Epachthosaurus

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Epachthosaurus
Temporal range: Late Cretaceous, 95–90  Ma
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Museo Egidio Feruglio Epachthosaurus.jpg
Cast mounted in rearing pose, Museo Egidio Feruglio
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Sauropodomorpha
Clade: Sauropoda
Clade: Macronaria
Clade: Titanosauria
Genus: Epachthosaurus
Powell, 1990
Type species
Epachthosaurus sciuttoi
Powell, 1990

Epachthosaurus (meaning "heavy lizard") was a genus of titanosaurian sauropod dinosaur from the Late Cretaceous. It was a basal lithostrotian titanosaur. Its fossils have been found in Central and Northern Patagonia in South America.

Contents

Discovery and naming

Skeleton cast, Coquimbo Epachthosaurus skeleton mount.jpg
Skeleton cast, Coquimbo

The type species, E. sciuttoi, was described by Powell in 1990. [1] The bones assigned to it by Powell in 1990 were, originally, assigned to Antarctosaurus sp. , and then to Argyrosaurus superbus?, before being named as a new taxon. [1]

The holotype specimen is MACN-CH 1317, which consists of an incomplete posterior dorsal vertebra. [1] [2] Another specimen, the paratype MACN-CH 18689, consists of a cast of six articulated caudal vertebrae, the partial sacrum, and a fragmentary pubic peduncle from the right ilium. [2]

A nearly complete specimen referred to Epachthosaurus, UNPSJB-PV 920, was recovered during field research conducted as part of the project Los vertebrados de la Formación Bajo Barreal, Provincia de Chubut, Patagonia, Argentina by researchers from the Laboratorio de Paleontologia de Vertebrados of the Universidad Nacional de la Patagonia. The specimen, which is one of the most complete titanosaurian skeletons known, consists of a complete, well-preserved, and articulated skeleton only missing the skull, neck, four or five cranial dorsal vertebrae, and several distal caudals. [2]

Description

The autapomorphies that distinguish Epachthosaurus from other genera are: [2] middle and caudal dorsal vertebrae with unique articular processes extending ventrolaterally from the hyposphene; a strongly developed intraprezygapophyseal lamina, and processes projecting laterally from the dorsal portion of the spinodiapophyseal lamina; hyposphene-hypantrum articulations in caudals 1–14; and a pedal phalangeal formula of 2-2-3-2-0. The genus shares the following apomorphies with various titanosaurians: [2] caudal vertebrae with ventrally expanded posterior centrodiapophyseal laminae; six sacral vertebrae; an ossified ligament or tendon above the sacral neural spines; procoelous proximal, middle, and distal caudal centra with well-developed distal articular condyles; semilunar sternal plates with cranioventral ridges; humeri with squared proximolateral margins and proximolateral processes; unossified carpals; greatly reduced manual phalanges; nearly horizontal, craniolaterally expanded iliac preacetabular processes; pubes proximodistally longer than ischia; and transversely expanded ischia.

Classification

Epachthosaurus is considered to be the most basal titanosaurian known with procoelous caudal vertebrae. [2]

Below is a phylogenetical cladogram showing the position of Epachthosaurus within Titanosauria: [3]

Titanosauria

Phuwiangosaurus

Andesaurus

Argyrosauridae

Argyrosaurus

Paralititan

Aeolosauridae

Janenschia

Aeolosaurus

Santa Rosa indet.

Antarctosauridae

Isisaurus

Alamosaurus

Opisthocoelicaudia

Antarctosaurus

Argentinosaurus

Aegyptosaurus

Epachthosaurus

Nemegtosauridae

Lirainosaurus

Saltasauridae

The cladogram below follows Mocho et al. (2019), placing Epachthosaurus within Lithostrotia, instead of a basal titanosaur. [4]

