Two new pit vipers discovered from Qinghai-Tibet Plateau
IMAGE: GLACIER PIT VIPER (GLOYDIUS SWILD SP. NOV.) view more
CREDIT: SHI ET AL.
Two new species of venomous snakes were just added to Asia’s fauna – the Nujiang pit viper (Gloydius lipipengi) from Zayu, Tibet, and the Glacier pit viper (G. swild) found west of the Nujiang River and Heishui, Sichuan, east of the Qinghai-Tibet Plateau. Researchers from the Institute of Vertebrate Paleontology and Paleoanthropology at the Chinese Academy of Sciences and Bangor University published the discovery in the open-access journal ZooKeys as part of a new molecular phylogenetic analysis of the Asian pit vipers.
The Nujiang pit viper has a greyish brown back with irregular black ring-shaped crossbands, wide, greyish-brown stripes behind the eyes, and relativity short fangs, while the Glacier pit viper is blueish-grey, with zigzag stripes on its back, and has relatively narrow stripes behind its eyes.
Interestingly, the Glacier pit viper was found under the Dagu Holy-glacier National Park: the glacier lake lies 2000 meters higher than the habitat of the snakes, at more than 4,880 m above sea level. This discovery suggests that the glaciers might be a key factor to the isolation and speciation of alpine pit vipers in southwest China.
The researchers also share the stories behind the snakes’ scientific names: with the new species from Tibet, Gloydius lipipengi, the name is dedicated to the senior author’s (Jingsong Shi) Master’s supervisor, Professor Pi-Peng Li from the Institute of Herpetology at Shenyang Normal University, just in time for Li’s sixtieth birthday. Prof. Li has devoted himself to the study of the herpetological diversity of the Qinghai-Tibet Plateau, and it was under his guidance that Jingsong Shi became an Asian pit viper enthusiast and professional herpetological researcher.
Gloydius swild, the new species from Heishui, Sichuan, is in turn named after the SWILD Group, which studies the fauna and biodiversity of southewst China. They discovered and collected the snake during an expedition to the Dagu Holy-glacier.
On top of their discoveries, the researchers were also astonished by the sceneries they encountered during their field work. During their expeditions, they experienced striking views of “sacred, crystal-like” glacier lakes embraced by mountains, as well as colourful broadleaf-conifer forests and morning mists falling over the village.
“During our expedition, we met a lot of hospitable Tibetan inhabitants and enjoyed their kindness and treats, which made the expedition more unforgettable,” they add.
CAPTION
Nujiang pit viper (Gloydius lipipengi sp. nov)
CREDIT
Shi et al.
Research article:
Shi J-S, Liu J-C, Giri R, Owens JB, Santra V, Kuttalam S, Selvan M, Guo K-J, Malhotra A (2021) Molecular phylogenetic analysis of the genus Gloydius (Squamata, Viperidae, Crotalinae), with description of two new alpine species from Qinghai-Tibet Plateau, China. ZooKeys 1061: 87-108. https://doi.org/10.3897/zookeys.1061.70420
JOURNAL
ZooKeys
ARTICLE TITLE
Molecular phylogenetic analysis of the genus Gloydius (Squamata, Viperidae, Crotalinae), with description of two new alpine species from Qinghai-Tibet Plateau, China
ARTICLE PUBLICATION DATE
4-Oct-2021
CAPTION
The glacier lake on the top of the mountain near the type locality of Glacier pit viper.
CAPTION
Misty morning near the habitat of Glacier pit viper
CREDIT
Shi et al.
COUNTERINTUITIVE
Threatened rattlesnakes’ inbreeding
makes species more resistant to bad
mutations
Scientists complete first genomic analysis of Eastern massasaugas
Peer-Reviewed PublicationCOLUMBUS, Ohio – The first look at a threatened rattlesnake species’ recent genetic history suggests that inbreeding necessitated by limited habitat may not be as detrimental as theory would predict it to be.
In fact, scientists speculate that Eastern massasauga rattlesnakes may have pre-adapted to living in small, isolated populations – where the most dangerous genetic mutations that arose could be easily exposed and purged.
Researchers sequenced the genomes of 90 Eastern massasauga rattlesnakes, which were listed as threatened under the Endangered Species Act in 2016 because of loss and fragmentation of their wetland habitat. For comparison, the researchers also sequenced 10 genomes of a close relative, the Western massasauga rattlesnake, a common species with no limitations on breeding opportunities and large populations.
