Magyarosaurus

Magyarosaurus ("Magyar lizard") is a genus of dwarf sauropod dinosaur from late Cretaceous Period (early to late Maastrichtian) in Romania. It is one of the smallest-known adult sauropods, measuring only six meters in length. The type and only certain species is Magyarosaurus dacus. It has been found to be a close relative of Rapetosaurus in the family Saltasauridae in the sauropod clade Titanosauria in a 2005 study.[2]

Magyarosaurus
Temporal range: Maastrichtian, 71–66 Ma
Magyarosaurus
Humerus, Deva Natural History Museum
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Saurischia
Suborder: Sauropodomorpha
Clade: Sauropoda
Clade: Titanosauria
Genus: Magyarosaurus
von Huene, 1932
Type species
Magyarosaurus dacus
(Nopcsa, 1915 [originally Titanosaurus dacus])
Other species

?M. hungaricus von Huene, 1932

Synonyms[1]

M. transsylvanicus von Huene, 1932

Description

Magyarosaurus- human size
Size compared with a human

Magyarosaurus was estimated to be 1.1 metric tons (1.1 long tons; 1.2 short tons) in weight.[3] It carried strange dermal armour.[4][5] The estimated length of Magyarosaurus is 6 metres (20 ft), according to Curry Rogers et al..[2] In 2010 Gregory S. Paul gave lower estimations of one tonne with the same length.[6]

Stein et al. (2010) found that none of Magyarosaurus close relatives had a reduced size. That means, for its clade, its small size therefore is a distinguishing autapomorphy.[7]

A distal caudal vertebrae was referred to the genus by Codrea et al. (2008). It was probably from near the middle of the tail as it has transitional features. Before it was definitively buried, the neural arch was broken off, probably by repositioning of the vertebrae from its original position. Its centrum is elongated, and measures 105 millimetres (4.1 in) long. Both sides that would have articulated with vertebrae were severely damaged. It is assigned to Magyarosaurus on the basis that no other sauropods are known from the region it was found in, and the fact that it is located between the two vertebrae compared with it because of its intermediate morphology.[1]

Discovery

Magyarosaurus sp - scapula
Magyarosaurus sp. scapula

Remains belonging to at least ten individuals have been recovered from the Hunedoara region (Sânpetru Formation) in the area which was during their discovery Hungary, but is now western Romania. Initially they were named Titanosaurus dacus, the specific name referring to the Dacians (who had lived in that place about 2000 years ago), by Baron Nopcsa in 1915.[8] Nopcsa had collected fossils in the area since 1895. The species was later renamed Magyarosaurus dacus by Friedrich von Huene in 1932.[9] von Huene in 1932 also named two other species: M. hungaricus and M. transsylvanicus. Larger, rarer M. hungaricus may represent a distinct taxon.[7]

The holotype, BMNH R.3861a, consists of a set of vertebrae. Numerous other bones have been found, mainly caudal vertebrae but also dorsals and elements of the appendicular skeleton. No remains of skulls are known. There has been a discovery of 14 fossil eggs which have been attributed to Magyarosaurus.[10]

Magyarosaurus coracoid
Coracoid

Paleontology investigations have been carried out at Râpa Roșie near Sebeş, on the southwestern side of the Transylvanian Basin. The investigations were started in 1969. Dinosaur bones were reported in earlier investigations. Based on the investigations carried out by Codrea and Dica in 2005, they have assigned the age of these formations to the Maastrichtian-Miocene age (also conjectured as of Eggenburgian-Ottnangian age). Some of the rare fossils found here are also vertebrates and one of these is of sauropod caudal vertebra. Paleontologists involved with the studies at Râpa Roșie have also opined that this is the only sauropod genus reported at any time in the latest Cretaceous Maastrichtian formations in Romania, which could be stated as Magyarosaurus.[1]

Paleobiology

Dwarfism

The islands it inhabited led to Magyarosaurus becoming a product of insular dwarfism as a result of selective pressures presented by limited food supplies and a lack of predators, all favoring a smaller body size.[7] This is seen in many other dinosaurs existing at the time, including the ornithopod Rhabdodon and the nodosaur Struthiosaurus. Nopcsa was the first to suggest island dwarfism as an explanation for the small size of Magyarosaurus compared to other sauropods. Later researchers doubted his conclusions, suggesting instead that the known Magyarosaurus fossil represented juveniles. However, a detailed study of bone growth patterns published in 2010 supported Nopcsa's original hypothesis, showing that the small Magyarosaurus individuals were adults.[7][3] Island dwarfism has been suggested to have led to isolated genera retaining more primitive characteristics.[4]

