This lava tube in Saudi Arabia has been a human refuge for 7,000 years
When ancient humans pushed into the Arabian Peninsula, they found a world marked by magma. Little is known about the lives of those humans. But a study published this month in the journal PLOS One has revealed that their occupation of this volcanic realm extended underground. Archaeologists at a site in northwestern Saudi Arabia have excavated a lava tube, the subterranean remnant of a lava flow, and found stone tool fragments, animal remains and human bones, the oldest of which were close to 7,000 years old.
Early humans probably used this volcanic cave, known as Umm Jirsan, as a way station during migrations between oases, rather than as a permanent habitat. Although only small sections of Umm Jirsan have been examined, the new study shows that it and other such caves in the area hold promise for understanding the migrations of early humans.
The notion that these migrants brought animals with them is supported not just by the remnants at the site. The team discovered 16 rock art panels in the entrance to another lava tube nearby. Some show people herding cattle, sheep and goats, sometimes with the aid of dogs; others depict people hunting.
The lava tubes offer a new way “of looking through time and through space,” said Michael Petraglia, the director of the Australian Research Center for Human Evolution at Griffith University and an author of the new study. Each could be an unopened window into the lives of humanity’s ancestors.
“This cave is just the beginning,” he said. — ROBIN GEORGE ANDREWS
A megaraptor emerges from footprint fossils
In real life, velociraptors topped out at the size of a Labrador retriever, much smaller than the human-size hunters portrayed in the “Jurassic Park” series. Still, some raptors did achieve imposing sizes. And in a paper published this month in the journal iScience, a team of paleontologists reported that it might have identified one of the largest raptors known to science based on a set of fossilized footprints found in China.
The raptor’s imprints are part of a larger dinosaur trackway discovered in southeastern China in 2020. During the Late Cretaceous Period, about 90 million years ago, the area was a muddy river plain, home to all manner of dinosaurs that left footprints.
Among them, researchers found a set of five raptor imprints that are more than 13 inches long, making them the largest such tracks in the fossil record. Based on their size, the dinosaur that left them was roughly 5 feet tall and 15 feet long, putting it in the neighborhood of the largest known raptors.
These distinct footprints inspired the paleontologists to name the new raptor Fujianipus (“the foot of Fujian”) yingliangi. The proportions of its toes make it likely that Fujianipus was a troodontid, a type of birdlike raptor that inhabited Asia and North America during the Cretaceous period.
According to W. Scott Persons, a paleontologist at the College of Charleston in South Carolina and co-author of the paper, giants such as Fujianipus are outliers because raptors “appear to have been way better at being small- and medium-sized carnivores.” — JACK TAMISIEA
Like moths to a flame? We may need a new phrase.
It used to be that you could put a black light at the edge of a cornfield at night and expect a bountiful harvest of moths the next morning. For entomologists, such light traps have provided an invaluable record of moth numbers. But in recent decades, light traps have shown dwindling catches of insects of all kinds. Some have interpreted these empty traps as evidence of their decline.
But there might be other factors at play. In a paper published this month in the Journal of Insect Conservation, researchers report that although some light traps are catching fewer corn earworm moths, a well-known agricultural pest, their yields in another kind of trap are as healthy as ever. The results suggest that something has changed in the moths’ attraction to light.
Why the difference? It might be, as Charles Darwin once suggested, that evolution has removed moths with an attraction to light from the gene pool, so that today’s corn earworm moth is no longer as drawn to light. But another explanation for the decline in light trap effectiveness might be that it’s a consequence of the world surrounding those light traps growing much brighter. With streetlights and other sources lighting up the night, moths may not be noticing the light traps as much as they notice other glowing things.
The findings are an important first step toward adjusting the way scientists approach insect monitoring, and the paper raises issues that the field is just starting to discuss, said Jolyon Troscianko, an ecologist at University of Exeter in England.
“This is very much a hot topic,” he said. — VERONIQUE GREENWOOD