Tag: newts

Southernmost crocodile newt record is a threatened new species

“Exceptional discovery” for its colors, the amphibian is also the first crocodile newt species known from the Central Highlands of Vietnam.

A spectacular crocodile newt from the Central Highlands of Vietnam was just published in the international peer-reviewed open-access academic journal ZooKeys.

“It is an exceptional discovery as it is one of the most colourful species in the genus Tylototriton. This is also the first time that a crocodile newt species is recorded from the Central Highlands of Vietnam. Occurring at elevations from 1,800 to 2,300 m above sea level, this discovery sets an elevational record for the genus in the country, with former distribution ranges between 250 m and 1,740 m.”

says discoverer and first author of the study Trung My Phung.

Furthermore, the discovery by the Vietnamese-German researcher team, which was supported by the Vietnam Academy of Science and Technology and the Cologne Zoo (Germany), represents the southernmost distribution range of the genus known to date.

The habitat of the new species is located approximately 370 air km away from the nearest Tylototriton population, which makes it an important discovery in terms of evolution and zoogeography. 

The name “ngoclinhensis” refers to the type locality of the new species, Ngoc Linh Mountain. Restricted to evergreen montane forest, the Ngoc Linh Crocodile Newt is currently known only from the Ngoc Linh Nature Reserve, Kon Tum Province, in the Central Highlands of Vietnam. This is the eighth salamander taxon described from Vietnam, and is the thirty-ninth Tylototriton species officially recognized.

The newly described crocodile newt Tylototriton ngoclinhensis sp. nov.
Photo by Prof. Dr. Tao Thien Nguyen.

Crocodile newts, scientifically known as the genus Tylototriton, include nearly 40 species inhabiting montane forest areas throughout the Asian monsoon climate zone. Remarkably, 15 of these species have been described in the past five years, and there remain several unnamed taxa, which contain cryptic species that are morphologically difficult to distinguish. 

Established in 1986, Ngoc Linh Nature Reserve is a key biodiversity area for rare species like the endangered Golden-winged Laughingthrush and the Truong Son Muntjac. The Ngoc Linh Crocodile Newt certainly will represent another flagship species of this protected area and its surroundings, say the researchers.

Ngoc Linh has become a hotspot of amphibian diversity, with numerous endemic species. An earlier study – published in the Nature Conservation journal in 2022 – highlighted the extraordinary endemism rate of amphibians in the Central Highlands of Vietnam.

“[The Central Highlands is] where the highest amphibian species diversity was recorded for Vietnam, with 130 species, while also containing the highest number of regionally occurring, micro-endemic amphibians, amounting for 26 species,”

explains one of the authors of this and the present study, Prof. Dr. Truong Quang Nguyen, vice director of the Institute of Ecology and Biological Resources (IEBR), Hanoi.

Scientists identify gaps in the protection of Vietnam’s amphibians

This recent discovery is another remarkable case, “demonstrating that the Central Highlands play a special role in Vietnamese amphibian diversification and evolution,” by the words of co-author Dr. Cuong The Pham from IEBR. 

The Ngoc Linh Crocodile Newt belongs to the group of range-restricted, so-called micro-endemic species, which face the greatest risk of extinction because of their presumably small population size. Unfortunately, on top of its special zoogeographic situation and rarity, its particularly colorful appearance will likely make it highly attractive to illegal collectors.

“Therefore, this discovery is of high conservation relevance,”

says one of the corresponding authors, Prof. Dr. Tao Thien Nguyen from the Institute of Genome Research, Hanoi.

The species should be provisionally considered to be listed as Endangered on the IUCN Red List of threatened species, the researchers say. All the species of the genus Tylototriton are already listed in the Appendices of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) and also in the Governmental Decree No. 84/2021/ND-CP of Vietnam. The new species thus is automatically protected under these regulations.

Now, conservation activities on site have priority, but the team is already working on breeding conservation measures, which is in line with the One Plan Approach to Conservation, developed by IUCN’s Conservation Planning Specialist Group, which combines in-situ and ex-situ efforts and various expertises for the optimum protection of a species. 

“This has already been successfully implemented for another recently discovered, micro-endemic crocodile newt species from Vietnam, Tylototriton vietnamensis, of which already more than 350 individuals could have successfully been reproduced at the Cologne Zoo in Germany and also at the Melinh Station for Biodiversity in Vietnam, which is a promising example for IUCN’s Reverse the Red campaign and the idea of the conservation zoo”,

says Prof. Dr. Thomas Ziegler, Vietnam conservation team member and coordinator from Cologne Zoo, Germany.

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Research article:

Phung TM, Pham CT, Nguyen TQ, Ninh HT, Nguyen HQ, Bernardes M, Le ST, Ziegler T, Nguyen TT (2023) Southbound – the southernmost record of Tylototriton (Amphibia, Caudata, Salamandridae) from the Central Highlands of Vietnam represents a new species. ZooKeys 1168: 193-218. https://doi.org/10.3897/zookeys.1168.96091

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Simplified method to survey amphibians will aid conservation

Researchers developed a method to determine which amphibians inhabit a specific area. The new technique will resolve some of the issues with conventional methods, such as capture and observational surveys.

