Fig 5 - uploaded by Rong Yufen
Content may be subject to copyright.
Majority consensus trees showing positions of Chunerpeton tianyiense (in green) and crown Cryptobranchidae (in blue). (A) First analysis, generated using modified codings for Chunerpeton. (B) Second analysis, generated using modified codings for Iridotriton and Jeholotriton. See text for details and tree statistics.

Majority consensus trees showing positions of Chunerpeton tianyiense (in green) and crown Cryptobranchidae (in blue). (A) First analysis, generated using modified codings for Chunerpeton. (B) Second analysis, generated using modified codings for Iridotriton and Jeholotriton. See text for details and tree statistics.

Source publication
Article
Full-text available
Lacustrine deposits of Juro-Cretaceous age in northeastern China have yielded some of the best-preserved fossils of early crown salamanders. One of those taxa, Chunerpeton tianyiense, has been considered as a crown or stem member of the family Cryptobranchidae, significant for implying a long evolutionary history for cryptobranchids and for calibra...

Contexts in source publication

Context 1
... our first analysis, we modified fourteen codings (Appendix A, Section 3) for Chunerpeton in the matrix of Jia and Gao (2019), based on the new fossils we examined. The result of this analysis produced 30 most parsimonious trees (tree length = 314; consistency index = 0.449; retention index = 0.718). The 50% majority consensus tree (Fig. 5A) recovers Chunerpeton as the sister to two contemporary Chinese taxa (Beiyanerpeton + Qinglongtriton). The existence of this clade of Chunerpeton + (Beiyanerpeton + Qinglongtriton) is supported by three synapomorphies: separate nasals without midline contact [character 8(1)]; well-developed anterolateral process of parietal sur- passing ...
Context 2
... 3), based on details in relevant publications ( Evans et al., 2005;Wang and Rose, 2005;Carroll and Zheng, 2012), whereas both taxa were excluded in preceding study (Jia and Gao, 2019). Our second analysis produced 51 most parsimonious trees (tree length = 319; consistency index = 0.429; retention index = 0.708). The 50% majority consensus tree (Fig. 5B) retains the sister pair of Beiyanerpeton + Qinglongtriton in the same basal position, but shifts Chunerpeton one node crownward to become the sister to the remaining Mesozoic (except Karaurus) and all recent salamanders. Once again, Chunerpeton is far removed from crown Cryptobranchidae. As for the two re-coded taxa, Iridotriton ...
Context 3
... the family-level relations of living salamanders recovered in our first two analyses are inconsistent with molecular results (cf. Fig. 5A, B versus Fig. 6B), we performed a third analysis in which relationships of recent families were constrained by the molecular tree (Pyron and Wiens, 2011, Fig. 6B) and all fossil taxa are set as 'floaters'. That analysis produced 1211 most parsimonious trees and tree length equals to 344. The 50% majority consensus tree (Fig. 6A) recovers a trichotomy ...

Citations

... Several genera and species are known from the Middle/Late Jurassic boundary of China, including the stem-urodeles Chunerpeton tianyiensis [30,37,38] and Neimengtriton daohugouensis [30,39,40]. Beiyanerpeton jianpingensis [41] and Qinglongtriton gangouensis [42] were recovered in an earlybranching position within Salamandroidea by Jia & Gao [43], whereas Linglongtriton daxishanensis [43] and Pangerpeton sinensis [44] were placed on the stem-hynobiid lineage [43]. ...
Article
Full-text available
The disjunct geographical range of many lineages of caudates points to a complex evolutionary and biogeographic history that cannot be disentangled by only considering the present-day distribution of salamander biodiversity. Here, we provide a critical reappraisal of the published fossil record of caudates from the Palearctic and quantitatively evaluate the quality of the group's fossil record. Stem-Urodela and Karauridae were widespread in the Palearctic in the Middle Jurassic, suggesting an earlier, unsampled diversification for this group. Cryptobranchidae reached Europe no later than the Oligocene, but this clade was subsequently extirpated from this continent, as well as from western and central Asia. The relatively recent appearance of hynobiids in the fossil record (Early Miocene) is most likely an artefact of a taphonomic bias against the preservation of high-mountain, stream-type environments which early members likely inhabited. Salamandroids first appear in Europe, expanding into Asia by the Miocene. The apparently enigmatic and disjunct distribution of extant caudate lineages is therefore explained by a wider past geographical range, as testified by the fossil record, which was fragmented during the late Cenozoic by a combination of tectonic (i.e. the uplift of the Tibetan Plateau) and climatic drivers, resulting in regional extirpations.
