Graciliceratops Temporal range: Late Cretaceous, ~ | |
---|---|
Skeletal diagram featuring the known elements from the holotype | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Dinosauria |
Clade: | † Ornithischia |
Clade: | † Neornithischia |
Clade: | † Ceratopsia |
Clade: | † Neoceratopsia |
Genus: | † Graciliceratops Sereno, 2000 |
Type species | |
†Graciliceratops mongoliensis Sereno, 2000 |
Graciliceratops (meaning "slender horn") is a genus of neoceratopsian dinosaurs that lived in Asia during the Late Cretaceous period.
The holotype, ZPAL MgD-I/156, was discovered at the Bayan Shireh Formation in Mongolia, coming from the Sheeregeen Gashoon locality near Sainshand. The discoveries were made during field exploration by the Polish-Mongolian Palaeontological Expedition, in 1971. Four years later, in 1975, the specimen was described by Teresa Maryańska and Halszka Osmólska and referred to the genus Microceratops. [1] However, Paul Sereno noted that the referral for this specimen was injustified and overall, the genus lacked diagnosis, therefore, Microceratops (now named Microceratus [2] ) was considered a nomen dubium. The referred specimen was redescribed by him, creating a new genus and species: Graciliceratops mongoliensis. [3]
The holotype is fragmentary, consisting of a very fragmented skull with mandibles; vertebrae, four cervicals, twelve dorsals and seven sacrals; right scapula; proximal end of left scapula; left coracoid; right humerus, radius and fragmentary ulna; proximal and distal end of left humerus; proximal fragments of both pubis; fragments of both ilium and fragment of right ischium; right femur, tibia and nearly complete pes; distal part of left tibia, fragmentary left pes; tarsals and isolated ribs. [1] The generic name, Graciliceratops, is derived from the Latin gracilis (meaning slender) and the Greek κέρας (kéras, meaning horn) in reference to its fragile build. Lastly, the specific name, mongolienses, is to emphasize the place of its discovery: Mongolia. [3]
Although very damaged, the skull measures approximately 20 cm (200 mm), the arches and centra of the sacral vertebrae are not fused, which indicates that this specimen was not fully grown when it died, probably a juvenile individual. [1] Its size is estimated at 60 cm (2.0 ft) long with a weight between 2.27 to 9.1 kg (5.0 to 20.1 lb). [4] However, due to the immature nature of the specimen, the adult size is estimated around 2 m (6.6 ft), or similar to Protoceratops . The frill has large fenestrae bounded by very slender struts. This structure is very similar to that of the later Protoceratops. Graciliceratops is recognised by the fragile frill and characteristic tibial-femoral ratio (1.2:1); the frill is also briefly elongated with well developed squamosal processes. [3] Seven sacral vertebrae were identified and not fused. The scapula is very gracile in constitution but thicker at the glenoid, with a relatively large coracoid; the humerus is also very slender. The femur measures 9.5 cm (95 mm), it is lightly curved and has a large head; the fourth trochanter is fragile and place above the midlength of the femoral end. Being larger than the femur, the tibia measures 11 cm (110 mm) and its proximal articulation is more developed than distally. The right pes is virtually complete, only lacking the distal end of the IV metatarsal. The pedal unguals are dorsoventrally flattened and somewhat sharply-developed. [1]
During the description of Aquilops in 2014, an extensive Ceratopsia phylogenetic analysis was conducted. Graciliceratops was found to be a basal neoceratopsian. Below are the results obtained for the Neoceratopsia: [5]
Graciliceratops was unearthed from the Sheeregeen Gashoon beds, which are part of the Upper Bayan Shireh. The presence of caliche, fluvial and lacustrine sediments, indicate a semiarid climate with rivers and large lakes around the zone. [6] [7] Fossilized fruits have also been recovered from the upper and lower parts of the formation, suggesting the existence of Angiosperm plants. [8] Magnetostratigraphic and calcite U–Pb analyses indicate that the formation lies within the Cretaceous Long Normal, which was deposited until the end of the Santonian around 95.9 ± 6.0 million to 89.6 ± 4.0 million years ago. [9] [10]
It lived alongside other dinosaurs from the upper part, most notably the large dromaeosaurid Achillobator , the tyrannosauroid Alectrosaurus , therizinosaurs Erlikosaurus , ‘’Enigmosaurus’’, and Segnosaurus , the pachycephalosaur Amtocephale , the ornithomimid ‘’Garudimimus’’, the ankylosaurs Talarurus , ‘’Amtosaurus’’, ‘’Maleevus’’, and Tsagantegia , the large sauropod Erketu and the basal hadrosauroid Gobihadros . [6] [11] [8] Additional paleofauna has been recovered, expanding the aquatic biodiversity: Paralligator , [12] Lindholmemys [13] and the shark Hybodus . [14] The discoveries of azhdarchids pterosaurs have been reported from at least two locations, compromising mainly cervical vertebrae. [15]
Segnosaurus is a genus of therizinosaurid dinosaur that lived in what is now southeastern Mongolia during the Late Cretaceous, about 102–86 million years ago. Multiple incomplete but well-preserved specimens were discovered in the Gobi Desert in the 1970s, and in 1979 the genus and species Segnosaurus galbinensis were named. The generic name Segnosaurus means "slow lizard" and the specific name galbinensis refers to the Galbin region. The known material of this dinosaur includes the lower jaw, neck and tail vertebrae, the pelvis, shoulder girdle, and limb bones. Parts of the specimens have gone missing or become damaged since they were collected.
