Vertebrates with jaws including the fishes, amphibians, reptiles, birds and mammals.
The Infraphylum Gnathostomata is a member of the Subphylum Vertebrata. Here is the complete "parentage" of Gnathostomata:
- Domain: Eukaryota
- Kingdom: Animalia
C. Linnaeus, 1758 - animals
- Subkingdom: Bilateria (Hatschek, 1888) Cavalier-Smith, 1983 - bilaterians
- Kingdom: Animalia C. Linnaeus, 1758 - animals
The Infraphylum Gnathostomata is further organized into finer groupings including:
- Superclass (2): Osteichthyes · Tetrapoda
- Series (3): Amniota · Atherinomorpha · Percomorpha
- Class (13): Actinopterygii · Agnatha · Amphibia · Aves · Chondrichthyes · Gastropoda · Mammalia · Osteichthyes · Placodermi · Reptilia · Sauropsida · Secernentea · Synapsida
The Actinopterygii (), or ray-finned fishes, constitute a class or sub-class of the bony fishes. [more]
Amphibians are members of the class Amphibia, a group of vertebrates whose living forms include frogs, toads, salamanders, newts and caecilians. They are characterized as non-amniote, ectothermic tetrapods, meaning their eggs are not surrounded by membranes, they are cold-blooded, and they have four limbs. Most amphibians lay their eggs in water and the larvae undergo metamorphosis from a juvenile form with gills to an adult air-breathing form with lungs. Some, however, are paedomorphs that retain the juvenile water-breathing form throughout life. Mudpuppies and olms are examples of this, retaining juvenile gills into adulthood. Adult amphibians also use their skin for respiration. [more]
Chondrichthyes (; from Greek ???d?- chondr- 'cartilage', ????? ichthys 'fish') or cartilaginous fishes are jawed fish with paired fins, paired nares, scales, two-chambered hearts, and skeletons made of cartilage rather than bone. The class is divided into two subclasses: Elasmobranchii (sharks, rays and skates) and Holocephali (chimaeras, sometimes called ghost sharks, which are sometimes separated into their own class). [more]
The Gastropoda or gastropods, more commonly known as snails and slugs, are a large taxonomic class within the phylum Mollusca. The class Gastropoda includes snails and slugs of all kinds and all sizes from microscopic to quite large. There are huge numbers of sea snails and sea slugs, as well as freshwater snails and freshwater limpets, and land snails and land slugs. [more]
Mammals are members of class Mammalia (), air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young. Most mammals also possess sweat glands and specialised teeth, and the largest group of mammals, the placentals, have a placenta which feeds the offspring during gestation. The mammalian brain, with its characteristic neocortex, regulates endothermic and circulatory systems, the latter featuring red blood cells lacking nuclei and a large, four-chambered heart maintaining the very high metabolism rate they have. Mammals range in size from the 30?40 millimeter (1- to 1.5-inch) bumblebee bat to the 33-meter (108-foot) blue whale. [more]
Osteichthyes (), also called bony fish, are a taxonomic group of fish that have bony, as opposed to cartilaginous, skeletons. The vast majority of fish are osteichthyes, which is an extremely diverse and abundant group consisting of over 29,000 species. It is the largest class of vertebrates in existence today. Osteichthyes is divided into the ray-finned fish (Actinopterygii) and lobe-finned fish (Sarcopterygii). The oldest known fossils of bony fish are about 420 million years ago, which are also transitional fossils, showing a tooth pattern that is in between the tooth rows of sharks and bony fishes. [more]
Placodermi (from the Greek p??? = plate and d???a = skin, literally "plate-skinned") is a class of armoured prehistoric fish, known from fossils, which lived from the late Silurian to the end of the Devonian Period. Their head and thorax were covered by articulated armoured plates and the rest of the body was scaled or naked, depending on the species. Placoderms were among the first jawed fish; their jaws likely evolved from the first of their gill arches. A 380-million-year-old fossil of one species represents the oldest known example of live birth. [more]
Reptiles (Reptilia) are members of a group of air-breathing, ectothermic (cold-blooded) vertebrates which are characterized by laying shelled eggs (except for some vipers and constrictor snakes that give live birth), and having skin covered in scales and/or scutes. They are tetrapods, either having four limbs or being descended from four-limbed ancestors. Modern reptiles inhabit every continent with the exception of Antarctica. Reptiles originated around 320-310 million years ago during the Carboniferous period, having evolved from advanced reptile-like amphibians that became increasingly adapted to life on dry land. Four living orders are typically recognized: [more]
Sauropsida ("lizard faces") is a group of amniotes that includes all existing reptiles and birds and their fossil ancestors, including the dinosaurs, the immediate ancestors of birds. Sauropsida is distinguished from Synapsida, which includes mammals and their fossil ancestors. [more]
Secernentea are the main class of nematodes, characterised by numerous and an excretory system possessing lateral canals. Like all nematodes, they have no circulatory or respiratory system. [more]
At least 4 species and subspecies belong to the Class Synapsida.
More info about the Class Synapsida may be found here.
- Perrucci S, Rossi G, Macchioni G, The Journal of eukaryotic microbiology.;45(2):198-201.
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