Anatomy of the Critically‐Endangered Anji Salamander (Hynobius amjiensis) Provides New Insights Into Morphological Evolution of Salamanders

Journal of Morphology, Journal Year: 2025, Volume and Issue: 286(2)

Published: Jan. 29, 2025

ABSTRACT The Anji Salamander ( Hynobius amjiensis ) is a critically‐endangered amphibian endemic to the Tianmushan Mountain area in southeastern China. As most of its congeneric species ancestral salamander family Hynobiidae, osteology H . has remained essentially unknown and hampered efforts understanding morphological evolutionary patterns early salamanders. Here, we investigate skeletal anatomy based on microcomputed tomography scans post‐metamorphosed juvenile adult specimens. Our results reveal Hynobiidae more early‐tetrapod‐like plesiomorphic characters than expected, as stapedial foramen middle ear two centralia centrale‐radius contact limb. We demonstrate that first known living with whose absence was believed unite salamanders anurans, hence opens major questions evolution modern amphibians: if some caecilians had inherited from their common ancestor, when how many times lost independently amphibians, did this structural loss impact phylogenetic clades? findings hyper‐ossified pectoral pelvic girdles postminimus pes functional features hynobiids are potentially informative phylogeny ontogeny

Language: Английский

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A chronostratigraphic and biostratigraphic framework for the Yanliao Biota of northeastern China: Implications for Jurassic terrestrial ecosystems and evolution

Palaeogeography Palaeoclimatology Palaeoecology, Journal Year: 2023, Volume and Issue: 630, P. 111818 - 111818

Published: Sept. 19, 2023

Language: Английский

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Middle Jurassic stem hynobiids from China shed light on the evolution of basal salamanders

iScience, Journal Year: 2021, Volume and Issue: 24(7), P. 102744 - 102744

Published: June 17, 2021

The Hynobiidae are an early-diverging clade of crown-group salamanders (urodeles) with important bearing on the evolution urodeles. Paleobiology and early-branching patterns remain unclear owing to a poorly documented fossil record. We reported newly referred specimen stem hynobiid, originally named as "Liaoxitriton daohugouensis," but here Neimengtriton daohugouensis comb. nov., predates previously estimated origination time for at least 8 Myr. interpret N. semiaquatic adult stage, unknown paleoecological preference among Mesozoic salamanders. Phenotypic variations enlighten unrecognized association between caudosacral vertebrae fertilization modes in early Our cladistic analyses based morphological characters not only recognize several hynobiids establish Panhynobia nomen cladinovum total-group also shed light sequential features this primitive urodele clade.

Language: Английский

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Palatal morphology predicts the paleobiology of early salamanders

eLife, Journal Year: 2022, Volume and Issue: 11

Published: May 16, 2022

Ecological preferences and life history strategies have enormous impacts on the evolution phenotypic diversity of salamanders, but yet established reliable ecological indicators from bony skeletons hinder investigations into paleobiology early salamanders. Here, we statistically demonstrate by using time-calibrated cladograms geometric morphometric analysis 71 specimens in 36 species, that both shape palate many non-shape covariates particularly associated with vomerine teeth are ecologically informative stem- basal crown-group Disparity patterns within morphospace preferences, strategies, taxonomic affiliations were analyzed detail, evolutionary rates ancestral states reconstructed. Our results show is heavily impacted convergence constrained feeding mechanisms also exhibits clear stepwise alternative configurations to cope similar functional demand. Salamanders diversified before Middle Jurassic achieved all their present Early Cretaceous. reveal last common ancestor salamanders share other modern amphibians a unified biphasic preference, metamorphosis significant expansion ecomorphospace

Language: Английский

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Comparative osteology of the hynobiid complexLiua‐Protohynobius‐Pseudohynobius(Amphibia, Urodela): Ⅰ. Cranial anatomy ofPseudohynobius

