Regurgitalite

The term "regurgitalite" was proposed by Adrian Hunt in 1992 as "consonant with coprolite and cololite, to refer to regurgitated material." The alternate spelling "regurgitalith" appeared in Bertling et al. (2006), though this was an unintentional orthographic variation rather than a proposed new term. More specific terminology has been developed for particular types of regurgitalites. "Strigilite" refers to fossilized owl pellets, derived from the Latin strix (owl). "Ornithoregurgitalite" is used for regurgitalites produced by birds generally, while "gastroregurgitalite" specifically refers to material regurgitated from the stomach rather than the oral cavity. ==Characteristics==

Regurgitalites can be distinguished from coprolites by several diagnostic features, though identification often requires detailed chemical and microstructural analysis: • Shape and thickness: Regurgitalites are typically thin and irregularly shaped, composed of randomly grouped and intermingled angular skeletal fragments of varying sizes. Coprolites, by contrast, tend to be massive, thick, and possess a more regular shape. • Phosphatic matrix: Regurgitalites typically lack the phosphatic matrix characteristic of coprolites. The absence of this matrix reflects the shorter residence time in the digestive tract. • Gastric etching: Bone and shell fragments in regurgitalites often show minimal gastric etching (acid damage from stomach acids), as the material was expelled before significant digestion occurred. Coprolite inclusions typically show more pronounced signs of digestion. • Soft tissue preservation: Regurgitalites may preserve soft tissues such as muscle fibers, which would not survive passage through the entire digestive tract. • Articulation: Skeletal remains in regurgitalites often retain some degree of articulation and show low degrees of roundness at fragment edges. ==Fossil record==

Marine regurgitalites Marine regurgitalites are known from various Mesozoic deposits. The Triassic Polzberg Konservat-Lagerstätte in Austria has yielded regurgitalites containing ammonoid shells and cephalopod remains, likely produced by large durophagous fish such as the cartilaginous fish Acrodus. Terrestrial regurgitalites Fossilized owl pellets (strigilites) are documented from the Oligocene Orella Member of the White River Formation in Wyoming, representing the oldest unambiguous record of fossil owl pellets. Despite frequent suggestions that owl pellets are important contributors to the Cenozoic microvertebrate fossil record, relatively few fossil owl pellets have been documented from pre-Quaternary deposits, though they are abundant in some Quaternary cave deposits. ==Scientific significance==

Regurgitalites provide direct evidence of ancient predator-prey relationships and feeding behaviors that cannot be obtained from body fossils alone. They offer insights into the behavioral ecology and physiology of extinct species, revealing information about diet, hunting strategies, and digestive capabilities. Because regurgitated material spends less time in the digestive tract than fecal matter, regurgitalites can preserve prey items in better condition, sometimes retaining soft tissues and articulated skeletal elements. The study of regurgitalites has contributed to understanding of ancient food chains and trophic interactions. For example, the presence of ammonoid-bearing regurgitalites in Triassic deposits supports evidence that durophagous predation was intense during this period, contributing to the "Mesozoic Marine Revolution." ==See also==