Histology

Sauropoda (8030762510)
Limb bone

In 2010, Koen Stein et al. studied the histology of Magyarosaurus. They found that even the smallest individuals appeared to be adults. They also retained "M." hungaricus to represent the larger specimens that were too big to be variations of the smaller specimens. The histology of Magyarosaurus showed that it had a very reduced growth rate, but even so, had a high metabolic rate.[7]

Armour

An osteoderm discovered in the "La Cãrare" locality. The locality is near Sînpetru village, in the Hațeg Basin of Romania. The osteoderm was assigned to Magyarosaurus dacus. This shows that dermal armour had a wide distribution in these Late Cretaceous sauropods.[5] The osteoderms was peculiar in shape and size,[5] and led to eggs being assigned to its family, Nemegtosauridae, and possibly to Magyarosaurus.[4]

Possible eggs

Campanian Romanian representative fauna
Fossils from the Late Cretaceous of Romania, including Magyarosaurus (E–F)

Lithostrotian eggs have been assigned to Nemegtosauridae. The eggs possibly persist to either Magyarosaurus dacus or Paludititan, the former being more likely.[4] The Hațeg Basin was a large nesting place in the late Cretaceous, and is served as that for hadrosaurids, and titanosaurs. 11 eggs have been assigned to Nemegtosauridae, all from the Sânpetru Formation.[4] Embryos were preserved inside the eggs, and one egg shows proof of dermal armouring.[4]

The eggs were uncovered in 2001, during a field expedition by a Belgo-Romanian team. They were originally identified as in nests, but now it has been shown that no nesting structures has been preserved.[4]

Paleoecology

During the early Maastrichtian, the Hațeg Basin was subhumid, and had seasonal precipitation. However, during the later age of the formation, a large-scale paleoenvironmental change occurred, the region transformed into an extensive wetland.[11]

Magyarosaurus dacus is known from the early Maastrichtian of the Sânpetru Formation, part of the Hațeg Basin in Romania.[11][2][12] Also known from the Hațeg Basin are the small, basal hadrosaurid Telmatosaurus;[7] the small nodosaurid Struthiosaurus;[13] the maniraptorans Balaur, Bradycneme, and Elopteryx;[13] the pterosaur Hatzegopteryx;[3][14] and the two species of the euornithopod Zalmoxes.[7]

M. sp. is known from a vertebrae. The vertebrae was found in the latest Cretaceous of the Sebeş Formation, although it was probably eroded from the Şard Formation and placed there. Alongside Magyarosaurus existed Kallokibotion, an ancient turtle;[1] Balaur, a two-clawed dromaeosaurid;[13] and Eurazhdarcho, an azhdarchid.[14] Alongside Magyarosaurus, Telmatosaurus and Zalmoxes also are dwarfed genera, as proven by their histology.[7]

