Bedbugs’ dinosaur age origins


This April 2017 video from the USA says about itself:

Bedbugs have pestered us for centuries. These bedbug fossils were recently recovered from Paisley Caves, Oregon, the site of the oldest dated archaeological human remains in North America, and are approximately 9,400 years old.

Bedbugs nearly vanished in the United States during the 1940s and ’50s due to improved hygiene … but are on the rise again due to global travel and a increasing resistance to common pesticides.

A new study finds that bedbugs — just like flies and other insects — have favorite colors. They really like dark red and black, and they shun dazzling white and bright yellow. These apple seed-sized insects probably instinctively prefer black and red shelters over white and yellow ones because they offer better protection from predators such as ants and spiders, Pereira said.

By Jennifer Leman, 1:47pm, May 16, 2019:

Bloodthirsty bedbugs have feasted on prey for 100 million years

New genetic analyses reveal the insects evolved from at least the Cretaceous

The first bedbug infestations may have occurred in the beds of Cretaceous critters.

Scientists previously assumed bloodsuckers’ first hosts were bats. But a new genetic analysis of 34 bedbug species reveals that bedbugs appeared 30 million to 50 million years before the nocturnal mammals, says Michael Siva-Jothy, an evolutionary biologist at the University of Sheffield in England, and his colleagues.

The analysis, published online May 16 in Current Biology, pegs the emergence of ancient bedbugs at more than 100 million years ago. It also fleshes out more of the pests’ history. For instance, two bedbug species that humans are most familiar with didn’t evolve just to plague us. The common bedbug (Cimex lectularius) and the tropical bedbug (C. hemipterus) emerged around 47 million years ago, long before early human ancestors meandered into bedbug-infested caves, the team found (SN Online: 4/10/17).

The new study “puts the Cimicidae family on the map in terms of understanding its diversity, understanding its evolutionary history in a way that no other previous studies had,” says Zach Adelman, a molecular geneticist at Texas A&M University in College Station, who was not involved in the study.

To build a collection of bedbug specimens, a global network of scientists plucked insects from damp caves and dusty museum exhibits over 15 years. For each species, researchers looked at four genes known to mutate at a constant rate, like an evolutionary timekeeper. The team then calibrated that data with the known fossil records from two insects — an ancient species of bedbug and a closely related insect species — to create its timeline.

The genetic analysis can’t say what Cretaceous critters ancient bedbugs snacked on. But a computer simulation and modern-day behavior — bedbugs prefer hosts that sleep for long periods in one place — suggest that the insects probably fed on small mammals and birds.

Using the feeding habits of modern bedbugs, the team also mapped the likeliest hosts their ancestors would have preyed on. It found that bedbugs were initially picky eaters that preyed on only one type of mammal or bird. Some bedbug lineages continue to dine on a single host. But over time, some swapped furry for feathered prey, and a few even broadened their palate to include a variety of hosts, including humans.

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‘Human-Neandertal split about 1 million years ago’


This March 2017 video says about itself:

National Geographic | THE NEANDERTHALS | FIRST PEOPLES OF EUROPE | HD Full Documentary

Neanderthals or Neandertals were a species or subspecies of archaic human, in the genus Homo, which became extinct around 40,000 years ago. They were closely related to modern humans, sharing 99.7% of DNA.

By Bruce Bower, 2:00pm, May 15, 2019:

Fossil teeth push the human-Neandertal split back to about 1 million years ago

A new study estimates the age of these hominids’ last common ancestor

People and Neandertals separated from a common ancestor more than 800,000 years ago — much earlier than many researchers had thought.

That conclusion, published online May 15 in Science Advances, stems from an analysis of early fossilized Neandertal teeth found at a Spanish site called Sima de los Huesos. During hominid evolution, tooth crowns changed in size and shape at a steady rate, says Aida Gómez-Robles, a paleoanthropologist at University College London. The Neandertal teeth, which date to around 430,000 years ago, could have evolved their distinctive shapes at a pace typical of other hominids only if Neandertals originated between 800,000 and 1.2 million years ago, she finds.

Gómez-Robles’ study indicates that, if a common ancestor of present-day humans and Neandertals existed after around 1 million years ago, “there wasn’t enough time for Neandertal teeth to change at the rate [teeth] do in other parts of the human family tree” in order to end up looking like the Spanish finds, says palaeoanthropologist Bernard Wood of George Washington University in Washington, D.C.

Many researchers have presumed that a species dubbed Homo heidelbergensis, thought to have inhabited Africa and Europe, originated around 700,000 years ago and gave rise to an ancestor of both Neandertals and Homo sapiens by roughly 400,000 years ago. Genetic evidence that Sima de los Huesos fossils came from Neandertals raised suspicions that a common ancestor with H. sapiens existed well before that (SN Online: 3/14/16). Recent Neandertal DNA studies place that common ancestor at between 550,000 and 765,000 years old. But those results rest on contested estimates of how fast and how consistently genetic changes accumulated over time.

With that molecular debate in mind, Gómez-Robles calculated the rate at which eight ancient hominid species evolved changes in tooth shape. That enabled her to gauge how long it must have taken for Sima de los Huesos teeth to evolve after Neandertals diverged from a common ancestor with H. sapiens.

Gómez-Robles used two possible evolutionary trees for the eight hominid species to estimate dental evolution rates. Aside from the Spanish Neandertals and Stone Age H. sapiens, teeth in her study came from African hominids dating to as early as 3.2 million years ago.

Moving back the date of an evolutionary split between Neandertals and H. sapiens appears reasonable based on the new data, says paleoanthropologist Aurélien Mounier of Musée de l’Homme in Paris. The timing of that split could still change, though, if further research modifies the Spanish fossils’ age, he says.

Other Spanish hominid teeth dating to nearly 800,000 years ago display some Neandertal features, supporting the new study’s conclusions, says New York University paleoanthropologist Shara Bailey. But it’s unclear if Gómez-Robles’ contention that hominid teeth evolved at a steady rate will hold true, Bailey says.

Declining fertility rates may explain Neanderthal extinction: here.