Dinosaur age lizard footprints discovery


Scientists think that these fossilized footprints may represent the earliest evidence of a lizard running on two legs. Here, a front print (left) and a back print (right) are shown

By Helen Thompson, 1:19pm, February 15, 2018:

Fossil footprints may put lizards on two feet 110 million years ago

But the prints aren’t clear-cut, others say

Fossilized footprints from an iguana-like reptile provide what could be the earliest evidence of a lizard running on two legs.

The 29 exceptionally well-preserved lizard tracks, found in a slab of rock from an abandoned quarry in Hadong County, South Korea, include back feet with curved digits and front feet with a slightly longer third digit. The back footprints outnumber the front ones, and digit impressions are more pronounced than those of the balls of the feet. The lizard’s stride length also increases across the slab.

That’s what you’d expect to see in a transition from moseying along on four legs to scampering on two, says Yuong-Nam Lee, a paleontologist at Seoul National University who first came across the slab back in 2004. A closer examination two years ago revealed the telltale tracks.

Lee and his colleagues attribute the tracks to a previously unknown lizard ichnospecies, that is a species defined solely by trace evidence of its existence, rather than bones or tissue. Lee and his colleagues have dubbed the possible perpetrator Sauripes hadongensis and linked it to an order that includes today’s iguanas and chameleons in the Feb. 15 Scientific Reports.

Bipedal running certainly would have come in handy when escaping predatory pterosaurs some 110 million to 128 million years ago, the age of the rock slab. Lizard tracks are pretty rare in the fossil record, due to the reptiles’ lightweight bodies and penchant for habitats that don’t make great fossils. Though tracks appear in older fossils from the Triassic Epoch, 200 million to 250 million years ago, those prints belong to more primitive lizardlike reptiles. The new find edges out another set from the same region as the oldest true lizard tracks in the world by a few million years, the researchers say.

Plenty of modern lizards use two legs to scurry around. Some studies have linked similarities in ancient lizard bone structure to bipedal locomotion, but it is unclear exactly when lizards developed bipedalism. Lee’s team argues that these tracks represent the earliest and only direct evidence of bipedal running in an ancient lizard.

Martin Lockley, a paleontologist at the University of Colorado Denver who studies ancient animal tracks, points to alternative explanations. S. hadongensis might have trampled over front prints with its back feet, obscuring them and giving the appearance of two-legged running. Preservation can vary between back and front footprints. And the stride lengths aren’t quite as long as what Lockley says he’d expect to see in running. “Running or ‘leaping’ lizards make for a good story, but I am skeptical based on the evidence,” he adds.

So it may take the discovery of more fossilized lizard prints to determine whether S. hadongensis’ tracks truly represent running on two legs rather than simply scurrying on four.

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Asian lizards evolution


This video is called Lepidodactylus lugubris (Mourning gecko) – social get together.

From the University of Kansas in the USA:

Swaths of Asia inhabited by surprisingly related ‘Lizards of the Lost Arcs’

January 25, 2018

A new paper appearing in Proceedings of the Royal Society B shows a varied collection of lizards throughout Asia to be unexpectedly close cousins of beach-dwelling mourning geckos, all descended from a common ancestor species that thrived along an ancient archipelago in the West Pacific that served as a “superhighway” of biodiversity.

The dispersal of these lizards, of the genus Lepidodactylus, touches upon a major theory of island biogeography developed by celebrated biologist E.O. Wilson, dubbed the “taxon cycle” model. The new paper also sheds light on lineage diversity and habitat use in the world’s most geologically complex insular region — Pacific island arcs spanning from the Philippines to Fiji.

“One of the things that I find exciting about this work is how our phylogeny, estimated from DNA sequence data, provides evidence for a giant, widespread radiation of variably sized mourning geckos, scaly-toed geckos and their relatives”, said co-author Rafe Brown, professor of ecology & evolutionary biology and senior curator at the KU Biodiversity Institute. “It was a big surprise to find groups of large-bodied, morphologically diverse, deep forest specialists, nested within a widespread clade of small-bodied coastal generalists — we didn’t think they were related at all.”

Brown said some of the mourning geckos’ closest relatives are physically very different, but all “conspicuously” live along island arcs or lost island arcs that have merged into continents, including the modern-day Philippines, northern and eastern New Guinea, eastern Melanesia, Vanuatu, Fiji, Christmas Island and Borneo.

