Utahdactylus

Last updated

Utahdactylus
Temporal range: Late Jurassic
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Clade: Ornithodira
Clade: Pterosauromorpha
Order: Pterosauria
Genus: Utahdactylus
Czerkas and Mickelson, 2002
Species:
U. kateae
Binomial name
Utahdactylus kateae
Czerkas and Mickelson, 2002

Utahdactylus was a genus of extinct reptile from the Kimmeridgian-Tithonian-age Upper Jurassic Morrison Formation of Utah, United States. Based on DM 002/CEUM 32588 (an incomplete skeleton described as including a fragment of the skull, a cervical vertebra, three back vertebrae, and a caudal vertebra, ribs, a scapula, coracoid, and limb bones), Czerkas and Mickelson (2002) identified it as a "rhamphorhynchoid" pterosaur. [1] Bennett (2007) later concluded that it has no diagnostic features of the Pterosauria, and cannot be positively identified beyond being an indeterminate diapsid. [2] More recent work on newly prepared material, however, seems to confirm once again that Utahdactylus was a pterosaur. [3]

Contents

History

The genus was named and described in 2002 by Stephen Czerkas and Debra Mickelson. The type species is Utahdactylus kateae. The genus name is derived from Utah and Greek daktylos, "finger". The specific name means "for Kate", referring to Kate Mickelson.

The holotype consists of some disarticulated bone fragments preserved on several chalkstone blocks. It is housed in the Dinosaur Museum, run by Czerkas himself.

The specimen was first described as a pterosaur, with a long tail and an estimated wingspan of 1.20 meters (3.94 feet). The authors considered it to be a "rhamphorhynchoid", i.e. a basal pterosaur, due to its long tail and large but not elongate cervical vertebrae, but without the typical groove in its forelimb bones. [1] It was regarded as a "rhamphorhynchoid" based on an unprepared specimen in the most recent review of Morrison pterosaurs. [4]

In 2007, pterosaur specialist Chris Bennett published a redescription wherein he disagreed with Czerkas' and Mickelson's conclusions. He found several of the bone identifications and interpretations to be mistaken, such as the skull bone (interpreted here as just a bone fragment of unknown origin), elongate tail vertebra (the presumed elongated extensions were ribs), humerus (unknown), and the orientation of the bone described as a scapulacoracoid (the scapula and coracoid parts had been confused). He could not locate other bones seen as impressions, and found no evidence to suggest that the identifiable bones came from a pterosaur. In fact, he found the general quality of the bone texture to differ from that of pterosaur bones. He concluded by classifying it as Diapsida incertae sedis , and a dubious name, adding an exhortation not to name pterosaurs from material lacking unequivocal pterosaur characters. [2]

Bennett's conclusion was rejected by Czerkas & Ford (2018), who affirmed the validity of initial interpretation of Utahdactylus as a pterosaur. The authors reported that the cervical of the holotype specimen was completely prepared out of the matrix along with the scapulacoracoid, a sacrum, and part of a mandible. The study of the glenoid indicated that it had a pterosaur saddle-shaped articulation for the humerus. In addition, the authors reported a parallel alignment of the dentaries, indicating that they formed a mandibular symphysis. Czerkas & Ford interpreted the presence of the elongate mandibular symphysis and spoon-like expansion of the anterior end of the jaws as aligning Utahdactylus with pterodactyloids, and specifically within Ctenochasmatidae. The authors interpreted Utahdactylus as the first known gnathosaur from North America. [3]

See also

Related Research Articles

<i>Kentrosaurus</i> Extinct genus of dinosaurs from late Jurassic in Lindi Region, Tanzania

Kentrosaurus is a genus of stegosaurid dinosaur from the Late Jurassic in Lindi Region of Tanzania. The type species is K. aethiopicus, named and described by German palaeontologist Edwin Hennig in 1915. Often thought to be a "primitive" member of the Stegosauria, several recent cladistic analyses find it as more derived than many other stegosaurs, and a close relative of Stegosaurus from the North American Morrison Formation within the Stegosauridae.

