Vietnamese customers have been enjoying a lizard common in the menu of restaurants around the Mekong River Delta. It turns out that lizard is a self-reproducing, endemic, all-female new species.
Although this kind of lizard has been a traditional food item in southern Vietnam for very long time, it had remained unidentified and had not been described in scientific records.
Rather recently, it came to the attention of Mr. Ngo Van Tri, a Vietnamese researcher working at the Institute of Tropical Biology’s Department of Environmental Management in Ho Chi Minh City (HCMC), who noticed that the lizards on display at a restaurant in the locality of Bà Ria, Vung Tao Province, south-east of HCMC, where remarkably alike. He inspected about 60 reptiles and determined that all of them were female.
Courtesy of Dr. Lee Grismer
Dr. L. Lee Grismer, Herpetologist, Dept. of Biology, La Sierra University, Riverside, CA.
Ngo Van Tri (“Gecko King” to his friends) decided to ask for assistance to identify the lizard from herpetologist Dr. Lee Grismer, of La Sierra University, Riverside, CA .
Dr. Grismer, along with his son Jesse Grismer, then a M.Sc. student at Villanova University, Pennsylvania (currently PhD student at University of Kansas), travelled to HCMC and then to the Restaurant at Bà Ria, close to one of the nine channels where the Mekong River flows into the South China Sea. To their chagrin the last of the lizards at the restaurant had already been cooked and served.
In an email interview, Lee Grismer said, “We had a reservation at the restaurant, but when we finally got there, the man had gotten drunk and served them all to his customers.”
Fortunately, other restaurants in the area still had some stock and provided valuable samples. Additionally, the researchers found enthusiastic assistance from local school kids who happily collected more lizards from the wild. The inspection of all the new samples, about 70, demonstrated that these were also all female.
The reptile was identified as a relative of the Leilopis lizards which are fairly common in South –East Asia with a range that extend through Myanmar, Thailand, Laos, Cambodia and Vietnam. They are also found in areas of Southern China, Indonesia and Malaysia. They are commonly known as butterfly lizards because of their colourful flanks, particularly in the males.
Courtesy of Dr. Lee Grismer
"Who's your mommy?" Maternal ancestor of Leilopis gnovantrii, a new species of Lizard from Viet Nam, was identified as Leiolopis guttata.
The researchers compared the Bà Ria lizards with other Leiolopis lizards already known to science by analyzing body measurements and scale counts and by conducting DNA analysis. The study demonstrated that the reptile is a new species related to the other species of Leilopis lizards, particularly to Leilopis guttata, and that it is endemic to Binh Chau-Phuoc Buu Nature Reserve, Xuyen Moc District, Bà Ria-Vung Tau Province of Viet Nam. Furthermore, the lizard’s population is composed exclusively of females, indicating that no males are required for the successful reproduction and survival of the species.
The new species was named Leilopis gnovantrii to honour its Vietnamese discoverer and its description was reported in the Journal Zootaxa.
How do the lizards reproduce without males?
Single-sex reproduction is uncommon in vertebrates. Only a few species of reptiles (geckos, komodo dragons, certain snakes) and fish (some sharks) can reproduce without male intervention. Some female bees and wasps can also reproduce without the genetic contribution of a male. The phenomenon is known as parthenogenesis. The mechanism consists in the females spontaneously ovulating without the egg being activated by sperm. This results in the females practically cloning themselves producing offspring which are also females. They maintain a level of genetic variability through the occurrence of random mutations.
A baby Komodo dragon born by parthenogenesis, photographed at Chester Zoo, Cheshire, England.
According to the researchers, the new species may have originated by hybridization, the mating of two related species. The researches point to Leilopis guttata, a similar, sexual species of lizard that occupies forest habitats in Vung Tau Province, as the maternal line of origin of the new species. Because the DNA available for analysis in the new species comes only from females, the paternal line of the hybrid has not been determined.
L. gnovantrii occupies diverse environments that include forested areas and coastal dunes, thereby being able to successfully use areas of varied characteristics. The lizard is most active during the morning hours and later in the day hides in deep burrows in the sand where they also lay their eggs.
Traditional floating market of Cần Thơ, Mekong River Delta, Vietnam.
I asked Dr. Lee Grismer if, because of the facts that these lizards are only females, they have such a peculiar mode of reproduction which naturally doesn’t provide for much genetic variation, and they are regularly hunted to provide meals for the local people, could result in the new species running the risk of becoming endangered. “I highly doubt it. The Vietnamese have been eating this species for a long time and there seems to be plenty of them.” said Dr. Grismer.
Based on the fact that the lizards still abound after being in the menu of local restaurants for many years and that even schoolchildren can get them out from their burrows in the dunes, it seems there is enough evidence to believe they will continue doing their “male-less” parthenogenetic “trick” for a very long time.