Mexico takes ‘unprecedented’ action to save vaquita

by Mongabay.com on 15 October 2017

A team of marine mammal experts have begun a search for the last vaquitas (Phocoena sinus) in a last-ditch effort to capture the remaining 30 porpoises until they’re no longer threatened by gillnets.

VaquitaCPR seeks to house the vaquita in sea pens and includes plans for long-term care and breeding.

Though seen as ‘risky’ and ‘bold,’ many conservation organizations agree that finding the animals before it’s too late is the only option.

A team of marine mammal experts is searching for the last vaquitas (Phocoena sinus) in the Gulf of California. They’ve gathered in northern Mexico, at the invitation of the government of Mexico, to make a last-ditch effort to capture and keep the remaining 30 porpoises safe until they’re no longer threatened by the gillnets that have decimated their numbers in recent years.

“We are watching this precious native species disappear before our eyes,” said Rafael Pacchiano, Mexico’s minister of the environment and natural resources, in a January 2017 statement from the National Marine Mammal Foundation (NMMF). “This critical rescue effort is a priority for the Mexican government and we are dedicated to providing the necessary resources in order to give the plan its best chance of success.”

Read more  

We’ve drawn iconic sail-wearing Dimetrodon wrong for 100 years

13 October 2017

By Colin Barras

Dimetrodon, one of the most recognisable of the pre-dinosaur predators, is due a makeover. For more than a century, it has been depicted as a sluggish, belly-dragging beast with sprawling legs – but it might actually have held its legs in a more upright position and kept its stomach off the ground as it walked.

Often mistaken for a dinosaur, Dimetrodon actually belonged to a group called the pelycosaurs that were more closely related to mammals. It lived between about 290 and 272 million years ago, with some species measuring more than 3 metres from nose to tail. Its most iconic feature was a gigantic sail on its back, the function of which is still debated.

Nineteenth Century artists drew Dimetrodon as a sluggish-looking animal with legs sprawled out to each side of its body, resting its weight on an enormous belly – and even in the 21st century nothing much has changed.

“I was baffled as I was going through the literature how little this had been questioned,” says Caroline Abbott at the College of William & Mary in Williamsburg, Virginia. It’s particularly surprising given that the fossil trackways left by Dimetrodon seem to tell a different story. The relatively narrow distance between left and right sets of footprints suggest Dimetrodon did not have sprawling legs.

“That’s where the real head-scratcher is,” says Abbott. “The trackways are more narrow than you’d expect and in a lot of cases they lack belly dragging marks.”

Continued 

Myanmar caves yield up 19 new gecko species - via Herp Digest

Mongabay, by Shreya Dasgupta, October 11, 2017

            •          Scientists have discovered 19 new species of strikingly patterned geckos within a small area of 90 kilometers by 50 kilometers in Myanmar.

            •          These geckos are most likely restricted to the limestone hills and towers within which they were found.

            •          Conservationists hope that these newly discovered animals can serve as "ambassadors" for the limestone hills, especially since many of these hills are being mined by cement companies.

In a tiny, remote region of Myanmar, scientists have discovered 19 new species of strikingly patterned geckos.

These lizards were found in isolated limestone hills and towers (known as karst) within a small area of 90 kilometers by 50 kilometers (56 miles by 31 miles), and are most likely restricted to these limestone blocks, the researchers say.

“I was quite surprised both by the numbers but even more so by the close proximity of the species to one another,” Lee Grismer of La Sierra University in California, who led the surveys, told Mongabay. “Nothing like this has ever been discovered in this group. The published official count now is 15 and I will submit a paper soon describing another four.”

The 15 officially described species include three new dwarf geckos from the genus Hemiphyllodactylus, reported in the Journal of Natural History. The list also includes 12 new species of bent-toed geckos from the genus Cyrtodactylus, described in a study that will soon be published in the Zoological Journal of the Linnean Society.

A new species of Cyrtodactylus, a bent-toed gecko discovered in Myanmar. Photo by L. Lee Grismer.

Finding these geckos wasn’t easy.

Guided by people from local villages, forest officials and Buddhist monks, Grismer and his team spent several nights searching for geckos in thick, remote karst forests and dark limestone caves.

Not all the newly described geckos were unknown. The monks who occupied monasteries associated with some of the caves might have seen some of the lizards now and then, Grismer said. “But some of the other caves were unoccupied and we had to hike quite a distance to get to them,” he added.

Sometimes their hikes took them through treacherous regions held by armed insurgents.

The research team walking toward Chaunghanakwa, a limestone karst. Photo by L. Lee Grismer.

The team has named one of the newly discovered dwarf geckos Hemiphyllodactylus tonywhitteni after Tony Whitten of Fauna & Flora International, a UK-based conservation nonprofit that supported Grismer’s surveys. H. tonywhitteni is known only from Phapant Cave, a complex of three caves along a narrow river in Shan State.

