Mammals - Our Complete List
The Oldest Known Fossilized Skin Shows How Life Adapted To Land
A dark sliver of rock pulled from an Oklahoma limestone quarry is the world's oldest fossil cast of skin ever found.
The fossil is nearly 290 million years old, and once dressed an early member of the amniotes, a clade of four-legged vertebrates that evolved from amphibians and includes all reptiles, birds and mammals, researchers report January 11 in Current Biology. It's 21 million years older than the only other reported fossilized skin from the Paleozoic Era, spanning 541 million to 252 million years ago, during which animals moved onshore and diversified.
"This is definitively the oldest [known] piece of mummified skin," says paleontologist Ethan Mooney of the University of Toronto Mississauga. It fits "into a broader story of how the first animals left the water and went onto land."
Fossil collectors Bill and Julie May found the cast, along with exquisitely preserved skin impressions, at an Oklahoma quarry in an ancient limestone cave system known as Richards Spur.
There, a special concoction of cave conditions contributed to the fossils' superb preservation. Corpses were buried in fine sediments, which excluded oxygen and slowed decay, and were exposed to groundwater rich in iron, an element that helps preserve tissues. Also, the site was an ancient oil seep. Petroleum and tar permeated the remains, sealing them off from decaying conditions while also staining them black.
Captorinhus, an early amniote (illustrated), walked on solid ground during the Permian period, which stretched from around 299 million to 252 million years ago. Michael deBragaThe skin samples all possess nonoverlapping scales, though the scale sizes, distributions and abundances vary. The specimens probably come from different places on the amniote body, Mooney's team suggests, and possibly different animals too.
Cast cross sections revealed a thickened outer skin layer, or epidermis. The development of a robust epidermis would have protected the early amniotes from the elements while also helping it retain water.
That surficial innovation eventually led to bird feathers and mammalian hair follicles. Tough and bumpy amniote skin, Mooney says, was "the first stage."
Cannibal Tree Frogs Are Invading The US: Human Hand-sized Amphibians From Cuba Have Been Spotted In Georgia - And Officials Urge Residents To 'kill Them' On The Spot
Cannibal tree frogs from Cuba are invading parts of the US - and wildlife officials are urging people to kill the amphibians on the spot.
The warning is due to the human hand-sized frogs eating those native to North America, which would lead to 'ecological problems.'
The invasive creature also' secretes an irritating liquid from their skin when touched,' with consequences to humans or small animals that 'remain understudied.'
Wildlife managers are still uncertain how far north this tropical cannibal frog, which migrated through Florida from Cuba, the Caymans and the Bahamas, will spread.
State biologists have reported that some Cuban tree frogs have hitched rides as far north as Chattanooga, Tennessee and are quickly devising strategies to survive the winter.
Biologists with Georgia's Wildlife Resources Division have issued an all-points bulletin for an invasive frog they fear could cause 'ecological problems' in the South. The carnivorous Cuban tree frog threatens to eat competitors as it crowds them out of the food chain
'One thing that they've learned to take advantage of,' according to the wildlife biologist for Georgia's Department of Natural Resources Wildlife Resources Division, 'is the things we build our houses out of.'
'They've been known to hide in transformer boxes,' said senior wildlife biologist Daniel Sollenberger, specializing in herpetology, or the study of reptiles and amphibians.
'Electrical boxes are warmer because of the resistance of the electricity,' Sollenberger told the Augusta Chronicle, giving the tree frogs refuge from the cold.
The only known 'breeding population' of Cuban tree frogs in Georgia is on Jekyll Island, the coastal state park 50 miles north of Florida.
And Georgia's Jekyll Island Authority, the governing entity assigned to manage Jekyll Island State Park, has encouraged visitors to help keep tabs on the Cuban tree frog via their hotline.
But the cannibal tree frogs have proven adept at migrating, according to Sollenberger, particularly by hiding out in shipments of house plants and vegetation sold for gardening and landscaping purposes.