Lithostrotia

Malawisaurus

Paludititan

Lohuecotitan

Epachthosaurus

Opisthocoelicaudiinae

Alamosaurus

Opisthocoelicaudia

Saltasaurinae

Neuquensaurus

Rocasaurus

Saltasaurus

Lirainosaurinae

Lirainosaurus

Atsinganosaurus

Ampelosaurus

Bonatitan

Rapetosaurus

Nemegtosaurus

Aeolosaurinae

Gondwanatitan

Aeolosaurus

Rinconsauria

Rinconsaurus

Muyelensaurus

Bonitasaura

Lognkosauria

Mendozasaurus

Futalognkosaurus

Paleoecology

Epachthosaurus is known from the early Late Cretaceous of the Bajo Barreal Formation. Other fauna from the formation include the basal chelid turtles Bonapartemys and Prochelidella , the abelisaurid Xenotarsosaurus , and an unidentified carnotaurine abelisaurid. [2] The Bajo Barreal Formation dates back to the late Cenomanian and early Turonian of the Cretaceous. [2] Other genera that lived alongside Epachthosaurus are Secernosaurus , Notohypsilophodon , Drusilasaura , Campylodoniscus , Aniksosaurus , and Sarmientosaurus . [5] [6]

Related Research Articles

<i>Argentinosaurus</i> Late Cretaceous giant sauropod dinosaur genus

Argentinosaurus is a genus of giant sauropod dinosaur that lived during the Late Cretaceous period in what is now Argentina. Although it is only known from fragmentary remains, Argentinosaurus is one of the largest known land animals of all time, perhaps the largest, reaching 30–35 metres (98–115 ft) in length and 60–75 tonnes in body mass. It was a member of Titanosauria, the dominant group of sauropods during the Cretaceous.

<span class="mw-page-title-main">Titanosauria</span> Extinct clade of dinosaurs

Titanosaurs were a diverse group of sauropod dinosaurs, including genera from all seven continents. 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. This group includes some of the largest land animals known to have ever existed, such as Patagotitan—estimated at 37 m (121 ft) long with a weight of 69 tonnes —and the comparably-sized Argentinosaurus and Puertasaurus from the same region.

<i>Argyrosaurus</i> Genus of herbivorous titanosaurian sauropod dinosaur

Argyrosaurus is a genus of titanosaurian sauropod dinosaur that lived about 70 million years ago, during the Late Cretaceous Period of what is now Argentina.

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

Aeolosaurus is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous Period of what is now South America. Like most sauropods, it would have been a quadrupedal herbivore with a long neck and tail. Aeolosaurus is well known for a titanosaur, as it is represented by the remains of several individuals belonging to at least two species. However, like most titanosaurs, no remains of the skull are known. The holotype of Aeolosaurus rionegrinus consists of a series of seven tail vertebrae, as well as parts of both forelimbs and the right hindlimb. It was discovered in the Angostura Colorada Formation in Argentina, which dates from the Campanian stage of the Late Cretaceous, about 83 to 74 million years ago. The species A. maximus was transferred over to the new genus Arrudatitan in 2021.

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

Ampelosaurus is a titanosaurian sauropod dinosaur from the Late Cretaceous Period of what is now France. 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.

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

Andesaurus is a genus of basal titanosaurian sauropod dinosaur which existed during the middle of the Cretaceous Period in South America. Like most sauropods, belonging to one of the largest animals ever to walk the Earth, it would have had a small head on the end of a long neck and an equally long tail.

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

Neuquensaurus is a genus of saltasaurid sauropod dinosaur that lived in the Late Cretaceous, about 80 million years ago in Argentina and Uruguay in South America. Its fossils were recovered from outcrops of the Anacleto Formation around Cinco Saltos, near the Neuquén river from which its name is derived.

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

Pellegrinisaurus is a genus of titanosaurian sauropod dinosaur that lived in South America during the Late Cretaceous period. The holotype was found in the Allen Formation, Argentina.

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

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

Puertasaurus is a genus of sauropod dinosaur that lived in South America during the Late Cretaceous Period. It is known from a single specimen recovered from sedimentary rocks of the Cerro Fortaleza Formation in southwestern Patagonia, Argentina, which probably is Campanian or Maastrichtian in age. The only species is Puertasaurus reuili. Described by the paleontologist Fernando Novas and colleagues in 2005, it was named in honor of Pablo Puerta and Santiago Reuil, who discovered and prepared the specimen. It consists of four well-preserved vertebrae, including one cervical, one dorsal, and two caudal vertebrae. Puertasaurus is a member of Titanosauria, the dominant group of sauropods during the Cretaceous.