The Ohio State University team found that the most potentially damaging gene mutations were less abundant in the Eastern than the Western species. This finding suggests the breeding limitations of small, isolated populations might be accompanied by an evolutionary advantage of being able to elbow out genetic variants that get in the way of survival, said H. Lisle Gibbs, professor of evolution, ecology and organismal biology at Ohio State and senior author of the study.
“This is something that has been reported very recently in other endangered species, but it’s the first time it’s been shown in a reptile,” Gibbs said. “We always worry about genetics and the loss of variation and what it means to be in a small population in which there’s lots of inbreeding. At least in this species, maybe it’s not such a big deal.
“From a conservation perspective, perhaps we can downplay genetics and say ecology – such as habitat restoration – is more important.”
Gibbs completed the study with Alexander Ochoa, a former postdoctoral researcher at Ohio State who is now a postdoctoral scholar at the University of Central Florida. The research is published in the journal Molecular Ecology.
Eastern massasauga rattlesnakes live in isolated spaces in midwestern and eastern North America, and evolutionary theory posits that the inevitable inbreeding in such populations threatens species with extinction as genetic mutations accumulate. The smallest populations might reach 30 snakes, but Ohio’s Killdeer Plains Wildlife Area is home to one of the most genetically diverse and largest populations in the country, numbering in the thousands.
Gibbs has studied Eastern massasaugas for over two decades and, as director of the Ohio Biodiversity Conservation Partnership, advises the Ohio Department of Natural Resources on management of the species.
“Through years and years of study, we know that most populations are isolated, like little natural zoos scattered throughout the landscape,” Gibbs said. “Due to habitat degradation, we’ve known they show little variation – but we’ve never actually looked at variation in genes that code for things that matter to a rattlesnake.”
Only recently has it been possible to apply the research techniques perfected with the human genome to work with this species. Gibbs and Ochoa zeroed in on identifying mutations in genes that may affect survival and reproduction to gauge how hazardous inbreeding might be to Eastern massasaugas.
Though a higher overall number of potentially deleterious mutations were found in the common Western massasaugas, that didn’t translate to more threats to their survival because most troublesome gene copies were offset by protective copies. That can happen only in heterozygotes, which have two different copies, or alleles, of a particular gene – one inherited from each parent. Because of generations of inbreeding, Eastern massasaugas are much more likely to have two copies of the same allele.
“That’s why inbreeding has impacts – because that’s when you get two bad alleles showing up together, with no good allele to compensate, so there is a negative effect,” Gibbs said. “There’s more inbreeding, so overall you get more mostly bad mutations together, but the really bad ones, because they’re exposed, are also eliminated at a much greater rate.”
Through another analytical technique comparing the narrowing of the Eastern and Western massasauga genetic makeup over several hundred years, Gibbs and Ochoa confirmed the impact human activity has had on the Eastern massasauga’s swampy habitat. Unlike the Eastern species, Western massasaugas live in grassy and woodland regions of the south-central United States that are less densely populated by humans.
“We looked at what has happened in these snakes and their population sizes over the last 300 years, which is when humans have been tromping all over North America, impacting the landscape,” Gibbs said. “The impacts in terms of reducing population sizes are greater in Eastern than in Western massasaugas over this period.”
The findings could influence management decisions. A common conservation practice would involve introducing snakes from a more genetically diverse population into a highly isolated group to counter the effects of inbreeding. But it turns out the Eastern massasauga might benefit more from preservation of its habitat while the genetics takes care of itself.
“This counterintuitive result makes us rethink what living in a small population is, and whether genetic problems are as important as we think they are,” Gibbs said. “This is certainly not to say living in a small population isn’t bad – it just may be that the genetic effects are not as bad as we thought.”
This work was supported by the State Wildlife Grants Program administered jointly by the U.S. Fish and Wildlife Service and the Ohio Division of Wildlife, with funds provided by the Ohio Biodiversity Conservation Partnership between Ohio State and the Ohio Division of Wildlife, as well as the National Science Foundation.
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Contact: H. Lisle Gibbs, Gibbs.128@osu.edu
Written by Emily Caldwell, Caldwell.151@osu.edu
JOURNAL
Molecular Ecology
METHOD OF RESEARCH
Data/statistical analysis
SUBJECT OF RESEARCH
Animals
ARTICLE TITLE
Genomic signatures of inbreeding and mutation load in a threatened rattlesnake
ARTICLE PUBLICATION DATE
27-Aug-2021
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