But state biologists report that some Cuban tree frogs have hitched rides as far north as Chattanooga, Tennessee and are quickly devising strategies to survive the winter
'They get transported around on vehicles or nursery plants,' Sollenberger said.
'For instance, if you go to Lowe's and buy a tree and if that tree came from a nursery in Florida there might be a Cuban tree frog hitching a ride on it.'
The senior wildlife biologist told local reporters that residents of more coastal cities like Brunswick and Savannah, Georgia have witnessed cannibal frogs 'breeding in retention ponds and ditches,' but it's unclear if the frog-eaters will creep westward.
'We don't know how far inland they could go,' Sollenberger said, 'because they're somewhat tropical.'
While the Cuban tree frog's omnivorous meaty diet is something it shares with all other frogs, its interest in eating its own kind is rare and, in part, a testament to its large adult size.
'They will eat a lot of insects,' according to Sollenberger. '[But] they will also eat anything that they can fit in their mouth. They will even eat smaller tree frogs.'
'There's at least some anecdotal evidence from Florida,' he added, 'that they actually can reduce populations of native frogs.'
'If we want to have some native wildlife left in our yards, this could be a problem.'
James Stroud, an assistant professor of Biology at the Georgia Institute of Technology, told DailyMail.Com that he agrees these concerns are warranted.
'In Louisiana, where they were first recorded as invasive in 2017,' Stroud wrote via email, 'it appears that native frogs are subsequently disappearing in those areas. This could be due to either predation or competition with the invasive Cuban tree frogs.'
'It is possible that Cuban tree frogs will represent a novel ecological threat to protected insect species in Georgia,' Stroud noted.
'Cuban tree frogs are also able to secrete an irritating liquid from their skin when touched,' he advised DailyMail.Com.
'While this is not known to be poisonous to humans or small animals, the broader ecological consequences in new environments remain understudied.'
Sollenberger is taking reports on Cuban tree frog sightings and can be reached by email at: daniel.Sollenberger@dnr.Ga.Gov
Georgia's Jekyll Island Authority wildlife hotline, which is also tracking the frog, can be reached at: (912) 222-5992
Listening For The Songs Of The Amphibians
"The male Kumbara night frog is the ideal partner that every woman looks for," jokes Girish Janney, standing ankle-deep in the waters of a perennial stream, in one of the thickest and darkest stretches of the central Western Ghats — Kattale Kaanu — near the famous Jog Falls.
"The female Kumbara night frog hops off, laying hundreds of eggs at suitable locations. It is the male that 'looks after' and protects the eggs from predators by 'packing' them with mud. Thus, it gets its name — Kumbara or potter," says the 41-year-old researcher about the endemic frog species.
Two decades ago, research on amphibians was all but absent. It was then that Girish started on his mission to document indigenous species of frogs under the guidance of S V Krishnamurthy, a scientist. "One could find a large number of scientists working on bigger mammals and avians. I wanted to take up research work on a species that indicates environmental health and highlights the ill effects of degradation of forests, streams and nature," says Girish.
Frogs are micro-habitat indicators and even slight changes in their surroundings will result in lifecycle alterations. For instance, a decrease in the population of frogs in a particular area means the flow of the stream has been altered or that the canopy cover has been tampered with.
Research
The Kumbara night frog (Nyctibatrachus kumbara) is among several amphibians that Girish, an environment science guest lecturer at Indira Gandhi Government First Grade College for Women, Sagar, has been studying for the last 20 years in and around the Western Ghats.
Even though Janney graduated with a degree in Electronics, Mathematics and Computer Science, he found that his true calling was environmental science. He went on to complete his Master's degree in this subject from Kuvempu University. For his PhD thesis, he opted for the Kumbara night frog.
His work has exposed the rich life of nocturnal frogs in the Malnad region. "As I started studying the habitat, population, and other aspects of the Kumbara night frog, we came to learn about various night frogs here," he says.