References

  1. ^ a b c d Codrea, V.A.; Murzea-Jipa, C.; Venczel, M. (2008). "A Sauropod Vertebrae at Râpa Roşie (Alba District)" (PDF). Acta Palaeontologica Romaniae. 6: 43–48.
  2. ^ a b c Curry Rogers, K. (2005). "Titanosauria: A phylogenetic Overview" in Curry Rogers, K. and Wilson, J.A. (eds), The Sauropods: Evolution and Paleobiology. Berkeley: University of California Press. ISBN 0-520-24623-3
  3. ^ a b c Scott, C. (2012). "Change of Die". In McArthur, C. & Reyal, M. (eds.). Planet Dinosaur. Firefly Books. pp. 200–208. ISBN 978-1-77085-049-1.CS1 maint: Uses editors parameter (link)
  4. ^ a b c d e f g Grellet-Tinner, G; Codrea, V; Folie, A; Higa, A.; Smith, T. (2012). Andrew A. Farke (ed.). "First evidence of reproductive adaptation to "island effect" of a dwarf Cretaceous Romanian titanosaur, with embryonic integument in ovo". PLoS ONE. 7 (3): e32051. Bibcode:2012PLoSO...732051G. doi:10.1371/journal.pone.0032051. PMC 3297589. PMID 22412852.
  5. ^ a b c Csiki, Z. (1999). "New evidence of armoured titanosaurids in the Late Cretaceous - Magyarosaurus dacus from the Hateg Basin (Romania)". Oryctos. 2: 93–99.
  6. ^ Paul, G.S. (2010) The Princeton Field Guide to Dinosaurs, Princeton University Press p. 213
  7. ^ a b c d e f g h Stein, K.; Csiki, Z.; Curry Rogers, K.; Weishampel, D.B.; Redelstorff, R.; Carballidoa, J.L.; Sandera, P.M. (2010). "Small body size and extreme cortical bone remodeling indicate phyletic dwarfism in Magyarosaurus dacus (Sauropoda: Titanosauria)". Proceedings of the National Academy of Sciences of the United States of America. 20. 107 (20): 9258–9263. Bibcode:2010PNAS..107.9258S. doi:10.1073/pnas.1000781107. PMC 2889090. PMID 20435913.
  8. ^ Nopcsa, F (1915). "Die Dinosaurier der siebenburgischen Landesteile Ungarns". Ungar. Geol. Reichsanst. 23: 1–26.
  9. ^ von Huene, F. (1932). "Die fossile Reptil-Ordnung Saurischia, ihre Entwicklung und Geschichte." Mong. Geol. Pal., 4(1) pts. 1 and 2, viii +361 pp.
  10. ^ "Briefing", Geology Today 7(1): p. 2-6.
  11. ^ a b Therrien, F.; Zelenitsky, D.K.; Weishampel, D.B. (2009). "Palaeoenvironmental reconstruction of the Late Cretaceous Sânpetru Formation (Haţeg Basin, Romania) using paleosols and implications for the "disappearance" of dinosaurs". Palaeogeography, Palaeoclimatology, Palaeoecology. 272 (1–2): 37–52. Bibcode:2009PPP...272...37T. doi:10.1016/j.palaeo.2008.10.023.
  12. ^ B. Vila; A. Galobart; J.U. Canudo; J. Le Loeff; et al. (2012). "The diversity of sauropod dinosaurs and their first taxonomic succession from the latest Cretaceous of southwestern Europe: Clues to demise and extinction". Palaeogeography, Palaeoclimatology, Palaeoecology. 350-352 (15): 19–38. Bibcode:2012PPP...350...19V. doi:10.1016/j.palaeo.2012.06.008.
  13. ^ a b c Weishampel, D.B. & Jianu, C.M. (2011). Transsylvanian Dinosaurs. The Johns Hopkins University Press. pp. 37–38. ISBN 978-1-4214-0027-3.CS1 maint: Uses authors parameter (link)
  14. ^ a b Vremir, M. T. S.; Kellner, A. W. A.; Naish, D.; Dyke, G. J. (2013). Viriot, Laurent (ed.). "A New Azhdarchid Pterosaur from the Late Cretaceous of the Transylvanian Basin, Romania: Implications for Azhdarchid Diversity and Distribution". PLoS ONE. 8 (1): e54268. Bibcode:2013PLoSO...854268V. doi:10.1371/journal.pone.0054268. PMC 3559652. PMID 23382886.
Ampelosaurus

Ampelosaurus ( AM-pi-loh-SOR-əs; meaning "vine lizard") is a titanosaurian sauropod dinosaur hailing from the Late Cretaceous Period of what is now Europe. Its type species is A. atacis, named by Le Loeuff in 1995. A possible unnamed species has given Ampelosaurus an age reaching to the latest Cretaceous, from about 70 to 66 million years ago.

Like most sauropods, it would have had a long neck and tail but it also carried armor in the form of osteoderms. Over 500 bones have been assigned to Ampelosaurus and all but the braincase (assigned to A. sp.) has been assigned to A. atacis. They are assigned to the same species because all the differences in the limb proportions have been linked to individual variation. A. atacis is known from a few, well-preserved teeth and some cranial material. A right scapula was discovered associated with a coracoid. The blade of the scapula, contrary to most titanosaurs, is triangular. The blade narrows at one end instead of showing an expansion like most other genera. A. atacis is also known from a pubis about 75 centimetres (30 in) long and an ilium. Aside from that, it is known from a partial forelimb, and many femora.

