Prehistoric turtles and climate change


This March 2014 video is called Global Warming 56 Million Years Ago: What it Means for Us .

From the University of Florida in the USA:

Tropical turtle discovery in Wyoming provides climate-change clues

Published: February 23 2015

Tropical turtle fossils discovered in Wyoming by University of Florida scientists reveal that when the earth got warmer, prehistoric turtles headed north. But if today’s turtles try the same technique to cope with warming habitats, they might run into trouble.

While the fossil turtle and its kin could move northward with higher temperatures, human pressures and habitat loss could prevent a modern-day migration, leading to the extinction of some modern species.

The newly discovered genus and species, Gomphochelys (pronounced gom-fo-keel-eez) nanus, provides a clue to how animals might respond to future climate change, said Jason Bourque, a paleontologist at the Florida Museum of Natural History at UF and the lead author of the study, which appears online this week in the Journal of Vertebrate Paleontology</em>.

The wayfaring turtle was among the species that researchers believe migrated 500-600 miles north 56 million years ago, during a temperature peak known as the PaleoceneEocene Thermal Maximum. Lasting about 200,000 years, the temperature peak resulted in significant movement and diversification of plants and animals.

“We knew that some plants and lizards migrated north when the climate warmed, but this is the first evidence that turtles did the same,” Bourque said. “If global warming continues on its current track, some turtles could once again migrate northward, while others would need to adapt to warmer temperatures or go extinct.”

The new turtle is an ancestor of the endangered Central American river turtle and other warm-adapted turtles in Belize, Guatemala and southern Mexico. These modern turtles, however, could face significant roadblocks on a journey north, since much of the natural habitat of these species is in jeopardy, said co-author Jonathan Bloch, a Florida Museum curator of vertebrate paleontology.

“If you look at the waterways that turtles would have to use to get from one place to another, it might not be as easy as it once was,” Bloch said. “Even if the natural response of turtles is to disperse northward, they have fewer places to go and fewer routes available.”

To put the new turtle in evolutionary context, the researchers examined hundreds of specimens from museum collections around the country, including turtles collected during the 1800s housed at the Smithsonian Institution. Co-author Patricia Holroyd, a vertebrate paleontologist at the University of California, Berkeley, said the fossil history of the modern relatives of the new species shows they could be much more wide-ranging, if it were not for their restricted habitats.

The Central American river turtle is one of the most endangered turtles in the world, threatened by habitat loss and its exploitation as a human food source, Holroyd said.

“This is an example of a turtle that could expand its range and probably would with additional warming, but — and that’s a big but — that’s only going to happen if there are still habitats for it,” she said.

Eocene fossil seashell discovery on Texel island


Venericor planicosta

Translated from Ecomare museum on Texel island in the Netherlands, 19 February 2015:

Never before had a Venericor planicosta seashell been found across the whole Wadden Sea region. The shell lived in the Eocene epoch, 56 to 42 million years ago.

Subtropical

Last year, Ms. Kenselaar found it on the beach at Den Hoorn. The shell for a while remained in her cottage, but last week she took it to Ecomare. Curator Arthur Oosterbaan showed it to various experts, and they all said the same thing: Venericor planicosta. It lived in our region in the early and middle Eocene. That’s about 15 million years after the extinction of the dinosaurs. Europe then was an archipelago with a subtropical climate.

In the Netherlands, until this discovery, this fossil species had really only been known from the south-west of the country.

Fossil haddock bones on Dutch beaches


This video from the USA says about itself:

27 April 2011

Kemmerer, Wyoming boasts the site of the largest concentration of [Eocene] fossil fish.

On Dutch beaches, like of Texel island and the Zandmotor, many small fossil fish bones, cleithrum bones, were found. Recent research found out these bones belonged to Melanogrammus aeglefinus, the haddock, a species still living today.

The bones are about 100,000 years old, from the Eemien, the time before the last ice age. Last month, the research was published in Cranium journal.

In Belgium, cleithrum bones have been found of an older haddock species, now extinct, from the Pliocene age. That species is called Melanogrammus conjunctus.

Giant fossil penguin discovery in Antarctic


This video says about itself:

5 October 2010

Scientists have unearthed fossilized remains of a five-foot-tall (150-centimeter-tall) penguin in present-day Peru. The 36-million-year-old fossil sheds light on bird evolution, according to National Geographic grantee Julia Clarke. Video produced by the University of Texas at Austin.

From New Scientist:

Extinct mega penguin was tallest and heaviest ever

01 August 2014 by Jeff Hecht

Forget emperor penguins, say hello to the colossus penguin. Newly unearthed fossils have revealed that Antarctica was once home to the biggest species of penguin ever discovered. It was 2 metres long and weighed a hefty 115 kilograms.

Palaeeudyptes klekowskii lived 37 to 40 million years ago. This was “a wonderful time for penguins, when 10 to 14 species lived together along the Antarctic coast”, says Carolina Acosta Hospitaleche of the La Plata Museum in Argentina.

