Serration is a saw-like appearance or a row of sharp or tooth-like projections. A serrated cutting edge has many small points of contact with the material being cut. By having less contact area than a smooth blade or other edge, the applied pressure at each point of contact is greater, and the points of contact are at a sharper angle to the material being cut. This causes a cutting action that involves many small splits in the surface of the material being cut, which cumulatively serve to cut the material along the line of the blade.
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👉 Serration in the context of Archosaurian
Archosauria or archosaurs (/ˈɑːrkəˌsɔːr/) is a clade of diapsid sauropsid tetrapods, with birds and crocodilians being the only known extant representatives. Although broadly classified as reptiles, which traditionally exclude birds, the cladistic sense of the term includes all living and extinct relatives of birds and crocodilians such as non-avian dinosaurs, pterosaurs, phytosaurs, aetosaurs and rauisuchians as well as many Mesozoic marine reptiles. Modern paleontologists define Archosauria as a crown group that includes the most recent common ancestor of living birds and crocodilians, and all of its descendants.
The base of Archosauria splits into two clades: Pseudosuchia, which includes crocodilians and their extinct relatives; and Avemetatarsalia, which includes birds and their extinct relatives (such as non-avian dinosaurs and pterosaurs). Older definitions of the group Archosauria rely on shared morphological characteristics, such as an antorbital fenestra in the skull, serrated teeth, and an upright stance. Some extinct reptiles, such as proterosuchids and euparkeriids, also possessed these features yet originated prior to the split between the crocodilian and bird lineages. The older morphological definition of Archosauria nowadays roughly corresponds to Archosauriformes, a group named to encompass crown-group archosaurs and their close relatives.
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Serration in the context of Archosaur
Archosauria (lit. 'ruling reptiles') or archosaurs (/ˈɑːrkəˌsɔːr/) is a clade of diapsid sauropsid tetrapods, with birds and crocodilians being the only known extant representatives. Although broadly classified as reptiles, which traditionally exclude birds, the cladistic sense of the term includes all living and extinct relatives of birds and crocodilians such as non-avian dinosaurs, pterosaurs, phytosaurs, aetosaurs and rauisuchians as well as many Mesozoic marine reptiles. Modern paleontologists define Archosauria as a crown group that includes the most recent common ancestor of living birds and crocodilians, and all of its descendants.
The base of Archosauria splits into two clades: Pseudosuchia, which includes crocodilians and their extinct relatives; and Avemetatarsalia, which includes birds and their extinct relatives (such as non-avian dinosaurs and pterosaurs). Older definitions of the group Archosauria rely on shared morphological characteristics, such as an antorbital fenestra in the skull, serrated teeth, and an upright stance. Some extinct reptiles, such as proterosuchids and euparkeriids, also possessed these features yet originated prior to the split between the crocodilian and bird lineages. The older morphological definition of Archosauria nowadays roughly corresponds to Archosauriformes, a group named to encompass crown-group archosaurs and their close relatives.
Serration in the context of Zelkova
Zelkova (from the Georgian dzelkva, 'stone pillar') is a genus of six species of deciduous trees in the elm family Ulmaceae, native to southern Europe, and southwest and eastern Asia. They vary in size from shrubs (Z. sicula) to large trees up to 35 m (115 ft) tall (Z. carpinifolia). The bark is smooth, dark brown. Unlike elms, the branchlets are never corky or winged. The leaves are alternate, with serrated margins, and (unlike the related elms) a symmetrical base to the leaf blade. The leaves are in two distinct rows; they have pinnate venation and each vein extends to the leaf margin, where it terminates in a tooth. There are two stipules at each node, though these are caducous (shed early), leaving a pair of scars at the leaf base. Zelkova is polygamous. Staminate flowers are clustered in the lower leaf axils of young branchlets; the perianth is campanulate, with four to six (to seven) lobes, and the stamens are short. Pistillate and hermaphrodite flowers are solitary, or rarely in clusters of two to four, in the upper leaf axils of young branchlets. The fruit is a dry, nut-like drupe with a dorsal keel, produced singly in the leaf axils. The perianth and stigma are persistent.