Jeholornis curvipes: a new Cursorial, Nonperching, and Seed-eating Bird From Lower Cretaceous Jehol Biota

A new long-tailed basal bird from the Lower Cretaceous of north-eastern China

Authors:

Lefèvre et al

Abstract:

A new basal Avialae, Jeholornis curvipes sp. nov., from the Yixian Formation (Lower Cretaceous) of Liaoning Province (north-eastern China) is described. A revision of long-tailed birds from China and a phylogenetic analysis of basal Avialae suggest that Jeholornithiformes were paraphyletic, with Jixiangornis orientalis being the sister-taxon of pygostylia. The phylogenetic analysis also recovered that the tail reduction is a unique event in the evolution of birds. Jeholornis species were cursorial, nonperching, and seed-eating birds.

A New Specimen of Aptian Cretaceous Enantiornithine Bohaiornis guoi Suggests Raptorial Lifestyle

A New Specimen of Large-Bodied Basal Enantiornithine Bohaiornis from the Early Cretaceous of China and the Inference of Feeding Ecology in Mesozoic Birds

Authors:

Li et al

Abstract:

A new specimen of Bohaiornis guoi from the Jiufotang Formation, comprising a nearly complete skeleton, sheds light on enantiornithine morphological variation and ecological specialization. The new specimen was collected from near Lamadong Village in Liaoning Province, which is the same area where the sub-adult holotype specimen was reported. It provides new information on the cranial and pectoral girdle anatomy of the species, e.g., broad nasal, strikingly robust acromion, medially curved acrocoracoid process. In contrast to the holotype, the newly referred specimen has small rounded stones in the thoracic region that in other extinct taxa has been interpreted as direct evidence of diet. Direct evidence of diet is so far unknown in other Enantiornithes. Specifically the lack of “stomach stones” or gastroliths in enantiornithines despite their excellent fossil record has been proposed to be related to their insectivorous diet as well as to their arboreal ecology. We hypothesize that cranial morphology as well as the number and shape of the preserved stones in Bohaiornis may be most consistent with a raptorial ecology previously unknown for Enantiornithes and considered rare for Avialae. While rostrum shape has a strong relationship to feeding ecology in living birds, in basal avialan birds most diversity is in dental morphology, number, and distribution of the teeth.

Archaeopteryx Feather Colors Are Fanciful

The Archaeopteryx, which lived around 150 million years ago and was a mixture of bird traits (notably feathers) and reptile traits (teeth, claws on its wings), was previously thought to have black feathers. But a new analysis of three Archaeopteryx fossils has revealed that the ancient bird's feathers were in fact light in color, with a dark edge and tips.

The distinct black-and-white patterns on the bird's plumage are comparable to the pigmentation of a magpie, said study co-author Roy Wogelius, a geochemist at the University of Manchester.

"This creature was actually doing very well in terms of evolutionary state. It already has a key adaptation that we see in many modern species of bird," said study leader and University of Manchester paleontologist Phil Manning, who is a National Geographic grantee.

Like modern-day birds, the Archaeopteryx would have benefited from the different shadings.

The scan found traces of copper that produced the dark tips of the bird's feather; copper has properties that can keep away bacteria that would otherwise fray wings. The copper also slowed the "microbial breakdown" of the fossil, Manning notes: "It's the reason the feather has been preserved for 150 million years to the point where we still see astounding resolution in the fossil."

Aurornis xui: Feathered Relative of Early Birds, Proves Feathers Before Flight

Feathered dinosaurs used to be as valuable as gold dust. Now, so many specimens have been unearthed that museums are overflowing. But for all the specimens, a crucial question has remained unanswered: which species was the original ancestor of birds?

A new species found in China has shed light on the answer. The two-foot long Aurornis xui, the “daybreak bird,” fleshes out the relationships between bird-like dinosaurs and, along with its cousin species Archaeopteryx and Anchiornis, restores its lineage as the likely predecessors of birds.

The early relationships of a group called Avialae, the dinosaur line leading directly to modern birds, have been a hot point of debate. Over the last few years, with new bird-like dinosaur discoveries, some palaeontologists have even removed the iconic Archaeopteryx and its relatives from the Avialae group altogether. However, this shift would have meant that powered flight evolved multiple times in feathered dinosaurs, a less likely situation than one such adaptation.

Now, Aurornis xui, named in honor of dinosaur hunter Xu Xing, appears to have settled that part of the debate. Along with Anchiornis of the same age (about 155-160 million years), and Archaeopteryx (150 million years), Aurornis fits within the earliest ancestry of Avialae. The existence of three contemporary species allowed researchers to triangulate their relationships based on their appearance. Archaeopteryx was knocked off its perch as the oldest bird back in 2009 by Anchiornis, and now Aurornis has finished the dethroning, with the three species together sitting at the very base of the Avialae lineage that would later give rise to all other birds.

For a moment when I saw the reconstruction, I thought the chickensaurus project was successful!