She has been excavating fossil deposits on Seymour Island, off the Antarctic peninsula. This was a warmer region 40 million years ago, with a climate like that of present-day Tierra del Fuego, the islands at the southern tip of South America.

The site has yielded thousands of penguin bones. Earlier this year, Acosta Hospitaleche reported the most complete P. klekowskii skeleton yet, although it contained only about a dozen bones, mostly from the wings and feet (Geobios, DOI: 10.1016/j.geobios.2014.03.003).

Now she has uncovered two bigger bones. One is part of a wing, and the other is a tarsometatarsus, formed by the fusion of ankle and foot bones. The tarsometatarsus measures a record 9.1 centimetres. Based on the relative sizes of bones in penguin skeletons, Acosta Hospitaleche estimates P. klekowskii was 2.01 meters long from beak tip to toes.

Its height will have been somewhat less than its length owing to the way penguins stand. But it was nevertheless larger than any known penguin.

Fossil and present penguins

Emperor penguins can weigh 46 kilograms and reach lengths of 1.36 metres, 0.2 metres above their standing height. Another extinct penguin used to hold the height record, at around 1.5 metres tall.

P. klekowskii‘s tarsometatarsus “is the longest foot bone I’ve ever seen. This is definitely a big penguin,” says Dan Ksepka at the Bruce Museum in Greenwich, Connecticut. However, he cautions that the estimate of its length is uncertain because giant penguins had skeletons “very differently proportioned than living penguins”.

Larger penguins can dive deeper and stay underwater longer than smaller ones. A giant like P. klekowski could have stayed down for 40 minutes, giving it more time to hunt fish, says Acosta Hospitaleche.

Journal reference: Comptes Rendus Palevol, DOI: 10.1016/j.crpv.2014.03.008

Hedgehog fossil discovery in Canada


This video is called Tiny Hedgehog Fossil Could Answer Climate-Change Questions.

From Wildlife Extra:

Fossils of tiny, unknown, hedgehog found in Canada

Fossil remains of a tiny hedgehog, about two inches long, that lived 52 million years ago have been discovered in British Columbia by scientists from University of Colorado Boulder.

Named Silvacola acares, which means tiny forest dweller, it is perhaps the smallest hedgehog ever to have lived and is both a genus and species new to science.

“It is quite tiny and comparable in size to some of today’s shrews,” said lead author Jaelyn Eberle.

“We can’t say for sure it had prickly quills, but there are ancestral hedgehogs living in Europe about the same time that had bristly hair covering them, so it is plausible Silvacola did, too.”

The fossils were found in north-central British Columbia at a site known as Driftwood Canyon Provincial Park that was likely to have been a rainforest environment during the Early Eocene Epoch.

See also here. And here.

Egyptian fossil relatives of Madagascar bats discovered


This video from the USA says about itself:

26 Sep 2012

Dr. Nancy Simmons specializes in the morphology and evolutionary biology of bats (Chiroptera). Together with several collaborators, she is developing a data set of morphological characters scored in species representing all major clades of bats. These data include new information gained from high-resolution CT scans of rare bats and are being combined with DNA sequence data to develop a robust higher-level phylogeny for Chiroptera.

With collaborators, she is doing an in-depth study of the evolution of megabats — flying foxes and their relatives — using both molecular and morphological data. Dr. Simmons is also working with an expert on echolocation behavior to develop a method for coding features of echolocation calls for phylogenetic analysis.

From the American Museum of Natural History in the USA:

Sucker-Footed Bat Fossils Broaden the Bat Map

by AMNH on 02/04/2014 05:00 pm

Today, Madagascar sucker-footed bats are found only on their island home, but new research from the American Museum of Natural History and Duke University shows that wasn’t always the case. The discovery of two extinct relatives in northern Egypt suggests the unusual creatures, which evolved sticky footpads to roost on slick surfaces, are primitive members of a group of bats that evolved in Africa and ultimately went on to flourish in South America.

A team of researchers described the two bat species from several sets of fossilized jawbones and teeth unearthed in the Sahara. The findings, reported on February 4 in the journal PLOS ONE, represent the first formal description of the family in the fossil record and show the sucker-footed bat family to be at least 36 million years older than previously known.

“We’ve assumed for a long time that they were an ancient lineage based on DNA sequence studies that have placed them close to very old groups in the bat family tree,” said Nancy Simmons, co-author on the study and a curator in the Department of Mammalogy.

But until now, scientists lacked any fossil evidence to confirm it.

Today, the sucker-footed bats consist of two species, Myzopoda aurita (see images of these bats here) and M. schliemanni, endemic to Madagascar. In contrast to almost all other bats, they don’t cling upside-down to cave ceilings or branches. Sucker-footed bats roost head-up, often in the furled leaves of the traveler’s palm, a plant in the bird-of-paradise family. To stick to such a smooth surface, the bats evolved cup-like pads on their wrists and ankles. Scientists previously suspected the pads held the bats up by suction, but recent research has demonstrated the bats instead rely on wet adhesion, like a tree frog.

