Scleromochlus, Woodward, 1907

Gen. et sp. indet.

Referred specimens. TTU-P 11254f, distal end of a left femur; TTU-P 11254g, proximal end of left tibia; TTU-P 11254h, a fragmentary right tibia; TTU-P 11254i, two procoelous vertebrae and fragmentary undetermined shafts of bones.

Description and remarks. The thin-walled limb bones are extremely long and slender which is reminiscent to that of some basal ornithodirans such as Scleromochlus and Saltopus ( Benton, 1999; Benton and Walker, 2011), as well as that of pterosaurs ( Sereno, 1991a). But in a closer look, these limb bones are anatomically inconsistent with that of any typical archosaurian ( Figures 9 View Figure 9 A-G). The distal end of the femur does not bear a tibiofibular crest which is an archosauriform synapomorphy ( Nesbitt, 2011, character 322), whereas twin concave facets (i.e. cotyles) on the proximal tibia are comparable to that of lepidosaurians like Clevosaurus (Fraser, 1988) . Moreover, the procoelous state of the two severely damaged vertebrae ( Figure 9H View Figure 9 ) is considered to be a characteristic of a large number of squamates ( Romer, 1956), but also of many tanystropheids ( Pritchard et al., 2015) and the new basal archosauromorph Ozimek volans Dzik and Sulej, 2016 . The fragmentary shafts around the procoelous vertebrae are missing both ends but their morphology is identical to that of other described limb bones. Given that the procoelous vertebrae are attributed to the same taxon with the limb bones, these fragments may represent a small-sized lepidosauromorph taxon or a basal archosauromorph related to Sharovipterygidae . A tanystropheid affinity, on the other hand, is less likely since the basal forms possess a sigmoidal femur whereas more derived forms still retain the curvature at the distal end of femur ( Pritchard et al., 2015). All these elements are considered as saurian bones due to their incomplete and distorted condition which prevents a more detailed identification.