Girish's research work has not only enriched the scientific world with grassroots-level data from one of 36 bio-hotspots in the world but has also helped documentary makers produce award-winning films. His biggest contribution, as a teacher, has been encouraging students and local communities to participate in research and become citizen scientists.
Batrachologist Gururaj K V says there are very few researchers in India who are conducting such extensive studies on frogs.
"Girish, over the years, has taken up the herculean task of ecological study of frogs. His research features the population of frogs in particular streams, factors that affect their life cycles, the impact of a decrease in canopy cover or water availability that would disturb the breeding habitat of these frogs," he adds. Such research can be instrumental in preventing development work in sensitive areas in the region.
Prashanth Nayaka, the director of 'Kappe Raaga', which won several national and international awards, credits Girish for introducing the Kumbara frog to him.
"It was Girish who helped us understand the behaviour, habitat and life cycle of the frog. Sitting next to a small stream in the dense jungle, Girish braved leeches, torrential rain and venomous snakes to help complete the documentary. The tiny Kumbara frog is hard to identify as it can easily camouflage itself," he says.
The filmmakers made the documentary in Kannada as they intended to educate locals about the species. Apart from 'Kappe Raaga', Girish's inputs have also helped documentary makers of 'Wild Karnataka', 'Little Planet' and 'The Last Hope'.
Science for the masses
This is in line with Girish's belief that no conservation efforts can be successful unless locals understand the importance. For him, children are the best influencers. This is why the researcher has been taking students to the heart of the forest to explain the connection between flora, fauna and humans through an initiative he co-founded — the Panchavati Research Academy for Nature (Prana).
The group usually frequents sacred groves, community forest areas and with the help of the forest department, even protected areas. More than 1,000 students of schools and colleges have benefited from Prana.
During field visits, Girish elaborates on the link between various organisms in the ecosystem. The classes are a hit among the students as they get live demonstrations on mushrooms, lichens, orchids, insects, birds, mammals and other organisms dwelling in the forest.
His initiative, 'Aaduva Makkalige Kaadupaata', has helped cultivate a new crop of citizen scientists in the Sharavathi valley.
Another popular effort is the 'Hakki Habba', through which Girish and his friends Pradeep Kallalli and Puneeth teach students about the different species of birds, their features and habitats through games and activities.
Bhuvanamitra S (28), a geospatial manager currently working with a private company in Bengaluru, is an ecology enthusiast inspired by Girish. "Just 300 m from my grandfather's house in Kanive Bagilu in Hosanagar, a perennial stream flows. Though I knew a few frogs lived here, I had never gone to check on them. It was only when Girish sir came to our village for his research that I started following him. I learnt about the amazing world of the amphibian in my backyard. He sowed the seeds of curiosity in me (at 11 years old) and today wherever I see a water body, I look for frogs," he says.
Another major part of his environmental outreach is with tribal communities. Ganapathi K T, a member of Hasala Haddi community in Kalamanji village says it was Girish's efforts that helped them save the Arichatige plants (Memecylon umbellatum/talbotianum) in the area. These trees are used as brooms in paddy fields.
Extensive extraction had resulted in a temporary extinction of these plants in a section of Siddapur taluk of Uttara Kannada district. "Girish spoke to us about the sustainable utilisation of forest products. We have realised now that we should not destroy our surroundings as that could affect our future," he says.
Forestry
Girish also closely works with educational institutes to improve green cover on their campus. Over the last three years, his organisation has helped develop 'Kyasadavi' forests. A tweaked form of the Japanese model of Miyawaki forestry, under the Kyasadavi method, Girish and his students have planted 150 species of local forest plants at three sites in Sagar taluk. To strike a chord with locals, the forestry method is named after the Malabar Giant Squirrel, which the term Kyasadavi means.
The researcher is still observing the survival rates of the mini-forest planted three years ago, among other parameters.
In the Miyawaki method, the focus is on tree species. In Kyasadevi, creepers are also considered, says Savinaya Malve, a botany lecturer who works with Girish.
Comments
Post a Comment