Titanosaurians were a flourishing group of sauropod dinosaurs during Cretaceous times. The Spanish locality from the latest Cretaceous of “Lo Hueco” yielded a relatively well preserved, titanosaurian braincase, which shares a number of unique features with A. atacis from France. However, it appeared to differ from A. atacis in some traits also. The specimen has been provisionally identified as Ampelosaurus sp.; it is most likely a mature titanosaurian since the bones of the braincase have largely fused together.

Ampelosaurus lived alongside many other animals. Over 8500 specimens have been found alongside it, including gastropods, bivalves, crocodiles, other sauropods, plants and invertebrates in the Villalba de la Sierra, Gres de Saint-Chinian, Marnes Rouges Inférieures and Gres de Labarre formations. Recent attention has made Ampelosaurus one of the most well-known dinosaurs known from France.

Balaur bondoc

Balaur bondoc is a species of theropod dinosaur from the late Cretaceous period, in what is now Romania. It is the type species of the monotypic genus Balaur, after the balaur (Romanian pronunciation: [baˈla.ur]), a dragon of Romanian folklore. The specific name bondoc means "stocky", so Balaur bondoc means "stocky dragon" in Romanian. This name refers to the greater musculature that Balaur had compared to its relatives. The genus, which was first described by scientists in August 2010, is known from two partial skeletons (including the type specimen).

Fossils of Balaur were found in a part of Cretaceous Romania called Hațeg Island. Hațeg Island is commonly referred to as the "Island of the Dwarf Dinosaurs", and was part of the European archipelago of the Tethys Sea approximately 70 million years ago, when world sea levels were higher and much of Europe was tropical or sub-tropical. Early studies of the fossils placed the animal among the group of dromaeosaurid dinosaurs that includes Velociraptor, which was similar in size. Subsequent phylogenetic analyses have since placed Balaur among basal avialans, the group that includes modern birds. Unlike other early paravians, Balaur had not just one but two large, retractable, sickle-shaped claws on each foot, and its limbs were proportionally shorter and heavier than those of its relatives. As with other dinosaurs from Hațeg, such as Magyarosaurus, a dwarf sauropod, its strange features have been argued to show the effects of its island habitat on its evolution.

Brasilotitan

Brasilotitan is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous (early Maastrichtian) Adamantina Formation of Brazil. The type species is Brasilotitan nemophagus.

Cetiosauridae

Cetiosauridae is a family of sauropod dinosaurs. While traditionally a wastebasket taxon containing various unrelated species, some recent studies have found that it may represent a natural clade. Additionally, at least one study has suggested that the mamenchisaurids may represent a sub-group of the cetiosaurids, which would be termed Mamenchisaurinae.

Diplodocinae

Diplodocinae is an extinct subfamily of diplodocid sauropods that existed from the Late Jurassic to Early Cretaceous of North America, Europe and South America, about 161.2 to 136.4 million years ago. Genera within the subfamily include Tornieria, Supersaurus, Leinkupal, Galeamopus, Diplodocus, Kaatedocus and Barosaurus.Cladogram of the Diplodocidae after Tschopp, Mateus, and Benson (2015).

Eomamenchisaurus

Eomamenchisaurus (meaning "dawn Mamenchisaurus") is a genus of mamenchisaurid sauropod dinosaur from the Middle Jurassic of Yuanmou, Yunnan, China. The type species is E. yuanmouensis, described by Lü Junchang et al. in 2008.

Europasaurus

Europasaurus is a basal macronarian sauropod, a form of quadrupedal herbivorous dinosaur. It lived during the Late Jurassic (middle Kimmeridgian, about 154 million years ago) of northern Germany, and has been identified as an example of insular dwarfism resulting from the isolation of a sauropod population on an island within the Lower Saxony basin.

Ferganasaurus

Ferganasaurus was a genus of dinosaur first formally described in 2003 by Alifanov and Averianov. The type species is Ferganasaurus verzilini. It was a sauropod similar to Rhoetosaurus. The fossils were discovered in 1966 in Kyrgyzstan from the Balabansai Formation and date to the Callovian stage of the Middle Jurassic.

