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Drew J, Philipp C, Westneat MW (2013)

How Ancient Shark-Tooth Swords Uncovered Two Long-Lost Species

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Drew J, Philipp C, Westneat MW (2013)

By Chris Gayomali

Biologist Joshua Drew's surprise discovery began as many do: "I just wanted to... look at really cool stuff," he tells The Los Angeles Times. Drew, now a postdoctoral researcher at Columbia University, was with a few colleagues at the Field Museum of Natural History in Chicago scoping out a new exhibit — a collection of "badass" swords, knives, and lances once used by the inhabitants of the Central Pacific's Gilbert Islands 130 years ago to rip their enemies to shreds.

This particular arsenal wasn't pounded out of iron or steel, though. The 124 flesh-tearing weapons on display had a more biological origin, and were carved out of wood, with each blade edge carefully outfitted with rows of dagger-like shark teeth. 

Drew was admiring the pieces when he noticed something strange: A few of the teeth appeared to belong to dusky and spottail sharks, which, oddly, aren't typically found near the Gilbert Isles. How could he tell, you might ask? Well, he was in a natural history museum, and could easily look up fossil records to confirm his suspicions.

"Shape, serration patterns, and other features of shark teeth were enough for researchers to identify the species," says LiveScience.

Using field guides and the museum's collections of shark jaws, the researchers identified teeth from eight species of shark on 122 weapons and teeth collections from the Gilbert Islands. The most common of those species was the silvertip shark (C. albimarginatus), whose teeth graced 34 weapons. Gilbert Islands weapon-makers also used teeth from silky sharks, oceanic whitetip sharks, tiger sharks, blue sharks, and hammerheads. [Live Science]

Yet, a deep-dive through history revealed no evidence that the dusky and spottail sharks had ever lived in Gilbert Island's reefs. While trading with other far-away cultures could explain how the teeth got there, the likelier answer is one we've already heard before:

"Probably, they were fished out," says Drew. Although it's not clear why the sharks disappeared,says Ed Yong at National Geographic — "people were hacking off shark fins in the Gilbert Islands as far back as 1910 and by the 1950s, around 3,000 kilograms of fins were being shipped from the islands every year." It's become so bad that some conservationists estimate that 100 million sharks are killed worldwide every year

After publishing their findings this month in the journal PLoS One, Drew and his team hope that the discovery of a "shadow biodiversity" along the Gilbert Islands' waters will aid conservation efforts for marine animals that have been over-fished for decades:

Given the importance of these species to the ecology of the Gilbert Island reefs and to the culture of the Gilbertese people, documenting these shifts in baseline fauna represents an important step toward restoring the vivid splendor of both ecological and cultural diversity. [PLoS One]

That's something worth sinking your teeth into.

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Sylke Rohrlach, Wikimedia Commons // CC BY-SA 4.0
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Animals
Scientists Discover 'Octlantis,' a Bustling Octopus City
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Sylke Rohrlach, Wikimedia Commons // CC BY-SA 4.0

Octopuses are insanely talented: They’ve been observed building forts, playing games, and even walking on dry land. But one area where the cephalopods come up short is in the social department. At least that’s what marine biologists used to believe. Now a newly discovered underwater community, dubbed Octlantis, is prompting scientists to call their characterization of octopuses as loners into question.

As Quartz reports, the so-called octopus city is located in Jervis Bay off Australia’s east coast. The patch of seafloor is populated by as many as 15 gloomy octopuses, a.k.a. common Sydney octopuses (octopus tetricus). Previous observations of the creatures led scientists to think they were strictly solitary, not counting their yearly mating rituals. But in Octlantis, octopuses communicate by changing colors, evict each other from dens, and live side by side. In addition to interacting with their neighbors, the gloomy octopuses have helped build the infrastructure of the city itself. On top of the rock formation they call home, they’ve stored mounds of clam and scallop shells and shaped them into shelters.

There is one other known gloomy octopus community similar to this one, and it may help scientists understand how and why they form. The original site, called Octopolis, was discovered in the same bay in 2009. Unlike Octlantis, Octopolis was centered around a manmade object that had sunk to the seabed and provided dens for up to 16 octopuses at a time. The researchers studying it had assumed it was a freak occurrence. But this new city, built around a natural habitat, shows that gloomy octopuses in the area may be evolving to be more social.

If that's the case, it's unclear why such octo-cities are so uncommon. "Relative to the more typical solitary life, the costs and benefits of living in aggregations and investing in interactions remain to be documented," the researchers who discovered the group wrote in a paper published in Marine and Freshwater Behavior and Physiology [PDF].

It’s also possible that for the first time in history humans have the resources to see octopus villages that perhaps have always been bustling beneath the sea surface.

[h/t Quartz]

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Criminal Gangs Are Smuggling Illegal Rhino Horns as Jewelry
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iStock

Valuable jewelry isn't always made from precious metals or gems. Wildlife smugglers in Africa are increasingly evading the law by disguising illegally harvested rhinoceros horns as wearable baubles and trinkets, according to a new study conducted by wildlife trade monitoring network TRAFFIC.

As BBC News reports, TRAFFIC analyzed 456 wildlife seizure records—recorded between 2010 and June 2017—to trace illegal rhino horn trade routes and identify smuggling methods. In a report, the organization noted that criminals have disguised rhino horns in the past using all kinds of creative methods, including covering the parts with aluminum foil, coating them in wax, or smearing them with toothpaste or shampoo to mask the scent of decay. But as recent seizures in South Africa suggest, Chinese trafficking networks within the nation are now concealing the coveted product by shaping horns into beads, disks, bangles, necklaces, and other objects, like bowls and cups. The protrusions are also ground into powder and stored in bags along with horn bits and shavings.

"It's very worrying," Julian Rademeyer, a project leader with TRAFFIC, told BBC News. "Because if someone's walking through the airport wearing a necklace made of rhino horn, who is going to stop them? Police are looking for a piece of horn and whole horns."

Rhino horn is a hot commodity in Asia. The keratin parts have traditionally been ground up and used to make medicines for illnesses like rheumatism or cancer, although there's no scientific evidence that these treatments work. And in recent years, horn objects have become status symbols among wealthy men in countries like Vietnam.

"A large number of people prefer the powder, but there are those who use it for lucky charms,” Melville Saayman, a professor at South Africa's North-West University who studies the rhino horn trade, told ABC News. “So they would like a piece of the horn."

According to TRAFFIC, at least 1249 rhino horns—together weighing more than five tons—were seized globally between 2010 and June 2017. The majority of these rhino horn shipments originated in southern Africa, with the greatest demand coming from Vietnam and China. The product is mostly smuggled by air, but routes change and shift depending on border controls and law enforcement resources.

Conservationists warn that this booming illegal trade has led to a precipitous decline in Africa's rhinoceros population: At least 7100 of the nation's rhinos have been killed over the past decade, according to one estimate, and only around 25,000 remain today. Meanwhile, Save the Rhino International, a UK-based conservation charity, told BBC News that if current poaching trends continue, rhinos could go extinct in the wild within the next 10 years.

[h/t BBC News]

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