Protoceratops is a genus of small protoceratopsid dinosaurs that lived in Asia during the Late Cretaceous, around 75 to 71 million years ago. The genus Protoceratops includes two species: P. andrewsi and the larger P. hellenikorhinus. The former was described in 1923 with fossils from the Mongolian Djadokhta Formation, and the latter in 2001 with fossils from the Chinese Bayan Mandahu Formation. Protoceratops was initially believed to be an ancestor of ankylosaurians and larger ceratopsians, such as Triceratops and relatives, until the discoveries of other protoceratopsids. Populations of P. andrewsi may have evolved into Bagaceratops through anagenesis.
Enigmosaurus is a genus of therizinosauroid that lived in Asia during the Late Cretaceous period. It was a medium-sized, ground-dwelling, bipedal herbivore that represents the third therizinosaur taxon from the Bayan Shireh Formation, although it is known from the lower part. The genus is monotypic, including only the type species E. mongoliensis, known from a well preserved pelvis and other tentative body remains.
Alectrosaurus is a genus of tyrannosauroid theropod dinosaur that lived in Asia during the Late Cretaceous period, about some 96 million years ago in what is now the Iren Dabasu Formation.
Achillobator is a genus of large dromaeosaurid theropod dinosaur that lived during the Late Cretaceous period about 96 million to 89 million years ago in what is now the Bayan Shireh Formation of Mongolia. The genus is currently monotypic, only including the type species A. giganticus. The first remains were found in 1989 during a Mongolian-Russian field expedition and later described in 1999. Remains at the type locality of Achillobator may represent additional specimens. It represents the first and largest dromaeosaurid known from the Bayan Shireh Formation.
Protoceratopsidae is a family of basal (primitive) ceratopsians from the Late Cretaceous period. Although ceratopsians have been found all over the world, protoceratopsids are only definitively known from Cretaceous strata in Asia, with most specimens found in China and Mongolia. As ceratopsians, protoceratopsids were herbivorous, with constantly replacing tooth batteries made for slicing through plants and a hooked beak for grabbing them. Protoceratopsids were small ceratopsians around 1-2.5 m in length. Their bony frill and horns were much smaller than more derived members of Ceratopsia, such as ceratopsids.
Microceratus is a genus of small ceratopsian dinosaur that lived in the Cretaceous period in Asia. It walked on two legs, had short front arms, a characteristic ceratopsian frill and beak-like mouth, and was around 60 cm (2.0 ft) long. It was one of the first ceratopsians, or horned dinosaurs, along with Psittacosaurus in Mongolia.
Dryptosaurus is a genus of basal eutyrannosaurian theropod dinosaur that lived on the island continent of Appalachia approximately 67.6 million years ago during the end of the Maastrichtian age of the Late Cretaceous period. Dryptosaurus was a large, bipedal, ground-dwelling carnivore that could grow up to 7.5 metres (25 ft) long and weigh up to 756–1,500 kilograms (1,667–3,307 lb). Although it is now largely unknown outside of academic circles, the famous 1897 painting of the genus by Charles R. Knight made Dryptosaurus one of the more widely known dinosaurs of its time, in spite of its poor fossil record. First described by Edward Drinker Cope in 1866 and later renamed by Othniel Charles Marsh in 1877, Dryptosaurus is among the first theropod dinosaurs ever known to science.
The Bayan Shireh Formation is a geological formation in Mongolia, that dates to the Cretaceous period. It was first described and established by Vasiliev et al. 1959.
Udanoceratops is a genus of large leptoceratopsid dinosaur that lived during the Late Cretaceous period of Mongolia.
Kuru is a genus of dromaeosaurid theropod from the Late Cretaceous Barun Goyot Formation of Mongolia. The genus contains only a single species, the type species Kuru kulla, which is known from a fragmentary skeleton including a partial skull.
