Talenkauen

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Talenkauen
Temporal range: Campanian-Maastrichtian
76–70  Ma
Talenkauen.jpg
Holotype MPM-10001
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade:† Ornithischia
Clade:† Ornithopoda
Clade:† Elasmaria
Genus:† Talenkauen
Novas et al. 2004
Species:
†T. santacrucensis
Binomial name
†Talenkauen santacrucensis
Novas et al. 2004

Talenkauen is a genus of basal iguanodont dinosaur from the Campanian or Maastrichtian age of the Late Cretaceous Cerro Fortaleza Formation, formerly known as the Pari Aike Formation of Patagonian Lake Viedma, in the Austral Basin of Santa Cruz, Argentina. [1] [2] It is based on MPM-10001A, a partial articulated skeleton missing the rear part of the skull, the tail, and the hands. The type and only species is Talenkauen santacrucensis. [2]

Contents

Discovery and naming

Lake Viedma, where the only known specimen of Talenkauen was found Lake Viedma (5465531443).jpg
Lake Viedma, where the only known specimen of Talenkauen was found

One among a string of discoveries of ornithopods in South America, following taxa such as Gasparinisaura and Anabisetia , the specimen that would become Talenkauen was collected in February 2000 and would later be described and named in a short 2004 paper by Fernando E. Novas and colleagues. It was discovered on Los Hornos Hill on the coast of Viedma Lake, in the Santa Cruz Province region of Argentina. [2] Geologically, it hails from the Cerro Fortaleza Formation. [1] [3] [lower-alpha 1] The holotype specimen is MPM–10001A, a relatively complete and articulated skeleton. [2] The name Talenkauen is derived from the words "Talenk, meaning small, and kauen, meaning skull, both from the Aonikenk language. The specific name santacrucensis refers to the province of Argentina where it was found. [2] Following its original, preliminary description, the taxon was described more thoroughly described in an unpublished PhD dissertation in 2007 by Andrea V. Cambiaso. In 2020 an extensive description was published by Sebastián Rozadilla and colleagues. [4]

It has been recognized that, nestled amongst the rock matrix of the holotype specimen, are a collection of minuscule bone fragments and teeth. Identifiable as the teeth of some degree of ornithopod, and associated with the adult specimen, this is considered to be a neonatal, or recently hatched, baby specimen of Talenkauen. It was described in a 2013 paper, which separated the specimen number MPM–10001 into MPM–10001A, for the adult specimen, and MPM–10001B, for the neonate. The specimen is one of only very few embryonic or hatchling ornithopod specimen, and was the very first discovered from the southern hemisphere. Wear on the tiny, 1.7mm wide tooth crowns indicate the individual had fed, meaning it was not an embryo and had hatched, but only recently before death. It was noted as possible that the adult had been practicing parental care due to the individuals being found together, but that more concrete evidence would be needed to confidently make such an assertion. [3]

Description

Life restoration Talenkauen.png
Life restoration

Talenkauen was rather like Dryosaurus in shape and build, but with a proportionally longer neck. The full length of the body is estimated at no more than 4 meters (13 feet). [5] However, Gregory S. Paul gave a higher estimate of 4.7 m (15 ft) in length and 300 kg (660 lb) in body mass. [6] Unlike more derived iguanodontians, it still had teeth in the tip of the beak (premaxillary teeth), and a first toe. More derived iguanodonts lose this toe, retaining only the three middle toes. The humerus has reduced areas for muscle attachment, a featured shared with other South American ornithopods like Notohypsilophodon and Anabisetia . This and other similarities to South American ornithopods suggests that there may have been a distinct Southern Hemisphere ornithopod group, but at the time the authors cautioned that such an interpretation was not entirely justified. In 2015, the describers of Morrosaurus found that such a clade did indeed exist. [5]

Alternate view of the holotype, MPM-10001 Talenkauen fossil.jpg
Alternate view of the holotype, MPM-10001

