Saltasauridae

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Saltasauridae
Skeletal reconstruction of Opisthocoelicaudia

Skeletal reconstruction of Opisthocoelicaudia

Temporal occurrence
Upper Cretaceous ( Santonium to Maastrichtian )
86.3 to 66 million years
Locations
  • North America
  • South America
  • Asia
Systematics
Lizard dinosaur (Saurischia)
Sauropods (Sauropoda)
Macronaria
Titanosauriformes
Titanosaurs (Titanosauria)
Saltasauridae
Scientific name
Saltasauridae
Bonaparte , Powell , 1980

The Saltasauridae are a group of sauropod dinosaurs within the Titanosauria . It comprises the most derived (most advanced) titanosaurs and existed in the late Upper Cretaceous to the Cretaceous-Tertiary mass extinction about 66 million years ago.

The internal systematics of the Titanosauria is highly controversial. The name Saltasauridae is not used by all researchers, and the number of genera assigned varies depending on the author. The Saltasauridae are often divided into two subgroups: the Saltasaurinae , which include very small forms from South America such as Saltasaurus , Neuquensaurus , Rocasaurus and Bonatitan , and the Opisthocoelicaudiinae , which include Opisthocoelicaudia and Alamosaurus .

This article deals with the taxon Saltasauridae from a cladistic point of view - for characteristics and biology of these animals see main article: Titanosauria .

Definitions and systematics

The taxon Saltasauridae was established in 1980 by José Bonaparte and Jaime Eduardo Powell . The group is defined as a node-based taxon ( node-based definition ), the last common ancestor of opisthocoelicaudia and Saltasaurus and all descendants of this ancestor with including (Wilson and Upchurch, 2003; Sereno, 1998). Almost all studies agree that Saltasaurus was the most derived Titanosauria, together with the closely related Neuquensaurus . The closest relatives of this group, also known as Saltasaurinae, are Opisthocoelicaudia and Alamosaurus . Whether Opisthocoelicaudia and Alamosaurus form a monophyletic group (Opisthocoelicaudiinae), as suggested by Sereno (1998) and Wilson (2002), for example, is controversial.

The Saltasaurinae was established by Powell (1992). It is defined as all Saltasaurids that are more closely related to Saltasaurus loricatus than to Opisthocoelicaudia skarzynskii (Wilson and Upchurch, 2003). The Opisthocoelicaudiinae, established by John McIntosh (1990), on the other hand, is defined as all Saltasaurids that are more closely related to Opisthocoelicaudia skarzynskii than to Saltasaurus loricatus (Wilson and Upchurch, 2003).

Since the relationships within the Titanosauria are very controversial, the number of genera assigned to the Saltasauridae varies in different studies. Wilson (2002) assigns the Saltasauridae to the Opisthocoelicaudiinae, consisting of Opisthocoelicaudia and Alamosaurus , and the Saltasaurinae, consisting of Saltasaurus and Neuquensaurus . Rocasaurus and Bonatitan are often ascribed to the Saltasaurinae . According to an analysis by Hocknull and colleagues (2009), the genera Diamantinasaurus and Lirainosaurus could also be representatives of the Saltasauridae. A careful classification according to Upchurch and colleagues (2004) assigns the group only the genera Saltasaurus , Neuquensaurus and Opisthocoelicaudia , while Alamosaurus and Rocasaurus are listed outside the group. These authors do not subdivide into the subgroups Saltasaurinae and Opisthocoelicaudiinae. In contrast to most other analyzes, Curry Rogers (2005) comes to the conclusion that Opisthocoelicaudia and Saltasaurus are only distantly related. Since the Saltasauridae must contain these two genera according to their definition, but the last common ancestor of both genera occupies a much more basal position in the family tree according to the analysis, Rogers assigns the Saltasauridae to a large part of the Titanosauria genera, including, for example, Malawisaurus and Argentinosaurus .

