Dino Glossary
Carcharodontosaurus life reconstruction. Image credit: Fred Wierum
This glossary explains a number of words that are frequently encountered in the field of dinosaur paleobiology. Becoming familiar with these terms will not only help readers understand the content on this website better, but other dinosaur related material as well.
Alvarezsaurid – A clade of small, lightly built theropod dinosaurs with highly reduced forelimbs and a single enlarged manual claw, often interpreted as adaptations for specialized feeding strategies such as insectivory.
Amniote – A vertebrate whose embryos develop within an amnion, allowing reproduction away from water; dinosaurs, birds, and mammals are amniotes.
Ankylosaur – A quadrupedal ornithischian dinosaur characterized by extensive dermal armor (osteoderms) and, in derived taxa, a bony tail club used for defense.
Archosaur – A major diapsid reptile clade including dinosaurs, birds, crocodilians, and their extinct relatives, united by shared skeletal and soft-tissue traits.
Basal – Referring to a taxon or anatomical condition that retains traits closer to the ancestral form of a clade.
Bone Bed – A sedimentary deposit containing numerous fossil bones, often representing mass mortality events or long-term accumulation.
Bone Histology – The microscopic study of bone tissue structure, used to infer growth rates, age at death, metabolism, and life history in extinct organisms.
Carnivore – An organism that primarily consumes animal tissue; many theropod dinosaurs were obligate carnivores.
Cancellous Bone (Spongy Bone) – Porous, lightweight bone tissue found in the interior of bones, important for shock absorption and structural efficiency.
Clade – A monophyletic group consisting of a common ancestor and all of its descendants, fundamental to modern phylogenetic classification.
Coelurosaur – A diverse theropod clade including tyrannosauroids, ornithomimosaurs, maniraptorans, and birds, often showing trends toward increased brain size and feather evolution.
Compact Bone (Cortical Bone) – Dense outer bone tissue providing strength and protection, commonly sampled in histological studies.
Cretaceous – The final period of the Mesozoic Era (approximately 145–66 million years ago), ending with the extinction of non-avian dinosaurs.
Derived – Describing traits that evolved later in a lineage and differ from the ancestral condition.
Dinosauria – The clade of archosaurs known as dinosaurs, defined by upright posture and distinctive hip anatomy.
Endothermy – The physiological regulation of internal body temperature; bone histology suggests many dinosaurs exhibited elevated metabolic rates relative to modern reptiles.
Fibrolamellar Bone – A rapidly deposited bone tissue combining woven bone and lamellar bone, commonly found in fast-growing dinosaurs and associated with high growth rates.
Flora – The plant life of a particular region or geological time interval, forming the base of terrestrial ecosystems.
Formation – A mappable geological unit consisting of rock layers with similar characteristics, frequently used to contextualize fossil occurrences.
Fossil – Preserved remains, impressions, or traces of ancient organisms, typically formed through burial and mineralization.
Gastrolith – Stones intentionally swallowed by some animals, including certain dinosaurs, likely aiding mechanical digestion.
Growth Ring (LAG – Line of Arrested Growth) – A histological feature representing periodic pauses in bone growth, often interpreted as annual markers similar to tree rings.
Herbivore – An organism that feeds primarily on plant material; most ornithischians and all sauropods were herbivorous.
Holotype – The single fossil specimen designated as the name-bearing reference for a species.
Haversian System – A structural unit of compact bone composed of concentric lamellae surrounding a central canal, indicative of bone remodeling and maturity.
Ichnofossil (Trace Fossil) – Fossilized evidence of organismal activity, such as footprints, trackways, nests, or coprolites.
Juvenile – A growth stage prior to skeletal maturity, often identifiable through bone histology and unfused skeletal elements.
Jurassic – The middle period of the Mesozoic Era (approximately 201–145 million years ago), noted for the diversification of large-bodied dinosaurs.
Lagerstätte – A fossil deposit exhibiting exceptional preservation, often retaining soft tissues or fine anatomical detail.
Lamellar Bone – Highly organized bone tissue deposited slowly, typically associated with skeletal maturity and reduced growth rates.
Mesozoic Era – The geological era spanning approximately 252–66 million years ago, encompassing the Triassic, Jurassic, and Cretaceous periods.
Morphology – The study of anatomical form and structure, including skeletal shape and functional adaptations.
Non-avian Dinosaur – All extinct dinosaurs excluding birds, used to distinguish them from their living avian descendants.
Ontogeny – The developmental history of an individual organism from early growth stages to adulthood.
Ornithischian – One of the two primary dinosaur hip clades, characterized by a retroverted pubis and predominantly herbivorous diets.
Osteoderm – Bony plates or nodules embedded in the skin, providing protection and structural support.
Paleobiology – The study of the biology, physiology, behavior, and life history of extinct organisms.
Paleoecology – The reconstruction of ancient ecosystems and organism–environment interactions.
Phylogeny – The evolutionary relationships among organisms, typically depicted as branching diagrams or cladograms.
Remodeling (Bone Remodeling) – The process by which bone tissue is resorbed and redeposited, leaving histological signatures that reflect age and biomechanical stress.
Sauropod – Large-bodied, long-necked, quadrupedal herbivorous dinosaurs, including some of the largest terrestrial animals known.
Sedimentary Rock – Rock formed by the accumulation and lithification of sediments, the primary medium for fossil preservation.
Theropod – A predominantly bipedal saurischian dinosaur clade, mostly carnivorous though some exceptions occur.
Triassic – The earliest period of the Mesozoic Era (approximately 252–201 million years ago), during which dinosaurs first evolved.
Type Specimen – A fossil specimen serving as the definitive reference for a species’ identification, usually a holotype.
