Ancient Carboniferous amphibian, new research


Acherontiscus caledoniae

From the University of Lincoln in England:

Research reveals surprisingly powerful bite of tiny early tetrapod

May 9, 2019

Micro-CT scanning of a tiny snake-like fossil discovered in Scotland has shed new light on the elusive creature, thought to be one of the earliest known tetrapods to develop teeth that allowed it to crush its prey.

Detailed scans of Acherontiscus caledoniae showed a unique combination of different tooth shapes and sizes as well as a deep lower jaw which scientists believe would have given the creature the ability to pierce, cut and grind the hard-shelled crustaceans that made up its diet.

Scientists led by the University Museum of Zoology in Cambridge alongside the University of Lincoln, the Natural History Museum in London and the University of Southampton, found that the dental pattern of Acherontiscus is at odds with that of several other tetrapods of this period, which tended to have uniform rows of cone-like teeth sometimes curved backwards at the tip. The variation in the shape and size of teeth shown in this fossil displays a level of dental adaptation that is unprecedented in such an early tetrapod.

As co-author Dr Marcello Ruta from the University of Lincoln’s School Of Life Sciences explains: “We found that Acherontiscus preceded the origin of modern tetrapod lineages and joined an array of primitive groups that independently acquired long and often miniaturized bodies, and exhibited either reduced or no limbs.”

The fossil is the only known specimen of this limbless tetrapod, which measured just 6 inches long and existed in swampy marshlands on the outskirts of Edinburgh some 330 million years ago. The delicate nature of the fossil meant that scientists were unable to use mechanical or chemical methods to free its skeleton from the surrounding rock, or study the specimen under a microscope.

Lead author Professor Jennifer Clack from the University Museum of Zoology in Cambridge said: “Using advanced techniques of micro-CT scanning, we were able to make sense of Acherontiscus’ complex skull, revealing minute anatomical details that allowed us to produce a greatly revised and much more complete reconstruction.

“We were particularly surprised to realize the great variety of shapes and sizes of its teeth. Acherontiscus is the earliest known tetrapod showing a crushing dentition, a feature with a rather discontinuous distribution in fossil and modern tetrapods.”

Fragments in the surrounding matrix have also revealed more about Acherontiscus’ habitat which will inform further research into the area as co-author Professor John Marshall from the University of Southampton’s School of Ocean and Earth Science explains: “Our study provided impetus for exploring the ecology and environments of the Scottish wetlands where Acherontiscus lived. Analysis of the content of fossil spores from about 0.2 grams of the matrix surrounding the creature suggests that this animal lived close to or within a still water body surrounded by herbaceous plants related to clubmosses. A more distant forest of larger, tree-like relatives of modern quillworts was also present.”

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Carboniferous ice age geology of Namibia


This 21 January 2019 video is called CARBONIFEROUS PERIOD. Giant insects and other strange creatures. Size comparison chart. Paleoart.

This 2015 video says about itself:

The “Karoo Ice Age” from 360–260 million years ago was the second major ice age of the Phanerozoic Eon. It is named after the tillite found in the Karoo region of South Africa, where evidence for this ice age was first clearly identified in the 19th century.

From West Virginia University in the USA:

Researcher unearths an ice age in the African desert

February 4, 2019

A field trip to Namibia to study volcanic rocks led to an unexpected discovery by West Virginia University geologists Graham Andrews and Sarah Brown.

While exploring the desert country in southern Africa, they stumbled upon a peculiar land formation — flat desert scattered with hundreds of long, steep hills. They quickly realized the bumpy landscape was shaped by drumlins, a type of hill often found in places once covered in glaciers, an abnormal characteristic for desert landscapes.

“We quickly realized what we were looking at because we both grew up in areas of the world that had been under glaciers, me in Northern Ireland and Sarah in northern Illinois,” said Andrews, an assistant professor of geology. “It’s not like anything we see in West Virginia where we’re used to flat areas and then gorges and steep-sided valleys down into hollows.”

After returning home from the trip, Andrews began researching the origins of the Namibian drumlins, only to learn they had never been studied.

