What started as routine fossil cleaning turned into a major scientific surprise when researchers uncovered a tiny claw in a 500-million-year-old specimen where no claw should exist. That detail revealed Megachelicerax cousteaui, the oldest known relative of spiders, pushing the origins of this group back by 20 million years. The fossil shows that key features of modern spiders and horseshoe crabs were already emerging during the Cambrian Explosion.

A new clinical trial suggests that what people eat could finally offer real relief for Crohn’s disease, a condition that has long lacked clear dietary guidance. Researchers found that a “fasting-mimicking diet” — involving just five days a month of very low-calorie, plant-based meals — led to noticeable improvements in symptoms for most participants. Even more striking, the diet didn’t just make patients feel better; it also reduced key biological markers of inflammation linked to the disease.

A new gene therapy is giving people born deaf the chance to hear, often within just weeks. In a small but groundbreaking study, researchers delivered a working copy of a key hearing gene directly into the inner ear using a single injection. All ten patients, ranging from young children to adults, experienced improved hearing, with some showing rapid gains in just one month.

Thousands of years ago in a cave on Hispaniola, an unusual chain of events left behind a rare scientific treasure: bees nesting inside fossilized bones. After giant barn owls repeatedly brought prey like hutias into the cave, their remains accumulated in silt-rich chambers—creating a strange underground environment. Later, burrowing bees took advantage of the soft sediment and even reused tiny cavities in fossilized jaws and bones as ready-made nests, coating them with a smooth, waterproof lining.

A newly identified gene mutation may help explain why schizophrenia patients struggle to update their understanding of reality. The mutation disrupts a brain circuit involved in flexible decision-making, causing mice to stick with outdated choices even when conditions change. Researchers pinpointed the issue to a key thalamus–prefrontal cortex pathway. By reactivating this circuit, they were able to restore normal behavior—raising hope for future therapies.

A puzzling wrinkled rock formation in Morocco has led scientists to rethink where ancient microbes could live. Instead of shallow, sunlit waters, these microbes may have thrived deep in the ocean, fueled by chemicals delivered by underwater landslides. The discovery suggests that dark, nutrient-rich environments hosted thriving ecosystems much earlier than expected. It also raises the possibility that many similar fossils have been overlooked or misinterpreted.

A new concept suggests SpaceX’s Starship could revolutionize a future mission to Uranus, one of the solar system’s most overlooked planets. By refueling in orbit and helping slow the spacecraft on arrival, it could cut travel time nearly in half. That’s a big deal for a mission that would otherwise take over a decade just to arrive. If it works, it could finally open the door to studying this strange, tilted world up close.

A new study reveals that aging lungs may play a major role in why flu and COVID can become so dangerous for older adults. Researchers found that certain lung cells can trigger an exaggerated immune response, creating clusters of inflammatory cells that end up damaging lung tissue instead of protecting it. In experiments, activating this aging-related signal in young mice caused their lungs to behave like older ones, leading to severe illness.

A new study suggests that one of the most widely used health metrics, BMI, may be getting it wrong for a large portion of the population. By comparing BMI classifications with precise body fat measurements using advanced DXA scans, researchers found that more than one-third of adults were placed in incorrect weight categories. Many people labeled as overweight or obese did not actually have the corresponding body fat levels, while others were missed entirely.

Fast fashion might come with a hidden danger: lead. Researchers testing children’s shirts from multiple retailers found every sample exceeded U.S. safety limits, raising concerns about toxic exposure—especially since young kids often chew on clothing. Brightly colored fabrics like red and yellow showed particularly high levels, likely due to chemicals used to fix dyes. Simulations suggest that even brief mouthing could expose children to unsafe amounts of lead, a substance known to harm brain development and behavior.

Nature Medicine, Published online: 03 April 2026; doi:10.1038/s41591-026-04256-2

Whole-genome phylogenetic analyses have identified a case of monkeypox virus clade IIb lineage in the Republic of the Congo and co-circulation of three clade lineages, emphasizing the importance of improved surveillance given the risk of possible recombination events in the future.

Nature Medicine, Published online: 03 April 2026; doi:10.1038/s41591-026-04302-z

Exposome analyses across 34 countries showed that social exposures were associated with faster functional brain aging and physical exposures with faster structural brain aging.

Nature Medicine, Published online: 03 April 2026; doi:10.1038/s41591-026-04305-w

To accelerate therapeutic development and equip stakeholders with clear benchmarks, the authors outline target product profiles for therapies designed to delay or prevent the onset of clinical symptoms of Alzheimer’s disease.

npj Digital Medicine, Published online: 03 April 2026; doi:10.1038/s41746-026-02579-5

An AI-based mental health guardrail and dataset for identifying psychiatric crises in text-based conversations

npj Digital Medicine, Published online: 03 April 2026; doi:10.1038/s41746-026-02544-2

User-preference alignment with uncertainty-aware interactive rectification for liver organ and tumor segmentation and analysis from CT images

npj Digital Medicine, Published online: 03 April 2026; doi:10.1038/s41746-026-02557-x

Label-free pathological subtyping of non-small cell lung cancer using deep classification and virtual immunohistochemical staining

npj Digital Medicine, Published online: 03 April 2026; doi:10.1038/s41746-026-02512-w

Sensor-based digital health technologies to capture endpoints in recent clinical trials: a scoping review

Nature, Published online: 03 April 2026; doi:10.1038/d41586-026-01105-7

The 2027 budget proposal would curb federal payments for scientific publishing and reduce funding for many US institutions.

Nature Cancer, Published online: 03 April 2026; doi:10.1038/s43018-025-01108-9

Applications of digital pathology in clinical oncology have largely depended on the requirement for labeled data and model re-training. A study now presents PRET, a training-free framework with robust performance for pan-cancer diagnosis that adapts pathology foundation models to diverse tasks at inference stage, from screening and subtyping tasks to segmentation and metastasis detection tasks.

Nature Cancer, Published online: 03 April 2026; doi:10.1038/s43018-026-01138-x

Leptomeningeal metastases are a devastating complication of solid tumors; how this niche becomes pro-metastatic remains poorly understood. A study now reveals that tumor cells prime a pre-metastatic niche within the leptomeninges via exosome-derived 5-HIAA, triggering vascular leakiness and accumulation of disseminated tumor cells.