Talenkauen is most noted for a set of smooth, ovoid plates found along the side of the rib cage. These plates can be long (180 millimeters, or 7.1 in), but are very thin (only 3 millimeters thick [0.1 in]). They were present with at least the first eight ribs, attaching along the middle portion of a rib and lying flat. [2] Several other dinosaurs are known to have had similar plates, including Hypsilophodon , Nanosaurus , Parksosaurus , Thescelosaurus , [7] and Macrogryphosaurus (also from Argentina, but from somewhat older rocks), which may have been related. [8] Because of the fragility of the plates, and the fact that they may not have always turned to bone in the living animal, they may have been more widespread than currently known. Novas and colleagues suggested that the plates may be homologous to uncinate processes, strip-like bony projections found on the ribs of a variety of animals including the tuatara, crocodiles, birds, and some maniraptoran theropod dinosaurs. In birds, uncinate processes help to ventilate the lungs, working with rib cage muscles, and Novas and colleagues proposed a similar function for the plates of Talenkauen. [2] This homology was rejected in a more recent study by Richard Butler and Peter Galton because of the plates' form. [7] The plates were too thin and limited in location to have been very useful as defensive devices. [2]

Classification

Through cladistic analysis, it was found to be more basal than Dryosaurus and Anabisetia, but more derived than Tenontosaurus and Gasparinisaura . [2] More recently, the describers of Macrogryphosaurus found their genus and Talenkauen to be related, and coined the clade Elasmaria for the two genera. [8] In 2015, several other Patagonian and Antarctic ornithopods were also found to be related. [5]

The simplified cladogram below results from analysis by Rozadilla et al., 2019, showing all members of Elasmaria forming a polytomy. [9]

Clypeodonta

Hypsilophodon

Elasmaria

Fulgurotherium

Trinisaura

Gasparinisaura

Qantassaurus

Notohypsilophodon

Morrosaurus

Kangnasaurus

Anabisetia

Atlascopcosaurus

Macrogryphosaurus

Talenkauen

Dryomorpha

Palaeoecology

Reconstructed skeleton Talenkauen skeleton.jpg
Reconstructed skeleton

Talenkauen, as a basal ornithopod, would have been a small, bipedal herbivore. [10] Other dinosaurs from the Pari Aike Formation include the giant titanosaurid Puertasaurus [11] and the large predatory theropod Orkoraptor . [12]

Related Research Articles

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

Megaraptor is a genus of large theropod dinosaur that lived in the ages of the Late Cretaceous. Its fossils have been discovered in the Patagonian Portezuelo Formation of Argentina, South America. Initially thought to have been a giant dromaeosaur-like coelurosaur, it was classified as a neovenatorid allosauroid in previous phylogenies, but more recent phylogeny and discoveries of related megaraptoran genera has placed it as either a basal tyrannosauroid or a basal coelurosaur with some studies still considering it a neovenatorid.

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

Notohypsilophodon is a genus of ornithopod dinosaur from the Late Cretaceous of Argentina. It was described as the only "hypsilophodont" known from South America, although this assessment is not universally supported, and Gasparinisaura is now believed to have been a basal euornithopod as well.

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

Anabisetia is a genus of ornithopod dinosaur from the Late Cretaceous Period of Patagonia, South America. It was a small bipedal herbivore, around 2 metres long.

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

Fulgurotherium is a dubious genus of ornithischian dinosaur from the Late Cretaceous (Cenomanian) Griman Creek Formation. It lived in what is now Australia.

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

Kangnasaurus is a genus of iguanodontian ornithopod dinosaur found in supposedly Early Cretaceous rocks of South Africa. It is known from a tooth and possibly some postcranial remains found in the early-Aptian Kalahari Deposits Formation. It was probably similar to Dryosaurus.

<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.

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

Orkoraptor is a genus of medium-sized megaraptoran theropod dinosaur from the late Cretaceous Period of Argentina. It is known from incomplete fossil remains including parts of the skull, teeth, tail vertebrae, and a partial tibia. The specialized teeth resemble those of some maniraptoriform theropods, namely the deinonychosaurs and compsognathids. This and other anatomical features led the authors who described it to suggest that it was a maniraptoran coelurosaur. However, subsequent studies found it to be a megaraptoran. Found in the Cerro Fortaleza Formation of Southern Patagonia, it is one of the southernmost carnivorous dinosaurs known from South America.

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

Macrogryphosaurus is a genus of elasmarian dinosaur from the Coniacian age Upper Cretaceous Sierra Barrosa Formation of Argentina in Patagonia. It was described by Jorge Calvo and colleagues in 2007, with M. gondwanicus as the type and only species.

