| Gansuids Temporal range: Cretaceous | |
|---|---|
 | |
| Fossil specimen of Gansus zheni | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | Theropoda |
| Clade: | Avialae |
| Clade: | Euornithes |
| Family: | † Gansuidae Hou & Liu, 1984 |
| Type genus | |
| Gansus Hou & Liu, 1984 | |
| Genera | |
| |
Gansuidae is an extinct family of euornithean birds known from the Early Cretaceous of China and possibly the Late Cretaceous of Mongolia.
The Gansuidae was originally established as a monotypic family by Hou & Liu in their 1984 description of their new genus Gansus from the Xiagou Formation. Their characterization for this clade included shorebirds with slender toes, a long digit IV, and a laterally compressed tarsometatarsus shorter than the third and fourth digits. [1] A second Gansus species, G. zheni, was described in 2014 from the Jiufotang Formation. [2]
The clade received little attention in the following years, with most analyses failing to recover a substantial clade of taxa besides Gansus spp. However, the 2024 description of the genus Shuilingornis —also from the Jiufotang Formation—shed light on the relationships of several euornithean birds, with several taxa clustering in a monophyletic clade. Besides Gansus (the type genus of the family) and Shuilingornis, the group likely also includes Changzuiornis (Jiufotang Fm.), [3] Iteravis (Yixian Formation), [4] and Khinganornis (Longjiang Formation). [5] These five genera were found in Aptian-aged (Early Cretaceous) outcrops in China. [6]
The genus Hollanda is known from a fragmentary skeleton described in 2010 from the Campanian-aged (Late Cretaceous) Barun Goyot Formation of Mongolia. Originally identified as an ornithuromorphan, [7] later analyses recovered conflicting phylogenetic positions, suggesting possible affinities with Songlingornis [8] or even the Enantiornithes. [9] In their description of Shuilingornis, Wang et al. (2024) noted Hollanda as one of several "wildcard taxa". When included in their phylogenetic analyses, it was recovered as a late-diverging member of the Gansuidae, as the sister taxon to Changzuiornis. However, they cautioned that these particular results were tentative and should not be considered definitive without the discovery of additional fossil material. [6]
In their phylogenetic analyses, Wang et al. (2024) recovered the Gansuidae as a clade of euornithean birds as the sister taxon to the Ornithuromorpha. Their results are displayed in the cladogram below: [6]
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The Enantiornithes, also known as enantiornithines or enantiornitheans in literature, are a group of extinct avialans, the most abundant and diverse group known from the Mesozoic era. Almost all retained teeth and clawed fingers on each wing, but otherwise looked much like modern birds externally. Over eighty species of Enantiornithes have been named, but some names represent only single bones, so it is likely that not all are valid. The Enantiornithes became extinct at the Cretaceous–Paleogene boundary, along with Hesperornithes and all other non-avian dinosaurs.
The Yixian Formation is a geological formation in Jinzhou, Liaoning, People's Republic of China, that spans the Barremian stage of the Early Cretaceous. It is known for its exquisitely preserved fossils, and is mainly composed of basalts interspersed with siliciclastic sediments.
Gansus is a genus of aquatic birds that lived during the Aptian age of the Early Cretaceous (Aptian-Albian) period in what are now Gansu and Liaoning provinces, western China. The rock layers from which their fossils have been recovered are dated to 120 million years ago. It was first described in 1984 on the basis of an isolated left leg. It is the oldest-known member of the Ornithurae, the group which includes modern birds (Neornithes) and extinct related groups, such as Ichthyornis and Hesperornithes.
The Xiagou Formation is the middle strata of the Xinminbao Group. It is named for its type site in Xiagou, in the Changma Basin of Gansu Province, northwestern China and is considered Early Cretaceous in age. It is known outside the specialized world of Chinese geology as the site of a Lagerstätte in which the fossils were preserved of Gansus yumenensis, the earliest true modern bird.
The Jehol Biota includes all the living organisms – the ecosystem – of northeastern China between 133 and 120 million years ago. This is the Lower Cretaceous ecosystem which left fossils in the Yixian Formation and Jiufotang Formation. These deposits are composed of layers of tephra and sediment. It is also believed to have left fossils in the Sinuiju series of North Korea. The ecosystem in the Lower Cretaceous was dominated by wetlands and numerous lakes. Rainfall was seasonal, alternating between semiarid and mesic conditions. The climate was temperate. The Jehol ecosystem was interrupted periodically by ash eruptions from volcanoes to the west. The word "Jehol" is a historical transcription of the former Rehe Province.
