Ecological preferences and life history strategies have enormous impacts on the evolution and phenotypic diversity of salamanders, but the yet established reliable ecological indicators from bony ...skeletons hinder investigations into the paleobiology of early salamanders. Here, we statistically demonstrate by using time-calibrated cladograms and geometric morphometric analysis on 71 specimens in 36 species, that both the shape of the palate and many non-shape covariates particularly associated with vomerine teeth are ecologically informative in early stem- and basal crown-group salamanders. Disparity patterns within the morphospace of the palate in ecological preferences, life history strategies, and taxonomic affiliations were analyzed in detail, and evolutionary rates and ancestral states of the palate were reconstructed. Our results show that the palate is heavily impacted by convergence constrained by feeding mechanisms and also exhibits clear stepwise evolutionary patterns with alternative phenotypic configurations to cope with similar functional demand. Salamanders are diversified ecologically before the Middle Jurassic and achieved all their present ecological preferences in the Early Cretaceous. Our results reveal that the last common ancestor of all salamanders share with other modern amphibians a unified biphasic ecological preference, and metamorphosis is significant in the expansion of ecomorphospace of the palate in early salamanders.
A new salamandroid salamander, Qinglongtriton gangouensis (gen. et sp. nov.), is named and described based on 46 fossil specimens of juveniles and adults collected from the Upper Jurassic (Oxfordian) ...Tiaojishan Formation cropping out in Hebei Province, China. The new salamander displays several ontogenetically and taxonomically significant features, most prominently the presence of a toothed palatine, toothed coronoid, and a unique pattern of the hyobranchium in adults. Comparative study of the new salamander with previously known fossil and extant salamandroids sheds new light on the early evolution of the Salamandroidea, the most species-diverse clade in the Urodela. Cladistic analysis places the new salamander as the sister taxon to Beiyanerpeton, and the two taxa together form the basalmost clade within the Salamandroidea. Along with recently reported Beiyanerpeton from the same geological formation in the neighboring Liaoning Province, the discovery of Qinglongtriton indicates that morphological disparity had been underway for the salamandroid clade by early Late Jurassic (Oxfordian) time.
A Jurassic salamander, Beiyanerpeton jianpingensis (gen. et sp. nov.), from a recently found site in western Liaoning Province, China is the earliest known record of Salamandroidea. As a Late ...Jurassic record of the group, it extends the range of the clade by approximately 40 Ma. The Late Jurassic taxon is neotenic and represented by exceptionally preserved specimens, including fully articulated cranial and postcranial skeletons and bony gill structures close to the cheek region. The fossil beds, consisting of dark-brown volcanic ash shales of the Upper Jurassic Tiaojishan (Lanqi) Formation (Oxfordian), underlie trachyandesite rocks that have yielded a SHRIMP zircon U-Pb date of 157 ± 3 Ma. The fossiliferous beds are substantially older than the Jehol Group, including the Yixian Formation (40Ar/39Ar dates of 122–129 Ma), but slightly younger than the Middle Jurassic Daohugou horizon (40Ar/39Ar date of 164 ± 4 Ma). The early fossil taxon shares with extant salamandroids derived character states, including: separated nasals lacking a midline contact, angular fused to the prearticular in the lower jaw, and double-headed ribs on the presacral vertebrae. In contrast to extant salamandroids, however, the salamander shows a discrete and tooth-bearing palatine, and unequivocally nonpedicellate and monocuspid marginal teeth in large and presumably mature individuals. The finding provides insights into the evolution of key characters of salamanders, and also provides direct evidence supporting the hypothesis that the split between Cryptobranchoidea and Salamandroidea had taken placed before the Late Jurassic Oxfordian time. In this aspect, both paleontological and molecular data now come to agree.
Plumage Color Patterns of an Extinct Dinosaur Li, Quanguo; Gao, Ke-Qin; Vinther, Jakob ...