“The last rocks we were shown on the trip are from a time period when southern Africa was covered by ice,” Andrews said. “People obviously knew that part of the world had been covered in ice at one time, but no one had ever mentioned anything about how the drumlins formed or that they were even there at all.”

Andrews teamed up with WVU geology senior Andy McGrady to use morphometrics, or measurements of shapes, to determine if the drumlins showed any patterns that would reflect regular behaviors as the ice carved them.

While normal glaciers have sequential patterns of growing and melting, they do not move much, Andrews explained. However, they determined that the drumlins featured large grooves, which showed that the ice had to be moving at a fast pace to carve the grooves.

These grooves demonstrated the first evidence of an ice stream in southern Africa in the late Paleozoic Age, which occurred about 300 million years ago.

“The ice carved big, long grooves in the rock as it moved,” Andrews said. “It wasn’t just that there was ice there, but there was an ice stream. It was an area where the ice was really moving fast.”

McGrady used freely available information from Google Earth and Google Maps to measure their length, width and height.

“This work is very important because not much has been published on these glacial features in Namibia,” said McGrady, a senior geology student from Hamlin. “It’s interesting to think that this was pioneer work in a sense, that this is one of the first papers to cover the characteristics of these features and gives some insight into how they were formed.”

Their findings also confirm that southern Africa was located over the South Pole during this period.

“These features provide yet another tie between southern Africa and south America to show they were once joined,” Andrews said.

The study, “First description of subglacial megalineations from the late Paleozoic ice age in southern Africa” is published in the Public Library of Science’s PLOS ONE journal.

“This is a great example of a fundamental discovery and new insights into the climatic history of our world that remain to be discovered,” said Tim Carr, chair of the Department of Geology and Geography.

Edaphosaurus, ancient sail-backed mammal-like reptile


This 28 January 2019 video says about itself:

Edaphosaurus, meaning “pavement lizard” for dense clusters of teeth) is a genus of extinct edaphosaurid synapsid. It lived in what is now North America and Europe around 300 to 280 million years ago, during the late Carboniferous to early Permian periods.

Edaphosaurus is important as one of the earliest known large plant-eating (herbivorous) amniote tetrapods (four-legged land-living vertebrates). In addition to the large tooth plates in its jaws, the most characteristic feature of Edaphosaurus is a sail on its back which is unique in shape and morphology. Edaphosaurus species measured from 0.5 metres (1.6 ft) to almost 3.5 metres (11.5 ft) in length and weighed over 300 kilograms (660 lb).

Like its more famous relative Dimetrodon, Edaphosaurus had a sail-like fin that was supported by bones of the vertebral column. Edaphosaurus differs from Dimetrodon in having cross-bars on the spines that supported its fin. Edaphosaurus and other members of the Edaphosauridae evolved tall dorsal sails independently of sail-back members of the Sphenacodontidae. Dimetrodon and Secodontosaurus that lived at the same time are an unusual example of parallel evolution.

Prehistoric giant millipedes, video


This 23 January 2019 video says about itself:

Arthropleura: They Could Grow Larger Than A Man

Arthropleura (Greek for jointed ribs) is a genus of extinct millipede arthropods that lived in what is now northeastern North America and parts of Europe around 315 to 299 million years ago, during the late Carboniferous Period.

The larger species of the genus are the largest known land invertebrates of all time, and would have had few, if any, predators. Arthropleura species ranged in length from 0.3 to 2.3 metres (0.98 to 7.55 ft) and a width up to 50 centimetres (1.6 ft). Arthropleura was able to grow larger than modern arthropods, partly because of the greater partial pressure of oxygen in Earth’s atmosphere at that time and because of the lack of large terrestrial vertebrate predators.

The flattened body of Arthropleura is composed of approximately 30 jointed segments, each of which was covered by two side plates and one center plate. The ratio of pairs of legs to body segments was approximately 8:6, similar to some present-day millipedes.