Whitten “championed a broad range of conservation efforts in Indonesia and the Asia Pacific for well over a quarter of a century,” the authors write in the Journal of Natural History paper. “His tireless efforts to conserve and help manage karst ecosystems have been a great inspiration to the senior author [Lee Grismer].”

“It is always terribly flattering to learn that there is a species with your name attached,” Whitten told Mongabay. “I would add my hope that this amazing discovery, and more to come, will increase people’s understanding of, and concern for, karst systems and their biodiversity which until recently had little or no profile.”

Hemiphyllodactylus montawaensis, a new species of a dwarf gecko, discovered in Myanmar. Photo by L. Lee Grismer.

The discovery of the new geckos also shows that these limestone blocks harbor an “unprecedented degree of biodiversity” of not just invertebrates like snails or insects, but of backboned animals as well, according to Grismer. The isolated limestone hills act as islands within a sea of rice paddies, he said, making them the only places left for forest-adapted species to survive.

Whitten hopes that these newly discovered animals can serve as “ambassadors” for the limestone hills, especially since many of these hills are being mined. In fact, some of the limestone blocks within the team’s research were being mined by cement companies and smaller village operations at the time of the surveys.

“When assessments are made of these areas for development projects it’s simply not enough to look at mammals and birds which can walk, jump or fly away from danger, and may not be that dependent on the hills anyway,” Whitten said. “One rather has to give attention to the geckos and cave fauna whose ranges are limited to these hills and caves. To not do so can lead to extinctions.”

Grismer’s team will soon start surveying Kayah State in eastern Myanmar, an area bordering Thailand that has never been explored for its reptiles,  according to a press release by La Sierra University.

Another new species of Cyrtodactylus discovered in Myanmar. Photo by L. Lee Grismer.

Citation:  Grismer LL et al (2017) Phylogenetic taxonomy of Hemiphyllodactylus Bleeker, 1860 (Squamata: Gekkonidae) with descriptions of three new species from Myanmar. Journal of Natural History. DOI: 10.1080/00222933.2017.1367045

            •          Grismer LL et al (2017). Zoological Journal of the Linnean Society. DOI: in press

Female dolphins have weaponised their vaginas to fend off males

11 October 2017

By Josh Gabbatiss

Some female dolphins have evolved a secret weapon in their sexual arms race with males: vaginas that protect them from fertilisation by unwelcome partners.

Penises come in a wide variety of shapes and sizes, especially in dolphins and other cetaceans. That seems to imply a similar diversity in vaginas, but Dara Orbach of Dalhousie University, Canada, says there is “a huge lag” in our understanding of female genitalia.

That is partly because it is tricky to visualise vaginal structure. To overcome this problem, Orbach has created silicone moulds of cetaceans’ vaginas, revealing complex folds and spirals.

“There’s this unparalleled level of vaginal diversity that we had no idea existed before,” Orbach says.

Similarly complex vaginal structures are found in several species of duck. Orbach’s collaborator Patricia Brennan of Mount Holyoke College, Massachusetts, has previously found evidence that duck vaginas have evolved to make it harder for males to force copulation. So Orbach wondered if female cetaceans’ unusual vaginas had also evolved to keep out unwanted sperm.

Orbach, Brennan and their colleagues obtained genitals from marine mammals that had died of natural causes: common and bottlenose dolphins, common porpoises and common seals. They inflated the males’ penises with saline to see how they looked when they were erect, and compared them with the vaginal moulds. They also took CT scans of penises inserted into the corresponding vaginas, to determine whether they fitted in easily and the best positions.

Continued  

Blind cave fish lost eyes by unexpected evolutionary process

12 October 2017

By Michael Le Page

We’ve found out why a Mexican cavefish has no eyes – and the surprising answer is likely to be seized upon by those who think the standard view of evolution needs revising.

Over the past few million years, blind forms of the Mexican tetra (Astyanax mexicanus) have evolved in caves. Maintaining eyes and the visual parts of the brain uses lots of energy, so the loss of eyes is a big advantage for animals living in the dark. Instead the cavefish “see” by sucking.

It was assumed that these fish became blind because mutations disabled key genes involved in eye development. This has been shown to be the case for some other underground species that have lost their eyes.

But Aniket Gore of the US’s National Institute of Child Health and Human Development and colleagues haven’t found any disabling changes in the DNA sequences of eye development genes in the cavefish.

Instead, the genes have been switched off by the addition of chemical tags called methyl groups. This is what is known as an epigenetic, rather than genetic, change.

“Although a central role for DNA methylation in development and disease has been well-documented, our results suggest that epigenetic processes can play an equally important role in adaptive evolution,” the team writes.

Read more