For Y'all Data - How Ancient Mayan Rhythm Decor Led To A Novel Expect At Freshwater Mussels Due South Of The Border

The ancient Maya are non especially known for their dear of freshwater mussels. Mathematics, maize, pyramids in addition to human sacrifice, yes. But bivalves? Not therefore much.

The Maya cutting freshwater mussels into minor rings that showed off their iridescent mother-of-pearl interiors
and sewed these sequin-like "sparklers" into vesture [Credit: Florida Museum/Kristen Grace]

Yet Florida Museum of Natural History archaeologists Ashley Sharpe in addition to Kitty Emery could non sift through a unmarried handbag of stuff from their dig sites close the Mexican-Guatemalan edge without turning upwards mussels: discarded shells from meals, shells used every bit pigment pots, crunch pendants, crunch discs sewn into vesture similar iridescent sequins in addition to soil crunch pulverisation that may pick out been an early on shape of glitter. They fifty-fifty establish corpses carefully buried with bivalves clasped inwards their hands.

But when Sharpe in addition to Emery documented their findings, they ran into a work - matching the right bring upwards to the right mussel species.

"Either no 1 had given names to them or nosotros had the work where naturalists had given 50 dissimilar names to 1 thing," said Sharpe, a University of Florida doctoral graduate in addition to at in 1 lawsuit a inquiry archeologist at the Smithsonian Tropical Research Institute. "We could say the Maya were identifying dissimilar types of mussels in addition to using them inwards dissimilar ways, but I would cease upwards simply referring to them every bit 'mussel a' in addition to 'mussel b.'"

Enter John Pfeiffer, a Florida Museum doctoral educatee researching freshwater mussel classification in addition to evolution. After listening to a inquiry presentation past times Pfeiffer, Sharpe in addition to Emery, curator of environmental zooarchaeology, struck a bargain with him - they would pick out fresh specimens from the plain if he would consummate the deoxyribonucleic acid analysis to position them.

Archaeologist Kitty Emery said Mayan artwork depicts people wearing carved bits of mussels
as jewelry or woven into vesture [Credit: Florida Museum/Kristen Grace]

Their collaboration produced the starting fourth dimension molecular written report of freshwater mussels native to United Mexican States in addition to Central America, adding what Pfeiffer described every bit a crucial in addition to long-missing slice to our agreement of North American freshwater mussels.

"This is the most geographically inclusive interpretation of North American freshwater mussel evolution," said Pfeiffer, the study's atomic number 82 author. "You actually can't utter comprehensively virtually North American freshwater mussels unless y'all consider these groups inwards United Mexican States in addition to Central America, but if they existed due south of Texas, they pretty much got ignored."

North America is the epicenter of freshwater mussel variety in addition to abode to the most species-rich mussel subfamily, Ambleminae, whose classification got a shake-up every bit a effect of the team's study. Amblemines pick out garnered the mass of North American mussel research, partly because of the striking agency they disperse their young.

Several amblemine groups attract host fish past times using convincing "lures" that resemble slow meals such every bit minor fish, insects in addition to crayfish. When a fish nibbles the lure, the woman someone squirts out tiny parasitic larvae, which clamp downwards on the fish's gills or fins where they volition rest until they are large plenty to drib off in addition to bury inwards the riverbed. Without this strategy, the mussel's offspring would live flushed helplessly downstream.

This mussel pendant, virtually the width of a baseball, was establish at a Mayan burial site inwards Republic of Guatemala
[Credit: Florida Museum/Kristen Grace]

Pfeiffer got hooked past times these lures every bit well.

"I was amazed that animals that expect similar rocks total of snot pick out these remarkable traits in addition to behaviors that tin fool actually visually oriented predators," he said. "How they evolved such accurate replicas of their hosts' prey made me desire to written report natural pick in addition to evolution."

Mussels play a telephone commutation role inwards the wellness of freshwater systems, acting every bit the livers of rivers in addition to streams past times filtering in addition to cleaning their waters. But mussel numbers are plummeting globally. Damming, H2O pollution, invasive species, the loss of their host fish in addition to habitat degradation pick out pose freshwater mussels alongside North America's most endangered animals, Pfeiffer said.

"Over 2 dozen species pick out gone extinct inwards the final 200 years," he said.

