Dinosaur ichnofauna from Lower Cretaceous of Mongolia + Jurassic anurans from Tendaguru

[Ben Creisler]

Ben Creisler

bcre...@gmail.com

New papers:

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Buuvei Mainbayar, Masato Fujita, Ryuji Takasaki, Khishigjav Tsogtbaatar, Zorigt Badamkhatan, Nymsambuu Odgerel & Shinobu Ishigaki (2026)
A dinosaur ichnofauna from the Lower Cretaceous Shinekhudag Formation, Mongolia
Ichnos (advance online publication)
doi: https://doi.org/10.1080/10420940.2026.2645024
https://www.tandfonline.com/doi/full/10.1080/10420940.2026.2645024


The early Cretaceous dinosaur fauna of Mongolia is poorly known, in contrast to the extensively documented Upper Cretaceous record. Here we describe recently excavated dinosaur trackways from the historic Saijrakh locality from the Barremian–Aptian Shinekhudag Formation. The ichnoassemblage includes multiple trackways of large sauropods and theropods preserved on a single bedding plane. The sauropod trackways are wide-gauge and exhibit a unique mosaic of features: the manus prints have a distinct pollex impression (a plesiomorphic trait), but also possesses posterior lobes suggestive of derived soft-tissue pads. The pes prints are characterized by straight, anteriorly directed digits I–IV. The combination of primitive and derived characters is most consistent with a basal titanosauriform trackmaker, providing new insights into sauropod locomotor evolution. Associated theropod tracks are large, broad (as wide as its length), and functionally tridactyl, with wide interdigital angles (>60°). The theropod tracks confirm the presence of large predators in this ecosystem. Beyond individual morphologies, the high density of trackways, with frequent overprinting, indicates that the site represents a zone of repeated transit or a high-traffic corridor. The parallel sauropod trackways may further infer that these large-bodied herbivores followed optimal pathways to minimize locomotor costs as modern elephants do.

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Free pdf:

Alfred J. A. Lemierre, Wolf-Dieter Heinrich & David C. Blackburn (2026)
The oldest Jurassic anurans from continental Africa (Tendaguru Hill, Tanzania).
Fossil Record 29(1): 115-133.
doi:  https://doi.org/10.3897/fr.29.175525
https://fr.pensoft.net/article/175525/list/9/


Anurans are a diverse clade of tetrapods with a rich evolutionary history beginning ~250 Ma. Most time-calibrated molecular phylogenetic analyses place the early diversification of anurans during the Jurassic, with the emergence of several major modern anuran clades linked to the break-up of the Pangea. However, remains of crown-anurans before the Cretaceous are scarce, especially in Gondwana. Here, we described the first lissamphibian specimens from Jurassic outcrops in continental sub-Saharan Africa, with five specimens from the Jurassic Middle Dinosaur Member of the Tendaguru Formation (Tendaguru Hill, Tanzania). The specimens represent at least two distinct lissamphibian taxa, based on humeral morphologies. Comparisons with humeri from other lissamphibian clades reveal that the morphology of the Tendaguru specimens fits within Salientia (stem-Anura). Further, two humeri can be securely assigned to Anura, making these the oldest occurrence of the crown-group in Africa as well as within Gondwana.

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