Some studies use alternate names for the same group. For example, Upchurch (1998) uses the name Titanosauridae to refer to the grouping Alamosaurus , Opisthocoelicaudia and Saltasaurus . The name Titanosauridae is traditionally used to refer to a group of advanced titanosaurs. However, many researchers no longer recognize this name, as it is based as a rank-based taxon on Titanosaurus as a nominotypical taxon, which, however, is often considered invalid due to a lack of diagnostic features. The name Eutitanosauria could also be a synonym of the Saltasauridae. Some researchers use alternative definitions, referring to the same group that other researchers refer to as Saltasauridae as Saltasaurinae (e.g., Curry Rogers and Forster, 2001).

General characteristics and synapomorphies

Saltasaurids were small to medium-sized sauropods. The Saltasaurinae, which is restricted to South America, is characterized by a generally very small body size with lengths between 12 and 15 meters and includes some of the smallest known sauropods. While skin bone plates (osteoderms) were detected in Saltasaurus , these were probably missing in Opisthocoelicaudia and Alamosaurus . Saltasaurids are characterized by relatively short tails with only 35 caudal vertebrae and limbs that are slightly bent outwards. These features can already be found in less derived titanosaurs, but were most pronounced in the Saltasauridae as the most derived sauropod group.

According to Upchurch and colleagues (2004), the group can be distinguished from other groups on the basis of the following characteristics ( synapomorphies ): The upper arm bone (humerus) has a rounded crest at the upper (proximal) end. The posterior vertebrae show parapophyses , which lie directly below the diapophyses . The anterior (proximal) caudal vertebrae show broad and deep depressions (fossae) on the ventral side (ventral). The spinous processes of the anterior caudal vertebrae are wider than they are high and are made up of various complex lamina.