Making audio conservation decisions hinges on a detailed noesis of which species alive where, but the lack of molecular information on United Mexican States in addition to Central America's mussel species left what Pfeiffer called a "black hole" inwards our comprehension of North America's mussels.

The abundance of names assigned to Mexican in addition to Central American mussels may
have led to an overestimation of the region’s mussel diversity, Pfeiffer said.
DNA showed that many mussels with unique names belong to the
 same species [Credit: Florida Museum/Kristen Grace]

"It was similar Mexican in addition to Central American mussels hardly existed, every bit if they were non critically of import to agreement the development in addition to ecology of the group," Pfeiffer said. "That persuasion is reflected inwards many treatments of North American freshwater mussels. But these regions part many of the same lineages. Mussels don't attention virtually borders."

In a previous study, Pfeiffer, Sharpe, Emery in addition to Larry Page, Florida Museum curator of ichthyology, used deoxyribonucleic acid testify to present that a Central American mussel species listed every bit federally endangered was nearly genetically identical to a mutual species inwards the States The populations inwards United Mexican States in addition to Republic of Guatemala simply represented the species' southernmost residents.

"It seemed strange to us that this species that is widespread from Minnesota to southern Texas of a precipitous became a distinct in addition to critically endangered species in 1 lawsuit y'all crossed the Rio Grande," Pfeiffer said. "The specimens Ashley collected from Republic of Guatemala allowed us to attempt out our hypothesis in addition to ultimately right the species' classification. This is 1 event of how the mussel variety of United Mexican States in addition to Central America may pick out been overestimated."

But he understands firsthand how classifying species without the assist of deoxyribonucleic acid tin live difficult. When Sharpe in addition to Emery returned with their specimens in addition to tissue samples, he sorted the shells based on what he suspected the species groupings were. Circular, bumpy shells went inwards 1 pile, apartment shells with white interiors inwards another, in addition to therefore on. Then the deoxyribonucleic acid results rolled in.

"We got the molecular information back, in addition to it pretty much trashed many of our shell-based hypotheses," Pfeiffer said. "Some shells looked similar dead ringers for belonging to 1 special grouping but ended upwards beingness distant relatives. Shells that I had sorted into vi piles based on their characteristics had nearly identical molecular sequences. There's clearly a lot of plasticity inwards crunch shape."

Mussels’ rich colors fade over time. Seeing fresh examples of the archaeological specimens helped
Sharpe and Emery sympathize why the Maya favored surely species for ornamentation
[Credit: Florida Museum/Kristen Grace]

The deoxyribonucleic acid clarified species' identities in addition to their relationships to 1 another, providing a baseline for futurity conservation assessments, Pfeiffer said. The squad every bit good recognized a novel tribe of amblemines that could assist scientists amend sympathize the development of the subfamily's sophisticated host infection strategies.

But the researchers pick out plenty of piece of work ahead.

"We've made to a greater extent than or less practiced progress, but at that topographic point are all the same many to a greater extent than taxa to live sampled in addition to regions to live explored," he said. "Really, we've simply scratched the surface."

Meanwhile, inwards Guatemala, Sharpe is turning her attending to patterns she in addition to Emery had noticed previously, with species names inwards paw - how to a greater extent than or less mussels were in 1 lawsuit mutual in addition to therefore completely disappeared or how the Maya switched from eating to a greater extent than or less species to using them alone for ornamentation. Having modern specimens to compare with archaeological ones every bit good clarifies why the Maya may pick out used surely species for specific functions. Many of the now-bleached shells used for jewelry or burial décor had lustrous, purplish interiors when they were plucked fresh from the river.

"There were surely species used inwards burials regionwide, but only at 1 signal inwards fourth dimension - it was similar a fad," Sharpe said. "Working with John allowed us to expect at things inwards a agency that nosotros never idea nosotros could do. Without the genetic data, nosotros actually couldn't sort these shells."

As a mussel geek, how does Pfeiffer experience virtually the lifestyles of the ancient Maya, whose diet, clothing, architecture in addition to burials were therefore populated with mussels?

"I'm variety of jealous," he said.

The squad published its findings inwards Zoologica Scripta.

Author: Natalie van Hoose | Source: Florida Museum of Natural History [November 26, 2018]


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