Glossary H
Habitat
The usual or typical location and environment in which an organism lives.
Hallux
The first digit of the foot; the big toe or another analogous structure.
Hapantotype
One or more preparations of directly related individuals representing differing stages in the life cycle together forming a name-bearing type in an extant species of protozoa. A hapantotype is a series that must not be restricted by lectotype selection; however, if a hapantotype is found to contain individuals of more than one species, components may be eliminated until it contains individuals of only one species.
Hatchling
A newly hatched organism; a dinosaur or other organism that has just hatched from an egg.
Haversian bone / Haversian growth / Haversian system
A type of secondary bone, either compact or cancellous (spongy), that replaces primary bone; it forms a series of distinctive vascular canals (Haversian canals); among modern vertebrates, the compact form of Haversian bone is found only in endotherms (i.e., birds, mammals) and thus its presence in certain dinosaurs suggests that they grew in similar ways. Thus, Haversian growth, Haversian system. (From Clopton Havers, 1650-1702, English physician noted for his research in bone structure)
Head-butting
A distinctive behavior pattern in which two members of the same species, typically two males contesting for dominance of a group, repeatedly collide head to head with each other; observed in some modern mammals; e.g., bighorn sheep and also speculated to have occurred in certain dinosaurs.
Herbivore / Herbivorous
An organism whose diet consists exclusively or mainly of plants. Thus, Herbivorous
Herding
The behavior pattern of forming large groups or herds; typically used to refer to larger plant-eating animals.
Heterochrony / Heterochronous / Heterochronic
The condition of having a different onset and cessation of growth, or an different rate of growth for a given feature, relative to the onset, cessation, or rate of development of this same feature in an ancestor. Thus, Heterochronous, Heterochronic
High-pressure mineral phases
Mineral forms that are stable only at the extremely high pressures typical of Earth’s deep interior but not its surface. Such pressures are generated instantaneously during meteorite impact. For example, stishovite is the high-pressure polymorph of quartz, a common crustal mineral.
Hindlimbs
Back or rear legs
Histology
The study of the fine structure of body tissues.
Humerus
Upper forearm or foreleg bone
Hummocky
Uneven, \"lumpy\" terrain.
Hyperextended
Over-straightened, bent backwards on itself
Hyposphene
Hypo joint on the arch of a vertebra