An advanced, new long-legged bird from the Early Cretaceous of the Jehol Group (northeastern China): insights into the temporal divergence of modern birds
Authors:
Liu et al
Abstract:
We describe a new ornithuromorph bird species, Gansus zheni from the Lower Cretaceous lacustrine deposits of the Jiufotang Formation (Jehol Group), Liaoning Province, China. A cladistic analysis resolves Gansus zheni as the sister taxon of the roughly contemporaneous Gansus yumenensis (Xiagou Formation, Gansu Province), and together as the most immediate outgroup to Ornithurae. Gansus zheni is the most advanced bird known today for the Jehol Biota. Its discovery provides the best-documented case of inter-basinal correlations (Jehol and Changma basins of Liaoning and Gansu provinces, respectively) using low-taxonomic clades of fossil birds. The existence of close relatives of Ornithurae in deposits formed at about 120 million years ago helps to mitigate the long-standing controversy between molecular and paleontological evidence for the temporal divergence of modern birds (Neornithes).
A new species from an ornithuromorph (Aves: Ornithothoraces) dominated locality of the Jehol Biota
Authors:
Zhou
Abstract:
We report on a new species of ornithuromorph bird, Iteravis huchzermeyeri gen. et sp. nov., from the previously unreported Sihedang locality of the Lower Cretaceous Yixian Formation, the oldest ornithuromorph bearing deposit in the world. Unlike most other Cretaceous localities, specimens from this new quarry are largely referable to Ornithuromorpha, similar to the Lower Cretaceous Aptian Xiagou Formation in Gansu Province. Also similar to the Xiagou avifauna, the fauna at Sihedang is largely dominated by a single taxon (described here). Differences in faunal dominance may suggest the Sihedang records a unique ecological habitat. This may also explain the dominance of Gansus in the younger Xiagou Formation locality and suggests that previous hypotheses regarding the shift in dominance between Enantiornithes and Ornithuromorpha need to be reassessed in terms of potential ecological biases due to limited sampling. Furthermore, the recognition of an ornithuromorph dominated locality in the Sihedang significantly weakens the signal of such an inferred trend. Compared to most Jehol birds, the new specimen is relatively better preserved in three dimensions revealing morphological details of the skeleton, as well as preserves feather impressions including a rectricial morphology previously unknown among Mesozoic birds.
New Information on Hongshanornithidae (Aves: Ornithuromorpha) from a new subadult specimen
Authors:
Zheng et al
Abstract:
We report a new species of basal ornithuromorph bird, Tianyunornis cheni gen et sp nov, based on a nearly complete and articulatd subadult individual from Lower Cretaceous Yixian Formation in the eastern region Nei Mongol, China. The new specimen shws Characeristic of the Hongshanornithidae (Hongshanornis longicreta, Longicrusavis houi, and Parahongshanornis chaoyanensis_, such as a small body size and elongate hindlimbs relative to their forelimbs, but it also possess some unique features that support the erection of a new genus and species, including a stright dentary (a simoidal dentary was previously considered an autapomorphy of hongshanornithids), teeth preserved on both the upper and lower jaws, sternal caudolateral trabecula has a distinct fan-shaped expended distal end. With the addition of this new taxon, Hongshanornithidae represents the most diverse recoginuzed clade of Early Cretaceous orinthuromorphs. The new specimen reveals new important morphological information regarding the Hongshanornithidae and confirms the controversial presence of teeth in this clade.
A new specimen of the Early Cretaceous bird Hongshanornis longicresta: insights into the aerodynamics and diet of a basal ornithuromorph
Authors:
Chiappe et al
Abstract:
The discovery of Hongshanornis longicresta, a small ornithuromorph bird with unusually long hindlimb proportions, was followed by the discovery of two closely related species, Longicrusavis houi and Parahongshanornis chaoyangensis. Together forming the Hongshanornithidae, these species reveal important information about the early diversity and morphological specialization of ornithuromorphs, the clade that contains all living birds. Here we report on a new specimen (DNHM D2945/6) referable to Hongshanornis longicresta that contributes significant information to better understand the morphology, trophic ecology, and aerodynamics of this species, as well as the taxonomy of the Hongshanornithidae. Most notable are the well-preserved wings and feathered tail of DNHM D2945/6, which afford an accurate reconstruction of aerodynamic parameters indicating that as early as 125 million years ago, basal ornithuromorphs had evolved aerodynamic surfaces comparable in size and design to those of many modern birds, and flight modes alike to those of some small living birds.
