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.
Aquatic animalAn aquatic animal is any animal, whether vertebrate or invertebrate, that lives in a body of water for all or most of its lifetime.
AnimalBiological kingdomAnimals are multicellular, eukaryoticorganisms belonging to the biologicalkingdomAnimalia (). Animals consume organic material, breathe oxygen, have muscle cells, can reproduce sexually, and grow from a hollow sphere of cells, the blastula, during embryonic development. With few exceptions, animals are able to move. Animals form a clade, meaning that they arose from a single common ancestor.
GillA gill () is a specialized respiratory organ that many aquatic animals use for aquaticgas exchange, i.e. to extract dissolved oxygen from water and to excrete carbon dioxide. Branchia (pl.: branchiae, from Ancient Greek ) is the zoologists' academic name for gills. The gills of some semi-aquaticclades (e.g. crabs, terrestrial hermit crabs and amphibious fishes), have also adapted to allow airrespiration (breathing) on land provided the gills are kept moist.
AnamniotesThe anamniotes are an informal group of vertebrates comprising all fish and amphibians, which lay their eggs in aquatic environments. They are distinguished from the amniotes (reptiles, birds and mammals), which can reproduce on dry land either by laying shelled eggs or by carrying fertilized eggswithin the female.
AgnathaAgnatha (; from Ancient Greek (a-) 'without' and (gnáthos) 'jaws') or jawless fish is a paraphyleticinfraphylum of animals in the subphylumVertebrata of the phylumChordata, characterized by the lack of jaws. The group consists of both living (cyclostomes such as hagfishes and lampreys) and extinctclades (e.g. conodonts and cephalaspidomorphs, among others).Limb (anatomy)A limb (from Old English lim, meaning "body part") is a jointed, muscled appendage of tetrapod vertebrate animals used for weight-bearing, terrestrial locomotion and physical interaction with other objects. The distalmost portion of a limb is known as its extremity.
GnathostomataGnathostomata (; from Ancient Greek: (gnathos) 'jaw' + (stoma) 'mouth') are jawedvertebrates. Gnathostome diversity comprises roughly 60,000 species, which accounts for 99% of all extant vertebrates, including all living bony fishes (both ray-finned and lobe-finned, including the terrestrialtetrapods) and cartilaginous fishes, as well as extinctprehistoric fish such as placoderms and acanthodians.
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.
Digit (anatomy)A digit is one of several most distal parts of a limb, such as fingers or toes, present in many vertebrates.
NeontologyNeontology is a part of biology that, in contrast to paleontology, studies and deals with living (or, more generally, recent) organisms. It is the study of extant taxa (singular: extant taxon): taxa (such as species, genera and families) with members still alive, as opposed to (all) being extinct.*As an Amazon Associate I earn from qualifying purchases.