Contrary to earlier and popular beliefs, Arthropleura was not a predator but an herbivorous arthropod. Because none of the known fossils have the mouth preserved, scientists suppose that Arthropleura did not have strongly sclerotized and powerful mouth parts, because such would have been preserved at least in some of the fossils.

Some fossils have been found with lycopod fragments and pteridophyte spores in the gut and in associated coprolites. Fossilized footprints from Arthropleura have been found in many places. These appear as long, parallel rows of small prints, which show that it moved quickly across the forest floor, swerving to avoid obstacles, such as trees and rocks. Its tracks have the ichnotaxon name Diplichnites cuithensis. Tracks from Arthropleura up to 50 cm wide have been found at Joggins, Nova Scotia.

Arthropleura became extinct at the end of the Carboniferous period, when the moist climate began drying out, reducing the rainforests of the Carboniferous, and allowing the desertification characteristic of the Permian.

Oldest reptile tracks ever discovery in Grand Canyon, USA


UNLV geologist Stephen Rowland discovered that a set of 28 footprints left behind by a reptile-like creature 310 million years ago are the oldest ever to be found in Grand Canyon National Park. Credit: Stephen Rowland

From the University of Nevada, Las Vegas in the USA:

Tiny footprints, big discovery: Reptile tracks oldest ever found in Grand Canyon

Geologist investigating 310 million-year-old fossil trackway from ancient reptilian creature

November 8, 2018

A geology professor at the University of Nevada, Las Vegas, has discovered that a set of 28 footprints left behind by a reptile-like creature 310 million years ago, are the oldest ever to be found in Grand Canyon National Park.

The fossil trackway covers a fallen boulder that now rests along the Bright Angel Trail in the national park. Rowland presented his findings at the recent annual meeting of the Society of Vertebrate Paleontology.

“It’s the oldest trackway ever discovered in the Grand Canyon in an interval of rocks that nobody thought would have trackways in it, and they’re among the earliest reptile tracks on earth”, said Rowland.

Rowland said he’s not prepared to say that they’re the oldest tracks of their kind ever discovered, but it’s a possibility, as he’s still researching the discovery.

“In terms of reptile tracks, this is really old,” he said, adding that the tracks were created as the supercontinent Pangaea was beginning to form.

Rowland was first alerted to the tracks in spring 2016 by a colleague who was hiking the trail with a group of students. The boulder ended up along the trail after the collapse of a cliff.

A year later, Rowland studied the footprints up close.

“My first impression was that it looked very bizarre because of the sideways motion”, Rowland said. “It appeared that two animals were walking side-by-side. But you wouldn’t expect two lizard-like animals to be walking side-by-side. It didn’t make any sense.”

When he arrived home, he made detailed drawings, and began hypothesizing about the “peculiar, line-dancing gait” left behind by the creature.

“One reason I’ve proposed is that the animal was walking in a very strong wind, and the wind was blowing it sideways”, he said.

Another possibility is that the slope was too steep, and the animal sidestepped as it climbed the sand dune. Or, Rowland said, the animal was fighting with another creature, or engaged in a mating ritual.

“I don’t know if we’ll be able to rigorously choose between those possibilities”, he said.

He plans to publish his findings along with geologist Mario Caputo of San Diego State University in January. Rowland also hopes that the boulder is soon placed in the geology museum at the Grand Canyon National Park for both scientific and interpretive purposes.

Meanwhile, Rowland said that the footprints could belong to a reptile species that has never yet been discovered.

“It absolutely could be that whoever was the trackmaker, his or her bones have never been recorded,” Rowland said.

Carboniferous-Permian plant extinction harmed amphibians, helped reptiles


This video says about itself:

30 March 2015

Dave and Palaeo After Dark’s James explore the Carboniferous forests in the ‘Carboniferous Forest Simulator‘!

This fantastic software is free for educational, museum or personal use. We really need to get our full support behind this project!

The programme, in its ‘alpha testing’ stage can be downloaded here.

Details of the development of the project can be found here.

