Research alert! Rebecca Oppenheimer, a curator in the Museum’s Department of Astrophysics, co-discovered the first brown dwarf, Gliese 229B, in 1995. Since then, there’s been a long-standing mystery: Why does this brown dwarf shine so faintly despite having a significant mass—70 times that of Jupiter?

The answer, which is detailed in her latest study with Caltech—out today in the journal Nature—is that this brown dwarf is actually two objects, orbiting very closely around each other.

“These two worlds whipping around each other are actually smaller in radius than Jupiter. They’d look quite strange in our night sky if we had something like them in our own solar system,” Oppenheimer said. The discovery leads to new questions about how tight-knit brown dwarf duos like this one form and suggests that similar systems are likely out there. Read more.

Image: K. Miller, R. Hurt (Caltech/IPAC)

Research alert! A new study shows how climate change affected the diversity of Congo River fish during glacial periods—crucial knowledge for understanding modern threats to fish in this species-rich region.

Over the last about 2.6 million years, polar ice caps have continuously expanded and retracted during glacial and interglacial cycles. This is thought to be a significant driver of biodiversity on land, but less is known about its effect on freshwater systems, especially in the Congo River. 

Using molecular tools, scientists focused on four species of fish endemic to the lower Congo River, known as lamprologine cichlids. Their findings, published in the journal Integrative and Comparative Biology, suggest speciation of Congo fish likely occurred when the river’s water level decreased, isolating populations of fish into smaller pockets of water, leading to the rise of new species over time. 

Learn more about how climate change impacts river fish.

Image: © Melanie Stiassny, Lamprologus lethops pictured

Research alert! A new study finds that an extremely well-preserved fossil of Triarthrus eatoni, a trilobite found in upstate New York, has an additional set of legs underneath its head! What did researchers learn from this discovery? Find out with Museum Curator Melanie Hopkins, who coauthored the research. Read more.

Research alert! A new study finds that an extremely well-preserved fossil of Triarthrus eatoni from upstate New York has an additional set of legs underneath its head. By making comparisons with another well-preserved trilobite species, Olenoides serratus from British Columbia, researchers from the Museum and Nanjing University in China have proposed a model for how appendages were attached to the head in relation to the grooves in the exoskeleton. 

“The number of these segments and how they are associated with other important traits, like eyes and legs, is important for understanding how arthropods are related to one another, and therefore, how they evolved,” said Melanie Hopkins, curator and chair of the Museum’s Division of Paleontology. 

Research alert! Two new fossils of a mouse-sized animal from the age of dinosaurs indicate that early mammals grew more slowly and lived longer than their modern descendants—rewriting our understanding of the lives of the very earliest mammals. An international study led by researchers at National Museums Scotland and published today in the journal Nature, compares two Krusatodon kirtlingtonensis fossils discovered decades apart in Scotland’s Isle of Skye. One of the fossils, the only juvenile Jurassic mammal skeleton known to science, was discovered in 2016 by Roger Benson, the Museum’s Macaulay Curator in the Division of Paleontology, and colleagues.

“These fossils are among the most complete mammals from this time period in the world,” said Elsa Panciroli, the lead author of the study and an associate researcher of paleobiology at National Museums Scotland. 

Learn how these small animals give us unprecedented insights into the lives of early mammals.

Image: © Maija Karala

The iconic frog-eating bat (Trachops cirrhosus), best known for hunting amphibians in the Neotropics, is one of the most easily recognizable bat species. But new research, led by Angelo Soto-Centeno, who is joining the Museum as an assistant curator in the Department of Mammalogy next month, along with Museum Curator Nancy Simmons and colleagues at the Universidade Federal do Espírito Santo in Brazil, suggests that these bats actually comprise three separate species across their range—knowledge that’s vital for future conservation efforts. 

“Frog-eating bats are very iconic and easy to identify, with long woolly fur, large ears, and wartlike protrusions on its chin and snout that make it very recognizable,” Soto-Centeno said. “But that has led to underestimation of its diversity. Detailed taxonomic accounts like this are the first step for making effective conservation decisions concerning these animals.”

Read more about their results, published today in the journal American Museum Novitates.

Photo: © Sherri and Brock Fenton

One small step for leeches, one giant leap for leechkind! For the first time, we have concrete evidence that at least one species of terrestrial leech in Madagascar can jump. Mai’s work is important to conservation efforts because leeches are increasingly being collected to survey vertebrate biodiversity. By analyzing their blood meals, researchers are able to identify other animals living alongside the leeches, ranging from wildcats to frogs to ground-dwelling birds. Read more about Mai's research in our latest blog post.

