Silvadectes
Encyclopedia
Silvadectes is an extinct genus
of diadectid
reptiliomorph. It is known from several nearly complete articulated skeletons collected from the Early Permian Tambach Formation in the Thuringian Forest
of central Germany
. The type species
is S. absitus. It was first described in 1998 as Diadectes
absitus, but was later placed in its own genus in 2010.
-like cheek with distinctive cusps. As in other forms, Silvadectes has procumbent teeth at the front of the upper and lower jaws and spade-shaped teeth further back in the jaws. A unique feature of Silvadectes is an enlarged dorsal projection of the ilium
, a hip bone. The added height of the projection makes the ilium higher than it is long.
than other species of Diadectes, outside the derived clade
composed of these species. In these analyses, the genus Diasparactus
was more closely related to the other species of Diadectes than was D. absitus. Below is a cladogram from the 2010 study showing the phylogenetic position of Silvadectes:
. This was the first species-level identification of track makers from the Paleozoic
era, making the ichnofossils the oldest known identifiable trackways. The spacing of the footprints indicates that Silvadectes and other diadectids walked with their feet directly underneath their bodies in a similar manner to mammals. This finding contrasts with earlier depictions of diadectids and other reptiliomorphs as sprawling animals.
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 diadectid
Diadectidae
Diadectidae is an extinct family of large diadectomorph reptiliomorphs. Diadectids lived in North America and Europe during the Late Carboniferous and Early Permian. They were the first herbivorous tetrapods, and also the first fully terrestrial animals to attain large sizes. Footprints indicate...
reptiliomorph. It is known from several nearly complete articulated skeletons collected from the Early Permian Tambach Formation in the Thuringian Forest
Thuringian Forest
The Thuringian Forest running northwest to southeast, forms a continuous stretch of ancient rounded mountains posing ample difficulties in transit routing save through a few navigable passes in the southern reaches of the German state of Thuringia. It is about long and wide...
of central Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
. The type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
is S. absitus. It was first described in 1998 as Diadectes
Diadectes
Diadectes was a genus of large, very reptile-like amphibians that lived during the early Permian period...
absitus, but was later placed in its own genus in 2010.
Description
Silvadectes grew to about 6 feet (1.8 m) in length. It has several characteristics that are primitive among diadectids. The skull and lower jaw are lower and less robust than those of related forms, and the genus lacks wide molarMolar
Molar may refer to:*Molar , the fourth kind of tooth in mammals*Molar , another name for the Spanish wine grape Listan Negro*Molar concentration, a unit of concentration, or molarity, of solutions equal to 1 mole per litre*Molar volume...
-like cheek with distinctive cusps. As in other forms, Silvadectes has procumbent teeth at the front of the upper and lower jaws and spade-shaped teeth further back in the jaws. A unique feature of Silvadectes is an enlarged dorsal projection of the ilium
Ilium
-Places:* Ilion or, Latinized, Ilium, another name for the legendary city of Troy, hence the title of Homer's Iliad*Ilium , an ancient city in Epirus...
, a hip bone. The added height of the projection makes the ilium higher than it is long.
Classification
The genus Silvadectes was erected in 2010 for Diadectes absitus. Previous phylogenetic analyses of diadectids had found D. absitus to be more basalBasal (phylogenetics)
In phylogenetics, a basal clade is the earliest clade to branch in a larger clade; it appears at the base of a cladogram.A basal group forms an outgroup to the rest of the clade, such as in the following example:...
than other species of Diadectes, outside the derived clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
composed of these species. In these analyses, the genus Diasparactus
Diasparactus
Diasparactus is an extinct genus of diadectid.In Diasparactus, the spines of the dorsal vertebrae are higher than in other genera in the family.-Diasparactus zenos:...
was more closely related to the other species of Diadectes than was D. absitus. Below is a cladogram from the 2010 study showing the phylogenetic position of Silvadectes:
Trackways
Many well-preserved articulated skeletons of early tetrapods have been found in association with footprints in the Tambach Formation. In 2007, the footprints of the ichnospecies Ichniotherium cottae were attributed to Silvadectes absitus. Ichniotherium sphaerodactylum, another ichnospecies from the formation, was attributed to the related diadectid OrobatesOrobates
Orobates is an extinct genus of diadectid. It lived in the middle Permian, about 260 million years ago. Its remains were found in Germany....
. This was the first species-level identification of track makers from the Paleozoic
Paleozoic
The Paleozoic era is the earliest of three geologic eras of the Phanerozoic eon, spanning from roughly...
era, making the ichnofossils the oldest known identifiable trackways. The spacing of the footprints indicates that Silvadectes and other diadectids walked with their feet directly underneath their bodies in a similar manner to mammals. This finding contrasts with earlier depictions of diadectids and other reptiliomorphs as sprawling animals.