Horshamosaurus Temporal range: Early Cretaceous, | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Dinosauria |
Clade: | † Ornithischia |
Clade: | † Thyreophora |
Clade: | † Ankylosauria |
Family: | † Nodosauridae |
Genus: | † Horshamosaurus Blows, 2015 |
Species: | †H. rudgwickensis |
Binomial name | |
†Horshamosaurus rudgwickensis Blows, 2015 | |
Synonyms | |
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Horshamosaurus is a genus of herbivorous ankylosaurian dinosaur from the Early Cretaceous of England. It lived during the Barremian of the Cretaceous and the type species is Horshamosaurus rudgwickensis.
In 1985, at the marl quarry of the Rudgwick Brickworks Company near Rudgwick in West Sussex, fossils were dug up of dinosaurs by John Underhill. These were secured by two volunteers of the Horsham Museum: Morris Zdzalek and Sylvia Standing. After 1988, the finds were exhibited in the museum as Iguanodon bones. Subsequently, neurologist William T. Blows, an amateur paleontologist who already had extensively published on the subject of armoured dinosaurs, determined that the bones were not iguanodontian but instead represented ankylosaurian remains.
In 1996, on basis of the finds, a new species of the genus Polacanthus , Polacanthus rudgwickensis, was named and described by Blows. The specific name refers to the provenance from Rudgwick. [1]
The material, holotype HORSM 1988.1546, was found in a layer of grey-green marl beds of the lower Weald Clay dating from the Barremian age, over 125 million years old. It is fragmentary and includes two incomplete dorsal vertebrae, part of a front tail vertebra, bone fragments of other vertebrae, a partial left scapulocoracoid of the shoulder girdle, the distal end of a humerus, a nearly complete right tibia, rib fragments, and two osteoderms. [1]
In 2015, Blows made it a separate genus Horshamosaurus, the generic name referring to Horsham. Its type species is Polacanthus rudgwickensis. The combinatio nova is Horshamosaurus rudgwickensis. [2]
In 2020, Horshamosaurus was determined to be dubious, and not diagnosable beyond Nodosauridae. The presumed tibia was also re-interpreted as being an ischium. [3]
Horshamosaurus seems, at roughly five metres length, to have been about 30% longer than the type species of Polacanthus, Polacanthus foxii and differs from it in numerous characters of the vertebrae and dermal armour. Apart from the greater length, in 1996 several traits were established, distinguishing Horshamosaurus from Polacanthus. The centrum facets of the back and tail vertebrae have a round instead of a heart-shaped profile. The transverse processes of the vertebrae each have two ridges at their undersides delimiting a depression and gradually merging with the vertebral body. The transverse processes of the front tail vertebrae have a distinctive top ridge, running from the front to the rear, merging with the neural arch at the base of the process, while sloping downwards at its inner side. The "pseudoacromion" is located close to the front edge of the shoulder blade. The rear ribs are large and tall instead of rather slender. The shinbone is relatively longer. The osteoderm spikes on the back have a circular base of which the front underside is excavated but the rear underside solid, instead of an oval base with a uniformly concave underside. One of the osteoderms seems to have been part of the back armour and is large and flat with a concave underside; plates of such a type have not been discovered with Polacanthus foxii.
In 2015, three traits were added. The shoulder blade is robust and large, fused with the coracoid. The vertebral centra of the front tail vertebrae are shorter and especially taller. With the tail vertebrae, the base of the side process covers the top half of the centrum, seen from the front or from behind, instead of a quarter of the height.
Horshamosaurus was in cladistic analyses not recovered as a sister species of Polacanthus. In 2015, Blows did not place Horshamosaurus in a Polacanthidae but in a more derived position in the Ankylosauria. He suggested it was a member of the Nodosauridae.
Nodosaurus is a genus of herbivorous nodosaurid ankylosaurian dinosaur from the Late Cretaceous, the fossils of which are found exclusively in the Frontier Formation in Wyoming.
Euoplocephalus is a genus of large herbivorous ankylosaurid dinosaurs, living during the Late Cretaceous of Canada. It has only one named species, Euoplocephalus tutus.
Hylaeosaurus is a herbivorous ankylosaurian dinosaur that lived about 136 million years ago, in the late Valanginian stage of the early Cretaceous period of England. It was found in the Grinstead Clay Formation.
Polacanthus, deriving its name from the Ancient Greek polys-/πολύς- "many" and akantha/ἄκανθα "thorn" or "prickle", is an early armoured, spiked, plant-eating ankylosaurian dinosaur from the early Cretaceous period of England.
Minmi is a genus of small herbivorous ankylosaurian dinosaur that lived during the early Cretaceous Period of Australia, about 120 to 112 million years ago.
Edmontonia is a genus of panoplosaurin nodosaurid dinosaur from the Late Cretaceous Period. It is part of the Nodosauridae, a family within Ankylosauria. It is named after the Edmonton Formation, the unit of rock where it was found.
Gastonia is a genus of herbivorous ankylosaurian dinosaur from the Early Cretaceous of North America, around 139 to 134.6 million years ago. It is often considered a nodosaurid closely related to Polacanthus. Gastonia has a sacral shield and large shoulder spikes.
Ankylosauridae is a family of armored dinosaurs within Ankylosauria, and is the sister group to Nodosauridae. The oldest known Ankylosaurids date to around 122 million years ago and went extinct 66 million years ago during the Cretaceous–Paleogene extinction event. These animals were mainly herbivorous and were obligate quadrupeds, with leaf-shaped teeth and robust, scute-covered bodies. Ankylosaurids possess a distinctly domed and short snout, wedge-shaped osteoderms on their skull, scutes along their torso, and a tail club.
