Lockley and Harris (2011) suggested Evazoum was made by a sauropodomorph
, but again the resemblances are all symplesiomorphies below the level of the Dinosauria.
The bones represent about 20 embryonic individuals of the long-necked sauropodomorph
Lufengosaurus, the most common dinosaur in the region during the Early Jurassic period.
In North America, for instance, sauropodomorphs and ornithischians didn't even show up until after the Triassic was over, Irmis reports in an upcoming issue of Earth and Environmental Science Transactions of the Royal Society of Edinburgh.
Sauropodomorphs came in two forms--the big bipedal omnivores and the bigger, four-legged, barrel-chested, long-necked herbivores (Brachiosaurus shown).
Some researchers call it an early theropod, but others say it falls even deeper back in the family tree, somewhere just outside being either a theropod or a sauropodomorph.
Not that such classifications were significant at the time; if you were prey in the early Triassic, says Langer, "it probably wouldn't matter if you were being chased by a basal theropod or a basal sauropodomorph.
Particularly noteworthy is the relative abundance of the ichnotaxon Otozoum moodii, which has been plausibly attributed to sauropodomorphs (Rainforth 2003) and some of which are beautifully preserved.
Sauropodomorphs are locally very abundant at higher latitudes, and their absence in various tropical and subtropical Pangaean assemblages during the Triassic (Rowe et al.
The hallmark of this loss of provincialism is the appearance of basal sauropodomorphs in the McCoy Brook Formation, as documented by skeletal remains at Wasson Bluff and Otozoum tracks elsewhere.
Sauropodomorphs were distributed across the globe during the Early Jurassic, when all of the continents were still together in the supercontinent named Pangaea.
Millions of years later, sauropodomorphs evolved into gigantic sauropods, long-necked plant eaters whose fossils are well known from elsewhere in Utah, including Dinosaur National Monument.
Early sauropodomorphs, including Seitaad, had long necks and tails with small heads and leaf-shaped teeth, suggesting that they were specialized for an herbivorous (plant-eating) diet.