No. 12 December 2021Armoured ankylosaur
The holotype specimen of the armoured dinosaur Spicomellus afer. Spicomellus (pictured here) is the earliest ankylosaur so far described and the first from Africa. The specimen comprises spikes directly fused to the animal’s ribs, a morphology unique to this species.
See Maidment et al.
No. 11 November 2021Reproductive modes
Live birth has evolved from egg-laying ancestors multiple times independently. The European common lizard, Zootoca vivipara (pictured here), is a rare example of a vertebrate with populations that are either egg-laying or live-bearing. Hybrids resulting from crosses between egg-laying and live-bearing lizards provide the opportunity to explore the genetic basis of pregnancy.
See Recknagel et al.
No. 10 October 2021Monarch butterfly declines
Monarch butterflies in eastern North America migrate thousands of kilometers, from central Mexico (seen here in winter colonies) to the Midwestern U.S. and southern Canada, over multiple generations each year. Integrating data on monarchs and potential stressors across the migratory cycle reveals the increasingly important role of breeding-season climate in recent population changes.
See Zylstra et al.
No. 9 September 2021Neanderthal art
The toe bone of a giant deer, from Einhornhöhle(Germany), was intentionally engraved by Neanderthals about 51,000 years ago — long before our species, Homo sapiens, arrived in Europe. The stacked-offset chevron pattern is unique in the Eurasian context at that time. The engraved bone demonstrates the capacity of Neanderthals for symbolic behaviour, abstract cognition and potentially for communication via symbols.
See Leder et al.
No. 8 August 2021The young ones
An exceptionally preserved juvenile specimen of the lower Cambrian chancelloriid Allonnia phrixothrix from the Haiyan Lagerstätte of southwest China.
See Yang, X. et al.
No. 7 July 2021Y chromosomes matter
Females of Poecilia parae are large and grey (centre), but males are always one of five discrete morphs that differ in colour, body size and mating behaviour. Each morph has a unique Y chromosome, allowing the different complex reproductive strategies to be passed on perfectly from father to son.
See Sandkam, B. A.et al.
No. 6 June 2021Flexible pollinators
Female longhorn bee (Melissodes sp.) on orange sneezeweed (Hymenoxys hoopesii) at Hannagan Meadow in Arizona. Native bees that are flexible in their interaction patterns are able to colonize different habitat patches in the landscape. This interaction flexibility could be a potential mechanism for ecological communities to maintain ecosystem function despite the pressures of different extinction drivers.
See Gaiarsa et al.
No. 5 May 2021Bioherm biodiversity
More than 1,200 animal taxa were recorded on Halimeda bioherms in the Great Barrier Reef. Most (78%) were invertebrates, such as this crinoid (feather star) photographed within a Halimeda algal meadow at 26-m water depth.
See McNeil et al.
No. 4 April 2021Tundra traits
Diapensia lapponica on an exposed, windy ridge at Ammalortup Nunaa, Greenland. Microclimate and soil chemistry shape plant communities across Arctic and Antarctic tundra. Variation in local environmental conditions heavily influences both structural and leaf economic traits. These trait–environment relationships are generalizable across tundra plant communities and spatial scales.
See Kemppinen et al.
No. 3 March 2021Parasexual recombination in cancer cells
Within a colony that originates from a single hybrid cell and is formed by spontaneous fusion of differentially labelled breast cancer cells, most cells maintain the expression of both parent-specific fluorescent markers. However, a subset of cells lost the expression of the green marker, with some cells migrating away from the colony, suggesting subclonal diversification within the progeny of the hybrid clone.
See Miroshnychenko et al.
No. 2 February 2021Tropical forest community structure
A view through the canopy of this Bornean rain forest in Lambir Hills National Park (Malaysia) shows the diversity of plant forms present in one of the most species-rich forests on Earth, where fundamental trade-offs in resource allocation constrain tree species’ life histories along a narrow axis from fast growth and low survival to slow growth and high survival.
See Russo et al.
No. 1 January 2021Early hominin microevolution
Specimen DNH 155 from Drimolen, South Africa is the best-preserved cranium of Paranthropus robustus yet known, and its anatomy as well as its chronological and geographical provenance document microevolutionary change within the species.
See Martin et al.