Have you ever seen a leech jump? Let us know in the comments!

Research alert! New insights into mammalian tooth, jaw, and ear evolution, gleaned from analyzing fossils of two Jurassic-era mammal species from China, are reshaping how scientists think about early mammals. This research, led by scientists at the Museum and the Chinese Academy of Sciences, focuses on two new species of fossil mammals—Feredocodon chowi and Dianoconodon youngi—that offer new evidence about early mammalian evolution.

“Scientists have been trying to understand how the mammalian middle ear evolved since Darwin’s time,” said Jin Meng, a curator in the Museum’s Division of Paleontology and a corresponding author on both papers. “These new fossils bring to light a critical missing link and enrich our understanding of the gradual evolution of the mammalian middle ear.”

Check out our latest blog post to learn more!

Image: Chuang Zhao

Research alert! A team of international scientists has discovered the largest known freshwater dolphin, an ancient species that lived in the Peruvian Amazon some 16.5 million years ago. Pebanista yacuruna, which likely measured 10-11.5-feet (3-3.5 meters) long, inhabited what is now the Amazon River basin before this system had its major connection to the Atlantic Ocean. 

“Discoveries by our international collaborative teams tell us the kinds of tropical life that existed during times in Earth’s history when virtually nothing had been known before,” said John Flynn, the Museum’s Frick Curator of Fossil Mammals and a co-author on the new study, which was published in the journal Science Advances. “This is crucial to understanding the history and pathways that led to the remarkably rich modern Amazonian biodiversity.” 

Learn more about this animal, and its surprising modern relatives, in our latest blog post.

New research alert! A study from the Museum and the Carnegie Institution for Science has found nearly 31 confirmed and 1,000 potential members of stellar associations, or “swarms”—stars of similar ages and compositions that are drifting together through space—in our own corner of the Milky Way. The study could help astronomers better understand the evolution of stars and the properties of exoplanets. These stars’ ages vary from a few million to a billion years old, depending on the group. This range offers astronomers a sweeping view of stellar evolution among our cosmic neighbors. Read more about this study, here: https://goo.gl/eiq7w7 Photo: NASA, star cluster Cygnus OB2 pictured

A new study of fossilized dinosaur embryos suggests that the young of these prehistoric animals were slow to develop, with some spending up to sixth months inside their eggs before hatching. Detailed in the journal Proceedings of the National Academy of Sciences, this drawn-out development cycle not only surprised scientists—it may have contributed to the downfall of the dinosaurs.

“We know very little about dinosaur embryology, yet it relates to so many aspects of development, life history, and evolution,” said study co-author Mark Norell, Macaulay Curator of Paleontology at the American Museum of Natural History. “This work is a great example of how new technology and new ideas can be brought to old problems.”

Using a combination of computed tomography (CT) scanning and powerful microscopes, Norell and colleagues from the University of Calgary and Florida State University examined the teeth of fossilized dinosaur embryos in unprecedented detail, shining new light on specimens about which not much is known.

Read more about this new research on the blog. 

Fossil Reveals Ostrich Relatives Once Lived in North America

New research reveals that 50-million-year-old bird fossil specimens, some of which are on display in the Museum’s special exhibition Dinosaurs Among Us, are from a previously unknown relative of the modern-day ostrich.

The study, published recently in the Bulletin of the American Museum of Natural History, is co-authored by Sterling Nesbitt of Virginia Tech and Julia Clarke of the University of Texas at Austin, both of whom are also research associates at the Museum.

“This is one of the earliest well-represented bird species after the age of large dinosaurs,” said Nesbitt of the specimen, which was found more than a decade ago—with bones, feathers, and even soft tissues intact—in a former lakebed in Wyoming.

Read the full story.

Scorpions Share Similar Tastes in Burrow Architecture

New research on the burrows of scorpions in diverse environments finds that these predatory arachnids build strikingly similar architectural features in their homes, suggesting that burrows are part of the arachnids’ “extended physiology,” and are vital to their survival in some of the world’s most inhospitable places.

“It’s amazing how ubiquitous scorpion burrows are in some parts of the world, yet very little has been done to study them until now,” said Lorenzo Prendini, a curator in the American Museum of Natural History’s Division of Invertebrate Zoology and co-author of the new study.

Read more and see renderings of these scorpion burrows.