<i>Austrocheirus</i> Genus of reptiles (fossil)

Austrocheirus is an extinct genus of theropod dinosaur that lived during the Late Cretaceous period. It was named and described by Martin Ezcurra, Federico Agnolin and Fernando Novas in 2010. It contains the type species Austrocheirus isasii. The generic name means "southern hand". The specific epithet honours discoverer and preparator Marcelo Pablo Isasi.

Bonapartenykus is a monospecific genus of alvarezsauroid dinosaur from Argentina that lived during the Late Cretaceous (Campanian-Maastrichtian) in what is now the upper Allen Formation of the Río Negro Province. The type and only species, Bonapartenykus ultimus, is known from a nearly articulated but partial skeleton that was found in close association to two incomplete eggs and several clusters of eggshells belonging to the oogenus Arriagadoolithus. Bonapartenykus was named in 2012 by Federico L. Agnolin, Jaime E. Powell, Fernando E. Novas and Martin Kundrát. Bonapartenykus has an estimated length of 2.5 m (8.2 ft) and weight of 72 kg (159 lb), making it the largest member of the clade Alvarezsauroidea.

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

Elasmaria is a clade of ornithopods known from Cretaceous deposits in South America, Antarctica, and Australia that contains many bipedal ornithopods that were previously considered "hypsilophodonts".

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

Trinisaura is a genus of ornithopod dinosaur that lived during the late Campanian stage of the Upper Cretaceous, around 73 to 72 million years ago in what is now James Ross Island off the coast of northern Antarctica near Patagonia. It is known from a single, incomplete postcranial skeleton that includes several vertebrae, a partial pelvis, and nearly complete right hindlimb. The fossils were collected in 2008 by paleontologists Juan Moly and Rodolfo Coria from the sandstone of the Snow Hill Island Formation. It remained undescribed in the collections of the Museo de La Plata until its description by Coria and colleagues in 2013, being the basis of the novel genus and species Trinisaura santamartaensis. The genus name is to commemorate the efforts of Argentine geologist Trinidad "Trini" Diaz and the Latin root -sauros, meaning "lizard". The species name is after Santa Marta Cove, where the fossils were collected.

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

Morrosaurus is an extinct genus of herbivorous elasmarian dinosaur that lived in the late Cretaceous in Antarctica. The only known species is the type Morrosaurus antarcticus.

Tralkasaurus is a genus of abelisaurid dinosaur from the Huincul Formation from Río Negro Province in Argentina. The type and only species is Tralkasaurus cuyi, named in 2020 by Mauricio Cerroni and colleagues based on an incomplete skeleton. A medium-sized abelisaurid, Tralkasaurus exhibits a conflicting blend of characteristics found among the early-diverging abelisauroids with others that characterize the highly specialized clade Brachyrostra, and thus its position within the clade is poorly-resolved.

<i>Niebla antiqua</i> Extinct species of dinosaur

Niebla is a genus of abelisaurid theropod dinosaur from the Late Cretaceous Period (Campanian-Maastrichtian) of Río Negro province, Argentina. The genus contains a single species, Niebla antiqua, and is known from a partial, non-articulated skeleton. The holotype, found in the Allen Formation, represents an adult individual.

<i>Maip</i> Genus of megaraptoran dinosaurs

Maip is a genus of large megaraptorid theropod dinosaur from the Late Cretaceous (Maastrichtian) Chorrillo Formation of Santa Cruz, Argentina. The genus contains a single species, M. macrothorax, known from an incomplete, disarticulated skeleton. Maip may represent the largest megaraptorid known from South America, and possibly the world.

<i>Meraxes</i> Genus of carcharodontosaurid dinosaurs

Meraxes is a genus of large carcharodontosaurid theropod dinosaur from the Late Cretaceous Huincul Formation of Patagonia, Argentina. The genus contains a single species, Meraxes gigas.

Patagopelta is an extinct genus of nodosaurine dinosaur from the Late Cretaceous Allen Formation of Argentina. The genus contains a single species, P. cristata, known from a partial skeleton. Patagopelta is a very small ankylosaur, comparable in size to the dwarf nodosaurid Struthiosaurus, about 2 m (6.6 ft) long.

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

Yatenavis is an extinct genus of enantiornithine bird from the Late Cretaceous Chorrillo Formation of Santa Cruz Province, Argentina. The genus contains a single species, Y. ieujensis, known from a partial humerus.

