Birds Down Under

One of the earliest ever bird fossils has been found in Antarctica.

Fossils representing Cretaceous lineages of crown clade birds (Aves) are exceptionally rare but are crucial to elucidating major ecological shifts across early avian divergences. Among the earliest known putative crown birds is Vegavis iaai, a foot-propelled diver from the latest Cretaceous (69.2–68.4 million years ago) of Antarctica with controversial phylogenetic affinities. Initially recovered by phylogenetic analyses as a stem anatid (ducks and closely related species), Vegavis has since been recovered as a stem member of Anseriformes (waterfowl), or outside Aves altogether. 

Here we report a new, nearly complete skull of Vegavis that provides new insight into its feeding ecology and exhibits morphologies that support placement among waterfowl within crown-group birds. Vegavis has an avian beak (absence of teeth and reduced maxilla) and brain shape (hyperinflated cerebrum and ventrally shifted optic lobes). The temporal fossa is well excavated and expansive, indicating that this bird had hypertrophied jaw musculature. The beak is narrow and pointed, and the mandible lacks retroarticular processes. Together, these features comprise a feeding apparatus unlike that of any other known anseriform but like that of other extant birds that capture prey underwater (for example, grebes and loons). The Cretaceous occurrence of Vegavis, with a feeding ecology unique among known Galloanserae (waterfowl and landfowl), is further indication that the earliest anseriform divergences were marked by evolutionary experiments unrepresented in the extant diversity.

Christopher R. Torres, et al., "Cretaceous Antarctic bird skull elucidates early avian ecological diversity." 638(8049) Nature 146 (2025) DOI: 10.1038/s41586-024-08390-0

Hat tip to Science Daily which provides additional explanation in a somewhat less jargon heavy way. It begins by stating:

Sixty-six million years ago, at the end of the Cretaceous Period, an asteroid impact near the Yucatán Peninsula of Mexico triggered the extinction of all known non-bird dinosaurs. But for the early ancestors of today's waterfowl, surviving that mass extinction event was like…water off a duck's back. Location matters, as Antarctica may have served as a refuge, protected by its distance from the turmoil taking place elsewhere on the planet. Fossil evidence suggests a temperate climate with lush vegetation, possibly serving as an incubator for the earliest members of the group that now includes ducks and geese.

Evidence For Non-Newtonian Gravity In Wide Binaries

A new paper shows statistically significant tensions between the assumption of Newtonian gravity (to which General Relativity conventionally applied reduces in the weak field regime) in the MOND transition region (which is not found in the non-MONDian field strength area) in an analysis of the Gaia DR3 dataset. 

The significance of the deviation is still below the five sigma discovery level (2.1 sigma in the MOND regime and 4.2 sigma for the weaker effect in the MOND transition regime), the expected value under a MOND hypothesis in the MOND transition region isn't entirely clear, and there are multiple potential sources of unmeasured systemic error (most importantly, the possibility that some data points that look like binary stars actually have three or more stars in the system with the smallest star going undetected). 

But, while it is not the definitive evidence, it is consistent with a MOND hypothesis, and it is still significant positive evidence of MONDian-like behavior in wide binary stars. This, at a minimum, justifies further investigation of, and research regarding, this hypothesis. 

(I've used a screenshot of the abstract rather than cutting and pasting it, in order to preserve the extensive formatting there.)

Kyu-Hyun Chae, "Low-Acceleration Gravitational Anomaly from Bayesian 3D Modeling of Wide Binary Orbits: Methodology and Results with Gaia DR3" arXiv:2502.09373 (February 13, 2025).