Ryukyu Sword Tailed Newt, or Firebellied Newt. Photo by Neil Dalphin via Creative Commons CC0.

An international collaborative research group of members from seven institutions has developed a method to determine which amphibians (frogs, newts and salamanders) inhabit a specific area. Their work was published in the open-access, peer-reviewed journal Metabarcoding and Metagenomics (MBMG).

To do so, the scientists amplified and analysed extra-organismal DNA (also known as environmental DNA or eDNA) found in the water. This DNA ends up in the water after being expelled from the amphibian’s body along with mucus and excrement. 

The research group included Postdoctoral Researcher Sakata K. Masayuki and Professor Minamoto Toshifumi (Kobe University), Associate Professor Kurabayashi Atsushi (Nagahama Institute of Bio-Science and Technology), Nakamura Masatoshi (IDEA Consultants, Inc.) and Associate Professor Nishikawa Kanto (Kyoto University). 

The newly developed technique will resolve some of the issues with conventional methods, such as capture and observational surveys, which require a specialist surveyor who can visually identify species. Conventional surveys are also prone to discrepancies due to environmental factors, such as climate and season.

The researchers hope that the new method will revolutionise species monitoring, as it will enable anyone to easily monitor the amphibians that inhabit an area by collecting water samples.  

While monitoring in general is crucial to conserve the natural ecosystems, the importance of surveying amphibians is even more pressing, given the pace of their populations’ decline.

Amongst major obstacles to amphibian monitoring, however, are the facts that they are nocturnal; their young (e.g. tadpoles) and adults live in different habitats; and that specialist knowledge is required to capture individuals and identify their species. These issues make it particularly difficult to accurately survey amphibians in a standardised way, and results of individual efforts often contradict each other.

On the other hand, eDNA analysis techniques have already been established in programmes targeted at monitoring fish species, where they are already commonplace. So, the researchers behind the present study joined forces to contribute towards the development of a similar standardised analysis method for amphibians.

First of all, the researchers designed multiple methods for analysing the eDNA of amphibians and evaluated their performance to identify the most effective method. Next, they conducted parallel monitoring of 122 sites in 10 farmlands across Japan using the developed eDNA analysis along with the conventional methods (i.e. capture surveys using a net and observation surveys). 

As a result, the newly developed method was able to detect all three orders of amphibians: Caudata (the newts and salamanders), Anura (the frogs), and Gymnophiona (the caecilians). 

Furthermore, this novel eDNA analysis method was able to detect more species across all field study sites than the conventional method-based surveys, indicating its effectiveness.

Research Background

Amphibian biodiversity is continuing to decline worldwide and collecting basic information about their habitats and other aspects via monitoring is vital for conservation efforts. Traditional methods of monitoring amphibians include visual and auditory observations, and capture surveys.

However, amphibians tend to be small in size and many are nocturnal. The success of surveys varies greatly depending on the climate and season, and specialist knowledge is required to identify species. Consequently, it is difficult to monitor a wide area and assess habitats. The last decade has seen the significant development of environmental DNA analysis techniques, which can be used to investigate the distribution of a species by analysing external DNA (environmental DNA) that is released into the environment along with an organism’s excrement, mucus and other bodily fluids. 

The fundamentals of this technique involve collecting water from the survey site and analysing the eDNA contained in it to find out which species inhabit the area. In recent years, the technique has gained attention as a supplement for conventional monitoring methods. Standardised methods of analysis have already been established for other species, especially fishes, and diversity monitoring using eDNA is becoming commonplace. 

However, eDNA monitoring of amphibians is still at the development stage. One reason for this is that the proposed eDNA analysis method must be suitable for the target species or taxonomic group, and there are still issues with developing and implementing a comprehensive method for detecting amphibians. If such a method could be developed, this would make it possible for monitoring to be conducted even by people who do not have the specialised knowledge to identify species nor surveying experience.

Hopefully, this would be established as a unified standard for large-scale monitoring surveys, such as those on a national scale. This research group’s efforts to develop and evaluate analysis methods will hopefully lay the foundations for eDNA analysis to become a common tool for monitoring amphibians, as well as fish. 

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Research article: 

Sakata MK, Kawata MU, Kurabayashi A, Kurita T, Nakamura M, Shirako T, Kakehashi R, Nishikawa K, Hossman MY, Nishijima T, Kabamoto J, Miya M, Minamoto T (2022) Development and evaluation of PCR primers for environmental DNA (eDNA) metabarcoding of Amphibia. Metabarcoding and Metagenomics 6: e76534. https://doi.org/10.3897/mbmg.6.76534