Huabeisaurus was a genus of dinosaur from the Late Cretaceous. It was a sauropod which lived in what is present-day northern China. The type species, Huabeisaurus allocotus, was first described by Pang Qiqing and Cheng Zhengwu in 2000. Huabeisaurus is known from numerous remains found in the 1990s, which include teeth, partial limbs and vertebrae. Due to its relative completeness, Huabeisaurus represents a significant taxon for understanding sauropod evolution in Asia. Huabeisaurus comes from Kangdailiang and Houyu, Zhaojiagou Town, Tianzhen County, Shanxi province, China. The holotype was found in the unnamed upper member of the Huiquanpu Formation, which is Late Cretaceous (?Cenomanian–?Campanian) in age based on ostracods, charophytes, and fission-track dating.
Talarurus is a genus of ankylosaurid dinosaur that lived in Asia during the Late Cretaceous period, about 96 million to 89 million years ago. The first remains of Talarurus were discovered in 1948 and later described by the Russian paleontologist Evgeny Maleev with the type species T. plicatospineus. It is known from multiple yet sparse specimens, making it one of the most well known ankylosaurines, along with Pinacosaurus. Elements from the specimens consists of various bones from the body; five skulls have been discovered and assigned to the genus, although the first two were very fragmented.
Goyocephale is an extinct genus of pachycephalosaurian ornithischian that lived in Mongolia during the Late Cretaceous about 76 million years ago. It was first described in 1982 by Altangerel Perle, Teresa Maryańska and Halszka Osmólska for a disarticulated skeleton with most of a skull, part of the forelimb and hindlimb, some of the pelvic girdle, and some vertebrae. Perle et al. named the remains Goyocephale lattimorei, from the Mongolian гоё (goyo), meaning "decorated", and the Ancient Greek κεφαλή (kephale), for head. The species name honours Owen Lattimore.
Gilmoreosaurus is the name given to a genus of dinosaur from the Cretaceous of Asia. The type species is Gilmoreosaurus mongoliensis. It is believed to be a hadrosaur or iguanodont from the Iren Dabasu Formation of Inner Mongolia, dating to 96 Ma ago. Additional specimens have been described as distinct species, including G. atavus from the Khodzhakul Formation of Uzbekistan and G. arkhangelskyi from the Bissekty Formation. However, these are based on very fragmentary remains, and their classification is dubious. An additional species, G. kysylkumense is sometimes included, though it has also been referred to the related genus Bactrosaurus.
Erketu is a genus of somphospondylan sauropod dinosaur that lived in Asia during the Late Cretaceous roughly between 96 million and 89 million years ago. Its fossils were found in Mongolia between 2002 and 2003 during a field expedition and first described in 2006; later on in 2010 due to some cervicals that were left behind in the expedition. Erketu represents one of the first sauropods described from the Bayan Shireh Formation. The elongated cervical vertebrae of Erketu indicates that it was the sauropod with the longest neck relative to its body size.
Erlikosaurus is a genus of therizinosaurid that lived in Asia during the Late Cretaceous period. The fossils, a skull and some post-cranial fragments, were found in the Bayan Shireh Formation of Mongolia in 1972, dating to around 96 million and 89 million years ago. These remains were later described by Altangerel Perle and Rinchen Barsbold in 1980, naming the new genus and species Erlikosaurus andrewsi. It represents the second therizinosaur taxon from this formation with the most complete skull among members of this peculiar family of dinosaurs.
The Djadochta Formation is a highly fossiliferous geological formation situated in Central Asia, Gobi Desert, dating from the Late Cretaceous period, about 75 million to 71 million years ago. The type locality is the Bayn Dzak locality, famously known as the Flaming Cliffs. Reptile and mammal remains are among the fossils recovered from the formation.
Chuanqilong is a monospecific genus of basal ankylosaurid dinosaur from the Liaoning Province, China that lived during the Early Cretaceous in what is now the Jiufotang Formation. The type and only species, Chuanqilong chaoyangensis, is known from a nearly complete skeleton with a skull of a juvenile individual. It was described in 2014 by Fenglu Han, Wenjie Zheng, Dongyu Hu, Xing Xu, and Paul M. Barrett. Chuanqilong shows many similarities with Liaoningosaurus and may represent a later ontogenetic stage of the taxon.
Ondogurvel is a genus of alvarezsaurid dinosaur from the Late Cretaceous (Campanian) Barun Goyot Formation in southern Mongolia. The type and only species is O. alifanovi, known from a partial skeleton consisting of fragments of two last dorsal vertebrae, three anterior sacral vertebrae, right ilium, left and right pubis and ischium, articulated right tibia, fibula, metatarsals II and IV, and phalanges IV-1 and IV-2, right carpometacarpus, left and right manual phalanx II-1, right femur, left pedal phalanx II-1, and fragments of unidentified phalanges.