Science (American Association for the Advancement of Science),
03/2010, Volume:
327, Issue:
5971
Journal Article
Peer reviewed
Open access
For as long as dinosaurs have been known to exist, there has been speculation about their appearance. Fossil feathers can preserve the morphology of color-imparting melanosomes, which allow color ...patterns in feathered dinosaurs to be reconstructed. Here, we have mapped feather color patterns in a Late Jurassic basal paravian theropod dinosaur. Quantitative comparisons with melanosome shape and density in extant feathers indicate that the body was gray and dark and the face had rufous speckles. The crown was rufous, and the long limb feathers were white with distal black spangles. The evolution of melanin-based within-feather pigmentation patterns may coincide with that of elongate pennaceous feathers in the common ancestor of Maniraptora, before active powered flight. Feathers may thus have played a role in sexual selection or other communication.
Indescent feather colors involved in displays of many extant birds are produced by nanoscale arrays of melanin-containing organelles (melanosomes). Data relevant to the evolution of these colors and ...the properties of melanosomes involved in their generation have been limited. A data set sampling variables of extant avian melanosomes reveals that those forming most iridescent arrays are distinctly narrow. Quantitative comparison of these data with melanosome imprints densely sampled from a previously unknown specimen of the Early Cretaceous feathered Microraptor predicts that its plumage was predominantly iridescent. The capacity for simple iridescent arrays is thus minimally inferred in pa ravi a n dinosaurs. This finding and estimation of Microraptor feathering consistent with an ornamental function for the tail suggest a centrality for signaling in early evolution of plumage and feather color.
Summary
Atherosclerosis is a chronic inflammatory disease. Recently, a growing body of evidence emphasizes that the monocyte and macrophage differentiation and activation are key processes in the ...development of atherosclerosis. However, the regulatory mechanism that manipulates the function of monocyte and macrophage is still unclear. Recent years, epigenetic mechanisms have received a wide attention and bring us a new field of vision. More and more evidence shows that epigenetics weighs heavily in atherosclerosis by regulating the function and differentiation states of monocyte and macrophage. In this review, we illuminate the epigenetic regulation mechanisms in monocyte and macrophage and their contributions to inflammatory processes of atherosclerosis to provide new thoughts and find novel targets or biomarkers for atherosclerosis.
A new fossil salamander,
(gen. et sp. nov.), is named and described based on specimens from the Lower Cretaceous Guanghua Formation of Inner Mongolia, China. The new discovery documents a far ...northern occurrence of Early Cretaceous salamanders in China, extending the geographic distribution for the Mesozoic fossil record of the group from the Jehol area (40th-45th parallel north) to near the 49th parallel north. The new salamander is characterized by having the orbitosphenoid semicircular in shape; coracoid plate of the scapulocoracoid greatly expanded with a convex ventral and posterior border; ossification of two centralia in carpus and tarsus; and first digit being about half the length of the second digit in both manus and pes. The new salamander appears to be closely related to hynobiids, although this inferred relationship awaits confirmation by research in progress by us on a morphological and molecular combined analysis of cryptobranchoid relationships. Comparison of adult with larval and postmetamorphic juvenile specimens provides insights into developmental patterns of cranial and postcranial skeletons in this fossil species, especially resorption of the palatine and anterior portions of the palatopterygoid in the palate and the coronoid in the mandible during metamorphosis, and postmetamorphic ossification of the mesopodium in both manus and pes. Thus, this study provides a rare case study of developmental features in a Mesozoic salamander.