From the University of Birmingham in England:

Rainforest collapse 307 million years ago impacted the evolution of early land vertebrates

February 7, 2018

Researchers at the University of Birmingham have discovered that the mass extinction seen in plant species caused by the onset of a drier climate 307 million years ago led to extinctions of some groups of tetrapods, the first vertebrates to live on land, but allowed others to expand across the globe. This research is published today (7th February 2018) in the journal Proceedings of the Royal Society B.

The Carboniferous and Permian periods (358 — 272 million years ago) were critical intervals in the evolution of life on land. During the Carboniferous Period North America and Europe lay in a single land mass at the equator which was covered by dense tropical rainforests. These rainforests flourished because of the warm humid climate, providing an ideal habitat for early tetrapods (vertebrates with four limbs), allowing them to diversify into a variety of species.

But towards the end of this period a major global environment change took place — just as the number of tetrapod species began to increase, the rainforests started to disappear. The climate became much drier causing the mass extinction of many species within the dominant plant groups, such as horsetails and club mosses. Despite this being a catastrophic event for plants, it has been unclear how this affected the early tetrapod community.

Previous attempts to estimate the diversity changes during this period have been hindered by the fossil record, which has not been sampled equally in different time intervals or geographic areas. To fill these gaps in the data, the Birmingham researchers compiled a new dataset from the Paleobiology Database and used advanced statistical methods to estimate diversity and biogeographic changes.

The results of the study show that tetrapod diversity decreased after the rainforest collapse and the onset of drier conditions, largely due to the reduction in suitable habitats for amphibians which needed wet environments to survive.

However they also found that after the rainforest collapse surviving tetrapod species began to disperse more freely across the globe, colonising new habitats further from the equator. Many of these survivors were early amniotes, such as early reptiles, whose generally larger size relative to early amphibians allowed them to travel longer distances, and their ability to lay eggs meant they were not confined to watery habitats.

Emma Dunne, from the University of Birmingham’s School of Geography, Earth and Environmental Sciences, said: ‘This is the most comprehensive survey ever undertaken on early tetrapod evolution, and uses many newly developed techniques for estimating diversity patterns of species from fossil records, allowing us greater insights into how early tetrapods responded to the changes in their environment.’

Dunne continued: ‘We now know that the rainiforest collapse was crucial in paving the way for amniotes, the group which ultimately gave rise to modern mammals, reptiles and birds, to become the dominant group of land vertebrates during the Permian period and beyond.’

Fish evolution, new discovery


Fukangichthys

By Viviane Callier, 2:17pm, September 18, 2017:

3-D scans of fossils suggest new fish family tree

Analysis of specimens from China implies ray-finned fishes are younger than previously thought

When it comes to some oddball fish, looks can be deceiving.

Polypterus, today found only in Africa, and its close kin have generally been considered some of the most primitive ray-finned fishes alive, thanks in part to skeletal features that resemble those on some ancient fish. Now a new analysis of fish fossils of an early polypterid relative called Fukangichthys [from the Triassic] unearthed in China suggests that those features aren’t so old. The finding shakes up the evolutionary tree of ray-finned fishes, making the group as a whole about 20 million to 40 million years younger than thought, researchers propose online August 30 in Nature.

Ray-finned fishes named for the spines, or rays, that support their fins — are the largest group of vertebrates, making up about half of all backboned animals. They include 30,000 living species, such as gars, bowfins and salmon. The group was thought to originate about 385 million years ago, in the Devonian Period. But the new research, using 3-D CT scans of the previously discovered fossils, shifts the fishes’ apparent origin to the start of the Carboniferous Period some 360 million years ago, says study coauthor Matt Friedman, a paleontologist at the University of Michigan in Ann Arbor.

One of the largest extinction events in Earth’s history marks the boundary between the Devonian and Carboniferous. “We know that many groups of backboned animals were hard hit by the event,” Friedman says. But after the massive die-off, ray-finned fishes popped up and, according to previous fossil evidence, their diversity exploded. The new finding “brings the origin of the modern ray-finned fish group in line with this conspicuous pattern that we see in the fossil record,” Friedman says. It suggests these vertebrates didn’t survive the event. They came after, then flourished.