<i>Tanystropheus</i> Extinct genus of reptiles

Tanystropheus is an extinct 6-meter-long (20 ft) archosauromorph reptile from the Middle and Late Triassic epochs. It is recognisable by its extremely elongated neck, which measured 3 m (9.8 ft) long—longer than its body and tail combined. The neck was composed of 12–13 extremely elongated vertebrae. With its very long but relatively stiff neck, Tanystropheus has been often proposed and reconstructed as an aquatic or semi-aquatic reptile, a theory supported by the fact that the creature is most commonly found in semi-aquatic fossil sites wherein known terrestrial reptile remains are scarce. Fossils have been found in Europe. Complete skeletons of small individuals are common in the Besano Formation at Monte San Giorgio in Italy and Switzerland; other fossils have been found in the Middle East and China, dating from the Middle Triassic to the early part of the Late Triassic.

<i>Jeholopterus</i> Genus of anurognathid pterosaur from the Jurassic period

Jeholopterus was a small anurognathid pterosaur from the Middle to Late Jurassic Daohugou Beds of the Tiaojishan Formation of Inner Mongolia, China, preserved with hair-like pycnofibres and skin remains.

<i>Klamelisaurus</i> Extinct genus of dinosaurs

Klamelisaurus is a genus of herbivorous sauropod dinosaur from the Middle Jurassic Shishugou Formation of China. The type species is Klamelisaurus gobiensis, which was named by Zhao Xijin in 1993, based on a partial skeleton discovered in 1982 near the abandoned town of Jiangjunmiao. Zhao described Klamelisaurus as the only member of a new subfamily, Klamelisaurinae, among the now-defunct primitive sauropod order Bothrosauropodoidea. Since Zhao's description, Klamelisaurus received limited attention from researchers until Andrew Moore and colleagues redescribed it in 2020.

<i>Campylognathoides</i> Genus of campylognathoidid pterosaur from the Early Jurassic

Campylognathoides is an extinct genus of pterosaur discovered in the Württemberg Lias deposits of Germany; this first specimen however, consisted only of wing fragments. Further better preserved specimens were found in the Holzmaden shale; based on these specimens, Felix Plieninger erected a new genus.

<span class="mw-page-title-main">Rhamphorhynchoidea</span>

The Rhamphorhynchoidea forms one of the two suborders of pterosaurs and represents an evolutionary grade of primitive members of flying reptiles. This suborder is paraphyletic unlike the Pterodactyloidea, which arose from within the Rhamphorhynchoidea as opposed to a more distant common ancestor. Because it is not a completely natural grouping, Rhamphorhynchoidea is not used as a formal group in most scientific literature, though some pterosaur scientists continue to use it as an informal grouping in popular works, such as The Pterosaurs: From Deep Time by David Unwin, and in some formal studies. Rhamphorhynchoids were the first pterosaurs to have appeared, in the late Triassic Period. Unlike their descendants, the pterodactyloids, most rhamphorhynchoids had teeth and long tails, and most species lacked a bony crest, though several are known to have crests formed from soft tissue like keratin. They were generally small, with wingspans rarely exceeding 2.5 meters, though one specimen alluded to by Alexander Stoyanow would be among the largest pterosaurs of all time with a wingspan of 10 meters, comparable to the largest azhdarchids. However, this alleged giant Jurassic pterosaur specimen is not recorded anywhere outside the original Time article. Nearly all rhamphorhynchoids had become extinct by the end of the Jurassic Period, though some anurognathids persisted to the early Cretaceous. The family Wukongopteridae, which shows a mix of rhamphorhynchoid and pterodactyloid features, is known from the Daohugou Beds which are most commonly dated to the Jurassic, but a few studies give a Cretaceous date. Furthermore, remains of a non-pterodactyloid from the Candeleros Formation extend the presence of basal pterosaurs into the at least early Late Cretaceous.

