Wolf-sized otters roamed Earth over 6 million years ago

January 25, 2017

Washington, Jan 25: Prehistoric otters may have been of the size of a modern wolf, say scientists who have discovered 6.24 million-year-old fossils of one of the largest otter species known to science. Remains of the large extinct otter, which had large, powerful jaws and is estimated to have weighed about 50 kilogrammes, was found in the northeastern Yunnan Province in China.

Wolf

The species, named Siamogale melilutra, belongs to an ancient lineage of extinct otters that was previously known only from isolated teeth from a different, much older species that was recovered in Thailand. Researchers from Cleveland Museum of Natural History in the US recovered a complete cranium, mandible, dentition and various skeletal elements - offering a wealth of insight into the taxonomy, evolutionary history and functional morphology of this new species.

"While the cranium is incredibly complete, it was flattened during the fossilisation process," said Denise Su, from the Cleveland Museum of Natural History. "The bones were so delicate that we could not physically restore the cranium. Instead, we CT-scanned the specimen and virtually reconstructed it in a computer," said Su.

The CT restoration showed a combination of otter-like and badger-like features, giving way to the species name "melilutra," which combines the Latin names for badger (meles) and otter (lutra). Siamogale melilutra had a large, powerful jaw with the enlarged, bunodont (rounded-cusped) teeth typical of many otter lineages.

This raises the question of whether these bunodont teeth were inherited by all otters from a common ancestor or evolved independently in different otter lineages over time because of the evolution of similar adaptations to thrive in similar environments - a phenomenon called "convergent evolution."

Through their analysis, researchers found that bunodont teeth independently appeared at least three times over the evolutionary history of otters, suggesting convergent evolution to be the cause. The completeness of the specimens from Shuitangba allows the scientists to better understand the evolutionary history of otters and specifically this enigmatic genus from the Miocene, of which there had been little information.

The findings show that Siamogale belongs to one of the oldest and most primitive lineages of the otter family, which goes back at least 18 million years in the form of Paralutra from Europe. The scientists are working to understand other aspects of the life of Siamogale melilutra.

"The discovery of the otter helps solve some questions about otter relationships, but has opened the door to new questions," said Xiaoming Wang from the Natural History Museum of Los Angeles County in the US. The study was published in The Journal of Systematic Paleontology.

Comments

Add new comment

  • Coastaldigest.com reserves the right to delete or block any comments.
  • Coastaldigset.com is not responsible for its readers’ comments.
  • Comments that are abusive, incendiary or irrelevant are strictly prohibited.
  • Please use a genuine email ID and provide your name to avoid reject.
News Network
April 28,2020

Los Angeles, Apr 28: People who experience loss of smell as one of the COVID-19 symptoms are likely to have a mild to moderate clinical course of the disease, according to a study which may help health care providers determine which patients require hospitalisation.

The findings, published in the journal International Forum of Allergy & Rhinology, follows an earlier study that validated the loss of smell and taste as indicators of infection with the novel coronavirus, SARS-CoV-2.

According to the scientists from the University of California (UC) San Diego Health in the US, patients who reported loss of smell were 10 times less likely to be hospitalised for COVID-19 compared to those without the symptom.

"One of the immediate challenges for health care providers is to determine how to best treat persons infected by the novel coronavirus," said Carol Yan, first author of the current study and rhinologist from the UC San Diego Health.

"If they display no or mild symptoms, can they return home to self-quarantine or will they likely require hospitalisation? These are crucial questions for hospitals trying to efficiently and effectively allocate finite medical resources," Yan said.

The findings, according to the researchers, suggest that loss of smell may be predictive of a milder clinical course of COVID-19.

"What's notable in the new findings is that it appears that loss of smell may be a predictor that a SARS-CoV-2 infection will not be as severe, and less likely to require hospitalisation," Yan said.

"If an infected person loses that sense, it seems more likely they will experience milder symptoms, barring other underlying risk factors," she added.

Risk factors for COVID-19 previously reported by other studies include age, and underlying medical conditions, such as chronic lung disease, serious heart conditions, diabetes, and obesity.

In the current study, the scientists made a retrospective analysis between March 3 and April 8 including 169 patients who tested positive for COVID-19 at UC San Diego Health.

They assessed olfactory and gustatory data for 128 of the 169 patients, 26 of whom required hospitalisation.

According to the researchers, patients who were hospitalised for COVID-19 treatment were significantly less likely to report anosmia or loss of smell -- 26.9 per cent compared to 66.7 per cent for COVID-19-infected persons treated as outpatients.

Similar percentages were found for loss of taste, known as dysgeusia, they said.