Vertebrate – An animal possessing a vertebral column; all dinosaurs belong to this group.
Woven Bone – Rapidly formed, disorganized bone tissue common in juveniles and fast-growing animals, often replaced later by lamellar bone.
Amniote – A vertebrate whose embryos develop within an amnion, allowing reproduction away from water; dinosaurs, birds, and mammals are amniotes.
Ankylosaur – A quadrupedal ornithischian dinosaur characterized by extensive dermal armor (osteoderms) and, in derived taxa, a bony tail club used for defense.
Archosaur – A major diapsid reptile clade including dinosaurs, birds, crocodilians, and their extinct relatives, united by shared skeletal and soft-tissue traits.
Basal – Referring to a taxon or anatomical condition that retains traits closer to the ancestral form of a clade.
Bone Bed – A sedimentary deposit containing numerous fossil bones, often representing mass mortality events or long-term accumulation.
Bone Histology – The microscopic study of bone tissue structure, used to infer growth rates, age at death, metabolism, and life history in extinct organisms.
Carnivore – An organism that primarily consumes animal tissue; many theropod dinosaurs were obligate carnivores.
Cancellous Bone (Spongy Bone) – Porous, lightweight bone tissue found in the interior of bones, important for shock absorption and structural efficiency.
Clade – A monophyletic group consisting of a common ancestor and all of its descendants, fundamental to modern phylogenetic classification.
Coelurosaur – A diverse theropod clade including tyrannosauroids, ornithomimosaurs, maniraptorans, and birds, often showing trends toward increased brain size and feather evolution.
Compact Bone (Cortical Bone) – Dense outer bone tissue providing strength and protection, commonly sampled in histological studies.
Cretaceous – The final period of the Mesozoic Era (approximately 145–66 million years ago), ending with the extinction of non-avian dinosaurs.
Derived – Describing traits that evolved later in a lineage and differ from the ancestral condition.
Dinosauria – The clade of archosaurs known as dinosaurs, defined by upright posture and distinctive hip anatomy.
Endothermy – The physiological regulation of internal body temperature; bone histology suggests many dinosaurs exhibited elevated metabolic rates relative to modern reptiles.
Fibrolamellar Bone – A rapidly deposited bone tissue combining woven bone and lamellar bone, commonly found in fast-growing dinosaurs and associated with high growth rates.
Flora – The plant life of a particular region or geological time interval, forming the base of terrestrial ecosystems.
Formation – A mappable geological unit consisting of rock layers with similar characteristics, frequently used to contextualize fossil occurrences.
Fossil – Preserved remains, impressions, or traces of ancient organisms, typically formed through burial and mineralization.
Gastrolith – Stones intentionally swallowed by some animals, including certain dinosaurs, likely aiding mechanical digestion.
Growth Ring (LAG – Line of Arrested Growth) – A histological feature representing periodic pauses in bone growth, often interpreted as annual markers similar to tree rings.
Herbivore – An organism that feeds primarily on plant material; most ornithischians and all sauropods were herbivorous.
Holotype – The single fossil specimen designated as the name-bearing reference for a species.
Haversian System – A structural unit of compact bone composed of concentric lamellae surrounding a central canal, indicative of bone remodeling and maturity.
Ichnofossil (Trace Fossil) – Fossilized evidence of organismal activity, such as footprints, trackways, nests, or coprolites.
Juvenile – A growth stage prior to skeletal maturity, often identifiable through bone histology and unfused skeletal elements.
Jurassic – The middle period of the Mesozoic Era (approximately 201–145 million years ago), noted for the diversification of large-bodied dinosaurs.
Lagerstätte – A fossil deposit exhibiting exceptional preservation, often retaining soft tissues or fine anatomical detail.
Lamellar Bone – Highly organized bone tissue deposited slowly, typically associated with skeletal maturity and reduced growth rates.
Mesozoic Era – The geological era spanning approximately 252–66 million years ago, encompassing the Triassic, Jurassic, and Cretaceous periods.
Morphology – The study of anatomical form and structure, including skeletal shape and functional adaptations.
Non-avian Dinosaur – All extinct dinosaurs excluding birds, used to distinguish them from their living avian descendants.
Ontogeny – The developmental history of an individual organism from early growth stages to adulthood.
Ornithischian – One of the two primary dinosaur hip clades, characterized by a retroverted pubis and predominantly herbivorous diets.
Osteoderm – Bony plates or nodules embedded in the skin, providing protection and structural support.
Paleobiology – The study of the biology, physiology, behavior, and life history of extinct organisms.
Paleoecology – The reconstruction of ancient ecosystems and organism–environment interactions.
Phylogeny – The evolutionary relationships among organisms, typically depicted as branching diagrams or cladograms.
Remodeling (Bone Remodeling) – The process by which bone tissue is resorbed and redeposited, leaving histological signatures that reflect age and biomechanical stress.
Sauropod – Large-bodied, long-necked, quadrupedal herbivorous dinosaurs, including some of the largest terrestrial animals known.
Sedimentary Rock – Rock formed by the accumulation and lithification of sediments, the primary medium for fossil preservation.
Theropod – A predominantly bipedal saurischian dinosaur clade, mostly carnivorous though some exceptions occur.
Triassic – The earliest period of the Mesozoic Era (approximately 252–201 million years ago), during which dinosaurs first evolved.
Type Specimen – A fossil specimen serving as the definitive reference for a species’ identification, usually a holotype.
Vertebrate – An animal possessing a vertebral column; all dinosaurs belong to this group.
Woven Bone – Rapidly formed, disorganized bone tissue common in juveniles and fast-growing animals, often replaced later by lamellar bone.