Askeptosaurus is an extinct genus of aquatic reptile belonging to the diapsid group. It was about 2 m (6 ft 8 in) long. The conservation status of a species is an indicator of the likelihood of that species continuing to survive. ... The Triassic is a geologic period that extends from about 251 to 200 Ma (million years ago). ... Scientific classification or biological classification is how biologists group and categorize extinct and living species of organisms. ... Phyla Subregnum Parazoa Porifera (sponges) Subregnum Agnotozoa Placozoa (trichoplax) Orthonectida (orthonectids) Rhombozoa (dicyemids) Subregnum Eumetazoa Radiata (unranked) (radial symmetry) Ctenophora (comb jellies) Cnidaria (coral, jellyfish, anemones) Bilateria (unranked) (bilateral symmetry) Acoelomorpha (basal) Myxozoa (slime animals) Superphylum Deuterostomia (blastopore becomes anus) Chordata (vertebrates, etc. ... Typical Classes Subphylum Urochordata - Tunicates Ascidiacea Thaliacea Larvacea Subphylum Cephalochordata - Lancelets Subphylum Myxini - Hagfishes Subphylum Vertebrata - Vertebrates Petromyzontida - Lampreys Placodermi (extinct) Chondrichthyes - Cartilaginous fishes Acanthodii (extinct) Actinopterygii - Ray-finned fishes Actinistia - Coelacanths Dipnoi - Lungfishes Amphibia - Amphibians Reptilia - Reptiles Aves - Birds Mammalia - Mammals Chordates (phylum Chordata) include the vertebrates, together with... Superclasses Anapsida Eurapsida Diapsida Reptilia was an old kingdom or phylum classification that has since been divided into 4 classes. ... Orders Procolophonia (extinct) Testudines Araeoscelidia (extinct) Avicephala (extinct) Younginiformes (extinct) Sauropterygia Ichthyosauria (extinct) Placodontia (extinct) Nothosauria (extinct) Plesiosauria (extinct) Sphenodontia Squamata Prolacertiformes (extinct) Archosauria Crurotarsi Order Aetosauria Order Phytosauria Order Rauisuchia Order Crocodilia Ornithodira Pterosauria (extinct) Marasuchus (extinct) Dinosauria (extinct) Order Saurischia Order Ornithischia Reptiles are tetrapods and amniotes, animals... Groups See Text Diapsids (two arches) are a group of tetrapod animals that developed two holes (temporal fenestra) in each side of their skulls, about 300 million years ago during the late Carboniferous period. ...

Askeptosaurus was a very thin, elongated creature that probably swam like an eel. It steered using its webbed feet. Judging from its long jaws, it was a fish eater. Paleontologists think Askeptosaurus hunted in deep waters, based on its large eyes (which would allow it to see better in dark water) and the protective bony ring around its them (also seen in ichthyosaurs), which prevented them from getting squashed in by the immense water pressure at great depths. Suborders Anguilloidei Nemichthyoidei Congroidei Synaphobranchoidei See text for families. ... It has been suggested that this article or section be merged with mandible. ... The Guppy, also known as guppie (Poecilia reticulata) is one of the most popular freshwater aquarium fish species in the world. ... A paleontologist carefully chips rock from a column of dinosaur vertebrae. ... gonfly]].]] In most vertebrates and some mollusks, the eye works by allowing light to enter it and project onto a light-sensitive panel of cells known as the retina at the rear of the eye, where the light is detected and converted into electrical signals, which are then transmitted to... Taxonomy See text Ichthyosaurs (Greek for fish lizard - ιχθυς meaning fish and σαυρος meaning lizard) were giant marine reptiles that resembled fish and dolphins. ... Water pressure is the pressure in any system for supplying water, usually a domestic water system, although the term is used in other contexts as well, such as a municipal water system. ...