Texasetes Temporal range: Early Cretaceous, | |
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The holotype coracoid (top) and humerus (bottom) at the USNM. | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Dinosauria |
Clade: | † Ornithischia |
Clade: | † Thyreophora |
Clade: | † Ankylosauria |
Family: | † Nodosauridae |
Subfamily: | † Nodosaurinae |
Clade: | † Panoplosaurini |
Genus: | † Texasetes Coombs, 1995 |
Species: | †T. pleurohalio |
Binomial name | |
†Texasetes pleurohalio Coombs, 1995 | |
Texasetes (meaning "Texas resident") 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 (late Albian) near Haslet, Tarrant County, Texas, which has also produced the nodosaurid ankylosaur Pawpawsaurus .
5 miles south of Haslet near Fort Worth, Texas, fossils of an ankylosaurid were excavated from strata of the upper Albian rocks from Lower Cretaceous in the Pawpaw Formation. [1] The fossils would later become the holotype (USNM 337987) of Texasetes, consisting of a skull fragment, 2 teeth, 5 cervical centra, 3 sacral centra, 16 caudal centra, partial scapulacoracoids, fragmentary pelvis, humeri, femora, tibiae, proximal ulnae, proximal radii, left metacarpal IV, left metatarsal IV, 3 phalanges, 2 unguals, and several osteoderms. [1] [2] These remains had initially been labeled as those of a sauropod, but were many years later recognized as ankylosaurian by M.K. Brett-Surman. [1] They were subsequently studied by ankylosaur expert Walter Preston Coombs, Jr, who named them in 1995 as the type species Texasetes pleurohalio, the generic name meaning “Texas dweller” and the specific name meaning “sea adjacent”. [1] Vickaryous et al. (2004) and Coombs (1995) describe Texasetes as having a horizontally oriented ilium, an imperforate acetabulum, and "characteristically ankylosaur scapula morphology, including a prominent acromion and prespinous fossa." [1] [2] [3]
Due to a lack of collection records, parts of the discovery and preservation of Texasestes remain unknown. Strangely, the specimen preserved little dorsal armor or ribs, the fossils most commonly found in ankylosaur skeletons. This led Coombs to speculate that the individual had died on the shore or in an inland river and had been flushed out to sea, decomposing and losing many of its elements like the distal limbs. [1] The individual was then buried quickly in marine sediments, according to the theory. This theory is the origin of the taxon’s specific name meaning. Additional evidence comes in the form of paleo ecology, with nodosaurids and basal ankylosaurs being more commonly found in fluvial or marine sediments than ankylosaurids. [1] [4]
Due to the fragmentary nature of Texasetes, little is known directly from the fossils and the uncertain phylogenetic position limits inferable traits. The preserved teeth are unique in that they have a large ridge leading up to the apex of the tooth's crown, with this feature known in only one other taxon from southern England. [5] The cervical vertebrae of Texasetes are concave, a trait shared with Animantarx , a possibly autapomorphy for the two. Texasetes preserves a highly elongated coracoid and thick glenoid plate compared to its relative Animantarx. [6] [1] Coombs (1995) diagnose Texasetes as having a horizontally oriented ilium, an imperforate acetabulum, and "characteristically ankylosaur scapula morphology, including a prominent acromion and prespinous fossa." [1] [3] Due to the taxon being a Nodosaurid, the taxon was covered in large armored osteoderms with smaller ossicles in-between, as inferred by Panoplosaurus , and no tail club. [7]
Coombs assigned the specimen to the family Nodosauridae, [1] but Vickaryous et al. consider it Ankylosauria incertae sedis . [3] Pawpawsaurus may be synonymous with Texasetes due to their shared age, formation, and close phylogenetic position, [8] though lack of overlap prevents a confident answer and in Arbour et al., 2016's phylogenetic analysis however, Pawpawsaurus was found closer to Europelta and Texasetes closer to Edmontonia . Additionally, a juvenile ankylosaur skeleton from the Paw Paw Formation was found to be closest related to neither Pawpawsaurus or Texasetes, but Niobrarasaurus in the 2016 analysis. [9] The 2018 phylogenetic analysis of Rivera-Sylva and colleagues is used below, limited to the relationships within Panoplosaurini. [10] [11]
Panoplosaurini |
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Ankylosauria is a group of herbivorous dinosaurs of the clade Ornithischia. It includes the great majority of dinosaurs with armor in the form of bony osteoderms, similar to turtles. Ankylosaurs were bulky quadrupeds, with short, powerful limbs. They are known to have first appeared in the Middle Jurassic, and persisted until the end of the Cretaceous Period. The two main families of Ankylosaurs, Nodosauridae and Ankylosauridae are primarily known from the Northern Hemisphere, but the more basal Parankylosauria are known from southern Gondwana during the Cretaceous.
