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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. [ABSTRACT FROM AUTHOR]

Here we describe life history traits in the giant cryptobranchid salamander Aviturus exsecratus from the Paleocene of Mongolia using non-destructive approach for skeletochronological analysis based on the counting of cyclical growth rings on articular surfaces of zygapophyseal processes of vertebrae (= zygapophyseal skeletochronology). We found that Aviturus exsecratus had a similar time of the attainment of sexual maturity and decreasing of juvenile growth (5–8 years) and estimated body size at maturity (50–60% of the maximum size) as modern cryptobranchids. Maximum longevity estimated for A. exsecratus is about 25 years. A. exsecratus had a developmental trajectory similar to that of modern cryptobranchids and is not characterized by extended ontogeny. PIN: Paleontological Institute; Russian Academy of Sciences; Moscow; Russia. [ABSTRACT FROM AUTHOR]

A new stem salamander, Kulgeriherpeton ultimum gen. et sp. nov., is described based on a nearly complete atlas from the Lower Cretaceous (Berriasian-Barremian) Teete vertebrate locality in southwestern Yakutia (Eastern Siberia, Russia). The new taxon is diagnosed by the following unique combination of atlantal characters: the presence of a transversal ridge and a depression on the ventral surface of the posterior portion of the centrum; ossified portions of the intercotylar tubercle represented by dorsal and ventral lips; the absence of a deep depression on the ventral surface of the anterior portion of the centrum; the absence of pronounced ventrolateral ridges; the absence of spinal nerve foramina; the presence of a pitted texture on the ventral and lateral surfaces of the centrum and lateral surfaces neural arch pedicels; the presence of a short neural arch with its anterior border situated far behind the level of the anterior cotyles; moderately dorsoventrally compressed anterior cotyles; and the absence of a deep incisure on the distal-most end of the neural spine. The internal microanatomical organization of the atlas is characterized by the presence of a thick, moderately vascularized cortex and inner cancellous endochondral bone. The recognition of stem salamanders and other vertebrates with Jurassic affinities in the Early Cretaceous high-latitude (paleolatitude estimate N 63-70°) vertebrate assemblage of Teete suggests that: (i) the large territory of present day Siberia was a refugium for Jurassic relicts; (ii) there were no striking differences in the composition of high-latitude Yakutian and mid-latitude Western Siberian Early Cretaceous vertebrate assemblages; and (iii) there was a smooth transition from the Jurassic to Cretaceous biotas in North Asia. [ABSTRACT FROM AUTHOR]

We provide a detailed redescription of all available material for the geologically oldest proteid salamander Bishara backa from the Upper Cretaceous (Santonian – lower Campanian) Bostobe Formation in Kazakhstan, consisting an atlantal centrum (neotype of Bishara backa) and a trunk vertebra. Bishara backa is characterised by the following combination of characters: large, dorsoventrally compressed and almost flat anterior cotyles of atlas enclosing an angle about 230°; anterior cotylar surfaces are continuous medially across lateral surfaces of small, dorsally placed intercotylar tubercle; ventrolateral ridges are alar-like; atlantal transverse processes are bicipitate; oblique anterior alar processes and lateral fossae on atlas present; transverse processes on trunk vertebra are bicipitate and divergent; alar processes on trunk vertebra are prominent; anterodorsal ridge on trunk vertebra is present; neural arch of trunk vertebra with high neural spine and grooves on its posterior face; two large subcentral foramina on ventral surface of the centrum. Our phylogenetic analyses finds Bishara backa as a crown proteid and a basal member of Eurasian clade of crown proteids (Bishara+Proteus+Mioproteus). We propose a model of proteid evolution that includes three main episodes of radiations with the last two taking place during the Late Cretaceous and the Palaeocene – Eocene thermal maximum. [ABSTRACT FROM AUTHOR]