A new hynobiid-like salamander (Amphibia, Urodela) from Inner Mongolia, China, provides a rare case study of developmental features in an Early Cretaceous fossil urodele

Jia, Jia; Gao, Ke‐Qin

doi:10.7717/peerj.2499

Cited by 22 publications

(55 citation statements)

References 79 publications

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“…The Siberian salamander, as well as other modern hynobiids 6 , 28 , retain many cranial morphological features that are widely distributed among more basal Middle Jurassic-Early Cretaceous crown-group taxa. These features, presumably plesiomorphic, include: similar composition of skull roof bones (including the presence of lacrimal bone); similar composition of palate and braincase bones; presence of the anteromedial fenestra in the palate and the anterodorsal (=internarial) fenestra between premaxillae (see descriptions and figures of the skulls of the Middle Jurassic-Early Cretaceous crown-group taxa 24 , 29 – 37 ). These similarities make modern hynobiids a potentially good model for the reconstruction of feeding biomechanics in most of Mesozoic basal crown-group salamanders, except taxa with very different proportions for their skulls (the Chinese Middle Jurassic cryptobranchoid Pangerpeton 38 ), highly paedomorphic skulls (the Chinese Middle Jurassic possible cryptobranchoid Jeholotriton 39 , 40 ) and taxa with principally different patterns of fenestration (the European Early Cretaceous salamandroid Valdotriton 41 ).…”

Section: Discussionmentioning

confidence: 99%

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Cranial biomechanics in basal urodeles: the Siberian salamander (Salamandrella keyserlingii) and its evolutionary and developmental implications

Zhou

Fortuny

Marcé‐Nogué

et al. 2017

Sci Rep

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Developmental changes in salamander skulls, before and after metamorphosis, affect the feeding capabilities of these animals. How changes in cranial morphology and tissue properties affect the function of the skull are key to decipher the early evolutionary history of the crown-group of salamanders. Here, 3D cranial biomechanics of the adult Salamandrella keyserlingii were analyzed under different tissue properties and ossification sequences of the cranial skeleton. This helped unravel that: (a) Mechanical properties of tissues (as bone, cartilage or connective tissue) imply a consensus between the stiffness required to perform a function versus the fixation (and displacement) required with the surrounding skeletal elements. (b) Changes on the ossification pattern, producing fontanelles as a result of bone loss or failure to ossify, represent a trend toward simplification potentially helping to distribute stress through the skull, but may also imply a major destabilization of the skull. (c) Bone loss may be originated due to biomechanical optimization and potential reduction of developmental costs. (d) Hynobiids are excellent models for biomechanical reconstruction of extinct early urodeles.

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Section: Discussionmentioning

confidence: 99%

“…Salamandrella keyserlingii and Paradactylodon persicus 9 , 23 ). Hynobiids retain countable primitive characters in their cranial morphology and development 1 , 4 , 24 .…”

Section: Introductionmentioning

confidence: 99%

Cranial biomechanics in basal urodeles: the Siberian salamander (Salamandrella keyserlingii) and its evolutionary and developmental implications

Zhou

Fortuny

Marcé‐Nogué

et al. 2017

Sci Rep

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“…Based on the fossil record from northern China, the evolutionary history of the Hynobiidae can be traced back to Aptian time (∼125 Ma) during the Early Cretaceous ( Chen & Gao, 2009 ; Gao, Chen & Jia, 2013 ; Jia & Gao, 2016b ). Several extinct taxa from China including Liaoxitriton and Nuominerpeton are apparently stem-group hynobiids, as evidenced by their possession of derived features shared with extant hynobiids, including: transverse and arched vomerine tooth rows; a deeply notched posterolateral border of the vomer for choana; and an optic foramen opening at the notched posterior border of orbitosphenoid ( Chen & Gao, 2009 ; Gao, Chen & Jia, 2013 ; Jia & Gao, 2016a ). The fossil record indicates that the split of the hynobiid from cryptobranchid clade seems to be a phylogenetic event that had taken place no later than the Aptian time (∼125 Ma).…”

Section: Introductionmentioning

confidence: 99%

Osteology ofBatrachuperus londongensis(Urodela, Hynobiidae): study of bony anatomy of a facultatively neotenic salamander from Mount Emei, Sichuan Province, China