Nodosauridae is a family of ankylosaurian dinosaurs known from the Late Jurassic to the Late Cretaceous periods in what is now Asia, Europe, North America, and possibly South America. While traditionally regarded as a monophyletic clade as the sister taxon to the Ankylosauridae, some analyses recover it as a paraphyletic grade leading to the ankylosaurids.
Texasetes is a genus of ankylosaurian dinosaurs from the late Lower Cretaceous of North America. This poorly known genus has been recovered from the Paw Paw Formation near Haslet, Tarrant County, Texas, which has also produced the nodosaurid ankylosaur Pawpawsaurus.
Hoplitosaurus was a genus of armored dinosaur related to Polacanthus. It was named from a partial skeleton found in the ?Barremian-age Lower Cretaceous Lakota Formation of Custer County, South Dakota. It is an obscure genus which has been subject to some misinterpretation of its damaged remains. Although there was a push to synonymize it with Polacanthus in the late 1980s-early 1990s, Hoplitosaurus has been accepted as a valid albeit poorly known genus in more recent reviews.
Mymoorapelta is a nodosaurid ankylosaur from the Late Jurassic Morrison Formation of western Colorado and central Utah, USA. The animal is known from a single species, Mymoorapelta maysi, and few specimens are known. The most complete specimen is the holotype individual from the Mygatt-Moore Quarry, which includes osteoderms, a partial skull, vertebrae, and other bones. It was initially described by James Kirkland and Kenneth Carpenter in 1994. Along with Gargoyleosaurus, it is one of the earliest known nodosaurids.
Panoplosaurus is a genus of armoured dinosaur from the Late Cretaceous of Alberta, Canada. Few specimens of the genus are known, all from the middle Campanian of the Dinosaur Park Formation, roughly 76 to 75 million years ago. It was first discovered in 1917, and named in 1919 by Lawrence Lambe, named for its extensive armour, meaning "well-armoured lizard". Panoplosaurus has at times been considered the proper name for material otherwise referred to as Edmontonia, complicating its phylogenetic and ecological interpretations, at one point being considered to have existed across Alberta, New Mexico and Texas, with specimens in institutions from Canada and the United States. The skull and skeleton of Panoplosaurus are similar to its relatives, but have a few significant differences, such as the lumpy form of the skull osteoderms, a completely fused shoulder blade, and regularly shaped plates on its neck and body lacking prominent spines. It was a quadrupedal animal, roughly 5 m (16 ft) long and 1,600 kg (3,500 lb) in weight. The skull has a short snout, with a very domed surface, and bony plates directly covering the cheek. The neck had circular groups of plates arranged around the top surface, both the forelimb and hindlimb were about the same length, and the hand may have only included three fingers. Almost the entire surface of the body was covered in plates, osteoderms and scutes of varying sizes, ranging from large elements along the skull and neck, to smaller, round bones underneath the chin and body, to small ossicles that filled in the spaces between other, larger osteoderms.
Lametasaurus named for the Lameta Formation, Jabalpur, India, is the generic name given to a possibly chimeric dinosaur species. The type species is L. indicus.
Polacanthinae is a subfamily of ankylosaurs, most often nodosaurids, from the Late Jurassic through Early Cretaceous of Europe and potentially North America and Asia. The group is defined as the largest clade closer to Polacanthus foxii than Nodosaurus textilis or Ankylosaurus magniventris, as long as that group nests within either Nodosauridae or Ankylosauridae. If Polacanthus, and by extent Polacanthinae, falls outside either family-level clade, then the -inae suffix would be inappropriate, and the proper name for the group would be the informally defined Polacanthidae.
Taohelong is a genus of nodosaurid dinosaur known from Lower Cretaceous rocks in north-central China.
This timeline of ankylosaur research is a chronological listing of events in the history of paleontology focused on the ankylosaurs, quadrupedal herbivorous dinosaurs who were protected by a covering bony plates and spikes and sometimes by a clubbed tail. Although formally trained scientists did not begin documenting ankylosaur fossils until the early 19th century, Native Americans had a long history of contact with these remains, which were generally interpreted through a mythological lens. The Delaware people have stories about smoking the bones of ancient monsters in a magic ritual to have wishes granted and ankylosaur fossils are among the local fossils that may have been used like this. The Native Americans of the modern southwestern United States tell stories about an armored monster named Yeitso that may have been influenced by local ankylosaur fossils. Likewise, ankylosaur remains are among the dinosaur bones found along the Red Deer River of Alberta, Canada where the Piegan people believe that the Grandfather of the Buffalo once lived.
Kunbarrasaurus is an extinct genus of small ankylosaurian dinosaur from the Cretaceous of Australia. The genus contains a single species, K. ieversi.
Stegouros is a genus of ankylosaurian dinosaur from the Late Cretaceous Dorotea Formation of southern Chile. The genus contains a single species, Stegouros elengassen, known from a semi-articulated, near-complete skeleton.
Vectipelta is an extinct genus of ankylosaurian dinosaur recovered from the Early Cretaceous Wessex Formation of England. The genus contains a single species, V. barretti, known from a partial skeleton including several osteoderms. It was historically known as the "Spearpoint ankylosaur" prior to its description.