Animantarx is a genus of nodosaurid ankylosaurian dinosaur from the Early and Late Cretaceous of western North America. Like other nodosaurs, it would have been a slow-moving quadrupedal herbivore covered in heavy armor scutes, but without a tail club. The skull measures approximately 25 cm in length, suggesting the animal as a whole was no more than 3 meters long.
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.
Niobrarasaurus is an extinct genus of nodosaurid ankylosaur which lived during the Cretaceous 87 to 82 million years ago. Its fossils were found in the Smoky Hill Chalk Member of the Niobrara Formation, in western Kansas, which would have been near the middle of Western Interior Sea during the Late Cretaceous. It was a nodosaurid, an ankylosaur without a clubbed tail. It was closely related to Nodosaurus.
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.
Aletopelta is a monospecific genus of basal ankylosaurid dinosaur from Southern California that lived during the Late Cretaceous in what is now the Point Loma Formation. The type and only species, Aletopelta coombsi, is known from a partial skeleton preserving osteoderms. It was originally described in 1996 by W. P. Coombs, Jr. and T.A. Deméré before being named in 2001 by Tracy Ford and James Kirkland. Aletopelta has an estimated size of 5 metres and weight of 2 tonnes. The holotype formed a miniature reef and was scavenged upon by invertebrates and sharks.
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.
Sauropelta is a genus of nodosaurid dinosaur that existed in the Early Cretaceous Period of North America. One species has been named although others may have existed. Anatomically, Sauropelta is one of the most well-understood nodosaurids, with fossilized remains recovered in the U.S. states of Wyoming, Montana, and possibly Utah. It is also the earliest known genus of nodosaurinae; most of its remains are found in a section of the Cloverly Formation dated to 108.5 million years ago.
Stegopelta is a genus of struthiosaurin nodosaurid dinosaur. It is based on a partial skeleton from the latest Albian-earliest Cenomanian-age Lower and Upper Cretaceous Belle Fourche Member of the Frontier Formation of Fremont County, Wyoming, USA.
Cedarpelta is an extinct genus of basal ankylosaurid dinosaur from Utah that lived during the Late Cretaceous period in what is now the Mussentuchit Member of the Cedar Mountain Formation. The type and only species, Cedarpelta bilbeyhallorum, is known from multiple specimens including partial skulls and postcranial material. It was named in 2001 by Kenneth Carpenter, James Kirkland, Don Burge, and John Bird. Cedarpelta has an estimated length of 7 metres and weight of 5 tonnes (11,023 lbs). The skull of Cedarpelta lacks extensive cranial ornamentation and is one of the only known ankylosaurs with individual skull bones that are not completely fused together.
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.
Denversaurus is a genus of panoplosaurin nodosaurid dinosaur from the late Maastrichtian of Late Cretaceous Western North America. Although at one point treated as a junior synonym of Edmontonia by some taxonomists, current research indicates that it is its own distinct nodosaurid genus.
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.
Pawpawsaurus, meaning "Pawpaw Lizard", is a nodosaurid ankylosaur from the Cretaceous of Tarrant County, Texas, discovered in May 1992. The only species yet assigned to this taxon, Pawpawsaurus campbelli, is based on a complete skull from the marine Paw Paw Formation.
Silvisaurus, from the Latin silva "woodland" and Greek sauros "lizard", is a nodosaurid ankylosaur from the Early to Late Cretaceous period. It is one of the only known dinosaur species named from Kansas and was designated the official state land fossil in 2023.
Palaeoscincus is a dubious genus of ankylosaurian dinosaur based on teeth from the mid-late Campanian-age Upper Cretaceous Judith River Formation of Montana. Like several other dinosaur genera named by Joseph Leidy, it is an historically important genus with a convoluted taxonomy that has been all but abandoned by modern dinosaur paleontologists. Because of its wide use in the early 20th century, it was somewhat well known to the general public, often through illustrations of an animal with the armor of Edmontonia and the tail club of an ankylosaurid.
Dracopelta is a monospecific genus of ankylosaur dinosaur from Portugal that lived during the Late Jurassic in what is now the Lourinhã Formation. The type and only species is Dracopelta zbyszewskii, which is represented by a partial skeleton including unpublished material.
Priconodon is an extinct genus of ankylosaurian dinosaur, mainly known from its large teeth. Its remains have been found in the Aptian-Albian age Lower Cretaceous Arundel Formation of Muirkirk, Prince George's County, Maryland, USA and the Potomac Group, also located in Maryland. As an ankylosaur, Priconodon would have been a large armored quadrupedal herbivore, though no size estimation has been done due to the scarcity of described remains.
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.