SauropsidaTaxonomic cladeSauropsida (Greek for "lizard faces") is a clade of amniotes, broadly equivalent to the classReptilia, though typically used in a broader sense to also include extinct stem-group relatives of modern non-avian reptiles and birds (which, as theropod dinosaurs, are nested within reptiles as more closely related to crocodilians than to lizards or turtles).
MammalA mammal (from Latin'breast') is a vertebrate animal of the classMammalia (). Mammals are characterized by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three middle ear bones. These characteristics distinguish them from reptiles and birds, from which their ancestors diverged in the Carboniferous period over 300 million years ago.
ReptileClass of animalsReptiles, as commonly defined, are tetrapodvertebrateanimals with an ectothermic metabolism and amniotic development. Reptiles traditionally comprise four orders: Testudines (turtles), Crocodilia (crocodiles, alligators and gharials), Squamata (lizards and snakes) and Rhynchocephalia (tuatara), with about 12,000 extant species listed in the Reptile Database.
Temporal fenestraTemporal fenestrae are openings in the temporal region of the skull of some amniotes, behind the orbit (eye socket). These openings have historically been used to track the evolution and affinities of reptiles. Temporal fenestrae are commonly (although not universally) seen in the fossilized skulls of dinosaurs and other sauropsids (the total group of reptiles, including birds).
TherapsidaTherapsida is a major group of eupelycosauriansynapsids. It includes mammals, as well as their ancestors and close relatives. Many defining traits of modern mammals had their origins within early therapsids. Changes in skeletal structure brought their limbs underneath their body mass which resulted in a more "standing" quadrupedal posture, as opposed to the lower sprawling posture of many reptiles and amphibians.
TetrapodA tetrapod (; from Ancient Greek (tetra)'four' and (poús)'foot') is any vertebrateanimal of the cladeTetrapoda (). The main diagnostic and defining trait (synapomorphy) of tetrapods is having four limbs, connected to the shoulder- and pelvic girdles, for which the group is named. As a clade, Tetrapoda is defined such that it includes every organism which descended from four-limbed ancestors, including those which have lost some or all of these limbs, e.g. snakes.
VertebrateSubphylum of chordatesVertebrates (), also called craniates, are animals with a vertebral column and a cranium. The vertebral column surrounds and protects the spinal cord, while the cranium protects the brain. The vertebrates make up the subphylumVertebrata ( ) with some 65,000 species, by far the largest ranked grouping in the phylumChordata. The vertebrates include mammals, birds, amphibians, and various classes of fishes and reptiles.
BirdWarm-blooded animals with wings and feathersBirds are vertebrate animals constituting the classAves, characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight skeleton. They are warm-blooded, live worldwide, and range in size from the 5.5 cm (2.2 in) bee hummingbird to the 2.8 m (9 ft 2 in) common ostrich. There are over 11,000 living species of birds, classified in 44 orders.
CladeIn biology, a clade () (from Ancient Greekκλάδος (kládos)'branch'), also known as a monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach to taxonomy adopted by most biological fields. The common ancestor may be an individual, a population, or a species (extinct or extant).
Skull roofThe skull roof or the roofing bones of the skull are a set of bones covering the brain, eyes and nostrils in bony fishes, including land-living vertebrates. The bones are derived from dermal bone and are part of the dermatocranium. In comparative anatomy, the term is applied to the whole dermatocranium.
Basal (phylogenetics)In phylogenetics, basal is the direction of the base (or root) of a rooted phylogenetic tree or cladogram. The term may be more strictly applied only to nodes adjacent to the root, or more loosely applied to nodes regarded as being close to the root. Extant taxa that lie on branches connecting directly to the root are not more closely related to the root than any other extant taxa.
ReptiliomorphaReptiliomorpha (meaning reptile-shaped; in PhyloCode known as Pan-Amniota) is a clade containing the amniotes and those tetrapods that share a more recent common ancestor with amniotes than with living amphibians (lissamphibians). It was defined by Michel Laurin (2001) and Vallin and Laurin (2004) as the largest clade that includes Homo sapiens, but not Ascaphus truei (tailed frog).
AmnioteAmniotes are tetrapod vertebrate animals belonging to the clade Amniota, a large group that comprises the vast majority of living terrestrial and semiaquatic vertebrates. Amniotes evolved from amphibious stem tetrapod ancestors during the Carboniferous period. Amniota is defined as the smallest crown clade (the group including all descendants of the last common ancestor) containing humans, the Greek tortoise, and the Nile crocodile.*As an Amazon Associate I earn from qualifying purchases.