Liaobatrachus Temporal range: Early Cretaceous, | |
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Artist's reconstruction | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Amphibia |
Order: | Anura |
Family: | Pelobatidae |
Genus: | † Liaobatrachus Ji & Ji, 1998 |
Type species | |
Liaobatrachus grabaui Ji & Ji, 1998 | |
Other species | |
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Synonyms | |
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Liaobatrachus (meaning "Liaoning frog") is a genus of prehistoric frog, the first fossil specimen of which was recovered from the Yixian Formation of Liaoning Province, China. It was the first Mesozoic era frog ever found in China. [1] The species Callobatrachus sanyanensis, Mesophryne beipiaoensis and Yizhoubatrachusmacilentus were classified as species of Liaobatrachus in one study, but this has been rejected by other authors. The genus has been considered a nomen dubium by some authors due to the poor preservation of the holotype specimen. [2] Fossils were found in the Sihetun locality of the western part of Liaoning province, in the lower part of the Yixian Formation, and date to approximately 124.6 Ma. Another specimen was collected near Heitizigou, 25 kilometres (16 mi) south of Beipiao. The specimen has a snout–vent length of 69 millimetres (2.7 in). [3] Liaobatrachus is considered to be the most basal member of Discoglossidae based on phylogenetic analysis. [4]
Fossil frogs are rarely found as multiple articulated skeletons, therefore the discovery of this taxon has provided important insight into anuran evolution. [5] [6]
The holotype, IVPP V11525, is known from a nearly complete skeleton exposed in a dorsal view on a shale slab. Its total body length (from snout to vent) is estimated at approximately 94 mm. [7] It differs morphologically in many respects from all other discoglossoids, including the number of presacral vertebrae (9 instead of the usual 8) and other primitive characters. Although it had a mosaic of primitive and derived characters, it can be unequivocally placed as the most basal taxon of the clade. This shows that the taxon diverged early from the stem and evolved separately as a distinct lineage by the Early Cretaceous in East Asia. [4]
The skull is described as being short and wide and is well preserved. The maxillary region is less well-preserved but it can be determined that each premaxilla bears 18–20 slender and conical teeth, and the maxilla bears approximately 40–50 fine pedicellate teeth. The vertebral column consists of nine presacral vertebrae, a single sacral vertebra, and a free urostyle. Three pairs of ribs were found associated with presacrals II–IV. The hind limbs are remarkably well-preserved and are slenderly built, with an approximate total length of 116 millimetres (4.6 in). Its hind feet have the phalangeal formula 2-2-3-4-3, with its fourth digit being the longest at 27 millimetres (1.1 in). [7]
Repenomamus is a genus of opossum- to badger-sized gobiconodontid mammal containing two species, Repenomamus robustus and Repenomamus giganticus. Both species are known from fossils found in China that date to the early Cretaceous period, about 125-123.2 million years ago. R. robustus is one of several Mesozoic mammals for which there is good evidence that it fed on vertebrates, including dinosaurs. Though it is not entirely clear whether or not these animals primarily hunted live dinosaurs or scavenged dead ones, evidence for the former is present in fossilized remains showcasing the results of what was most likely a predation attempt by R. robustus directed at a specimen of the dinosaur Psittacosaurus lujiatunensis. R. giganticus is among the largest mammals known from the Mesozoic era, only surpassed by Patagomaia.
Hyphalosaurus is a genus of freshwater aquatic reptiles, belonging to the extinct order Choristodera. They lived during the early Cretaceous period, about 123-120 million years ago. The genus contains two species, H. lingyuanensis from the Yixian Formation and H. baitaigouensis from both the Yixian and Jiufotang Formation of Liaoning Province, China. They are among the best-known animals from the Jehol Biota, with thousands of fossil specimens representing all growth stages in scientific and private collections.
Feilongus is an extinct genus of ctenochasmatid pterodactyloid pterosaur from the Barremian–Aptian-age Lower Cretaceous Yixian Formation of Beipiao, Liaoning, China.
Yixianopterus is a pterodactyloid pterosaur genus from the Barremian-Aptian-age Lower Cretaceous Yixian Formation of Liaoning, China. It is known from a single specimen, holotype JZMP-V-12, housed at the Benxi Geological Museum. This specimen was modified before acquisition, with much of the skull being fabricated. The Jinggangshan bedding in which the specimen was found is basaltic with siliciclastic sediments. Many organisms associated with this layer of the Yixian Formation are aquatic, indicating a marine environment with much volcanic activity.
Dongbeititan is a genus of sauropod dinosaur from the Early Cretaceous-age Yixian Formation of Beipiao, Liaoning, China. It is based on holotype DNHM D2867, a partial postcranial skeleton including bones from the limbs, shoulder and pelvic girdles, and vertebrae, which was described in 2007. Its describers suggested it was as a basal titanosauriform, not as derived as Gobititan or Jiutaisaurus, but more derived than Euhelopus, Fusuisaurus, and Huanghetitan. The type species is D. dongi, and it is the first named sauropod from the Yixian Formation, which is part of the well-known Jehol Group. The genus name refers to the region Dongbei and to Greek titan, "giant". The specific name honours the Chinese paleontologist Dong Zhiming. Like other sauropods, Dongbeititan would have been a large quadrupedal herbivore.