References

Notes

  1. ↑ Talenkauen was originally reported as being from the "Pari Aike Formation" and later reported as instead being from the Mata Amarilla Formation. [4] Geological studies found several names were being used for the same rock layers and advised use of the name Ceroo Fortaleza Formation over the former two as they were associated with incorrect dates or also used for other units. [1]

Citations

  1. 1 2 3 Sickmann, Zachary T.; Schwartz, Theresa M.; Graham, Stephan A. (2018). "Refining stratigraphy and tectonic history using detrital zircon maximum depositional age: an example from the Cerro Fortaleza Formation, Austral Basin, southern Patagonia". Basin Research. 30 (4): 708–729. Bibcode:2018BasR...30..708S. doi:10.1111/bre.12272.
  2. 1 2 3 4 5 6 7 8 9 Novas, Fernando E.; Cambiaso, Andrea V; Ambrioso, Alfredo (2004). "A new basal iguanodontian (Dinosauria, Ornithischia) from the Upper Cretaceous of Patagonia". Ameghiniana. 41 (1): 75–82.
  3. 1 2 Egerton, Victoria M.; Novas, Fernando E.; Doson, Peter; Lacovarae, Kenneth (2013). "The first record of a neonatal ornithopod dinosaur from Gondwana". Gondwana Research. 23 (1): 268–271. Bibcode:2013GondR..23..268E. doi:10.1016/j.gr.2012.08.010. hdl: 11336/8680 .
  4. 1 2 Rozadilla, Sebastián; Agnolín, Federico L.; Novas, Fernando Emilio (2020). "Osteology of the Patagonian ornithopod Talenkauen santacrucensis (Dinosauria, Ornithischia)". Journal of Systematic Palaeontology. 17 (24): 2043–2089. doi:10.1080/14772019.2019.1582562. S2CID   155344014.
  5. 1 2 3 Rozadilla, Sebastián (2016). "A new ornithopod (Dinosauria, Ornithischia) from the Upper Cretaceous of Antarctica and its palaeobiogeographical implications". Cretaceous Research. 57: 311–324. doi:10.1016/j.cretres.2015.09.009.
  6. ↑ Paul, Gregory S. (2016). The Princeton Field Guide to Dinosaurs. Princeton University Press. p. 310. ISBN   978-1-78684-190-2. OCLC   985402380.
  7. 1 2 Butler, Richard J.; Galton, Peter M. (2008). "The 'dermal armour' of the ornithopod dinosaur Hypsilophodon from the Wealden (Early Cretaceous: Barremian) of the Isle of Wight: a reappraisal". Cretaceous Research. 29 (4): 636–642. doi:10.1016/j.cretres.2008.02.002.
  8. 1 2 Calvo, J.O.; Porfiri, J.D.; Novas, F.E. (2007). "Discovery of a new ornithopod dinosaur from the Portezuelo Formation (Upper Cretaceous), Neuquén, Patagonia, Argentina". Arquivos do Museu Nacional. 65 (4): 471–483.
  9. ↑ Rozadilla, Sebastián; Agnolín, Federico Lisandro; Novas, Fernando Emilio (2019-12-17). "Osteology of the Patagonian ornithopod Talenkauen santacrucensis (Dinosauria, Ornithischia)". Journal of Systematic Palaeontology. 17 (24): 2043–2089. doi:10.1080/14772019.2019.1582562. ISSN   1477-2019. S2CID   155344014.
  10. ↑ Norman, David B. (2004). "Basal Iguanodontia". In Weishampel, D.B.; Dodson, P.; Osmólska, H. (eds.). The Dinosauria (2nd ed.). Berkeley: University of California Press. pp. 413–437. ISBN   978-0-520-24209-8.
  11. ↑ Novas, Fernando E.; Salgado, Leonardo; Calvo, Jorge; Agnolin, Federico (2005). "Giant titanosaur (Dinosauria, Sauropoda)from the Late Cretaceous of Patagonia". Revista del Museo Argentino de Ciencias Naturales. N.S. 7 (1): 37–41. doi: 10.22179/REVMACN.7.344 .
  12. ↑ Novas, F.E.; Ezcurra, M.D.; Lecuona, A. (2008). "Orkoraptor burkei nov gen. et sp., a large theropod from the Maastrichtian Pari Aike Formation, Southern Patagonia, Argentina". Cretaceous Research. 29 (3): 468–480. doi:10.1016/j.cretres.2008.01.001.
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