Bohaiornithids Temporal range: Early Cretaceous, | |
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Fossil specimen of Zhouornis hani | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Dinosauria |
Clade: | Saurischia |
Clade: | Theropoda |
Clade: | Avialae |
Clade: | † Enantiornithes |
Family: | † Bohaiornithidae Wang et al., 2014 |
Type species | |
† Bohaiornis guoi Hu et al., 2011 | |
Genera | |
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Bohaiornithidae is a group of early predatory enantiornithean dinosaurs from the early Cretaceous Period of China. All known specimens come from the Jiufotang Formation and Yixian Formation, dating to the early Aptian age, 125–120 million years ago. Bohaiornithidae was first coined by Wang and colleagues in 2014. They defined it as the natural group formed by all descendants of the common ancestor of the type species, Bohaiornis guoi , and Shenqiornis mengi . [2]
Similar to most enantiornitheans, bohaiornithids possessed teeth rather than a beak as in modern birds, although they could be distinguished from other enantiornitheans due to the structure of their teeth. Their teeth were large, robust and somewhat conical, but had sharply pointed tips which curved backwards. The first few teeth of the premaxillae are smaller than the rest of the teeth, but the other teeth in the front of the mouth were larger than those in the back. [3]
Bohaiornithids also had lateral trabeculae (a pair of long and thin bony projections on the rear edge of the sternum) which not only extended backwards, but also outwards. The tips of each branch of the furcula (wishbone) are wide and rounded in bohaiornithids, as opposed to the tapering tips in other enantiornitheans. Their scapulae (shoulder blades) slightly curve downwards, created a convex top edge and concave lower edge. Bohaiornithids also had gradually tapering pygostyles. A bohaiornithid's second (innermost) toes were thicker than their other toes, while their third (middle) toes were long and thin and all of their toe claws were very long and curved. [2]
Most adult bohaiornithids would have been rather similar in size and appearance to each other, and the family lacked the longevity and physical diversity of some other enantiornithean groups, such as the long-snouted longipterygids. The only specimens of bohaiornithids believed to have reached adulthood (the holotype of Zhouornis and a referred specimen of Bohaiornis ) were also the largest specimens, and were about the size of a pigeon, which is much larger than most other Jehol enantiornitheans with the exception of Pengornis and Xiangornis . [4] The smallest and youngest bohaiornithid specimens were about half the size of the largest ones. [3]
Many bohaiornithids have been found preserving feathers, and a few possessed a pair of long, ribbon-like tail feathers with barbs only at the tips. These specialized feathers are known in many enantiornithean specimens (as well as Confuciusornis ), and may be an example of sexual dimorphism, with the feathers being used by male members of a species for courtship display. A subadult specimen of an indeterminate bohaiornithid described in 2017 preserved feathers on various parts of the head and body which were analyzed and determined to have been iridescent in life. [3]
A referred adult specimen of Bohaiornis was preserved with several rocks concentrated in the stomach region. Rocks in the stomach of birds and other animals are often believed to be gastroliths swallowed to assist in the digestion of plant material. However, the rocks apparently swallowed by this specimen are much larger, coarser, and less numerous than most gastroliths, and were unlikely to have been used for the same purpose as those swallowed by herbivores. Instead, it has been suggested that they were swallowed to help clean the digestive tract, a usage which has been reported in living birds of prey as well as other carnivorous animals with high-fat diets, such as pinnipeds. [5] The description of this specimen claimed that it was plausible, but uncertain, that Bohaiornis was ecologically similar to birds of prey. [6]
However, these rocks were later found to be mineral concretions, probably formed from the same mineral as the fossil specimen. Thus, they are not indicative of diet. [7]
Bohaiornithids had foot proportions which were between those expected of arboreal and terrestrial birds, but their long claws make terrestrial habits unlikely. Nevertheless, bohaiornithids lacked many of the specialized foot features which allow modern birds to perch and climb tree trunks. Although long claws are known in modern birds of prey, bohaiornithids had short tarsometatarsals (ankle bones) which were dissimilar to most raptors with the exception of members of the subfamily Perninae. [2]
Among birds of prey, bohaiornithids had leg proportions most similar to ospreys, and thus it is conceivable that they were piscivorous. However, their teeth suggest a diet of hard-shelled creatures. [2]
The cladogram below was found in the phylogenetic analysis of Wang et al. 2014, which itself was an updated version of O’Connor et al. 2013. [8] The cladogram is based on a data matrix that includes 56 avialan taxa, scored based on 262 morphological traits. [2]
The Wang et al. phylogenetic analysis was reused during the description of Linyiornis in 2016. This study it indicated that previously known bohaiornithid taxa formed a polytomy with Linyiornis and Fortunguavis , supporting the possibility that those two genera are also examples of the family, although Fortunguavis is notoriously difficult to place phylogenetically. [9]
Confuciusornis is a genus of basal crow-sized avialan from the Early Cretaceous Period of the Yixian and Jiufotang Formations of China, dating from 125 to 120 million years ago. Like modern birds, Confuciusornis had a toothless beak, but closer and later relatives of modern birds such as Hesperornis and Ichthyornis were toothed, indicating that the loss of teeth occurred convergently in Confuciusornis and living birds. It was thought to be the oldest known bird to have a beak, though this title now belongs to an earlier relative Eoconfuciusornis. It was named after the Chinese moral philosopher Confucius. Confuciusornis is one of the most abundant vertebrates found in the Yixian Formation, and several hundred complete specimens have been found.
