BATS!

What Color Were Those Eocene Bats in the Fossils?

What colour were the animals that roamed the Earth 50 million years ago? For the first time, the original colour of a fossil mammal has been described by scientists from the University of Bristol, UK and Virginia Polytechnic Institute and State University, US.

The researchers combined morphological, experimental and chemical techniques to determine the colour of two species of bat, which lived in the Eocene Epoch, 56-33.9 million years ago.

By studying microscopic spherical and oblong-shaped structures in the fossils, they found that the bats were reddish-brown in colour. For years, scientists have been divided on whether these structures are melanosomes -organelles (subunits within in cell) that contain melanin and have distinct shapes in modern animals, which can be used to infer colour - or fossilised bacteria, which had eaten away at an animal before it was buried.

In this new study, Bristol-based Dr Jakob Vinther and Masters student Caitlin Colleary, now a PhD student at Virginia Tech, along with researchers from UT Austin and a number of other universities, show that the organic microbodies in the skin, hair, feathers and eyes of exceptionally preserved fossils (ranging in age from the Carboniferous to the Miocene, 300-20 million years ago) contain the remnants of melanin.

In order to identify the origin of these curious structures, the researchers replicated the conditions under which the fossils formed using high pressure, high temperature autoclave experiments. They showed that the fossils contain fossilised melanin by using Time-of-flight secondary ion mass spectroscopy (TOF-SIMS), which had changed in chemical composition over time.

Dr Vinther, who first described fossil melanosomes and reconstructed the colours of a feathered dinosaur, said: "This is a great leap forward in our understanding of how fossils are preserved. We now know how melanin is preserved and we have the methods to confidently detect it."

Melanin comes in two distinct colours: reddish brown phaeomelanin and black eumelanin.

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Humans Drove Caribbean Island Bats to Extinction

Sharing caves with millions of bats, the Caribbean's first humans may have driven some species of the winged mammals to extinction.

The new study appearing online today in Scientific Reports rejects previous research that directly connected climate change and the loss of land with the disappearance of bat populations.

Knowing when and how Caribbean bats went extinct could contribute to better understanding biodiversity and how to save modern-day wildlife from meeting the same fate, said co-author David Steadman, a University of Florida ornithologist.

"Ours are the first radiocarbon dates for bat fossils in the whole West Indies," said Steadman, curator of ornithology at the Florida Museum of Natural History on the UF campus. "The new dates prove that certain bat populations were still in existence much later than previously thought—around the same time humans arrived."

The new dates demonstrate that at least five species of bats withstood this climate change and reduced land area, only to be wiped out at a time when climate conditions were largely similar to those of today, said lead author J. Angel Soto-Centeno, a post-doctoral researcher at the American Museum of Natural History who began the research as a doctoral student studying mammalogy at the Florida Museum.

"Prehistoric and modern humans have had considerable impacts on island species and ecosystems, including the early Amerindians who settled in the Bahamas and altered the natural fire regimes on a large scale," Soto-Centeno said. "We found that the demise of bat populations in the Bahamas coincides with similar land mammal, reptile and bird losses on other Caribbean islands."

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Bats Act as a Reservoir for MERS?

A 100% genetic match for Middle East Respiratory Syndrome (MERS) has been discovered in an insect-eating bat in close proximity to the first known case of the disease in Saudi Arabia. The discovery points to the likely animal origin for the disease, although researchers say that an intermediary animal is likely also involved.

Led by team of investigators from the Center for Infection and Immunity (CII) at Columbia University's Mailman School of Public Health, EcoHealth Alliance, and the Ministry of Health of the Kingdom of Saudi Arabia, the study is the first to search for an animal reservoir for MERS in Saudi Arabia, and the first to identify such a reservoir by finding a genetic match in an animal. Results appear online in Emerging Infectious Diseases, a journal of the U.S. Centers for Disease Control and Prevention.

"There have been several reports of finding MERS-like viruses in animals. None were a genetic match. In this case we have a virus in an animal that is identical in sequence to the virus found in the first human case. Importantly, it's coming from the vicinity of that first case," says W. Ian Lipkin, MD, director of the Center for Infection and Immunity and a co-author of the study.

MERS was first described in September 2012 and continues to spread. Close to 100 cases have been reported worldwide, 70 of them from Saudi Arabia. The causative agent, a new type of coronavirus, has been determined; however, the origin of the virus has been unknown until now.

Over a six-week period during field expeditions in October 2012 and April 2013, the researchers collected more than 1,000 samples from seven bat species in regions where cases of MERS were identified in Bisha, Unaizah, and Riyadh. Extensive analysis was performed using polymerase chain reaction and DNA sequencing revealed the presence of a wide range of alpha and beta coronaviruses in up to a third of bat samples. One fecal sample from an Egyptian Tomb Bat (Taphozous perforatus) collected within a few kilometers of the first known MERS victim's home contained sequences of a virus identical to those recovered from the victim.

Bats are the reservoirs of viruses that can cause human disease including rabies, Hendra, Nipah, Marburg, and SARS. In some instances the infection may spread directly from bats to humans through inadvertent inhalation of infected aerosols, ingestion of contaminated food, or, less commonly, a bite wound. In other instances bats can first infect intermediate hosts. The researchers suggest that the indirect method for transmission is more likely in MERS.

"There is no evidence of direct exposure to bats in the majority of human cases of MERS," says Ziad Memish, MD, Deputy Minister of Health, Kingdom of Saudi Arabia, and lead author of the study. "Given that human-to-human transmission is inefficient, we speculate that an as-yet-to-be determined intermediate host plays a critical role in human disease."

"We are continuing to look for evidence of the virus in wildlife and domestic animals, and investigating the mechanisms by which the virus causes human disease," adds Dr. Lipkin. "This is but the first chapter in a powerful collaboration amongst partners committed to global public health."

Bat Evolution, a lecture