New Research Shows That Bioluminescence Evolved Frequently in Fish

New research shows that bioluminescence—a phenomenon in which organisms generate visible light through a chemical reaction—evolved many more times among marine fishes, and likely throughout the entire tree of life, than previously thought. In a study published in the journal PLOS ONE, scientists from the American Museum of Natural History, St. Cloud State University, and the University of Kansas reveal that bioluminescence evolved 27 times in marine ray-finned fishes—and 29 times if sharks and rays are counted. Here are some of these amazing bioluminescent fish:

Anglerfish This ceratioid anglerfish has a built-in fishing rod, a modified fin spine topped with a lure that pulses with bacterial light. Anglerfishes are the only animals known to light up in two ways: the genus Linophryne has glowing bacteria in the lure and their own chemicals that make light in a complex chin barbel. Image: © J. Sparks, R. Schelly, D. Roje

Hatchetfish  The deep-sea hatchetfish, which gets its name from the distinct hatchet-like shape of its body, has light-producing organs known as photophores that run along the length of their body and point downward. Hatchetfishes use these structurally complex photophores to mimic any down-welling sunlight and disappear from predators lurking below. Image: © J. Sparks, R. Schelly, D. Roje

Barbeled dragonfish  This barbeled dragonfish is a small bioluminescent deep-sea fish with a long protrusion attached to its chin, known as a barbel, which is tipped with a light-producing organ called a photophore. It also has large photophores below its eyes used to illuminate prey and potentially communicate, and along the sides of its body for camouflage. Image: © J. Sparks, R. Schelly, D. Roje

Stoplight loosejaw A stoplight loosejaw (Malacosteus niger), which is capable of engulfing prey nearly as large as its own body. It has both red and blue/green photophores under its eyes. Its primary prey source, Euphausid shrimp, cannot detect red light. The loosejaw uses this “private” wavelength of light to illuminate and hunt the shrimp. Image: © Christopher Martinez

Learn more about this research. 

New Research: Bioluminescence Evolved Frequently in Fish

New research shows that bioluminescence—a phenomenon in which organisms generate visible light through a chemical reaction—evolved many more times among marine fishes, and likely throughout the entire tree of life, than previously thought. In a study published in the journal PLOS ONE today, scientists from the American Museum of Natural History, St. Cloud State University, and the University of Kansas reveal that bioluminescence evolved 27 times in marine ray-finned fishes—and 29 times if sharks and rays are counted.

“Our findings completely change how we look at the evolution of bioluminescence across all life,” said John Sparks, curator-in-charge of the Museum’s Department of Ichthyology and a co-author of the paper, which is the first to explore how frequently bioluminescence evolved in vertebrates. “This suggests that we need to take a closer look at the evolution and diversification of other lineages with bioluminescent members.”

Read the full story and see more bioluminescent fish.

Image: A stoplight loosejaw (Malacosteus niger), which can engulf prey nearly as large as its own body, produces multiple colors of light.© C. Martinez

Did you know? All scorpions, regardless of coloration, fluoresce under long-wave (360-400 nm) ultraviolet (UV) light, due to the presence of two compounds (beta carboline and 7-hydroxy-4-methylcoumarin) in their exocuticle. 

The significance, if any, of the fluorescence is subject to debate. It is widely thought to be nothing more than an incidental accident of chemistry. UV fluorescence is indisputably associated with the hardening of the scorpion exocuticle: the soft joints between hard plates don’t fluoresce; after molting, the soft plates doesn’t fluoresce until hardened; and the fluorescence increases with successive molts. 

The unique ability of scorpions to fluoresce under UV light greatly facilitates their collection and observation by scorpiologists at night!

Read new scorpion research by Lorenzo Prendini, a curator in the Museum’s Division of Invertebrate Zoology.

Image: A male Brachistosternus telteca scorpion as seen under ultraviolet light. © L. Prendini/R. Mercurio

New Research: DNA Study Suggests Scorpions Diversified as Andes Formed

The formation of the Andes mountain chain gave a powerful boost to South American biodiversity, and new research finds that scorpions were no exception.

A study published this week in the Journal of Biogeography suggests that the large number of scorpion species present in the genus Brachistosternus is likely due to the unique microclimates that formed as the Andes arose over the last 30 million years.

“There are more than 50 species of Brachistosternus scorpions, most of which live in or around the Andes, and this high diversity can largely be attributed to the formation of the mountains,” said author Lorenzo Prendini, a curator in the Museum’s Division of Invertebrate Zoology. “As the Andes uplifted, new valleys, slopes, and highlands formed, isolating ancestral populations of Brachistosternus and providing new habitats into which they were able to diversify.”

Read the full story on the Museum blog. 

Image: © L. Prendini/R. Mercurio