"Patients who reported loss of smell were 10 times less likely to be admitted for COVID-19 compared to those without loss of smell," said study co-author Adam S. DeConde.

"Moreover, anosmia was not associated with any other measures typically related to the decision to admit, suggesting that it's truly an independent factor and may serve as a marker for milder manifestations of Covid-19," DeConde said.

The researchers suspect that the findings hint at some of the physiological characteristics of the infection.

"The site and dosage of the initial viral burden, along with the effectiveness of the host immune response, are all potentially important variables in determining the spread of the virus within a person and, ultimately, the clinical course of the infection," DeConde said.

If the SARS-CoV-2 virus initially concentrates in the nose and upper airway, where it impacts olfactory function, that may result in an infection that is less severe and sudden in onset, decreasing the risk of overwhelming the host immune response, respiratory failure, and hospitalisation, the scientists added.

"This is a hypothesis, but it's also similar to the concept underlying live vaccinations," DeConde explained.

"At low dosage and at a distant site of inoculation, the host can generate an immune response without severe infection," he added.

Loss of smell, according to the study, might also indicate a robust immune response which has been localised to the nasal passages, limiting effects elsewhere in the body.

Citing the limitations of the study, the scientists said they relied upon self-reporting of anosmia from participants, which posed a greater chance of recall bias among patients once they had been diagnosed with COVID-19.

They added that patients with more severe respiratory disease requiring hospitalisation may not be as likely to recognise or recall the loss of smell.

So the researchers said more expansive studies are needed for validating the results.

Comments

Add new comment

  • Coastaldigest.com reserves the right to delete or block any comments.
  • Coastaldigset.com is not responsible for its readers’ comments.
  • Comments that are abusive, incendiary or irrelevant are strictly prohibited.
  • Please use a genuine email ID and provide your name to avoid reject.
Agencies
January 26,2020

New Delhi, Jan 26: Google on Sunday marked India's 71st Republic Day by dedicating a doodle illustrating the country's rich cultural heritage that permeates and unites the diverse nation.

From its world-famous landmarks like the Taj Mahal and India Gate, to the wide array of fauna such as its national bird (the Indian peafowl), to classical arts, textiles, and dances, the doodle, designed by Singapore-based artist Meroo Seth, brings together the rich cultural heritage of the country.

Republic Day marks the completion of India's transition towards becoming an independent republic after its constitution came into effect. The governing document had taken nearly three years of careful deliberation to finalise, and its eventual enactment was joyfully celebrated across the country.

While the Constitution was adopted by the Indian Constituent Assembly on 26 November 1949, it came into effect on January 26 -- a day when Declaration of Indian Independence (Purna Swaraj) was proclaimed by the Indian National Congress back in 1929, as opposed to the Dominion status offered by the British Regime.

Festivities embody the essence of diversity found in one of the world's most populous nations, celebrated over a three-day period with cultural events displaying national pride.

Last year's doodle on Republic Day, designed by artist Reshidev RK, had featured Rashtrapati Bhavan in the background along with a display of the country's iconic monuments and heritage.

Comments

Add new comment

  • Coastaldigest.com reserves the right to delete or block any comments.
  • Coastaldigset.com is not responsible for its readers’ comments.
  • Comments that are abusive, incendiary or irrelevant are strictly prohibited.
  • Please use a genuine email ID and provide your name to avoid reject.
News Network
May 6,2020

Hyderabad, May 6: Away from city lights, two hours before Sunrise, people in India and across the world can witness Annual Meteor Shower called Eta Aquarids till May 28.

Observed since time immemorial, Meteor shower are commonly known as shooting stars which are nothing but dust flakes of comet/asteroid entering earth atmosphere.

This Annual Eta Aquarids Meteor Shower peaked on Wednesday at 02.30 am on Wednesday whereas presence of Full Moon was an obstacle outshining bright streaks of lights of this meteor shower zipping across the South Eastern sky.

As this meteor shower is active till May 28, people can still watch this celestial spectacle in early morning every day, Planetary Society of India (PSI) Director N Sri Raghunandan Kumar interacting with UNI said.

As per International Meteor Organization (IMO), 50 meteors per hour are expected to be seen on day of peak today. And this number would vary as days pass on till May 28 while earth passes through dust cloud of comet debris in its orbit.

Comments

Add new comment

  • Coastaldigest.com reserves the right to delete or block any comments.
  • Coastaldigset.com is not responsible for its readers’ comments.
  • Comments that are abusive, incendiary or irrelevant are strictly prohibited.
  • Please use a genuine email ID and provide your name to avoid reject.