Journal of Anatomy, Journal Year: 2020, Volume and Issue: 238(2), P. 219 - 248

Published: Sept. 22, 2020

Abstract Hynobiidae are a clade of salamanders that diverged early within the crown radiation and retain considerable number features plesiomorphic for group. Their evolutionary history is informed by fossil record extends to Middle Jurassic Bathonian time. Our understanding evolution total group has benefited considerably from recent discoveries stem hynobiids but constrained inadequate anatomical knowledge some extant forms. Pseudohynobius derived hynobiid consisting five seven species living endemic southwestern China. Although this been recognized over 37 years, osteological details these remain elusive, which undoubtedly contributed taxonomic controversies complex Liua ‐ Protohynobius . Here we provide bone‐by‐bone study cranium in ( Ps. flavomaculatus , guizhouensis jinfo kuankuoshuiensis shuichengensis ) based on x‐ray computer tomography data 18 specimens. results indicate each combination differences morphology, proportions articulation patterns both dermal endochondral bones. establishes range intraspecific will serve as organizing hypotheses future studies more extensive collections become available. Morphological terrestrial ecological adaptation summarized. Based results, also discuss development several potential synapomorphies Hynobiidae, including orbitosphenoid articular.

Language: Английский

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The tooth-bearing skeletal elements of the Italian urodeles, a comparative tool for osteological identification

Acta Herpetologica, Journal Year: 2024, Volume and Issue: unknown

Published: Nov. 14, 2024

Urodele osteology is characterised by simplified skulls, loss of several bones and a specific sequence cranial limb ossification. The relatively few studies devoted to the comparative analysis isolated urodele are mostly focused on vertebrae occipital complexes, lesser extent humeri. tooth-bearing skeletal elements (premaxillae, maxillae, dentaries, vomers) strongly neglected in this respect, despite being robust as such sometimes found fossils. Herein, we provide for first time study dentigerous bones, focusing Italian urodeles. Thirteen 19 species present Italy, representing all genera except one, were analysed, total 70 dry-prepared skeletons. morphology urodeles described pictured, providing diagnostic characters dichotomous keys identification at genus level most cases, some. morphological included phylogenetic analysis, results which demonstrate that can have value useful assessing relationships living taxa

Language: Английский

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Osteological characteristics of the Setouchi salamander Hynobius setouchi (Urodela, Hynobiidae)

The Anatomical Record, Journal Year: 2021, Volume and Issue: 305(6), P. 1316 - 1342

Published: Sept. 30, 2021

This study described the detailed osteological features of Setouchi salamander Hynobius setouchi. H. setouchi, which is endemic to central Japan, was recently delineated from wide range nebulosus species based on molecular and external morphological characteristics. However, belonging genus have not been examined, has hindered understanding diversity in genus. To address this problem, elucidated using micro-computed tomography scanning whole-mount double staining methods. The articular, a part hypobranchial I, coracoid, pubis, carpus, tarsus were cartilaginous small-sized individuals partially or completely ossified large-sized individuals. degree ossification varied operculum, basibranchial II, ascending process palatoquadrate. associated with body size. lacrimal, manus, pes exhibited varying degrees articulation fusion irrespective Moreover, cranium setouchi several unique These characteristics will aid revising taxonomy phylogeny species.

Language: Английский

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Palatal morphology predicts the paleobiology of early salamanders

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2022, Volume and Issue: unknown

Published: Jan. 17, 2022

Abstract Ecological preferences and life history strategies have enormous impacts on the evolution phenotypic diversity of salamanders, but yet established reliable ecological indicators hinder investigations paleobiology early salamanders. Here we statistically demonstrate using geometric morphometric analysis that both shape palate many non-shape variables particularly associated with vomerine teeth are ecologically informative in stem- basal crown-group The morphology is heavily impacted by convergence constrained feeding mechanisms also exhibits clear stepwise evolutionary patterns alternative designs to cope similar functional demand. Paleoecological disparities salamanders had took place before Middle Jurassic achieved all Early Cretaceous. Metamorphosis significant expansion ecomorphospace common ancestor metamorphosed terrestrial, share unified lifestyles other modern amphibians.

Language: Английский

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