neck, the dorsal eminence tends to manifest as a prominent spike. This is taken to an extreme in desmatosuchines such as Longosuchus and Desmatosuchus, where the spike is enlarged into a sharply curved horn. In most aetosaurs (a major exception being desmatosuchines), the underside of the animal is also protected by osteoderms. These ventral (belly) osteoderms are generally smaller and flatter than the dorsal series, and are arranged into a larger number of rows (usually 5 - 14 rows), at least in the torso. Ventral osteoderms rows usually curve outwards and separate under the hip, leaving a wide gap for the cloacal opening. Large, hooked spines occur around this opening in Typothorax, one of the few exceptions to a general rule of smooth ventral osteoderms. Ventral rows break up into a shagreen of small plates on the neck, and a small number of wide rows under the tail. A dense assortment of small, non-overlapping plates, known as appendicular osteoderms, covered the front and hindlimbs. History Early European finds Aetosaur material was first described by Swiss paleontologist Louis Agassiz in 1844. He named the genus Stagonolepis from the Lossiemouth Sandstone in Elgin, Scotland, but considered the fossil to be a Devonian fish rather than a Triassic reptile. This may be because he considered the strata to be part of the Old Red Sandstone, and thus Paleozoic in age. Agassiz mistook the osteoderms for large rhomboidal scales, which he thought were arranged in a similar pattern to those of gars. He also thought that these supposed scales were very similar to those of the lobe-finned fish Megalichthys due to their large size. English biologist Thomas Henry Huxley reconsidered the fish scales described by Agassiz and considered them to belong to a crocodilian. He first proposed this to the Geological Society of London in 1858, and went into more detail in an 1875 paper in the society's quarterly journal. By this time, new material had been uncovered from Elgin that indicated that Stagonolepis was not a fish, but a reptile. However, Stagonolepis was still known primarily by scutes and imprints of scutes, many of which were not well preserved. More complete aetosaur remains were found from the Lower Stubensandtein of Germany in the 1870s. Among them were complete articulated skeletons of 22 aetosaurs. These specimens were found in a large sandstone outcrop near Stuttgart and were preserved together in an area less than