<span class="mw-page-title-main">Lithostrotia</span> Extinct clade of dinosaurs

Lithostrotia is a clade of derived titanosaur sauropods that lived during the Early Cretaceous and Late Cretaceous. The group was defined by Upchurch et al. in 2004 as the most recent common ancestor of Malawisaurus and Saltasaurus and all the descendants of that ancestor. Lithostrotia is derived from the Ancient Greek lithostros, meaning "inlaid with stones", referring to the fact that many known lithostrotians are preserved with osteoderms. However, osteoderms are not a distinguishing feature of the group, as the two noted by Unchurch et al. include caudal vertebrae with strongly concave front faces (procoely), although the farthest vertebrae are not procoelous.

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Drusilasaura is an extinct genus of possible lognkosaurian titanosaur sauropod dinosaur which lived during the late Cretaceous of Santa Cruz Province of southern Patagonia, Argentina.

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

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Normanniasaurus is an extinct genus of basal titanosaur sauropod known from the Early Cretaceous Poudingue Ferrugineux of Seine-Maritime, northwestern France.

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

Sarmientosaurus is a genus of titanosaurian sauropod dinosaur belonging to the Titanosauria. It lived in what is now South America, specifically Argentina, during the Upper Cretaceous Period about 95 million years ago. The type species is Sarmientosaurus musacchioi.

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

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Tengrisaurus is a genus of lithostrotian sauropod, from the Early Cretaceous (Barremian-Aptian) Murtoi Formation, Russia. It was described in 2017 by Averianov & Skutschas. The type species is T. starkovi. New remains were described in 2021 by Averianov, Sizov & Skutschas.

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References

  1. 1 2 3 Powell, J (1990). "Epachthosaurus sciuttoi (gen. et sp. nov.) un dinosaurio sauropodo del Cretácico de Patagonia (provincia de Chubut, Argentina)". Actas del Congreso Argentino de Paleontologia y Bioestratigrafia. 5: 125–128.
  2. 1 2 3 4 5 6 7 8 Martínez, R.D.; Giménez, O.; Rodríguez, J.; Luna, M.; Lamanna, M.C. (2004). "An Articulated Specimen of the Basal Titanosaurian (Dinosauria: Sauropoda) Epachthosaurus scuittoni from the Early Late Cretaceous Bajo Barreal Formation of Chubut Province, Argentina" (PDF). Journal of Vertebrate Paleontology. 24 (1): 107–120. doi:10.1671/9.1. S2CID   86150784.
  3. Klein, N.; Sander, P. M.; Stein, K.; Le Loeuff, J.; Carballido, J. L.; Buffetaut, E. (2012). Farke, Andrew A (ed.). "Modified Laminar Bone in Ampelosaurus atacis and Other Titanosaurs (Sauropoda): Implications for Life History and Physiology". PLOS ONE. 7 (5): e36907. Bibcode:2012PLoSO...736907K. doi: 10.1371/journal.pone.0036907 . PMC   3353997 . PMID   22615842.
  4. Mocho P, Páramo A, Escaso F, Marcos-Fernández F, Vidal D, Ortega F. 2019. Titanosaurs from Lo Hueco (Campanian-Maastrichtian) reveal new information about the evolutionary history of European titanosaurs, pp. 111. In: The Palaeontological Association (ed.), 63rd Annual Meeting, 15th–21st December 2019, University of Valencia, Spain, Programme Abstracts, AGM papers
  5. Martínez, Rubén D. F.; Lamanna, Matthew C.; Novas, Fernando E.; Ridgely, Ryan C.; Casal, Gabriel A.; Martínez, Javier E.; Vita, Javier R.; Witmer, Lawrence M. (26 April 2016). Joger, Ulrich (ed.). "A Basal Lithostrotian Titanosaur (Dinosauria: Sauropoda) with a Complete Skull: Implications for the Evolution and Paleobiology of Titanosauria". PLOS ONE . 11 (4): e0151661. Bibcode:2016PLoSO..1151661M. doi: 10.1371/journal.pone.0151661 . PMC   4846048 . PMID   27115989.
  6. Weishampel, D.B.; Dodson, P.; Osmolska, H. (2004). The Dinosauria (Second ed.) . University of California Press. pp.  300–400. ISBN   -0-520-24209-2.