I. randeckensis is found to nest with I. alpestris, with which it shares apomorphic character states in the morphology of premaxilla and nasal. The present analysis employed more morpholog- ical characters than hitherto considered, highlighting the need to conduct more osteological studies of extant salamanders. Its results are largely consistent with recent molecular phylogenetic studies: Tylototriton and Pleurodeles form a clade, with Notophthalmus and Euproctus falling within unresolved trichotomies, followed by Cynops and Ommatotriton as successive crownward clades, then Triturus sensu stricto (T. marmoratus and T. cristatus), and finally Lissotriton and Ichthyosaura as terminal sister taxa. SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP