For Chesapeake oysters, the way forward leads back—through the fossil record

NOVEMBER 21, 2019 

by Joseph McClain, The College of William & Mary

Big oyster/old oyster: Rowan Lockwood displays one of the 900 oyster fossils studied in a palaeobiological analysis of the oysters of the Chesapeake Bay. She and co-author Roger Mann believe fossil beds paint a picture of the oyster population of a healthy Chesapeake ecosystem. Credit: Stephen Salpukas 

Oysters once dominated the ecosystem of the Chesapeake Bay, and it would be difficult, if not impossible, for the Bay to return to full ecological health without restoring Crassostrea virginica to its glory days of the Chesapeake's apex filterer. 

Rowan Lockwood and Roger Mann believe that you have to go back to the fossil record to get your head around the idea of a fully oystered Chesapeake. Their paper, "A conservation paleobiological perspective on Chesapeake Bay oysters," appears in a special issue of Philosophical Transactions B, titled ""The past is a foreign country: how much can the fossil record actually inform conservation?". 

Lockwood is a professor in William & Mary's Department of Geology, which she chairs. Mann is a professor in the Department of Fisheries Science at the university's Virginia Institute of Marine Science. Their collaboration melds Lockwood's examination of long-dead oysters in the Chesapeake with Mann's expertise in the state of oysters today. 

Their paper looks at 900 fossil oysters from three Pleistocene reefs and compares them to oysters today. Lockwood and Mann employ conservation paleontology methods to create a model of how the Chesapeake Bay looked and functioned long before humans. 

Basically, the prehistoric oysters were bigger and more numerous—and therefore filtered more water. 

"This is clearly a case of bigger is better," Lockwood said. "Larger oysters filter significantly more water, remove more algae, produce more offspring, buffer more acidic bay water, recycle more nitrogen and possibly even bury more carbon than smaller ones." 

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Climate change created today's large crocodiles

SEPTEMBER 23, 2019

by Pedro L. Godoy, The Conversation

What does the term crocodylian bring to mind? A big reptile with a chomping jaw?

Crocodylians are the 27 species of crocodiles, alligators, caimans and gharials that live all over Earth today, except for in Europe and Antarctica. There are some smaller species, but these top predators are usually big, at least 2 meters long. They also share a general shape and look—for instance, how easily can you tell an alligator and a crocodile apart?

The fossil record of crocodylians is much richer, though, with many different forms and body sizes and extraordinary ecological diversity.

Over their long evolutionary history of more than 200 million years, crocs experimented with different lifestyles, as well as various body lengths. But exactly which environmental factors might have influenced the body sizes of crocs throughout their evolution? And does the body size of crocs suggest something about past species' extinction?

To investigate, my colleagues and I created a complete map of body sizes of crocs through time. Body size can reveal a lot about the biology of extinct animals. Our study was the first to apply some modern computational methods to understand body size evolution in crocs.

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Timetree dating in the absence of a fossil record in Asian Horned Frogs

Date: February 23, 2017

Source: Molecular Biology and Evolution (Oxford University Press)

Asian Horned frogs account for approximately half of the ancient family of frogs called Megophryidae. This group was previously estimated to have originated 100-126 million years ago (mya). Frogs of this family hopped alongside the famed Velociraptors and other dinosaurs during the Cretaceous period (145-66 mya). Despite the fact that these animals have been around for a long time, little is known about their evolutionary history. Furthermore, unlike their dinosaur contemporaries, these frogs did not leave behind any known fossils. Methods using information from DNA sequences exist for estimating the age of origin for such groups of animals but these methods rely heavily on fossils of related animal groups, which could prove unreliable for these species.

New research recently published in the scientific journal, Molecular Biology and Evolution, by a team of scientists from Ireland and India resolved a 195-year old confusion regarding relationships between the species of Asian Horned Frogs, an enigmatic group of frogs often with horn-like projections over their eyes. Using DNA sequences, they discovered many potentially new species in this group previously unknown to science. They also estimated the ages of species and groups of species using a method that had previously not been tried on amphibians and inadvertently discovered that until now scientists may have been overestimating the age of many frog families. Their discovery may open a new chapter on how scientists interpret the evolutionary history of many animals that currently have no known fossil record.