Gravisauria

Gravisauria is a clade of sauropod dinosaurs consisting of some genera, Vulcanodontidae and Eusauropoda.

Jiutaisaurus

Jiutaisaurus is a genus of sauropod dinosaur from the Quantou Formation of China. Jiutaisaurus was a sauropod which lived during the Cretaceous. The type species, Jiutaisaurus xidiensis, was described by Wu et al. in 2006, and is based on eighteen vertebrae.

Paludititan

Paludititan is a genus of herbivorous titanosaurian dinosaur which lived in the area of present Romania during the Late Cretaceous. It existed in the island ecosystem known as Hațeg Island.

Pilmatueia

Pilmatueia is a diplodocoid sauropod belonging to the family Dicraeosauridae that lived in Argentina during the Early Cretaceous.

Planet Dinosaur

Planet Dinosaur, is a six-part documentary television series created by Nigel Paterson and Phil Dobree, produced by the BBC, and narrated by John Hurt. It first aired in the United Kingdom in 2011, with VFX studio Jellyfish Pictures as its producer. It is the first major dinosaur-related series for BBC One since Walking with Dinosaurs. There are more than 50 different prehistoric species featured, and they and their environments were created entirely as computer-generated images, for around a third of the production cost that was needed a decade earlier for Walking with Dinosaurs. Much of the series' plot is based on scientific discoveries made since Walking with Dinosaurs. The companion book to Planet Dinosaur was released on 8 September 2011, and the DVD and Blu-ray were released on 24 October 2011.

Sânpetru Formation

The Sânpetru Formation is a Mesozoic geologic formation. Dinosaur remains are among the fossils that have been recovered from the formation. It is located in Romania, near Sânpetru village, part of Sântămăria-Orlea commune. It forms a component of the Hațeg Island fauna.

Tambatitanis

Tambatitanis is an extinct genus of titanosauriform dinosaur from the Early Cretaceous (probably early Albian) of Japan. It is known from a single type species, Tambatitanis amicitiae. It was probably around 14 meters long and its mass was estimated at some 4 tonnes. It was a basal titanosauriform and possibly belonged to the Euhelopodidae.

Tastavinsaurus

Tastavinsaurus is a genus of sauropod dinosaur belonging to the Titanosauriformes. It is based on a partial skeleton from the Early Cretaceous of Spain. The type species is Tastavinsaurus sanzi, named in honor of the Rio Tastavins in Spain and Spanish paleontologist José Luis Sanz.

Titanosauria

Titanosaurs (members of the group Titanosauria) were a diverse group of sauropod dinosaurs which included Saltasaurus and Isisaurus of Africa, Asia, South America, Europe and Australia. The titanosaurs were the last surviving group of long-necked sauropods, with taxa still thriving at the time of the extinction event at the end of the Cretaceous. The group includes the largest land animals known to have existed, such as Patagotitan—estimated at 37 m (121 ft) long with a weight of 69 tonnes (76 tons)—and the comparably sized Argentinosaurus and Puertasaurus from the same region. The group's name alludes to the mythological Titans of Ancient Greece, via the type genus (now considered a nomen dubium) Titanosaurus. Together with the brachiosaurids and relatives, titanosaurs make up the larger clade Titanosauriformes.

Titanosaurus

Titanosaurus (meaning 'titanic lizard' – named after the mythological Titans, deities of Ancient Greece) is a dubious genus of sauropod dinosaurs, first described by Lydekker in 1877. It is known from the Maastrichtian (Upper Cretaceous) Lameta Formation of India.

Vulcanodontidae

The Early Jurassic sauropod dinosaurs Zizhongosaurus, Barapasaurus, Tazoudasaurus, and Vulcanodon may form a natural group of basal sauropods called the Vulcanodontidae. Basal vulcanodonts include some of the earliest known examples of sauropods. The family-level name Vulcanodontidae was erected by M.R. Cooper in 1984. In 1995 Hunt et al. published the opinion that the family is synonymous with the Barapasauridae. One of the key morphological features specific to the family is an unusually narrow sacrum.

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