... Recently, several Late Jurassic salamanders (namely Chunerpeton, Beiyanerpeton, Qinglongtriton and Pangerpeton) previously hypothesised to be members of the crowngroup were recognised as stem salamanders (see Jones et al. 2022). Trunk vertebra PIN 4767/2 from the Peski locality differs from those of Chunerpeton, Beiyanerpeton, and Qinglongtriton in smaller size (see discussion of body/trunk vertebrae sizes of karaurids, Chunerpeton and Beiyanerpeton in Skutschas et al. 2016b; for size of Qinglongtriton see also Jia and Gao 2016); from Chunerpeton and Pangerpeton in the presence of bicipital transverse processes (versus unicipital transverse processes in Chunerpeton and Pangerpeton; see Wang and Evans 2006;Rong et al. 2020), from Chunerpeton in the presence of the spinal nerve foramina (absent in Chunerpeton see e.g. Rong et al. 2020), from Beiyanerpeton in the lacking of subcentral keel (subcentral keel is well-developed in Beiyanerpeton; see Gao and Shubin 2012), and from Qinglongtriton in having widely separated transverse processes (weakly bifurcated in Qinglongtriton; Jia and Gao 2016). ...
... Trunk vertebra PIN 4767/2 from the Peski locality differs from those of Chunerpeton, Beiyanerpeton, and Qinglongtriton in smaller size (see discussion of body/trunk vertebrae sizes of karaurids, Chunerpeton and Beiyanerpeton in Skutschas et al. 2016b; for size of Qinglongtriton see also Jia and Gao 2016); from Chunerpeton and Pangerpeton in the presence of bicipital transverse processes (versus unicipital transverse processes in Chunerpeton and Pangerpeton; see Wang and Evans 2006;Rong et al. 2020), from Chunerpeton in the presence of the spinal nerve foramina (absent in Chunerpeton see e.g. Rong et al. 2020), from Beiyanerpeton in the lacking of subcentral keel (subcentral keel is well-developed in Beiyanerpeton; see Gao and Shubin 2012), and from Qinglongtriton in having widely separated transverse processes (weakly bifurcated in Qinglongtriton; Jia and Gao 2016). ...
Article
Crown salamanders first appeared in the Middle Jurassic (Bathonian) and remains of these oldest representatives of the group have been found in various vertebrate localities in China, Western Siberia, and Western Europe. Here, we report the discovery of an indeterminate crown salamander in the Middle Jurassic (Bathonian) Peski locality of Moskvoretskaya Formation of the Moscow Region, Russia. This find (a fragmentary trunk vertebra) represents (1) new occurrence of the oldest crown salamanders; and (2) the first fossil record of crown salamanders in the Middle Jurassic of Eastern Europe. The trunk vertebra from the Peski locality resembles those of the modern crown salamanders of the Salamandroidea clade in the presence of spinal nerve foramina and bicapitate transverse processes. If our assignment of the Peski salamander to Salamandroidea is correct, then it is the oldest salamandroid in the fossil record.
... tlaxiacus were included in our metatree following the phylogenetic relationships proposed by Jetz and Pyron (2018), with the same branch lengths as the most closely related lineage. For the phylogenetic projection on the Principal Component Analysis and Ancestral reconstruction of shape (see more details in the following sections), we also included the phylogenetic relationships for the fossil taxa included in our dataset (Beiyanerpeton jianpingensis, Chunerpeton tianyiense, Nuominerpeton aquilonaris, and Pangerpeton sinensis) based on Rong et al. (2021). In this case, we inferred branch lengths for the whole tree with compute.brlen ...