"While this research particularly focused on frogs, many other animal groups also lack a fossil record, and so its very difficult to decipher their evolutionary histories. Our hope is that methods used here will prove beneficial for understanding how the distant ancestors of living animals may have coexisted in prehistoric times," explains lead author Dr. Stephen Mahony.

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How the Rockies prepared mammals for the cold

June 4, 2015

Chuck Bednar for redOrbit.com – @BednarChuck

Nearly 34 million years ago, European mammals were wiped out en masse due to plummeting temperatures during an event known as the Grande Coupure, yet at this same time, their North American counterparts were largely unfazed. Why?

A team of researchers from the Senckenberg Research Institutes in Germany, the University of Helsinki in Finland and Brown University in Rhode Island found the reason for this phenomenon – the rise of the Rocky Mountains across western North America during this transitional period that took place between the Eocene and Oligocene periods.

As they reported in a study published Wednesday in the Proceedings of the Royal Society B, the authors analyzed the fossil record of both continents, as well as previous oxygen isotope data that had revealed precipitation patterns and tectonic models of the Rockies’ growth. They discovered that North American mammals survived due to adaptive change, driven by the mountains.

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Tropical marine ecosystems most at threat from human impact

Date:April 30, 2015

Source:ARC Centre of Excellence in Coral Reef Studies

Summary:An international team of scientists has used the fossil record during the past 23 million years to predict which marine animals and ecosystems are at greatest risk of extinction from human impact. The researchers found those animals and ecosystems most threatened are predominantly in the tropics.

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The invisible extinction

A palaeontologist wonders whether the future fossil record will preserve evidence of animals that vanish today.

Alexandra Witze

21 October 2014

Of the 82 species of bats that are endangered or vulnerable, only three are preserved in the fossil record.

When Roy Plotnick thinks about species going extinct, he tries to envision how that might look to a scientist millions of years from now. Plotnick, a palaeontologist at the University of Illinois at Chicago, has launched an unusual thought experiment to consider whether animals that vanish today might never be represented in the future fossil record. He calls it the 'invisible extinction'.

Plotnick sat down with Nature this week at a Geological Society of America meeting in Vancouver, Canada, where he put these ideas forward.

What is the invisible extinction?

We’re in the middle of what is called the sixth extinction now. If we were to be looking back from a million years in the future, what would it look like? Would we know if species going extinct now had ever existed, if all we had to go on was fossil remains?

How do you study something like that?

We started with the International Union for the Conservation of Nature (IUCN) Red List, with the various categories of threatened species, and decided to go with mammals. There are 715 mammal species on the list. We matched the Red List to various data sets that describe modern mammals, to see which species in the list are found in the fossil record.

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New evidence of ancient multicellular life sets evolutionary timeline back 60 million years

(Phys.org) —A Virginia Tech geobiologist with collaborators from the Chinese Academy of Sciences have found evidence in the fossil record that complex multicellularity appeared in living things about 600 million years ago – nearly 60 million years before skeletal animals appeared during a huge growth spurt of new life on Earth known as the Cambrian Explosion.

The discovery published online Wednesday in the journal Nature contradicts several longstanding interpretations of multicellular fossils from at least 600 million years ago.

"This opens up a new door for us to shine some light on the timing and evolutionary steps that were taken by multicellular organisms that would eventually go on to dominate the Earth in a very visible way," said Shuhai Xiao, a professor of geobiology in the Virginia Tech College of Science. "Fossils similar to these have been interpreted as bacteria, single-cell eukaryotes, algae, and transitional forms related to modern animals such as sponges, sea anemones, or bilaterally symmetrical animals. This paper lets us put aside some of those interpretations."

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Darwin's Dilemma Resolved: Evolution's 'Big Bang' Explained by Five Times Faster Rates of Evolution

Sep. 12, 2013 — A new study led by Adelaide researchers has estimated, for the first time, the rates of evolution during the "Cambrian explosion" when most modern animal groups appeared between 540 and 520 million years ago.

The findings, published online today in the journal Current Biology, resolve "Darwin's dilemma": the sudden appearance of a plethora of modern animal groups in the fossil record during the early Cambrian period.

"The abrupt appearance of dozens of animal groups during this time is arguably the most important evolutionary event after the origin of life," says lead author Associate Professor Michael Lee of the University of Adelaide's School of Earth and Environmental Sciences and the South Australian Museum.

