Deiphon
Encyclopedia
Deiphon was a distinctive genus
of Silurian
phacopid
trilobite
s of the family Cheiruridae
found in Western and Central Europe
, and in Central and Eastern United States
. The type species
, D. forbesi, from Bohemia
, in what is now the Czech Republic
, was discovered and described by the French
paleontologist, Joachim Barrande
in 1850.
give these trilobites a cartoon "fish-skeleton" appearance. The defensive value of these highly elongate spines is also apparent, as they would have stuck in the throats of vertebrate
predators, such as the Silurian acanthodian Nostolepis
.
Each species differed from each other in the sizes of their glabella, as well as the size and curves of the pygidium and free cheek spines.
Cheirurids had the ability to enroll to protect their softer ventral area, and the spines would have thrust upward and outward. In all adult specimens of the genus, the body has up to nine segments, not including the cephalon or pygidium (which is formed from at least two fused and reduced segments).
and Cybelloides of the Ordovician, have been interpreted as being swimmers or plankters, the species of Deiphon have been popularly thought of as being planktonic, as well. Mostly, it is due to the idea that its globular glabellum was filled with fat or oil, thus, serving as a balloon to keep it in the water column, and its elongated pleural lobes serving to keep it from sinking. If it were a nektonic or planktonic trilobite, the spherical glabellum, coupled with its rib cage
-like pleural lobes and spine-like cephalon cheeks would have presented serious impediments to its hydrodynamic ability, and would have been either a drifter, or a very leisurely swimmer, feeding on phytoplankton, or slow-moving zooplankton.
On the other hand, because of Deiphons questionable hydrodynamics, and relatively tiny eyes (as opposed to the tremendous eyes normally found on other swimming or planktonic trilobites), some think of it as being a benthic predator that scurried on top of the substrate in search of prey, only swimming when necessary (such as evading larger predators). It may have even used its enormous glabellum to store subdued prey for later digestion.
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...
of Silurian
Silurian
The Silurian is a geologic period and system that extends from the end of the Ordovician Period, about 443.7 ± 1.5 Mya , to the beginning of the Devonian Period, about 416.0 ± 2.8 Mya . As with other geologic periods, the rock beds that define the period's start and end are well identified, but the...
phacopid
Phacopida
Phacopida is an order of trilobite that lived from the Ordovician to the Devonian. It is made up of a morphologically diverse group of related suborders....
trilobite
Trilobite
Trilobites are a well-known fossil group of extinct marine arthropods that form the class Trilobita. The first appearance of trilobites in the fossil record defines the base of the Atdabanian stage of the Early Cambrian period , and they flourished throughout the lower Paleozoic era before...
s of the family Cheiruridae
Cheiruridae
The family Cheiruridae was a family of phacopid trilobites of the suborder Cheirurina. Its members, as with other members of the suborder, had distinctive pygidia modified into finger-like spines. They first appeared near the very beginning of the Ordovician, and persisted until the...
found in Western and Central Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
, and in Central and Eastern United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. The type 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...
, D. forbesi, from Bohemia
Bohemia
Bohemia is a historical region in central Europe, occupying the western two-thirds of the traditional Czech Lands. It is located in the contemporary Czech Republic with its capital in Prague...
, in what is now the Czech Republic
Czech Republic
The Czech Republic is a landlocked country in Central Europe. The country is bordered by Poland to the northeast, Slovakia to the east, Austria to the south, and Germany to the west and northwest....
, was discovered and described by the French
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
paleontologist, Joachim Barrande
Joachim Barrande
Joachim Barrande was a French geologist and palaeontologist.Barrande was born at Saugues, Haute Loire, and educated in the École Polytechnique at Paris...
in 1850.
Description
The glabella was inflated, and globular-shaped, and covered in small wart-like bumps. If it was filled with fat, or oil, the glabellum would have helped to have made the creature positively buoyant. On the other hand, trilobites with large glabellae are often suspected of being predatory, as the volume of glabella would be filled with digestive organs, or used to store captured/swallowed prey. The free cheeks of the cephalon formed a pair of long, curved spines, and the segments of the pleural lobes were separated and elongated to form rib-like struts. These modifications, along with the "V" shaped pygidiumPygidium
The pygidium is the posterior body part or shield of crustaceans and some other arthropods, such as insects and the extinct trilobites. It contains the anus and, in females, the ovipositor...
give these trilobites a cartoon "fish-skeleton" appearance. The defensive value of these highly elongate spines is also apparent, as they would have stuck in the throats of vertebrate
Vertebrate
Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...
predators, such as the Silurian acanthodian Nostolepis
Nostolepis
Nostolepis is an extinct genus of acanthodian fish which lived in the Late Silurian to Middle Devonian . Members of the genus include Nostolepis gracilis and Nostolepis striata....
.
Each species differed from each other in the sizes of their glabella, as well as the size and curves of the pygidium and free cheek spines.
Cheirurids had the ability to enroll to protect their softer ventral area, and the spines would have thrust upward and outward. In all adult specimens of the genus, the body has up to nine segments, not including the cephalon or pygidium (which is formed from at least two fused and reduced segments).
Ecology
Because some of the other highly-derived cheirurid trilobites, such as the Devonian CrotalocephalusCrotalocephalus
Crotalocephalus is a genus of trilobite that lived from the Late Silurian to the Early Devonian. Its remains have been found in Asia, Australia, Africa, and Europe.-External links:* in the Paleobiology Database...
and Cybelloides of the Ordovician, have been interpreted as being swimmers or plankters, the species of Deiphon have been popularly thought of as being planktonic, as well. Mostly, it is due to the idea that its globular glabellum was filled with fat or oil, thus, serving as a balloon to keep it in the water column, and its elongated pleural lobes serving to keep it from sinking. If it were a nektonic or planktonic trilobite, the spherical glabellum, coupled with its rib cage
Rib cage
The rib cage is an arrangement of bones in the thorax of animals. It is formed by the vertebral column, ribs and sternum and encloses the heart and lungs....
-like pleural lobes and spine-like cephalon cheeks would have presented serious impediments to its hydrodynamic ability, and would have been either a drifter, or a very leisurely swimmer, feeding on phytoplankton, or slow-moving zooplankton.
On the other hand, because of Deiphons questionable hydrodynamics, and relatively tiny eyes (as opposed to the tremendous eyes normally found on other swimming or planktonic trilobites), some think of it as being a benthic predator that scurried on top of the substrate in search of prey, only swimming when necessary (such as evading larger predators). It may have even used its enormous glabellum to store subdued prey for later digestion.
External links
- Reconstruction of D. forbesi in comparison to Eurypterus remipedes http://www.deviantart.com/deviation/36974185/