Efraasia

Chapter • Meet the dinosaur

Overview

Efraasia minor was an early plant-eating dinosaur with a long neck, a small narrow skull and a body carried on sturdy hind limbs and balanced by a long, straight tail. The largest known individuals reached roughly 6.5 metres in length and are estimated to have weighed a few hundred kilograms, while several of the best-known specimens are juveniles only 2–3 metres long. The forelimbs were relatively long and ended in grasping hands armed with a large, powerful thumb claw. Efraasia had no feathers: as a basal sauropodomorph it almost certainly had scaly, leathery skin. Its body proportions place Efraasia awkwardly between bipedal and quadrupedal animals. The arms are too long for a strictly two-legged lifestyle, yet the hand looks built more for grasping than for bearing weight. Most researchers therefore describe Efraasia as facultatively bipedal: able to browse on all fours and to rise onto its hind legs to reach higher vegetation or to move faster. The fairly long neck gave it access to plants from ground level up to a couple of metres, an important step towards the feeding strategy of the giant sauropods that followed. The teeth were leaf-shaped with coarse serrations, a classic herbivore pattern among early sauropodomorphs. Efraasia probably cropped conifers, ferns, seed ferns and cycads, swallowing plant material largely unchewed since its teeth could not grind. Some palaeontologists suspect that the very earliest sauropodomorphs were partly omnivorous and occasionally took small prey or carrion, but there is no direct evidence of this in Efraasia — its teeth and jaws point to a mainly plant-based diet. The fossils come from sandstone beds in Baden-Württemberg, southern Germany, including sites near Pfaffenhofen, and were collected in the early twentieth century by the German palaeontologist Eberhard Fraas. Peter Galton named the genus Efraasia in his honour in 1973 (from "E. Fraas"). The species name minor dates back to Friedrich von Huene's 1908 description, when the bones were assigned to the predatory dinosaur Teratosaurus as "Teratosaurus minor". Over the twentieth century the same animal accumulated a string of names — Palaeosaurus diagnosticus, Sellosaurus fraasi and Efraasia diagnostica among them — until Adam Yates showed in 2003 that the differences mostly reflect growth stages of a single species. The material is housed mainly at the Staatliches Museum für Naturkunde in Stuttgart.

Chapter • Where it lived

Habitat

Efraasia lived roughly 215–205 million years ago, during the Norian stage of the Late Triassic. Its fossils come from the Löwenstein Formation (the Middle Stubensandstein) of Baden-Württemberg in southern Germany, with classic localities around Pfaffenhofen. The landscape was a broad lowland plain within the Germanic Basin, crossed by braided rivers that regularly flooded, dotted with sand flats, temporary lakes and stands of conifers, cycads and ferns. The climate was warm and strongly seasonal, alternating between dry spells and heavy rains — conditions recorded in the red and yellowish sandstones and mudstones in which the bones were preserved.

Chapter • Wild behavior

Behavior & Ecology

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Chapter • Scientific place

Taxonomy