<i>Parapsicephalus</i> Genus of rhamphorhynchid pterosaur from the Early Jurassic

Parapsicephalus is a genus of long-tailed rhamphorhynchid pterosaurs from the Lower Jurassic Whitby, Yorkshire, England. It contains a single species, P. purdoni, named initially as a species of the related rhamphorhynchid Scaphognathus in 1888 but moved to its own genus in 1919 on account of a unique combination of characteristics. In particular, the top surface of the skull of Parapsicephalus is convex, which is otherwise only seen in dimorphodontians. This has been the basis of its referral to the Dimorphodontia by some researchers, but it is generally agreed upon that Parapsicephalus probably represents a rhamphorhynchid. Within the Rhamphorhynchidae, Parapsicephalus has been synonymized with the roughly contemporary Dorygnathus; this, however, is not likely given the many differences between the two taxa, including the aforementioned convex top surface of the skull. Parapsicephalus has been tentatively referred to the Rhamphorhynchinae subgrouping of rhamphorhynchids, but it may represent a basal member of the group instead.

Kepodactylus is an extinct genus of ctenochasmatid pterodactyloid pterosaur from the Kimmeridgian-Tithonian-age Upper Jurassic Morrison Formation of Colorado, United States.

<i>Pterorhynchus</i> Genus of darwinopteran pterosaur from the Middle Jurassic

Pterorhynchus is an extinct genus of pterosaur from the mid-Jurassic aged Daohugou Formation of Inner Mongolia, China.

Jiangjunosaurus is a genus of herbivorous stegosaurian dinosaur from the Oxfordian-age Shishugou Formation of the Junggar Basin, Xinjiang, China.

<i>Amphicoelias</i> Extinct genus of dinosaurs

Amphicoelias is a genus of herbivorous sauropod dinosaur that lived approximately 150 million years ago during the Tithonian of what is now Colorado, United States. Amphicoelias was moderately sized at about 18 metres (59 ft) in length and 15 metric tons in body mass, shorter than its close relative Diplodocus. Its hindlimbs were very long and thin, and its forelimbs were proportionally longer than in relatives.

<i>Brachiosaurus</i> Sauropod dinosaur genus from the late Jurassic Period

Brachiosaurus is a genus of sauropod dinosaur that lived in North America during the Late Jurassic, about 154–150 million years ago. It was first described by American paleontologist Elmer S. Riggs in 1903 from fossils found in the Colorado River valley in western Colorado, United States. Riggs named the dinosaur Brachiosaurus altithorax; the generic name is Greek for "arm lizard", in reference to its proportionately long arms, and the specific name means "deep chest". Brachiosaurus is estimated to have been between 18 and 22 meters long; body mass estimates of the subadult holotype specimen range from 28.3 to 46.9 metric tons. It had a disproportionately long neck, small skull, and large overall size, all of which are typical for sauropods. Atypically, Brachiosaurus had longer forelimbs than hindlimbs, which resulted in a steeply inclined trunk, and a proportionally shorter tail.

<i>Spinophorosaurus</i> Middle Jurassic genus of sauropod dinosaur

Spinophorosaurus is a genus of sauropod dinosaur that lived in what is now Niger during the Middle Jurassic period. The first two specimens were excavated in the 2000s by German and Spanish teams under difficult conditions. The skeletons were brought to Europe and digitally replicated, making Spinophorosaurus the first sauropod to have its skeleton 3D printed, and were to be returned to Niger in the future. Together, the two specimens represented most of the skeleton of the genus, and one of the most completely known basal sauropods of its time and place. The first skeleton was made the holotype specimen of the new genus and species Spinophorosaurus nigerensis in 2009; the generic name refers to what was initially thought to be spiked osteoderms, and the specific name refers to where it was found. A juvenile sauropod from the same area was later assigned to the genus.

<i>Zhenyuanopterus</i> Genus of boreopterid pterosaur from the Early Cretaceous

Zhenyuanopterus is a genus of boreopterid pterosaur which is known from Lower Cretaceous Yixian Formation of Liaoning, China. It contains one species, Zhenyuanopterus longirostris, which was first described and named by Lü Junchang.

