Ruehleia

Chapter • Meet the dinosaur

Overview

Ruehleia bedheimensis was a medium-sized plant-eating dinosaur belonging to the early sauropodomorphs, the group often informally called prosauropods. It reached about six to eight metres in length and probably weighed between 600 and 1,500 kilograms. Its build was typical of plateosaur-grade animals: a long, flexible neck, a barrel-shaped body, powerful hind limbs and a long muscular tail that counterbalanced the front of the body. The forelimbs were shorter than the hind limbs and carried a large, curved thumb claw. No skull is known from the material, but in close relatives the head was small relative to the body and lined with leaf-shaped, coarsely serrated teeth. Ruehleia would have had scaly skin; no feather-like structures are known in sauropodomorphs. As with other early sauropodomorphs, posture remains a topic of discussion. The most widely accepted reconstruction today is that Ruehleia normally walked on two legs with the body held horizontally and the tail carried clear of the ground — never dragging. The hand was built for grasping and pulling branches rather than for weight-bearing, which supports habitual bipedality, though the animal may have propped itself on its forelimbs while browsing low vegetation. Its long neck let it reach both ground-level plants and foliage several metres up. Ruehleia was a herbivore. Its teeth were simple and coarsely serrated, suited to cropping plant material rather than chewing it. Food was probably processed in a muscular gut, and several close relatives have been found with stomach stones (gastroliths), although the role these played in digestion is debated. The diet likely consisted of conifer shoots, ferns, seed ferns and cycads, since grasses and flowering plants had not yet appeared. The fossils come from Bedheim in Thuringia, Germany, where they were collected by the German physician and amateur palaeontologist Hugo Rühle von Lilienstern during the first half of the twentieth century. The material, including a partial skeleton lacking the skull, remained undescribed in his private collection for decades before being transferred to the Museum für Naturkunde in Berlin. Only in 2001 did the palaeontologist Peter M. Galton give the animal its own name: the genus honours Rühle von Lilienstern, while the species name refers to the site at Bedheim. Its exact relationships are still uncertain — Ruehleia is usually placed close to Plateosaurus within Plateosauridae, though some analyses recover it as a slightly more basal plateosaurian.

Chapter • Where it lived

Habitat

Ruehleia lived roughly 214–208 million years ago, during the Norian stage of the Late Triassic. Its fossils come from the Knollenmergel beds (Trossingen Formation) at Bedheim in Thuringia, central Germany. At that time the region was a broad, low-lying plain with river floodplains and seasonal lakes under a semi-arid climate punctuated by heavy rainy seasons. Vegetation was dominated by conifers, cycads, seed ferns and ferns. Equivalent beds in southern Germany and Switzerland, such as those at Trossingen and Frick, have produced great numbers of skeletons of its close relative Plateosaurus.

Chapter • Wild behavior

Behavior & Ecology

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Chapter • Scientific place

Taxonomy