Batrachuperus yenyuanensis, commonly known as Yenyuan Stream Salamander, is a hynobiid species inhabiting high-altitude (2440-4025 m above sea level) mountain stream and pond environments along the ...eastern fringe of the Qinghai-Tibetan Plateau in western Sichuan Province, China. Although the species has been known for almost 70 years since its initial discovery in 1950, a thorough osteological description has never been provided. Our study provides a detailed account of the bony anatomy of this species, based on micro computed tomography scanning of multiple specimens collected from the type locality Shuangertang at Bailinshan, Yanyuan County, and several other localities in Sichuan Province. Our revised species diagnosis utilizes both bony and soft anatomical features. Comparative study of the specimens from the type locality in Yanyuan area with those from the nearby Xichang and Mianning areas confirms that they all pertain to Batrachuperus yenyuanensis, thereby removing doubt on the occurrence of the species in the latter areas. With this confirmation, the distribution of the species is extended from the type locality northwards some 180 km to the Mianning area, on both the west and east sides of the Yalong River, which is a major tributary of the upper Yangtze River. This distribution pattern indicates that the biogeographic origin and historical evolution of the species are closely associated with the orogeny of the Hengduan Mountains and formation of the Yalong River. Given the basalmost position of Batrachuperus yenyuanensis in relation to other congeneric species based on molecular studies, however, early expansion of the species distribution by dispersal is expected following the origin of the genus in early-middle Miocene in western Sichuan Province. Thus, the species may well have achieved its current distribution in western Sichuan before the drastic uplift of the Qinghai-Tibetan Plateau in Pliocene.
Hynobiidae are a clade of salamanders that diverged early within the crown radiation and that retain a considerable number of features plesiomorphic for the group. Their evolutionary history is ...informed by a fossil record that extends to the Middle Jurassic Bathonian time. Our understanding of the evolution within the total group of Hynobiidae has benefited considerably from recent discoveries of stem hynobiids but is constrained by inadequate anatomical knowledge of some extant forms. Pseudohynobius is a derived hynobiid clade consisting of five to seven extant species living endemic to southwestern China. Although this clade has been recognized for over 37 years, osteological details of these extant hynobiids remain elusive, which undoubtedly has contributed to taxonomic controversies over the hynobiid complex Liua‐Protohynobius‐Pseudohynobius. Here we provide a bone‐by‐bone study of the cranium in the five extant species of Pseudohynobius (Ps. flavomaculatus, Ps. guizhouensis, Ps. jinfo, Ps. kuankuoshuiensis and Ps. shuichengensis) based on x‐ray computer tomography data for 18 specimens. Our results indicate that the cranium in each of these species has a combination of differences in morphology, proportions and articulation patterns in both dermal and endochondral bones. Our study establishes a range of intraspecific differences that will serve as organizing hypotheses for future studies as more extensive collections of these species become available. Morphological features in the cranium for terrestrial ecological adaptation in Hynobiidae are summarized. Based on the results, we also discuss the evolution and development of several potential synapomorphies of Hynobiidae, including features of the orbitosphenoid and articular.
Our bone‐by‐bone study on the cranium of five species in a rare hynobiiid salamander genus, Pseudohynobius, not only reveal several morphological features for terrestrial adaptation in hynobiids, but also found several potential synapomorphies uniting crown or stem and crown Hynobiidae. Our findings are essential in understanding the palaeoecology and character evolution in hynobiid salamanders along with accumulating fossil discoveries of this clade in the Mesozoic Era.
Salamanders are a model system for studying the rates and patterns of the evolution of new anatomical structures. Recent discoveries of abundant Late Jurassic and Early Cretaceous salamanders are ...helping to address these issues. Here we report the discovery of well-preserved Middle Jurassic salamanders from China, which constitutes the earliest known record of crown-group urodeles (living salamanders and their closest relatives). The new specimens are from the volcanic deposits of the Jiulongshan Formation (Bathonian), Inner Mongolia, China, and represent basal members of the Cryptobranchidae, a family that includes the endangered Asian giant salamander (Andrias) and the North American hellbender (Cryptobranchus). These fossils document a Mesozoic record of the Cryptobranchidae, predating the previous record of the group by some 100 million years. This discovery provides evidence to support the hypothesis that the divergence of the Cryptobranchidae from the Hynobiidae had taken place in Asia before the Middle Jurassic period.Amphibia Linnaeus, 1758Lissamphibia Haeckel, 1866Caudata Scopoli, 1777Urodela Dumeril, 1806Cryptobranchoidea Dunn, 1922Cryptobranchidae Fitzinger, 1826Chunerpeton tianyiensis gen. et sp. nov.
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