Article
Morphological patterns are modeled by the interaction of functional, phylogenetic, ecological, and/or developmental constraints. In addition, the evolution of life cycle complexity can favor phenotypic diversity; however, the correlation between stages of development may constrain the evolution of some organs. Salamanders present microhabitat and life cycle diversity, providing an excellent framework for testing how these factors constrain phenotypic evolution. We reconstructed the morphological evolution of the terminal phalanx using a sample of 60 extinct and living species of salamanders. Using a geometric morphometric approach combined with comparative analyses, we further investigated the impact of phylogenetic, ecological, and/or life cycle factors on the shape of the terminal phalanx. We find that the phylogeny has some influence in determining the dorsal shape of the phalanges; whereas a relationship between microhabitat or life cycle and the dorsal and lateral shapes of the phalanx was not observed in the analyzed species. The allometric pattern found in the phalanx shape implies that small phalanges are more curved and with more truncated end than bigger phalanges. The evolutionary rate of phalanx shape was higher in the semiaquatic species, and the morphological disparity was significantly higher on biphasic groups. These results contradict the hypothesis that a complex life cycle constrains body shape. Finally, the phalanx shape of the salamander remains quite conserved from the Mesozoic. This configuration would allow them to occur in the different microhabitats occupied by the salamander lineages.
... S45 and S46). It has a single tooth row located on its anterior process ( Fig. 1 C and D) as found in neotenic adults of the amphibamiform Apateon caducus (44), Mesozoic salamanders such as Kokartus, Beiyanerpeton, Qinglongtriton, and Chunerpeton (21,24,28,29), and larval forms of some modern salamanders (47). The pterygoid has a shallow trough on its dorsal surface ( Fig. 1 A and B and SI Appendix, Figs. ...
... Nonbifurcated transverse processes are present on the first five caudal vertebrae ( Fig. 2 K, L, and O). The first four caudal vertebrae represent caudosacrals as defined in (27) and as also reported for Chunerpeton and Qinglongtriton (27,28). Most caudal vertebrae have long posteriorly projecting neural spines and even longer haemal arches ( Fig. 2O and SI Appendix, Fig. S62 and S65-S67) that suggest a powerful tail for swimming. ...
... Our results differ from those of previous analyses, which recovered most Mesozoic taxa (except for karaurids) as crown salamanders, either as stem-salamandroids [Beiyanerpeton and Qinglongtriton (21, 23, 24, 27, 28)] or stem-cryptobranchoids [Chunerpeton (21,23,24,27)]. The finding of a close relationship among Chunerpeton, Beiyanerpeton, and Qinglongtriton is consistent with the observation that they have relatively similar anatomy (28). Synapomorphies of the new Mesozoic Eurasian clade include monocuspid tooth crowns, a squamosal with a ventral process that is oriented anteroventrally, and a parasphenoid that widens anteriorly (Fig. 4). ...
Article
Full-text available
Salamanders are an important group of living amphibians and model organisms for understanding locomotion, development, regeneration, feeding, and toxicity in tetrapods. However, their origin and early radiation remain poorly understood, with early fossil stem-salamanders so far represented by larval or incompletely known taxa. This poor record also limits understanding of the origin of Lissamphibia (i.e., frogs, salamanders, and caecilians). We report fossils from the Middle Jurassic of Scotland representing almost the entire skeleton of the enigmatic stem-salamander Marmorerpeton . We use computed tomography to visualize high-resolution three-dimensional anatomy, describing morphologies that were poorly characterized in early salamanders, including the braincase, scapulocoracoid, and lower jaw. We use these data in the context of a phylogenetic analysis intended to resolve the relationships of early and stem-salamanders, including representation of important outgroups alongside data from high-resolution imaging of extant species. Marmorerpeton is united with Karaurus , Kokartus , and others from the Middle Jurassic–Lower Cretaceous of Asia, providing evidence for an early radiation of robustly built neotenous stem-salamanders. These taxa display morphological specializations similar to the extant cryptobranchid “giant” salamanders. Our analysis also demonstrates stem-group affinities for a larger sample of Jurassic species than previously recognized, highlighting an unappreciated diversity of stem-salamanders and cautioning against the use of single species (e.g., Karaurus) as exemplars for stem-salamander anatomy. These phylogenetic findings, combined with knowledge of the near-complete skeletal anatomy of Mamorerpeton, advance our understanding of evolutionary changes on the salamander stem-lineage and provide important data on early salamanders and the origins of Batrachia and Lissamphibia.