The two extinct species, Phasmatonycteris phiomensis and P. butleri, date to 30 and 37 million years ago, respectively, when the environment was drastically different. Northern Africa was more tropical, said Dr. Simmons, and home to a diverse range of mammals, including primates and early members of the elephant family.

“The habitat was probably fairly forested, and there was likely a proto-Nile River, a big river that led into the ancient Tethys Ocean,” said Gregg Gunnell, director of the Duke University Lemur Center‘s Division of Fossil Primates and a co-author on the paper.

The fossilized teeth imply that, like their living relatives, the ancient bats fed on insects. It’s impossible to know from the fossils if the extinct species had already evolved their characteristic sucker-feet, but the teeth shed light on another aspect of bat evolution. The presence of sucker-footed bats in Africa at least 37 million years ago supports the theory that this family is one of the most primitive members of a lineage that now dominates South America.

From vampires to fruit- and nectar-eaters to carnivores, the majority of South America’s bats belong to one large superfamily, known as Noctilionoidea.

“We think that the superfamily originated in Africa and moved eastward as Gondwana was coming apart,” Gunnell said. “These bats migrated to Australia, then actually went through Antarctica and up into South America using an ice-free corridor that connected the three continents until about 26 million years ago.”

According to this hypothesis, the sucker-footed bat fossils showed up right where scientists expected to find them: at the literal and figurative base of the Noctilionoidea family tree.

“Now, we can unambiguously link them through Africa,” Simmons said.

You can read the scientific paper here.

Like Darwin’s Finches, But Weirder, Bat Faces Showcase Amazing Adaptations: here.

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Tunisian fossil primate discovery


This video from the USA says about itself:

NOVA scienceNOW: 41 – First Primates.

From ScienceDaily:

Fossil Primate Shakes Up History of Tooth-Combed Primates

Dec. 11, 2013 — Fossils discovered in Tunisia challenge several hypotheses concerning the origin of tooth-combed primates (Malagasy lemurs, Afro-Asian lorises and African galagos). The fossils are of a small primate called Djebelemur, which lived around 50 million years ago. They were discovered by a French-Tunisian team from the Institut des Sciences de l’Evolution in Montpellier (CNRS/Université Montpellier 2/IRD) and the Office National des Mines (ONM) in Tunis.

According to the paleontologists, Djebelemur was probably a transitional form leading to the appearance of tooth-combed primates. However, according to genetic data, these primates appeared at least 15 million years earlier. Djebelemur therefore challenges the hypotheses put forward by molecular biology. The work, which has just been published in PLoS One, makes it possible to reconstruct a chapter in the evolutionary history of this lineage. In addition, it may help to refine genetic models.

Tooth-combed primates, also called strepsirrhines, comprise lemurs and lorisiforms (small primates which include lorises and galagos). In these primates, the anterior teeth of the lower jaw take the form of a comb. This is mainly used for grooming, but also, in some species, for procuring the natural gums that make up part of their diet.

A key question debated by primatologists concerns the time when strepsirrhine primates first appeared. Recent genetic data dates the origin of lemurs and lorises to the onset of the Tertiary period, just after the disappearance of the dinosaurs (approximately 65 million years ago). Some molecular biologists even believe that divergence of the two groups occurred 80 million years ago. However, paleontological data does not corroborate these hypotheses: the oldest known lorisiform fossil dates from a mere 37 million years ago. Could this simply be due to a gap in the fossil record? The fossils discovered by the Institut des Sciences de l’Evolution in Montpellier (CNRS/Université Montpellier 2/IRD) and the ONM in Tunis suggest otherwise: it is the genetic models that may need to be revised.

Discovered in the sediments of a former lake in Djebel Chambi National Park, Tunisia, the approximately 50 million-year-old fossils belong to a small primate called Djebelemur (lemur of the Djebel). This was a tiny animal weighing scarcely 70 g. It was most certainly nocturnal, a predator of insects and a tree-dweller. Some of its morphological characteristics suggest that it was a distant relative of lemurs, galagos and lorises. However, although it did not yet have such a specialized toothcomb, it exhibited a tooth structure that had already been transformed, an early stage of the anterior dentition of today’s strepsirrhines.

Djebelemur thus appears to be a transitional form, pre-dating the lorisiform-lemuriform divergence. Therefore, tooth-combed primates probably did not originate as early as molecular biologists have claimed. This is likely to have occurred less than 50 million years ago, the age of the Djebelemur fossil.

This is not the first time that genetic data disagrees with paleontological data. For many groups of mammals, geneticists tend to put forward earlier dates of origin than those provided by direct observation of the fossil record. Molecular biology increasingly seeks to refine its models by constraining them with fossil data. In the case of the origin of tooth-combed primates, Djebelemur could prove to be a significant milestone making it possible to reset the molecular clock and improve estimates of divergence dates derived from molecular phylogenies.