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Not just Shark Pictures: Elasmodiver contains photos of sharks, skates, rays, and chimaera's from around the world. It began as a simple web based field guide to help divers find the best places to encounter different species of sharks and rays but it has slowly evolved into a much larger project containing information on all aspects of shark diving and photography. There are now more than a thousand shark pictures and sections on shark evolution, biology, and conservation. There is a large library of reviewed shark books, a constantly outdated shark taxonomy page, a monster list of shark links, and deeper in the site there are numerous articles and stories about shark encounters. Elasmodiver is now so difficult to check for updates, that new information and pictures are listed on an Elasmodiver Updates Page that can be accessed here:
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ELASMODIVER EXPANDED If you're looking for a broader range of marine life pictures the following links represent a new area that contains pictures on other marine organisms and on marine habitats. This expansion of Elasmodiver is in its first stages but will eventually include pages on everything from sea stars to nudibranches. Creating this portal will take time and for now it consists of a token offering of fish pictures. Please return regularly to enjoy the progress.
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The taxonomy of sharks and rays is a subject that remains in hot debate. Although the majority of elasmobranch families have been nailed down there will always be individual species that don't quite fit the characteristics of their sibling species. Consequently species are occasionally reclassified or simply listed as awaiting review. One of the most confusing of families is the Potamotrygonidae - the fresh water stingrays of South America. Not only do these ray species adopt extremely varied patterns that are sometimes visually indistinguishable from other species, they also produce hybrids in certain parts of their ranges leaving us wondering what exactly a true species is anyway. Among shark taxonomists conservative estimates of the number of known shark species is now approaching 500. Combined with the 700 or more species of rays and skates there are well over a thousand valid species of elasmobranches. In the past many more species were described only to be discounted later as being synonymous with elasmobranches already described from other geographic areas. In recent years this problem has lessened because taxonomic data has become easier to share over the internet. However, taxonomists are as vain as the rest of us and their efforts to be the first to describe (and name) a new species there is often a counterproductive lack of collaboration. Some abyssal species have been described from only one or two specimens captured during deep water trawls. This implies that in all likelihood there are a number of shark and ray species lurking on the abyssal plain that have not yet been seen or captured. The best example being the relatively recent discovery of the Megamouth Shark. If this large and slow moving shark could remain hidden until the 1980's, who knows how many other elasmobranches have gone unnoticed. Following is a list (in need of an update) of all the described species of elasmobranches. Included at the bottom are the Holocephali; the chimaeras or ghost sharks that share many characteristics with modern sharks and rays but are thought to be descended from a different group that thrived during the Late Devonian Period.
KINGDOM METAZOA - Animals PHYLUM CHORDATA - Animals that at some point in their life cycle have the following: Pharyngeal slits (a series of openings connecting the inside of the throat to the outside of the neck. In fish these become gill slits), dorsal nerve cord (a bundle of nerve fibres running down the back, connecting the brain with the organs and extremities, a notochord (a cartilaginous rod supporting the nerve cord), post anal tail (an extension of the 'back' past the anal opening). SUBPHYLUM VERTEBRATA - Animals with a vertibral column or backbone and neural crest cells which are released as the nerve cord is forming, these cells move through the body to form major nerves, neural ganglia, and many head and facial features. Other features that separate vertebrates from other chordates include: a relatively well-developed brain, paired complex eyes, a muscularized mouth and pharynx, and a well-developed circulatory system with a heart. CLASS CHONDRICHTHYES - Cartilaginous fishes lacking true bone. Chondrichthyes can be split into two distinct subclasses ELASMOBRANCHII and BRADYODONTI. SUBCLASS ELASMOBRANCHII - SHARKS, SKATES AND RAYS (and some fossil relatives). Elasmobranchs have an upper jaw that is not fused to the braincase and separate slitted gill openings. SHARKS JUMP TO Order HEXANCHIFORMES - Sixgill, Sevengill and Frilled Sharks JUMP TO Order SQUALIFORMES - Dogfish Sharks JUMP TO Order PRISTIOPHORIFORMES - Sawsharks JUMP TO Order SQUATINIFORMES - Angelsharks JUMP TO Order HETERODONTIFORMES - Bullhead Sharks JUMP TO Order ORECTOLOBIFORMES - Carpetsharks JUMP TO Order LAMNIFORMES - Mackerel Sharks JUMP TO Order CARCHARHINIFORMES - Ground Sharks RAYS JUMP TO Order TORPEDINIFORMES - Electric rays JUMP TO Order MYLIOBATIFORMES - Stingrays, Eagle rays, Butterfly rays, Devil rays, Cownose rays JUMP TO Order PRISTIFORMES - Sawfishes JUMP TO Order RHINOBATIFORMES - Guitarfishes SKATES JUMP TO Order RAJIFORMES - Skates CHIMAERAS SUBCLASS HOLOCEPHALI - includes forms with an upper jaw fused to the braincase and a flap of skin, the operculum, covering the gill slits. The Holocephalii includes the chimaeras and ratfishes, which are relatively rare, often deep-water, mollusc-eating forms. JUMP TO Order CHIMAERIFORMES - Chimaeras Order HEXANCHIFORMES - Sixgill, Sevengill and Frilled Sharks BACK TO TOP
Order SQUALIFORMES - Dogfish Sharks BACK TO TOP
Order PRISTIOPHORIFORMES - Sawsharks BACK TO TOP
Order SQUATINIFORMES - Angelsharks BACK TO TOP
Order HETERODONTIFORMES - Bullhead Sharks BACK TO TOP
Order ORECTOLOBIFORMES - Carpetsharks BACK TO TOP
Order LAMNIFORMES - Mackerel Sharks BACK TO TOP
Order CARCHARHINIFORMES - Ground Sharks BACK TO TOP
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