... To keep the gender of species names consistent with that of genus names as per ICZN codes, we replaced the feminine/masculine species ending ('-is') by corresponding neuter forms ('-e') for genus names (e.g. Nuominerpeton) ending in the neuter noun 'herpeton' or 'ἑρπετόν' in Greek as suggested in Rong et al., 2021. In this study, each species is represented by one to three specimens, except for the only facultatively Besides the CT scan data obtained from MorphoSource, four fossil and all living specimens were micro-CT scanned using the following three high-resolution CT scanners: a Nikon XT H 320 LC scanner in the Industrial Micro-CT Laboratory at China University of Geosciences (Beijing); a GE Phoenix v/ tome/x 240kv/180kv scanner in the PaleoCT Lab at The University of Chicago; and a Quantum GX micro-CT Imaging System (PerkinElmer, Waltham, USA) at CIB (Dataset in Dryad). ...
Article
Full-text available
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 shares with other modern amphibians a unified biphasic ecological preference, and metamorphosis is significant in the expansion of ecomorphospace of the palate in early salamanders.
Article
Synonymic and related (logonymic) lists play important roles in taxonomy: they give the valid and correct nomina of the taxa of a zoological group, they allow to know whether nomina are available for naming newly recognised taxa, and they provide a condensed history of the taxonomy of the group. To be really useful, such lists should be complete and accurate. This is not always the case, in particular in many taxonomic and nomenclatural online databases, which should be used with great caution. Recommendations are offered concerning the presentation of such lists in order to make them more useful and reliable. They are illustrated by the family-series and genus-series logonymic lists of the amphibian family Cryptobranchidae.
Article
Full-text available
Molecular divergence dating has the potential to overcome the incompleteness of the fossil record in inferring when cladogenetic events (splits, divergences) happened, but needs to be calibrated by the fossil record. Ideally but unrealistically, this would require practitioners to be specialists in molecular evolution, in the phylogeny and the fossil record of all sampled taxa, and in the chronostratigraphy of the sites the fossils were found in. Paleontologists have therefore tried to help by publishing compendia of recommended calibrations, and molecular biologists unfamiliar with the fossil record have made heavy use of such works (in addition to using scattered primary sources and copying from each other). Using a recent example of a large node-dated timetree inferred from molecular data, I reevaluate all 30 calibrations in detail, present the current state of knowledge on them with its various uncertainties, rerun the dating analysis, and conclude that calibration dates cannot be taken from published compendia or other secondary or tertiary sources without risking strong distortions to the results, because all such sources become outdated faster than they are published: 50 of the (primary) sources I cite to constrain calibrations were published in 2019, half of the total of 280 after mid-2016, and 90% after mid-2005. It follows that the present work cannot serve as such a compendium either; in the slightly longer term, it can only highlight known and overlooked problems. Future authors will need to solve each of these problems anew through a thorough search of the primary paleobiological and chronostratigraphic literature on each calibration date every time they infer a new timetree, and that literature is not optimized for that task, but largely has other objectives.
Article
Checklists of all described organisms from the Daohugou biota, and insects from the Haifanggou Formation at Haifeng Village (Beipiao City, Liaoning Province) and the ‘Jiulongshan Formation’ at Zhouyingzi Village (Luanping County, Chengde City, Hebei Province), are provided. Fossil insects from the Daohugou biota are summarized, including a total of 760 valid species reported in 396 research papers from 2001 to April, 2021. The heyday of exploration of Daohugou insects has been lasted for a decade from 2006 to 2016 according to the number of published papers.