Jiang

Jia

Zhang

et al. 2018

PeerJ

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The Longdong Stream Salamander Batrachuperus londongensis, living in a mountain stream environment at Mt. Emei in Sichuan Province, China, represents a rare species that is facultatively neotenic in the family Hynobiidae. Although the species has been known to science for some 40 years since its initial discovery in the late 1970s, anatomical details of its osteology remain poorly understood and developmental information is still lacking for the species. This study (1) provides a detailed osteological account of B. londongensis based on micro-CT scanning and clearing and staining of multiple specimens from the type locality; (2) provides a discussion of intraspecific variation related to life-history differences; and (3) presents a discussion on limb features related to morphological evolution of limb patterns correlative with ecological adaptation to mountain stream environments. Osteological comparisons with congeneric species has led to recognition of several diagnostic features that are unique to B. londongensis, including: vomers widely separated from one another, lacking a midline contact; presence of uncommon perichondral ossification of the ascending process of the palatoquadrate as part of the suspensorium; and presence of a prominent posterodorsal process of the scapular blade, which serves as a ligamentous insertion of the levator muscle of the scapula. In addition, some but not all neotenic individuals retain the palatine as a discrete element, indicative of its delayed absorption after sexual maturity. Postmetamorphic and neotenic individuals are strikingly different in the complexity of hyobranchial structures. Neotenes display a high degree of ossification of hyobranchial elements, tend to increase ossification of both hypobranchial I and ceratobranchial I during aging, and retain fully ossified ceratobranchial III and IV; in contrast, these elements remain entirely cartilaginous or are totally lost by resorption in postmetamorphic individuals. In addition, all postmetamorphic forms display an inverted “T”-shaped basibranchial II, whereas neotenes show transformation from a “fork”-shaped to the “T”-shaped configuration after sexual maturity. B. londongensis displays a mosaic of apomorphic and plesiomorphic states in its limb ossifications: presence of a single centrale element in both the manus and pes is a derived condition in Hynobiidae and other families as well, whereas retention of a postminimus in the pes is obviously plesiomorphic within Urodela. Reduction in number of digits from five to four in the pes and possession of a cornified sheath covering the terminal phalanges are also derived features shared with some but not all mountain stream salamanders that are adapted to a similar type of environment.

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“…"Several other taxa [of Mesozoic salamanders] (e.g., Laccotriton, Sinerpeton, and Jeholotriton) are excluded from this analysis because they are anatomically uncertain and are currently under taxonomic revision" (Gao & Shubin, 2012: supplementary information: 3). This revision is ongoing (Jia & Gao, 2016b).…”

Section: Pennsylvanian Enigmamentioning

confidence: 99%

“…2, 3). Jia & Gao (2016b) pointed out that the ossified parts of radius and tibia are considerably longer and wider than those of ulna and fibula, respectively, in the smallest known larva of the Early Cretaceous urodele **Nuominerpeton. They considered this fact to be evidence of a preaxial-to-postaxial sequence in development.…”

Section: Preaxial Polarity In Limb Developmentmentioning

confidence: 99%

Peer Review #1 of "Phylogeny of Paleozoic limbed vertebrates reassessed through revision and expansion of the largest published relevant data matrix (v0.2)"

Pyron¹

2019

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The largest published phylogenetic analysis of early limbed vertebrates (Ruta M, Coates MI. 2007. Journal of Systematic Palaeontology 5:69-122) recovered e.g. Seymouriamorpha, Diadectomorpha and (in some trees) Caudata as paraphyletic and found the "temnospondyl hypothesis" on the origin of Lissamphibia (TH) to be more parsimonious than the "lepospondyl hypothesis" (LH)-though only, as we show, by one step. We report 4200 misscored cells, over half of them due to typographic and similar accidental errors. Further, some characters were duplicated; some had only one described state; for one, most taxa were scored after presumed relatives. Even potentially continuous characters were unordered, the effects of ontogeny were not sufficiently taken into account, and data published after 2001 were mostly excluded. After these issues are improved-we document and justify all changes to the matrix-, but no characters are added, we find (Analysis R1) much longer trees with e.g. monophyletic Caudata, Diadectomorpha and (in some trees) Seymouriamorpha; Ichthyostega either crownward or rootward of Acanthostega; and Anthracosauria either crownward or rootward of Temnospondyli. The LH is 9 steps shorter than the TH (R2; constrained) and 12 steps shorter than the "polyphyly hypothesis" (PH-R3; constrained). Brachydectes (Lysorophia) is not found next to Lissamphibia; instead, a large clade that includes the adelogyrinids, urocordylid "nectrideans" and aïstopods occupies that position. As expected from the taxon/character ratio, most bootstrap values are low. Adding 56 OTUs to the original 102 increases the resolution (and decreases most bootstrap values). The added taxa range in completeness from complete articulated skeletons to an incomplete lower jaw. Even though the lissamphibian-like temnospondyls Gerobatrachus, Micropholis and Tungussogyrinus and the extremely peramorphic salamander Chelotriton are added, the difference between LH (R4; unconstrained) and TH (R5) rises to 10 steps, that between LH and PH (R6) to 15; the TH also requires several more regains of lost bones than the LH. Casineria, in which we tentatively identify a postbranchial lamina, emerges rather far from amniote origins in a gephyrostegid-chroniosuchian grade. Bayesian inference (Analysis EB, settings as in R4) mostly agrees with R4. High posterior probabilities are found for Lissamphibia (1.00) and the LH (0.92); however, many branches remain weakly supported, and most are short, as expected from the small character sample.

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A new hynobiid-like salamander (Amphibia, Urodela) from Inner Mongolia, China, provides a rare case study of developmental features in an Early Cretaceous fossil urodele

Cited by 22 publications

References 79 publications

Cranial biomechanics in basal urodeles: the Siberian salamander (Salamandrella keyserlingii) and its evolutionary and developmental implications

Cranial biomechanics in basal urodeles: the Siberian salamander (Salamandrella keyserlingii) and its evolutionary and developmental implications

Osteology ofBatrachuperus londongensis(Urodela, Hynobiidae): study of bony anatomy of a facultatively neotenic salamander from Mount Emei, Sichuan Province, China

Peer Review #1 of "Phylogeny of Paleozoic limbed vertebrates reassessed through revision and expansion of the largest published relevant data matrix (v0.2)"

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