The diving anole lizard can breathe air while exhaling underwater. Inspired by observations of natural history in Haiti and Costa Rica, a team of biologists from the University of Toronto and elsewhere documented routine air-based underwater respiration in several distantly related semi-aquatic lizard species of the genus Anolis.
The diving anole lizard can breathe air
Their results appear in the journal Current Biology. (The diving anole lizard) Semi-aquatic anoles live along Neotropical streams and often dive for shelter, staying underwater for 16 minutes. It’s easy to imagine what these slow little lizards accomplish by hiding underwater from their predators, said co-author Dr. Lindsay Swier, a researcher in the Department of Biological Sciences at Binghamton University, which are really hard to find.
Department of Biological Sciences
But the real question is how they manage to stay underwater for so long. In the study, Drs. Swierk and her colleagues conducted experiments documenting routine air-based underwater respiration in various species of anoles. They found that these lizards could breathe with air trapped between their skin and the surrounding water (The diving anole lizard).
The diving anole lizard
“We found that semi-aqueous anoles release air in a bubble that clings to their skin,” said first author Chris Boccia, a researcher in the Department of Ecology and Evolutionary Biology at the University of Toronto. “The lizard then breathes air, a maneuver we have called ‘rebreathing’ after the diving technique.” The scientists believe that the hydrophobic skin.
Regularly diving Provide species
Which they observed in all of the anoles sampled, may have become extinct, facilitating the repeated evolution of particular reentries in the regularly diving Provide species. Their analyzes strongly suggest that special rebreathing is adaptive for specialists in semi-aquatic habitats (The diving anole lizard).
Air-based recirculation can improve dive performance by bringing air from the dead space of the oral cavity or plastron into the lungs, facilitating the removal of carbon dioxide or raising oxygen from the surrounding water. The authors used an oxygen sensor inside the rebreathing bubble to determine whether the anoles were consuming oxygen from the bubbles.
Discovery that different species
In a true form of scuba tank, they found that in support of this idea, the oxygen concentration in the anole air bubble decreases with the duration of the dive. Dr. “The discovery that different species of semi-aqueous anoles have sequentially transformed to extract oxygen from their respiring air bubbles raises other interesting questions,” Swierck said.
“For example, the rate of oxygen consumption from bubbles decreases over a longer period of time for dives of an anole, which can be attributed to a decrease in the metabolic rate of the anole with an increase in the dive time.”
Oligocene whales had teeth and baleen, new research suggests. A pair of paleontologists from San Diego State University and the San Diego Museum of Natural History have traced the transition from raptor feeding to filter feeding in the earliest cylindrical whales (mysticeti) in living species. An artist’s reconstruction of Etiosetus Veltoni.
“A strange phenomenon occurs with blue whales, humpback whales and modern gray whales: they have teeth in the womb but are born without teeth,” said Dr. Eric Ekdel and Dr. Thomas Demare. “The change of teeth is beards, a series of plates made of structures like thin, hair and nails grow from the palate that act as a strainer to feed small fish and small shrimp such as krill.”
In the adulthood of Etiocetus veltoni, an evolutionary cousin of today’s cylindrical whales, both the teeth and the cylinder were together, creating a very congested mouth. Paleontologists examined the 25-million-year-old Etiosetus veltoni skull using high-resolution computed tomography.
They found grooves and holes in the roof of the animal’s mouth that connect internally to a vascular canal that corresponds to the pattern of blood vessels that lead to cylinders in modern mystics. This shows that the blood supply to the teeth was chosen for a new task, supporting cylinder development in live cylinder whales.
Sperm whales & killer whales
The study also revealed distinct relationships between the main internal canal and the small channels that carry blood to the upper teeth, the patterns of blood supply to the teeth in live toothed whales such as sperm whales and killer whales, porpoises and dolphins.
We have found evidence supporting the co-occurrence of teeth and cylinders, indicating that the transition from tooth to bellen occurred in a staggered fashion only from teeth to teeth and from cylinders to cylinders, Dr. Ekdel said.
He stated: Our study provides strong fossil evidence of a major change in feeding behavior from a raptorial carnivorous mode of feeding to a bulk filter feeding mode for food, among the largest animals that inhabit Earth’s oceans. “Krill is about 1/600 the size of a blue whale.
It's like us that we are not eating anything bigger than a mole floating in a pool.
“The four main groups of surviving cylindrical whales follow different diets and use their cylindrical filters in different ways, so that they can use the resources of the sea instead of competing with each other for the same prey. Divide yourselves.” The study was published in the Zoological Journal of the Linnean Society.
How ancient whales lost their teeth and became the largest living filter in the world. Blue whales and their cousins are the only creatures on Earth that capture their food using baleen, giant keratin combs that filter millions of gallons of water a day for their microscopic purposes.
But the earliest ancestors of whales had teeth, just like killer whales today, and scientists have struggled to explain how their feeding systems evolved. Now a rare fossil provides an answer: Ancient whales probably first lost their teeth and sucked their food, just like salmon and some other fish, then evolved baleen.
