Edaphodon
Encyclopedia
Edaphodon was a prehistoric chimaeriforme
fish
genus
belonging to the family callorhinchidae. Edaphodon was a type of rabbitfish, a cartilaginous fish
related to shark
s and rays
, and indeed some rabbitfishes are still alive today. Edaphodon has under fifteen known species
, all of which are extinct. Chimaeriformes first appeared during the Devonian
period around 415 to 360 million years ago, but this particular genus was most prominent during the Late Cretaceous
. All Edaphodon species were situated in the Northern Hemisphere, apart from E. kawai, which was recently discovered in the Chatham Islands
near New Zealand
. This shows that the range of Edaphodon reached further than was previously thought.
materials. Thus only a few spine and tooth fragments remain in most cases. E. kawai has been compared to another prehistoric cartilaginous fish, Ischyodus
, which closely resembles the rabbitfish Chimaera monstrosa
. Whether the E. kawai remains are actually Ischyodus remains is yet to be seen.
Edaphodon is very similar to other rabbitfishes in appearance - it had dark scales, and fed using "grinding plates" of teeth that didn't regrow, unlike sharks. It is assumed that it laid eggs in a leathery pouch like other rabbitfish, but no occurrences of this have been recorded. Edaphodon had a sloping head and a mouth on its underside, allowing it to graze along the bottom of the ocean like a land-dwelling herbivore
.
Chimaera
Chimaeras are cartilaginous fish in the order Chimaeriformes, known informally as ghost sharks, ratfish , spookfish , or rabbitfishes...
fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
belonging to the family callorhinchidae. Edaphodon was a type of rabbitfish, a cartilaginous fish
Chondrichthyes
Chondrichthyes or cartilaginous fishes are jawed fish with paired fins, paired nares, scales, two-chambered hearts, and skeletons made of cartilage rather than bone...
related to shark
Shark
Sharks are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago....
s and rays
Batoidea
Batoidea is a superorder of cartilaginous fish commonly known as rays and skates, containing more than 500 described species in thirteen families...
, and indeed some rabbitfishes are still alive today. Edaphodon has under fifteen known species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
, all of which are extinct. Chimaeriformes first appeared during the Devonian
Devonian
The Devonian is a geologic period and system of the Paleozoic Era spanning from the end of the Silurian Period, about 416.0 ± 2.8 Mya , to the beginning of the Carboniferous Period, about 359.2 ± 2.5 Mya...
period around 415 to 360 million years ago, but this particular genus was most prominent during the Late Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
. All Edaphodon species were situated in the Northern Hemisphere, apart from E. kawai, which was recently discovered in the Chatham Islands
Chatham Islands
The Chatham Islands are an archipelago and New Zealand territory in the Pacific Ocean consisting of about ten islands within a radius, the largest of which are Chatham Island and Pitt Island. Their name in the indigenous language, Moriori, means Misty Sun...
near New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
. This shows that the range of Edaphodon reached further than was previously thought.
Description
Like most other chimaeriformes, Edaphodon is known mainly from poorly preserved specimens; this is due to Edaphodon being part of the chondrichthyes group, which are made of cartilaginousCartilage
Cartilage is a flexible connective tissue found in many areas in the bodies of humans and other animals, including the joints between bones, the rib cage, the ear, the nose, the elbow, the knee, the ankle, the bronchial tubes and the intervertebral discs...
materials. Thus only a few spine and tooth fragments remain in most cases. E. kawai has been compared to another prehistoric cartilaginous fish, Ischyodus
Ischyodus
Ischyodus is an extinct genus of cartilaginous fish belonging to the subclass Holocephali, which includes the modern-day chimaeras. Fossils are known from Europe , North America, and New Zealand....
, which closely resembles the rabbitfish Chimaera monstrosa
Chimaera monstrosa
Chimaera monstrosa, also known as the rabbit fish or rat fish, is a species of fish in the Chimaeridae family.-Anatomy and appearance:...
. Whether the E. kawai remains are actually Ischyodus remains is yet to be seen.
Edaphodon is very similar to other rabbitfishes in appearance - it had dark scales, and fed using "grinding plates" of teeth that didn't regrow, unlike sharks. It is assumed that it laid eggs in a leathery pouch like other rabbitfish, but no occurrences of this have been recorded. Edaphodon had a sloping head and a mouth on its underside, allowing it to graze along the bottom of the ocean like a land-dwelling herbivore
Herbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...
.
Species
Edaphodon has numerous species, all of which are extinct:- Edaphodon agassizi - BucklandWilliam BucklandThe Very Rev. Dr William Buckland DD FRS was an English geologist, palaeontologist and Dean of Westminster, who wrote the first full account of a fossil dinosaur, which he named Megalosaurus...
, 1835 - Edaphodon antwerpiensis - Leriche, 1926
- Edaphodon bucklandi - AgassizLouis AgassizJean Louis Rodolphe Agassiz was a Swiss paleontologist, glaciologist, geologist and a prominent innovator in the study of the Earth's natural history. He grew up in Switzerland and became a professor of natural history at University of Neuchâtel...
, 1843 - Edaphodon eyrensis - Long, 1985
- Edaphodon kawaiEdaphodon kawaiEdaphodon kawai was a prehistoric chimaeriforme fish species belonging to the genus Edaphodon, of which all the species are now extinct. Edaphodon kawai was a type of rabbitfish, a cartilaginous fish related to sharks and rays, and indeed, some rabbitfishes are still alive today...
- Consoli, 2006 - Edaphodon laqueatus - LeidyJoseph LeidyJoseph Leidy was an American paleontologist.Leidy was professor of anatomy at the University of Pennsylvania, and later was a professor of natural history at Swarthmore College. His book Extinct Fauna of Dakota and Nebraska contained many species not previously described and many previously...
, 1873 - Edaphodon leptognathus - (has not been formally classified) AgassizLouis AgassizJean Louis Rodolphe Agassiz was a Swiss paleontologist, glaciologist, geologist and a prominent innovator in the study of the Earth's natural history. He grew up in Switzerland and became a professor of natural history at University of Neuchâtel...
- Edaphodon minor
- Edaphodon mirabilis - (has not been formally classified)
- Edaphodon mirificus - LeidyJoseph LeidyJoseph Leidy was an American paleontologist.Leidy was professor of anatomy at the University of Pennsylvania, and later was a professor of natural history at Swarthmore College. His book Extinct Fauna of Dakota and Nebraska contained many species not previously described and many previously...
, 1856 - Edaphodon sedgwicki
- Edaphodon smocki - CopeEdward Drinker CopeEdward Drinker Cope was an American paleontologist and comparative anatomist, as well as a noted herpetologist and ichthyologist. Born to a wealthy Quaker family, Cope distinguished himself as a child prodigy interested in science; he published his first scientific paper at the age of nineteen...
- Edaphodon stenobryus - CopeEdward Drinker CopeEdward Drinker Cope was an American paleontologist and comparative anatomist, as well as a noted herpetologist and ichthyologist. Born to a wealthy Quaker family, Cope distinguished himself as a child prodigy interested in science; he published his first scientific paper at the age of nineteen...
- Edaphodon tripartitus - CopeEdward Drinker CopeEdward Drinker Cope was an American paleontologist and comparative anatomist, as well as a noted herpetologist and ichthyologist. Born to a wealthy Quaker family, Cope distinguished himself as a child prodigy interested in science; he published his first scientific paper at the age of nineteen...