Of 12 major Lepidodactylus lineages, interesting groups include a genus of obligate forest “slender gecko” species and two groups of mysterious “flap-legged” geckos endemic to the Philippines.

“The slender, long-bodied geckos of the genus Pseudogekko live deep in forests, and we didn’t think they were related to the small, primarily coastal scaly-toed geckos”, Brown said. “Another is Luperosaurus, the flap-legged geckos. They’re big and robust and have thorns and flaps all over their bodies, and some are orders of magnitude larger than mourning geckos. It’s astounding that these lizards that are so physically different have turned out to be close relatives.”

Brown’s collaborators included lead author Paul Oliver of Australian National University as well as Fred Kraus of the University of Michigan, Eric Rittmeyer of Rutgers University, Scott Travers of KU and Cameron Siler of the University of Oklahoma.

“To me, this work underscores how much we have yet to understand about the complexity of species diversification on our planet, particularly in island systems,” said Siler. “It is amazing to think about the role these ancient island systems played in the evolution of endemic communities in Wallacea, the West Pacific and Australasia.”

According to Brown, the findings were the result of extensive fieldwork among researchers as well as genetic analysis and data gleaned from biodiversity collections.

“No one research group could ever have put this together alone,” he said. “Firstly, we never knew these groups were closest relatives, and with separate research groups focusing on different regions with what we thought were unrelated lizard faunas, we might not have even put their DNA sequences into analyses together. The sheer magnitude of the sampling around New Guinea, Australasia, Borneo, Melanesia, Christmas Island, the Philippines and across the Pacific made this study possible. The key was putting together the efforts of many friends and colleagues who provided access to their samples and allowed us to paint the whole picture. Some of these lizards are super rare — there’s no way, in a single person’s career, could an individual go to all these places and collect all the necessary samples.”

Brown said the evolution of Lepidodactylus may be tied to the Vitiaz Arc, a near continuous chain of island arcs that stretched across the West Pacific some 30-40 million years ago during the Oligocene, which today is incorporated into present-day landforms ranging from the Philippines to Fiji.

“We used DNA sequencing data and sophisticated statistical analysis to estimate divergence of major groups in the phylogeny,” he said. “Those initial divergences probably date back to between 30 and 40 million years. When you scroll back into Earth’s history, the landmasses looked very different. One thing that jumps out is the inferred existence of a long chain of islands that stretched out across the Pacific called the Vitiaz Arc. This configuration of fragments of modern-day landmasses and islands that have since shifted but once lined up like a kind of superhighway for biodiversity across the Pacific. Given the timing, it seems like that big long chain of islands may have played a role in the evolution of this group.”

Brown said as the Vitiaz Arc fragmented and parts turned into the Philippines, Solomons, Fiji, Vanuatu and other islands that today are all very far apart, they may have facilitated the broad distribution of Lepidodactylus.

“If ancient lineages evolved and gained widespread distribution across this ancient arc, some really may have persisted for the past 30 to 40 million years,” he said.

The dispersal of the Lepidodactylus touches upon the model of the “taxon cycle” proposed by E.O. Wilson in his study of ants in Fiji and New Guinea. Wilson’s idea was that colonizer species are specialized to survive harsh island coastal terrains but eventually evolve traits to adapt to habitats away from island margins — more inland and upland — where some successor species thrive and others go extinct. In the meantime, the original costal colonizers often are replaced by successive waves of new invaders.

“It’s a very famous, influential idea about how species may colonize new islands and habitats and possibly evolve through predictable ecological transitions,” Brown said. “The idea is very provocative because we commonly think about evolution as determined in part by chance, but what some components of species geographical range evolution were almost deterministic? The brilliance of E.O. Wilson was his ability to conceive of a cyclic process based solely on patterns he saw in ant species’ distributions. He didn’t have the phylogenies we have today, but he inferred relations and put this together as a very clear model, with predictions that we can test today with DNA, sophisticated statistics and knowledge of species’ distributions.”

According to Brown, findings in the new paper include support for the taxon cycle model in Lepidodactylus but also some evidence that runs counter to it.

