The northernmost sauropod record in the Northern Hemisphere

Abstract

Isolated sauropod teeth from the Early Cretaceous Teete locality in Yakutia (Eastern Siberia, Russia) are the only evidence that sauropods lived in high latitudes (palaeolatitude estimate of N 62°) in the Northern Hemisphere. The spatulate broad tooth crowns of adult individuals lack marginal denticles while these are present in a juvenile tooth. The teeth have overlapping facets and likely belong to a basal macronarian. The juvenile tooth indicates that sauropods reproduced in high latitudes and possibly stayed there around the year. The Teete vertebrate assemblage comprises both endothermic, or presumably endothermic tetrapods (theropod dinosaurs, tritylodontids and mammals), and ectothermic tetrapods (salamanders, turtles, choristoderes and lizards), but no crocodyliforms. This suggests a temperate climate, with an annual mean temperature well above freezing level but below 14°C.

Wear patterns and dental functioning in an Early Cretaceous stegosaur from Yakutia, Eastern Russia

“…As was reported earlier by Averianov et al, 2019 [10], most of the stegosaur bones collected at Teete belong to juvenile individuals which suggests that stegosaurs permanently lived in this area and reproduced there. The finding of a juvenile stegosaurian tooth ZIN PH 33/246 ( Fig 15) at Teete is further support for this suggestion.…”

“…The stegosaurian teeth from Teete resemble the teeth of Stegosaurus in having a similar crown shape and number of denticles (9)(10)(11)(12)(13)(14), in having a pronounced ring-like cingulum, in lacking a well-pronounced primary ridge, and in the presence of a "complex network of secondary ridges" (see descriptions/figures of teeth of Stegosaurus in [18,24,25]). Thus, tooth morphology suggests that the Teete stegosaur is likely a derived stegosaur with possible stegosaurine affinities.…”

“…The Early Cretaceous (Berriasian-Barremian) Teete vertebrate assemblage in southwestern Yakutia (Eastern Siberia, Russia) was formed close to Mesozoic polar latitudes (paleolatitude estimate of N 62˚in Averianov et al, 2019 and N 66.5˚in Fossilworks, http://fossilworks.org.) and is widely known for its polar dinosaurs, as well as turtles, salamanders, and mammaliaforms and mammals [7][8][9][10][11][12][13][14]. The high-latitude dinosaurian assemblage of Teete includes stegosaurs, ornithopods, theropods, and sauropods [9,10].…”

“…and is widely known for its polar dinosaurs, as well as turtles, salamanders, and mammaliaforms and mammals [7][8][9][10][11][12][13][14]. The high-latitude dinosaurian assemblage of Teete includes stegosaurs, ornithopods, theropods, and sauropods [9,10]. Stegosaurian remains are the most abundant and are represented by numerous isolated teeth, vertebrae, ribs, rare long bones, elements of shoulder and pelvic girdles, and few fragmentary cranial bones.…”

Climatic constraints on the biogeographic history of Mesozoic dinosaurs

“…In particular, sauropod dinosaurs apparently peaked in diversity at southern palaeolatitudes of $40 -50 , 42 with their remains entirely unknown from palaeolatitudes greater than $66 in either hemisphere. 43,44 By contrast, the apparent peak in ornithischian diversity corresponds to higher palaeolatitudes ($50 -70 ) in both hemispheres. If correct, this might indicate broad biological differences between sauropods and other dinosaurs.…”