Mesophryne beipiaoensis is an extinct species of frog, from the Cretaceous Yixian Formation of Liaoning (China), and the only species in the genus Mesophryne. It is known from a single specimen collected near Heitizigou, 25 kilometres (16 mi) south of Beipiao, from which the specific epithet derives. The specimen has a snout–vent length of 69 millimetres (2.7 in). While some authors have suggested Mesophryne is a synonym of Liaobatrachus, this has been rejected by other authors. In a phylogenetic analysis it was found to be a crown group frog, which was more derived than Ascaphus and Leiopelma, but less so than alytids and other more advanced frogs.
Jeholotriton is a genus of primitive salamander from the Daohugou Beds near Daohugou village of Inner Mongolia, China.
Callobatrachus is an extinct genus of frog from the Early Cretaceous-age Yixian Formation of Liaoning, China. It was described in 1999 by K. Gao of the American Museum of Natural History and Y. Wang of the Chinese Academy of Sciences. It was discovered in the Sihetun locality of the western part of Liaoning province.
Pangerpeton is an extinct genus of salamanders. Its monotypic species is Pangerpeton sinensis.
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 Salientia are a total group of amphibians that includes the order Anura, the frogs and toads, and various extinct proto-frogs that are more closely related to the frogs than they are to the Urodela, the salamanders and newts. The oldest fossil "proto-frog" appeared in the early Triassic of Madagascar, but molecular clock dating suggests their origins may extend further back to the Permian, 265 million years ago.
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.
Thoraciliacus rostriceps is an extinct species of frog from the Cretaceous period and the only species of the genus Thoraciliacus, which is classified in the unranked clade Pipimorpha. A recent phylogenetic analysis confirmed this conclusion, and further suggested that Thoraciliacus rostriceps is more closely related to Pipidae and Shelaniinae than to Palaeobatrachus. Fossils of T. rostriceps were found in Makhtesh Ramon, Negev Desert, Israel and it is believed they lived during the Barremian. Other fossils have been found near Marydale, South Africa in an Upper Cretaceous lake.
Monjurosuchus is a genus of choristoderan reptile that lived in what is now China and Japan during the Early Cretaceous. It has large eyes, a rounded skull, robust legs with short claws, and a long, thin tail. Fossils have been found that preserve soft tissue, showing that it had soft skin and webbed feet.
Zhenyuanopterus is a genus of boreopterid pterosaur which is known from Lower Cretaceous Yixian Formation of Liaoning, China. It contains one species, Zhenyuanopterus longirostris, which was first described and named by Lü Junchang.
Longicrusavis is an extinct genus of basal ornithuromorph bird found only at Dawangzhangzi village in Liaoning Province, China. Longicrusavis was a ground dwelling carnivore, a wader, and part of biological family Hongshanornithidae, considered to have been a dominant species in the Jehol Biota, the prehistoric Chinese ecosystem which supported them. The name Hongshanornithidae represents one of China's oldest recorded cultures in the region, the Hongshan culture.
Liushusaurus is an extinct genus of lizard described by Susan E. Evans and Yuan Wang in 2010. The genus has a single species, Liushusaurus acanthocaudata, and is known from eight fossils, several of which preserve soft tissue detail. The specimens were found in the Lower Cretaceous aged Yixian Formation of Northeast China. Liushusaurus is one of eight lizards that are known and have been named from the Yixian Formation, part of the diverse Jehol Biota ecosystem.
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.
Daliansaurus is a genus of small troodontid theropod dinosaur, measuring approximately 1 metre long, from the Early Cretaceous of China. It contains a single species, D. liaoningensis, named in 2017 by Shen and colleagues from a nearly complete skeleton preserved in three dimensions. Daliansaurus is unusual in possessing an enlarged claw on the fourth digit of the foot, in addition to the "sickle claw" found on the second digit of the feet of most paravians. It also has long metatarsal bones, and apparently possesses bird-like uncinate processes. In the Lujiatun Beds of the Yixian Formation, a volcanically-influenced region with a cold climate, Daliansaurus lived alongside its closest relatives - Sinovenator, Sinusonasus, and Mei, with which it forms the group Sinovenatorinae.
Liaoningvenator is a genus of troodontid theropod dinosaur from the Early Cretaceous of China. It contains a single species, L. curriei, named after paleontologist Phillip J. Currie in 2017 by Shen Cai-Zhi and colleagues from an articulated, nearly complete skeleton, one of the most complete troodontid specimens known. Shen and colleagues found indicative traits that placed Liaoningvenator within the Troodontidae. These traits included its numerous, small, and closely packed teeth, as well as the vertebrae towards the end of its tail having shallow grooves in place of neural spines on their top surfaces.