COVER Scanning electron micrograph of minuscule coccolithophorid plankton cell wall coverings preserved as exquisite fossil impressions on the surface of 183-million-year-old Jurassic organic matter. Coccolithophores are a type of microscopic marine phytoplankton, and their hard calcareous plates, called coccoliths (~5 micrometers long), are normally abundant in the fossil record. Here they have dissolved from these ancient rocks deposited during a global warming interval, leaving only their imprint “ghosts” behind. See pages 795 and 853.

Credit: Sam M. Slater, Paul Bown, Richard J. Twitchett, Silvia Danise, Vivi Vajda

ONLINE COVER Dust devils rising in Jezero Crater on Mars. NASA's Perseverance Rover touched down in 2021 equipped with the most sophisticated dust sensors yet flown to Mars. It collected data on the aeolian processes in the roughly 45-km-wide Jezero Crater and recorded large amounts of highly active wind patterns. Using this data, Newman et al. quantify the processes that raise dust and maintain the ubiquitous Martian dust haze.

ONLINE COVER Boosting Locally Buffs Up Vaccine-Induced Immunity. This month’s cover shows an immunofluorescence image of a germinal center in a mouse lymph node 5 weeks after a priming immunization with influenza hemagglutinin. Primed B cells fate-mapped for AID expression (green) are present in the central area of a follicle of IgD-expressing B cells (red) near CD21/35-expressing follicular dendritic cells (blue). Kuraoka et al. observed more fate-mapped memory B cells in lymph node germinal centers when booster immunizations were given at the same tissue site as the original immunization rather than on the opposite side.

ONLINE COVER Special Issue on Robots in the Wild. Robots have been successfully deployed in a wide range of domains–including land, sea, air, and space–for a variety of applications such as search and rescue, oceanography, wildlife surveys, and space exploration. In this issue, Zhou et al. have developed a trajectory planner for swarms of micro drones that can be implemented using only an onboard computer. Their planner computes trajectories based on limited information from the drone's onboard sensors to enable collision-free flight in cluttered environments in the wild. This month's cover is a photo illustration of a swarm of micro-drones flying through a forest (see also the Focus by Soria).

ONLINE COVER This week, Tang et al. identify a long noncoding RNA that is enriched in osteoarthritis patient samples and exacerbates experimentally induced osteoarthritis in mice by enhancing NF-κB–mediated inflammatory signaling. The image shows a section of a mouse knee joint stained to show the articular cartilage at the ends of the femur and tibia in red.

ONLINE COVER Better Binders. This cryo-electron microscopy image shows a SARS-CoV-2 spike trimer (in blue, purple, and yellow) in complex with a multivalent minibinder protein, TRI2-2 (gold), that can simultaneously bind to all three receptor binding domains (RBDs) of the spike trimer. Hunt et al. developed multivalent minibinders that recognize the SARS-CoV-2 RBD with distinct binding patterns. TRI2-2 was protective when administered prophylactically or therapeutically in mice. Another minibinder, FUS231-P12, enabled SARS-CoV-2 antigen detection and could offer a potential new diagnostic tool. Together, these data support further development of multivalent minibinders for SARS-CoV-2 diagnostics and therapeutics.