Web links

Commons : Saltasauridae  - Collection of images, videos and audio files

Individual evidence

  1. ↑ Michael D. D'Emic, Jeffrey A. Wilson: New remains attributable to the holotype of Neuquensaurus australis (Dinosauria: Sauropoda): implications for saltasaurine systematics. In: Acta Palaeontologica Polonica. Vol. 56, No. 41, 2011, ISSN  0567-7920 , pp. 61–73, here p. 64, doi : 10.4202 / app.2009.0149 .
  2. ↑ Paul Sereno : Saltasauridae. (No longer available online.) In: Taxon Search. Archived from the original on April 6, 2015 ; accessed on August 30, 2014 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / www.taxonsearch.org
  3. ↑ a b c Jeffrey A. Wilson: An Overview of Titanosaur Evolution and Phylogeny. In: Fidel Torcida Fernández-Baldor, Pedro Huerta Hurtado (eds.): Actas de las III Jornadas Internacionales sobre Paleontología de Dinosaurios y Su Entorno. = Proceedings of the 3rd International Symposium about Paleontology of Dinosaurs and their Environment Paleontología de dinosaurios y su entorno. Salas de los Infantes (Burgos, España), 16 al 18 de septiembre de 2004. Colectivo arqueológico-paleontológico de Salas, Salas de los Infantes (Burgos, España) 2006, ISBN 84-8181-227-7 , pp. 169-190 .
  4. ^ Paul C. Sereno: A rationale for phylogenetic definitions, with application to the higher-level taxonomy of Dinosauria. In: New Yearbook for Geology and Paleontology. Treatises. Vol. 201, No. 1, 1998, ISSN  0077-7749 , pp. 41-83.
  5. ↑ a b Jeffrey A. Wilson: Sauropod dinosaur phylogeny: critique and cladistic analysis. In: Zoological Journal of the Linnean Society. Vol. 136, No. 2, 2002, ISSN  0024-4082 , pp. 215-275, doi : 10.1046 / j.1096-3642.2002.00029.x .
  6. ↑ Paul Sereno: Saltasaurinae. (No longer available online.) In: Taxon Search. Archived from the original on April 2, 2015 ; accessed on August 30, 2014 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / www.taxonsearch.org
  7. ^ Paul Sereno: Opisthocoelicaudiinae. (No longer available online.) In: Taxon Search. Archived from the original on May 16, 2012 ; accessed on August 30, 2014 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / www.taxonsearch.org
  8. ↑ a b Augustin G. Martinelli, Analía M. Forasiepi: Late Cretaceous vertebrates from Bajo de Santa Rosa (Allen Formation), Río Negro province, Argentina, with the description of a new sauropod dinosaur (Titanosauridae). In: Revista del Museo Argentino de Ciencias Naturales. NS Vol. 6, No. 2, 2004, ISSN  1514-5158 , pp. 257–305, Abstract (PDF; 75.55 kB) ( Memento of the original from March 4, 2016 in the Internet Archive ) Info: The archive link became automatic used and not yet tested. Please check the original and archive link according to the instructions and then remove this notice. . @1@ 2Template: Webachiv / IABot / www.macn.secyt.gov.ar
  9. ↑ a b Alejandro Otero: The appendicular skeleton of Neuquensaurus, a Late Cretaceous saltasaurine sauropod from Patagonia, Argentina. In: Acta Palaeontologica Polonica. Vol. 55, No. 3, 2010, pp. 399-426, doi : 10.4202 / app.2009.0099 .
  10. ↑ Scott A. Hocknull, Matt A. White, Travis R. Tischler, Alex G. Cook, Naomi D. Calleja, Trish Sloan, David A. Elliott: New mid-Cretaceous (latest Albian) dinosaurs from Winton, Queensland, Australia. In: PLoS ONE . Vol. 4, No. 7, 2009, e6190, doi : 10.1371 / journal.pone.0006190 .
  11. ^ A b Paul Upchurch , Paul M. Barrett , Peter Dodson : Sauropoda. In: David B. Weishampel , Peter Dodson, Halszka Osmólska (eds.): The Dinosauria . 2nd edition. University of California Press, Berkeley CA et al. 2004, ISBN 0-520-24209-2 , pp. 259-324.
  12. ↑ Kristina Curry Rogers: Titanosauria: A Phylogenetic Overview. In: Kristina Curry A. Rogers, Jeffrey A. Wilson (Eds.): The Sauropods. Evolution and Paleobiology. University of California Press, Berkeley CA et al. 2005, ISBN 0-520-24623-3 , pp. 50-103, doi : 10.1525 / california / 9780520246232.003.0003 .
  13. ↑ a b c d Jeffrey A. Wilson, Paul Upchurch: A Revision of Titanosaurus Lydekker (Dinosauria - Sauropoda), the first dinosaur genus with a 'gondwanan' distribution. In: Journal of Systematic Palaeontology. Vol. 1, No. 3, 2003, pp. 125-160, doi : 10.1017 / S1477201903001044 .
  14. ^ Paul Upchurch: The phylogenetic relationships of sauropod dinosaurs. In: Zoological Journal of the Linnean Society. Vol. 124, No. 1, 1998, pp. 43-103, doi : 10.1111 / j.1096-3642.1998.tb00569.x .
  15. ↑ Thomas R. Holtz Jr .: Supplementary Information. to: Thomas R. Holtz Jr .: Dinosaurs. The most complete, up-to-date Encyclopedia for Dinosaur Lovers of all ages. Random House, New York NY 2007, ISBN 978-0-375-82419-7 , online (PDF; 184.08 kB) .
  16. ↑ Michael D. D'Emic, Jeffrey A. Wilson, Sankar Chatterjee : The titanosaur (Dinosauria: Sauropoda) osteoderm record: review and first definitive specimen from India. In: Journal of Vertebrate Paleontology. Vol. 29, No. 1, 2009, pp. 165-177, doi : 10.1671 / 039.029.0131 .
  17. ↑ Jeffrey A. Wilson: Overview of Sauropod Phylogeny and Evolution. Kristina Curry Rogers, Jeffrey A. Wilson (Eds.): The Sauropods. Evolution and Paleobiology. University of California Press, Berkeley CA et al. a 2005, ISBN 0-520-24623-3 , pp. 15-49, digitized version (PDF; 384.37 kB) .