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Because skeletal remains of very small theropods are delicate and rare, diminutive tracks provide valuable, additional evidence of body size. The distinctive Asian ichnogenus Minisauripus has assumed importance in this debate and has played a role in the challenging question about whether it represents a small trackmaker species or juveniles of a larger species. New discoveries of Minisauripus footprints from the Lower Cretaceous Feitianshan Formation at Yangmozu in Sichuan Province, China, support the conclusion that all known examples of this ichnotaxon are small. The main Yangmozu site reveals 65 theropod tracks (~20 trackways) of different-sized trackmakers. Three trackways, comprising 10 pes imprints of 2.5-2.6 cm length, are assigned to Minisauripus. The remaining 17 trackways represent small-medium-sized theropods 2 (track lengths 9.9-19.6 cm), including one assigned to cf. Jialingpus. All unequivocally identified Minisauripus tracks from Korea (five sites) and China (three sites) fall in the size range of ~1.0-6.1 cm. Assuming a small adult trackmaker, and based on standard foot length, leg length and body length ratios, all Minisauripus tracks indicate trackmakers with hip heights of < ~5.0 and ~28.0 cm and body lengths in the range of ~12.0-72.0 cm. Based on lack of large tracks (longer than 6.1 cm) at any known sites, and various precedents in the ichnological literature we infer that Minisauripus represents a small theropod species. However, we cannot completely exclude the possibility that such tracks represent juveniles of larger trackmaking species.

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Considering the heterogeneous characteristics of rock at mesoscopic level, the damage propagation constitutive relation and evolution equation of freeze-thaw and loaded rock were established by using the theory of macro phenomenological damage mechanics and the generalized theory of strain equality. The evolutionary mechanisms of micro-structural damage and materials mechanical properties for the loaded rock were discussed under freeze-thaw condition, verified by experimental results of the freeze-thaw cycle and compression test of rock. It is shown that the freeze-thaw and loaded damage model can represent the complicated relations among the freeze-thaw, load and the damage inside the rock, reveal the coupling failure mechanism of macroscopic rock under the freeze-thaw and load from the micro-damage evolution. The combined effect of freeze-thaw and load exacerbates the total damage of rock with obvious nonlinear properties, but the coupling effect weakens the total damage. The lithology and initial damage state of the freeze-thaw and loaded rock in engineering structures in cold regions determine the weights of influence factors to mechanical properties, including environmental factor, loading factor and the coupling effects, so the rock performances different damage mechanical characteristic.