Other recent research has suggested that the transition from teeth to cisterns involves a slow and continuous change from one to the other. For example, a 30-million-year-old fossil whale found in Washington had small picket-shaped teeth, like an enclosure, that could filter for feeding.
Another hypothesis holds that for a time, whales fed on teeth and cylinders. But an analysis of nearly complete whale skulls presented here yesterday at the annual meeting of the Society for Vertebrate Paleontology contradicts both theories.
Instead, paleontologist Carlos Peredo of George Mason University (GMU) in Fairfax, Virginia, and GMU co-investigator Mark Uhne say that a fossil found in the 1970s in Oregon suggests that whales lost their teeth and subsequently they developed independently, without overlap in time.
The team used CT scans to look inside a 30-million-year-old skull that has yet to be named. Neither the teeth nor the bone structure necessary to support the cylinder was found, an important discovery in itself. But when Peredo looked closer, he realized to his surprise that the structure of the skull suggested a completely different feeding method: suction. I thought, ‘This is absurd,’ Peredo recalled during a break in the meeting.
The baleen of this gray whale may have evolved from ancestors that sucked its food. What Peredo and Uhne reassured was the shape of the skull, which could have supported the powerful facial muscles needed to suck up its prey fish. And the age of the whale put it in the gap between toothed whales and baleen whales. “We had a smoking gun,” Peredo said.
Alistair Evans, an evolutionary paleontologist at Monash University in Melbourne, Australia, who has studied the evolution of whales, says he finds the new theory “extremely likely.” His own, particularly a 2016 study of a toothed baleen whale, which he and his co-authors dubbed “Alfred” while waiting to receive its scientific name, suggests that the whale, despite its teeth, it also feeds by suction.
“This new fossil [from Oregon] being described fits our predictions and completely fills the gap in the fossil record,” he wrote in an email. He said the whales likely migrated to the baleen to catch more prey. It is not yet clear when Balen emerged. But, says Peredo, the transition was probably completed in the late Oligocene, about 23 million years ago.
Oldest side-necked turtle fossil in North America discovered. A new species and species of side-necked turtle that lived 96 million years ago (the late Cretaceous Senomanian age) have been identified from fossilized remains found in Texas. This discovery suggests that side-nesting turtles, which retract their necks sideways into their shells when threatened, migrated to North America during the Sino-Manian era, 100 to 94 million years ago.
Oldest side-necked turtle fossil
The reconstruction of the life of Plurochaiah Appalachius. Image credit: Brent Adrian / Midwestern University. Plurochaiah Appalachius life reconstruction. Image credit: Brent Adrian / Midwestern University. The new species is related to Botharymidae, an extinct group of side-necked turtles (plurodiran) that spread geographically and occupied a wide range of ecological niches.
The group originated from the southern continent of Gondwana, beginning in the early Cretaceous and migrating to the northern continents. The eponymous Plurochaiah Appalachius is one of the earliest examples of intercontinental dispersal by the new group of turtles and is the oldest rered found in the sediments of North America and Lauresia.
Oldest turtle fossil
Writer for the Department of Anatomy at Midwestern University, lead author, Drs. Brent Adrian said: “This discovery provides the earliest evidence for side-nesting turtles in North America and broadens our understanding of the earliest migration of extinct botremidids.” Fossil remains of Plurochaya appalachius were discovered at the Woodbine Group’s Arlington Arcosaur site in Texas, USA.
They predate Paiutemis tibert, a species of tortoise from Utah, previously identified as the oldest known side-necked turtle in North America. “The discovery further establishes the Arlington Arcosaur site as an important fossil unit revealing the foundations of an endemic Appalachian fauna,” said Dr. Adrian.
The Pleurochayah Appalachius had an intriguing combination of morphological adaptations to the highly aquatic lifestyle that possibly facilitated their long-distance migration. The bone in your upper arm shows large bony attachments to the muscles that support powerful recovery from swimming strokes.
The functional morphology of the bone also indicates that the turtle used a water rowing swimming mode, in contrast to the flapping motion of modern sea turtles. The microscopic anatomy of its shell reveals a relatively thick exterior compared to the inner crust, similar to the later sea-adapted species of boathermedid.
However, its marine adaptations are not derived from the later two Remedies, found later in the Upper Cretaceous in the North American fossil record. The Plurochaiah Appalachius skull had a unique combination of primitive and derived features that it shares with the other two Remedid species. It shares most of the characteristics with the two basal Remedid clades, Cerachellini and Kurmademidini.
Based on the findings, Dr. Adrian and his colleagues suggest that the first boetherid tortoises migrated from Gondwana to North America during the Senomanian era or earlier via the Mid-Atlantic Ocean or the Caribbean.
“It is likely that both the outbreaks of rheumatics in North America during or before the Cenomanian were influenced by the strange occurrence of the opening of the Central Atlantic and the periodic connections with the western interior maritime passage of the Gulf of Mexico,” said the paleontologist.
“However, allopatric species may be responsible for the multicontinent distribution of basal boramidides, as demonstrated for other late Lower Cretaceous pelomedsoid clades.” The study was published this week in the journal Scientific Reports.