“In some cases, lizard lineages limited to continental fragments have persisted,” he said. “And in some cases, we did not find the most ancient lizards to be specialists from interior habitats on the oldest land masses. Some ancient lineages are found today on the margins of arc islands or just on the edges of larger landmasses. There are exceptions to any rule, of course. For instance, Lepidodactylus ranauensisis — a species that looks like the kind of common lizard that you might expect to find on a coconut tree on a beach in the Philippines — is actually endemic to Mount Kinabalu on Borneo, maybe 32 million years old, and has no close relatives. Perhaps it is the only surviving member of a once more diverse group of lineages that have gone extinct. We just don’t know. But to find these single evolutionary relics is sort of exciting for a phylogeneticist.”

Fluorescescent chameleons, new study


This video from the USA says about itself:

Wild Chameleons in Florida?!

26 April 2016

On this episode of Coyote’s Backyard, the team and new friend David Humphlett discover an animal NONE of them expected to find! In all of their trips to South Florida Coyote and the crew have seen their fair share of amazing creatures. Everything from Alligators and Crocodiles to invasive Pythons and Knight Anoles have crossed their paths, but tonight they find something extremely rare – an invasive but very WILD Veiled Chameleon! Get ready to meet one very cool color shifter!

Although Veiled Chameleons are native to the Arabian Peninsula they have established breeding populations in South Florida in recent years due to favorable climate conditions and an abundance of specimens released from the exotic pet trade. The Chameleon discovered in this video was not released back into the wild and was instead given to an educational/research group.

From the Ludwig-Maximilians-Universität München in Germany:

Zoology: Luminescent lizards

January 16, 2018

Chameleons are known to communicate with conspecifics by altering their surface coloration. Munich researchers have now found that the bony tubercles on the heads of many species fluoresce under UV light and form impressive patterns.

Biogenic fluorescence is mainly known from marine organisms, but is rare in terrestrial vertebrates. “So we could hardly believe our eyes when we illuminated the chameleons in our collection with a UV lamp, and almost all species showed blue, previously invisible patterns on the head, some even over the whole body”, says David Prötzel, lead author of the new study and PhD student at the Bavarian State Collection of Zoology (ZSM). To understand the phenomenon, the researchers used a variety of modern methods. Micro-CT scans showed that the pattern of fluorescence exactly matched the distribution of tubercles pattern on the skull. The tissue analyses yielded another surprise: “Our histological 3D reconstruction shows that the skin covering the tubercles on the skull is very thin and consists only of a transparent layer of epidermis”, explains Dr. Martin Heß from the BioCenter of Ludwig-Maximilians-Universität (LMU) in Munich. These patches effectively act as windows that enable UV light to reach the bone, where it is absorbed and then emitted again as blue fluorescent light.

“It has long been known that bones fluoresce under UV light, but that animals use this phenomenon to fluoresce themselves has surprised us and was previously unknown”, says Dr. Frank Glaw, Curator of Herpetology at the Bavarian State Collection of Zoology.

The tubercles fluoresce under UV light to form distinct patterns that represent certain species or species groups. In addition, the males in most species of the genus Calumma have significantly more fluorescent tubercles than the females. Therefore, the researchers suspect that this fluorescence is not a mere coincidence, but helps the chameleons to recognize conspecifics, and presents a consistent pattern in addition to their skin-based colour language — especially as blue is a rare colour and easily recognisable in the forest.

Bearded dragon in Australia


This video says about itself:

13 December 2017

On this episode of Breaking Trail, Coyote finally catches one lizard he has always been after, the Bearded Dragon! One of Australia’s most iconic lizard species the Bearded Dragon is world-famous for its incredibly spiky appearance and popularity in the world of herpetology.

Bermuda skink at petrels’ nest


This video from Bermuda says about itself:

Bermuda Skink Takes A Tour Of The Cahow Nesting Burrow – Nov. 30, 2017

Who is that wandering down the tunnel of the nesting burrow on the Bermuda Cahow cam? It’s a Bermuda Skink! These critically endangered reptiles are endemic to Bermuda and one of the rarest lizards in the world. Historically, they also have a long-standing, important relationship with the Bermuda Petrel, as they serve as vital consumers of detritus in the burrows. Read more about the interrelationship here, & skinks here.

Slow worm sliding, video


This 31 October 2017 video shows a slow worm sliding through the grass near Deelerwoud nature reserve in the Veluwe region in the Netherlands.

Slow worms look like snakes, but are lizards.