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Isolated incompete salamander dentaries from the Lower Cretaceous Teete locality in Yakutia (Eastern Siberia, Russia) represent the northernmost occurrence of non-karaurid salamanders in the Mesozoic and are evidence that small-sized salamanders lived in high latitudes (paleolatitude estimate of N 62°–66.5°) in the Northern Hemisphere in the Early Cretaceous. These gracile and lightly built dentaries are characterized by the presence of numerous slender and closely spaced pedicellate teeth, a sharp ridge along the ventral edge of the postsymphyseal region, numerous neurovascular foramina that open into parallel longitudinal grooves on the labial surface, and a complex neurovascular system. The neurovascular system, which consists of a large longitudinal canal for the ramus mandibularis internus of the trigeminal nerve associated with smaller lateral canals and an entirely separate anterior part of the alveolar canal for the branches of the ramus alveolaris of the facial nerve, is similar to that of the long-lived Juro-Cretaceous small-sized non-karaurid salamanders of the genus Kiyatriton. The Teete faunal association "relic karaurid stem salamander—small-sized non-karaurid salamander" is characteristic for the "Great Siberian refugium" for Jurassic vertebrate relicts that covered the vast northeastern part of the Asiatic continent during the Early Cretaceous. [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]