<i>Ahshislepelta</i> Extinct genus of dinosaurs

Ahshislepelta is a monospecific genus of ankylosaur dinosaur from New Mexico that lived during the Late Cretaceous in what is now the Hunter Wash Member of the Kirtland Formation. The type and only species, Ahshislepelta minor, is known only from an incomplete postcranial skeleton of a small subadult or adult individual. It was named in 2011 by Michael Burns and Robert M. Sullivan. Based on the size of the humerus, Ahshislepelta is larger than Pinacosaurus mephistocephalus but smaller than Talarurus and Pinacosaurus grangeri.

<i>Martharaptor</i> Extinct genus of dinosaurs

Martharaptor is a genus of therizinosauroid theropod dinosaurs from the Early Cretaceous of the Cedar Mountain Formation in Utah. They can be distinguished from other therizinosauroids by means of several features of the skeleton which were intermediate between early therizinosaurs such as Falcarius and Beipiaosaurus, and more "advanced" members of the group like therizinosaurids. The deep and homogeneous hand claws clearly differ from the case in early therizinosauroids, but the foot has not yet acquired the robust morphology of therizinosaurids.

Daohugoupterus is a genus of pterosaur from the Middle to Late Jurassic Daohugou Beds of the Tiaojishan Formation in Inner Mongolia, China.

<i>Douzhanopterus</i> Genus of monofenestratan pterosaur from the Late Jurassic

Douzhanopterus is an extinct genus of monofenestratan pterosaur from the Late Jurassic of Liaoning, China. It contains a single species, D. zhengi, named by Wang et al. in 2017. In many respects, it represents a transitional form between basal pterosaurs and the more specialized pterodactyloids; for instance, its tail is intermediate in length, still being about twice the length of the femur but relatively shorter compared to that of the more basal Wukongopteridae. Other intermediate traits include the relative lengths of the neck vertebrae and the retention of two, albeit reduced, phalanx bones in the fifth digit of the foot. Phylogenetically, Douzhanopterus is nested between the wukongopterids and a juvenile pterosaur specimen from Germany known as the "Painten pro-pterodactyloid", which is similar to Douzhanopterus in many respects but approaches pterodactyloids more closely elsewhere.

<i>Mirarce</i> Extinct genus of birds

Mirarce is a genus of enantornithe bird from the Late Cretaceous of Utah. It contains a single species, M. eatoni. It was similar in size to modern turkeys.

Dearc is a genus of large-bodied rhamphorhynchine pterosaur from the Middle Jurassic Lealt Shale Formation of Scotland. The holotype, a juvenile or subadult that was still actively growing, has an estimated wingspan of 2.5 to 3 meters, making it the largest flying animal of its time. This pushes the origin of large pterosaurs back significantly, as it was previously assumed that pterosaurs did not reach greater body sizes until the short-tailed pterodactyloid lineages of the Cretaceous. The genus contains a single species, Dearc sgiathanach.

References

  1. 1 2 Czerkas, Stephen A.; Mickelson, Debra L. (2002). "The first occurrence of skeletal pterosaur remains in Utah". In Czerkas, Sylvia J. (ed.). Feathered Dinosaurs and the Origin of Flight. Blanding, Utah: The Dinosaur Museum. pp. 3–13. ISBN   978-1-932075-01-4.
  2. 1 2 Bennett, S. Christopher (2007). "Reassessment of Utahdactylus from the Jurassic Morrison Formation of Utah". Journal of Vertebrate Paleontology. 27 (1): 257–260. doi:10.1671/0272-4634(2007)27[257:ROUFTJ]2.0.CO;2. S2CID   129729571.
  3. 1 2 Stephen Czerkas; Tracy Ford (2018). "Pterosaur or diapsid? The search for the true Utahdactylus". Flugsaurier 2018: The 6th International Symposium on Pterosaurs. Los Angeles, USA. Abstracts: 35–36.
  4. King, Lorin R.; Foster, John R.; Scheetz, Rodney D. (2006). "New pterosaur specimens from the Morrison Formation and a summary of the Late Jurassic pterosaur record of the Rocky Mountain region". In Foster, John R.; Lucas, Spencer G. (eds.). Paleontology and Geology of the Upper Morrison Formation. New Mexico Museum of Natural History and Science Bulletin, 36. Albuquerque, New Mexico: New Mexico Museum of Natural History and Science. pp. 149–161.