Kangnasaurus
Encyclopedia
Kangnasaurus is a genus
of iguanodont
ian ornithopod dinosaur
found in supposedly Early Cretaceous
rocks of South Africa
. It is known from a tooth and possibly some postcranial remains. At times, it has been considered dubious
or a valid genus. It was probably similar to Dryosaurus
.
. The type species
is Kangnasaurus coetzeei. The generic name refers to the Kangnas farm; the specific name to the farmer, Coetzee. Kangnasaurus is based on holotype
SAM 2732, a tooth found at a depth of 34 metres in a well at Farm Kangnas, in the Orange River
valley of northern Cape Province
, South Africa
. The age of these rocks, conglomerate
s in an ancient crater lake
, is unclear; they are thought to be from the Early Cretaceous. Haughton thought SAM 2732 was a tooth from the upper jaw
, but Michael Cooper reidentified it as a lower jaw tooth in 1985. This had implications for its classification: Haughton thought the tooth was that of an iguanodontid, while Cooper identified it as from an animal more like Dryosaurus
, a more basal
ornithopod.
Haughton described several other fossils as possibly belonging to Kangnasaurus. These include five partial thigh bones
, a partial thigh bone and shin bone
, a partial metatarsal
, a partial shin and foot, vertebrae, and unidentified bones. Some of the bones apparently came from other deposits, and Haughton was not certain that they all belonged to his new genus. Cooper was also not certain, but described the other specimens as if they did belong to Kangnasaurus.
Kangnasaurus is usually regarded as dubious, although a 2007 review of dryosaurids by Ruiz-Omeñaca and colleagues retained it as potentially valid, differing from other dryosaurids by details of the thigh bone. Like other basal iguanodontians, it would have been a bipedal herbivore
.
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 iguanodont
Iguanodont
Iguanodonts were herbivorous dinosaurs that lived from the mid-Jurassic to Late Cretaceous. Some members include Camptosaurus, Callovosaurus, Iguanodon, Ouranosaurus, and the hadrosaurids or "duck-billed dinosaurs". Iguanodonts were one of the first groups of dinosaurs to be found...
ian ornithopod dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
found in supposedly Early Cretaceous
Early Cretaceous
The Early Cretaceous or the Lower Cretaceous , is the earlier or lower of the two major divisions of the Cretaceous...
rocks of South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
. It is known from a tooth and possibly some postcranial remains. At times, it has been considered dubious
Nomen dubium
In zoological nomenclature, a nomen dubium is a scientific name that is of unknown or doubtful application...
or a valid genus. It was probably similar to Dryosaurus
Dryosaurus
Dryosaurus is a genus of an ornithopod dinosaur that lived in the Late Jurassic period. It was an iguanodont . Fossils have been found in the western United States, and were first discovered in the late 19th century...
.
Description and history
Kangnasaurus was named in 1915 by Sidney H. HaughtonSidney H. Haughton
Sidney Henry Haughton, , was an English-born South African paleontologist and geologist. The eldest of three children born to Henry Charles Haughton and Alice Aves, he is best-known for his description of the sauropodomorph dinosaur Melanorosaurus in 1924, and his work on the geology of the...
. 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 Kangnasaurus coetzeei. The generic name refers to the Kangnas farm; the specific name to the farmer, Coetzee. Kangnasaurus is based on holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
SAM 2732, a tooth found at a depth of 34 metres in a well at Farm Kangnas, in the Orange River
Orange River
The Orange River , Gariep River, Groote River or Senqu River is the longest river in South Africa. It rises in the Drakensberg mountains in Lesotho, flowing westwards through South Africa to the Atlantic Ocean...
valley of northern Cape Province
Cape Province
The Province of the Cape of Good Hope was a province in the Union of South Africa and subsequently the Republic of South Africa...
, South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
. The age of these rocks, conglomerate
Conglomerate (geology)
A conglomerate is a rock consisting of individual clasts within a finer-grained matrix that have become cemented together. Conglomerates are sedimentary rocks consisting of rounded fragments and are thus differentiated from breccias, which consist of angular clasts...
s in an ancient crater lake
Crater lake
A crater lake is a lake that forms in a volcanic crater or caldera, such as a maar; less commonly and with lower association to the term a lake may form in an impact crater caused by a meteorite. Sometimes lakes which form inside calderas are called caldera lakes, but often this distinction is not...
, is unclear; they are thought to be from the Early Cretaceous. Haughton thought SAM 2732 was a tooth from the upper jaw
Maxilla
The maxilla is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible , which is also a fusion of two halves at the mental symphysis. Sometimes The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper...
, but Michael Cooper reidentified it as a lower jaw tooth in 1985. This had implications for its classification: Haughton thought the tooth was that of an iguanodontid, while Cooper identified it as from an animal more like Dryosaurus
Dryosaurus
Dryosaurus is a genus of an ornithopod dinosaur that lived in the Late Jurassic period. It was an iguanodont . Fossils have been found in the western United States, and were first discovered in the late 19th century...
, a more basal
Basal (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:...
ornithopod.
Haughton described several other fossils as possibly belonging to Kangnasaurus. These include five partial thigh bones
Femur
The femur , or thigh bone, is the most proximal bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in...
, a partial thigh bone and shin bone
Tibia
The tibia , shinbone, or shankbone is the larger and stronger of the two bones in the leg below the knee in vertebrates , and connects the knee with the ankle bones....
, a partial metatarsal
Metatarsus
The metatarsus or metatarsal bones are a group of five long bones in the foot located between the tarsal bones of the hind- and mid-foot and the phalanges of the toes. Lacking individual names, the metatarsal bones are numbered from the medial side : the first, second, third, fourth, and fifth...
, a partial shin and foot, vertebrae, and unidentified bones. Some of the bones apparently came from other deposits, and Haughton was not certain that they all belonged to his new genus. Cooper was also not certain, but described the other specimens as if they did belong to Kangnasaurus.
Kangnasaurus is usually regarded as dubious, although a 2007 review of dryosaurids by Ruiz-Omeñaca and colleagues retained it as potentially valid, differing from other dryosaurids by details of the thigh bone. Like other basal iguanodontians, it would have been a bipedal 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...
.