"These seemingly impossibly fast rates of evolution implied by this Cambrian explosion have long been exploited by opponents of evolution. Darwin himself famously considered that this was at odds with the normal evolutionary processes.

"However, because of the notorious imperfection of the ancient fossil record, no-one has been able to accurately measure rates of evolution during this critical interval, often called evolution's Big Bang.

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New contender for oldest dinosaur

Palaeontologists have found what is likely to be the oldest known dinosaur, filling in a yawning evolutionary gap.

A study in Biology Letters describes Nyasasaurus parringtoni, a new species from 10-15 million years before the previous earliest dinosaur specimens.

It walked on two legs, measured 2-3m in length with a large tail and weighed between 20 and 60kg.

The find suggests that many millions of years passed between dinosaurs' first members and their dominance on land.

"It fills a gap between what we previously knew to be the oldest dinosaurs and their other closest relatives," report co-author Paul Barrett, of the Natural History Museum in London, told BBC News.

The find shores up the idea that dinosaurs evolved on the southern parts of the supercontinent Pangaea

"There was this big gap in the fossil record where dinosaurs should've been present and this fossil neatly fills that gap."

However, the team behind the work has stopped short of definitively calling N parringtoni the earliest dinosaur, because the fossil skeletons used to define it were incomplete: one upper arm bone and six vertebrae.

Continued:  http://www.bbc.co.uk/news/science-environment-20594147

Book Worms? Medieval Tomes Hold Surprising Fossil Record

A smattering of white spots found among the ink in medieval books aren't just printing errors — they're actually an amazingly detailed "fossil" record of European beetles, new research finds.

The dots represent spots, or wormholes, where hatching beetles chewed their way out of the woodblocks used to print art and illustrations between the 1400s and 1800s.

This literary record reveals that two species that now overlap in Western Europe once kept their distance from each other along the entire continent. Without evidence of the wormholes, this history would have been impossible to discern, said study researcher Blair Hedges, a biologist at Pennsylvania State University.

Read on:  http://www.livescience.com/24937-medieval-books-worm-hole-history.html

Feathered Dinosaurs Drive Creationists Crazy

The dinosaurs of our childhood aren’t around anymore. The sluggish, swamp-bound pea-brains that haunted museum halls and trundled through picture books have been eviscerated by agile, hot-blooded, and, often, feathery dinosaurs that more accurately reflect what Tyrannosaurus rex and kin were actually like. What’s more, thanks to a heap of lovely fossils, we now know that even the most fearsome of the tyrant dinosaurs were closely related to the avian dinosaurs—the birds—that flit around our backyards today.

Not everyone is pleased with the dramatic dinosaur makeover. In “How Science Ruined Everything,” io9’s Esther Inglis-Arkell said, “Dinosaurs used to be cool, feathers came in, and now it’s like, they’re going to ruffle their plumage when they come after me, and that is not scary.” It’s not surprising that the new imagery of enfluffed dinosaurs makesVelociraptor and company seem more like chickenosaurs than the monsters we grew up with. I used to hate fluffy dinosaurs, too. When feathery dinosaurs started to appear in museum shops and poorly-rendered fuzzballs strutted through basic-cable documentaries, I mourned the loss of the reptilian monsters I once knew. But when I dug into why dinosaur depictions have changed so radically, I came away with a new appreciation of dinosaur feathers.

Paleontologists have uncovered scores of fluffy, fuzzy, bristly, and otherwise spectacularly-adorned dinosaur species throughout the group’s family tree. Feathers weren’t meant for flight from the start; at first they were adaptations for insulation and display—for showing off. By comparing the microscopic features of dinosaur feathers with those of modern birds, paleontologists are answering one of the most perplexing dinosaur mysteries: What color were they? (Some were iridescent blue; some were black and white like a magpie; and some had rust-colored stripes along their tails.) We can finally start to explore the beauty of the dinosaur palette, something I was told as child would be totally impossible. I’ll trade evolutionary secrets for slightly silly dinosaurs any day.

Continued:  http://www.slate.com/articles/health_and_science/science/2012/09/creationists_and_dinosaurs_answers_in_genesis_teams_with_dissident_scientists_to_deny_feathered_dino_fossil_record.single.html