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.
Jeholornis is a genus of avialan dinosaurs that lived between approximately 122 and 120 million years ago during the early Cretaceous Period in China. Fossil Jeholornis were first discovered in the Jiufotang Formation in Hebei Province, China and additional specimens have been found in the older Yixian Formation.
Hongshanornis is a genus of ornithuromorph birds known from early Cretaceous lake deposits of the Yixian Formation, Inner Mongolia, China. The holotype specimen, recovered in 2005, is currently held by the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing. It was found in the Jianshangou fossil beds, dated to 124.6 million years ago. Three additional specimens have been reported, though only one of those has been definitively identified as belonging to Hongshanornis. This latter specimen was found in the Dawangzhangzi fossil beds, which are about 122 million years old.
Cuspirostrisornis is a genus of enantiornithean bird. Only one species is known, Cuspirostrisornis houi, though some researchers believe this to be a synonym of the similar species Cathayornis yandica. It is known from one fossil found in the Jiufotang Formation in Liaoning province, People's Republic of China. The Jiufotang Formation is dated to the Early Cretaceous period, Aptian age, 120.3 +/-0.7 million years ago.
Yixianornis is a bird genus from the early Cretaceous period. Its remains have been found in the Jiufotang Formation at Chaoyang dated to the early Aptian age, around 120 million years ago. Only one species, Yixianornis grabaui, is known at present. The specific name, grabaui, is named after American paleontologist Amadeus William Grabau, who surveyed China in the early 20th century.
Pygostylia is a group of avialans which includes the Confuciusornithidae and all of the more advanced species, the Ornithothoraces.
Protopteryx is an extinct bird and possibly the basalmost enantiornithean, from the Cretaceous period. The type species is P. fengningensis. It was first discovered in the Sichakou Member of the Yixian Formation or Huajiying Formation of Hebei Province, northern China, dating from 131 Ma ago. Protopteryx has been found in the Daibeigou formation, as well. The name Protopteryx means "primitive feather": "proto-" meaning "the first of" and "-pteryx" meaning "feather" or "wing." The name comes from the fact that Protopteryx feathers are more primitive than those of modern birds, such as the two elongated tail feathers that lack barbs and rami.
Avisauridae is a family of extinct enantiornithine dinosaurs from the Cretaceous period, distinguished by several features of their ankle bones. Depending on the definition used, Avisauridae is either a broad and widespread group of advanced enantiornithines, or a small family within that group, restricted to species from the Late Cretaceous of North and South America.
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.
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.
Bohaiornis is a genus of enantiornithean dinosaurs. Fossils have been found from the Lower Cretaceous Jiufotang Formation of western Liaoning, China. The only known species, Bohaiornis guoi, was named by Dongyu Hu, Li Li, Lianhaim Hou and Xing Xu in 2011 on the basis of a fully articulated and well-preserved skeleton of a sub-adult. This specimen, LPM B00167, preserved two long, ribbon-like feathers attached to the tail rather than a fan of shorter pennaceous feathers. It was similar to the slightly older Eoenantiornis, but much larger in size. Bohaiornis is the type species of Bohaiornithidae, a family of large predatory enantiornitheans from the Early Cretaceous.
Sulcavis is a genus of enantiornithean birds. One species is named, Sulcavis geeorum. The fossil was found in Early Cretaceous rocks in Liaoning Province, China.
Parabohaiornis is an extinct genus of bohaiornithid enantiornithean dinosaur known from the Early Cretaceous of Liaoning Province, northeastern China. It contains a single species, Parabohaiornis martini.
Longusunguis is an extinct genus of bohaiornithid enantiornithean dinosaur known from the Early Cretaceous of Liaoning Province, northeastern China. It contains a single species, Longusunguis kurochkini.
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.
Pengornithidae is a group of early enantiornithines from the early Cretaceous Period of China, with the putative member Falcatakely possibly extending this clade's range into the Late Cretaceous of Madagascar, and several putative pengornithids also hail from this formation. Specimens of these animals have been found both in the Huajiying Formation and Jiufotang Formation of Liaoning and Hebei provinces, dating from the Hauterivian age to the Aptian age.
Cruralispennia is an extinct genus of enantiornithean bird. The only known specimen of Cruralispennia was discovered in the Early Cretaceous Huajiying Formation of China and formally described in 2017. The type species of Cruralispennia is Cruralispennia multidonta. The generic name is Latin for "shin feather", while the specific name means "many-toothed". The holotype of Cruralispennia is IVPP 21711, a semi-articulated partial skeleton surrounded by the remains of carbonized feathers.
Chiappeavis is a genus of enantiornithean bird from Early Cretaceous of northeastern China. The only species is Chiappeavis magnapremaxillo. Chiappeavis is classified within the family Pengornithidae. It is known from a single, almost complete skeleton including feather impressions discovered in the Jiufotang Formation of the Jehol Group. Long feathers formed a fan-shaped tail that was probably employed in flight.