The Jiufotang Formation is an Early Cretaceous geological formation in Chaoyang, Liaoning which has yielded fossils of feathered dinosaurs, primitive birds, pterosaurs, and other organisms. It is a member of the Jehol group. The exact age of the Jiufotang has been debated for years, with estimates ranging from the Late Jurassic to the Early Cretaceous. New uranium-lead dates reveal the formation is deposited in the Aptian stage of the Early Cretaceous. Fossils of Microraptor and Jeholornis are from the Jiufotang.
Shanweiniao is a genus of long-snouted enantiornithean birds from Early Cretaceous China. One species is known, Shanweiniao cooperorum. There is one known fossil, a slab and counterslab. The fossil is in the collection of the Dalian Natural History Museum, and has accession number DNHM D1878/1 and DNHM1878/2. It was collected from the Lower Cretaceous Dawangzhengzi Beds, middle Yixian Formation, from Lingyuan in the Liaoning Province, China.
The Yixian Formation is a geological formation in Jinzhou, Liaoning, People's Republic of China, that spans about 1.6 million years during the early Cretaceous period. It is known for its fossils, listed below.
Hongshanornithidae is an extinct group of early ornithuromorph birds from the early Cretaceous period of China. It includes the genera Hongshanornis and Tianyuornis from the Yixian Formation of Inner Mongolia, Longicrusavis from the Yixian Formation of Liaoning Province, Parahongshanornis from the Jiufotang Formation of Liaoning Province, and Archaeornithura, the oldest known member, from the Huajiying Formation of Hebei Province.
Songlingornithidae is a family of basal euornithean dinosaurs from the Early Cretaceous of China. All known specimens come from the Jiufotang Formation and the Yixian Formation, dating to the early Barremian and Aptian ages, 125–120 million years ago.
Yanornithiformes is an order of ornithuromorph dinosaurs from the early Cretaceous Period of China. All known specimens come from the Yixian Formation and Jiufotang Formation, dating to the early Aptian age, 124.6 to 120 million years ago.
Longipterygidae is a family of early enantiornithean avialans from the Early Cretaceous epoch of China. All known specimens come from the Jiufotang Formation and Yixian Formation, dating to the early Aptian age, 125-120 million years ago.
Luis María Chiappe is an Argentine paleontologist born in Buenos Aires who is best known for his discovery of the first sauropod nesting sites in the badlands of Patagonia in 1997 and for his work on the origin and early evolution of Mesozoic birds. He is currently the Vice President of Research and Collections at the Natural History Museum of Los Angeles County and director of the museum's Dinosaur Institute. He was a postdoctoral researcher at the American Museum of Natural History, New York after immigrating from Argentina. Chiappe is currently the curator of the award winning Dinosaur Hall at the Natural History Museum of Los Angeles County, an adjunct professor at the University of Southern California, BBC advisor and author of scientific and popular books.
Chuanqilong is a monospecific genus of basal ankylosaurid dinosaur from the Liaoning Province, China that lived during the Early Cretaceous in what is now the Jiufotang Formation. The type and only species, Chuanqilong chaoyangensis, is known from a nearly complete skeleton with a skull of a juvenile individual. It was described in 2014 by Fenglu Han, Wenjie Zheng, Dongyu Hu, Xing Xu, and Paul M. Barrett. Chuanqilong shows many similarities with Liaoningosaurus and may represent a later ontogenetic stage of the taxon.
Changzuiornis is an extinct genus of ornithuromorph bird from the Early Cretaceous of present-day China. It contains a single species, C. ahgmi.
Juehuaornis is an extinct genus of ornithuromorph dinosaurs from the Early Cretaceous of present-day China. It contains a single species, J. zhangi.
Khinganornis is a genus of ornithuromorph dinosaurs from the Early Cretaceous Longjiang Formation of Liaoning, China. The genus contains a single species, Khinganornis hulunbuirensis, known from a nearly complete fossil preserved on a slab and counter slab. The holotype most likely represents an adult individual.
Migmanychion is an extinct genus of maniraptoran theropod dinosaur from the Early Cretaceous Longjiang Formation of China. The genus contains a single species, M. laiyang, known from an incomplete left forelimb.
Shuilingornis is an extinct genus of gansuid euornithean birds from the Early Cretaceous Jiufotang Formation of China. The genus contains a single species, S. angelai, known from a nearly complete articulated skeleton. As a member of the Gansuidae, Shuilingornis represents one of the earliest known birds known to demonstrate semi-aquatic adaptations.
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